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MG TD TF 1500 - Machining the Cylinder Head
| I have removed the TF's cylinder head to renew the valve guide oil seals. Unfortunately I have found one of the exhaust seats to be cracked. I have always been proud that my car was fitted with a Mangoletsi stage 2 cylinder head. I now find that they have radiused the throats to all the valves to an extent that if I machined a recess for inserts I would break through into the ports themselves. Luckily I do have a spare head but think it is from a Wolsley (painted green). This is brand new but rusty and I am currently bead blasting this. Whilst the casting is exactly the same as my original some machining differs. The valves in the original head are bigger (see attached pic) and the new head has not been surfaced. You will see from the pic that the stage 2 head is flat across the total face. The replacement one I have has a recess across the top edge about 1/8" deep. The tuned one has been skimmed so much that the spark plug holes have broken through at the edges. I have always had a problem with running on when the ignition was turned off but put this down to modern petrol but now suspect this was due to either too high a compression or a sharp edge to the plug threads. I seek advice and comment on a number of things I am considering doing to the new head. I will fit new guides (the ones currently fitted are rusty in the bores) should I fit modern seals to both inlet and exhaust? Whilst the head is off I will fit hardened exhaust seats, should I open up the ports to take the larger valves as in the photo? (I assume the tuned head has bigger valves) The face of the head needs machining, how much metal should I remove? The "pillars" in the inlet ports are square edged, should I taper these to improve gas flow.
Is there anything online about tuning an EXPAG head. Cheers Jan T  |
| J Targosz |
| Jan. That's a real shame because Mangoletsi were a very respected tuning outfit back in the day. Are you sure it can't be saved? I could give you the name of a tuning outfit near me, that I have used and recommend. They rarely work on our engines these days but there are one or two guys there that know them and have all the expertise.
A good reference you should see is - Tuning the head of a T Type Engine by Hal Kramer - see nemgtr.com I could give you more, but no doubt others will jump in. Dave H |
| Dave Hill |
| Jan. That should be nemgtr.org Dave H |
| Dave Hill |
| January 2001 issue of TSO. Backcopies available from NEMGTR for $5 ($35 International for up to three). Email Sander (at) pshift.com Bud |
| Bud Krueger |
| Jan - I'd be interested to see what Mangolesi has done to your head. Can you take a few more pictures of the inlet side? Thanks.
The reason the M head has a flat surface and the W head has a stepped area is that the M head has been machined down significantly to increase the CR. Without knowing any of the details, I would say that your CR is perhaps TOO high with the M head, or perhaps better said, unnecessarily high. I would certainly go to Stage I, and perhaps to Stage 2, but when you start getting into the 9's you are asking for harder starts, rougher running, using premium gas, and some more power. The run-on you experience is indeed very probably from the sharp edge at the plug hole AND the high compression ratio. I would suggest you have the machinist imitate the changes to and configuration of the combustion chamber, to mimic the M modifications - but leave the head thicker. Tom Lange MGT Repair |
| t lange |
| You'll need to check the CR on the XPAW head - I think the standard is 7.25:1. You can't use the standard figures for TF head machining to get the ratio you want. My maximum machined XPAW head has only 8.5:1 compression - just right for the blower. David |
| D A Provan |
| The factory Special Tuning handbook gives the stock figures and the amounts to be removed for various different compression ratios. You can compare the XPAW (low-compression) head with those figures. Tom Lange MGT Repair |
| t lange |
| Jan Have you had a Pro. cylinder head worker look at the Mangoletsi head Most everything is recoverable/repairable these days- I'm sure there would be a seat insert available that would do the job Someone that does hard seat unleaded conversions would surely have seats to fit it How far away from Peter Burgess are you--- willy |
| William Revit |
| Hi All,
Picture attached for Tom. If you need more give me you email address and I can send multiples in one go. I also have original documentation from Mangoletsi. I don't know if my spare head is a XPAW. It looks exactly the same as the one from the TF but is thicker (76.75 mm) and has smaller valves. It has round water holes. The one from the TF has been modified though. The guy who is going to do the machining work is a cylinder head expert and has the top of the range Serdi machine. My problem is Mangoletsi have smoothed away metal in the ports under the valve seats. If I machine a recess for an insert I will break through into the port and there will be no support. I will set the head up on the Serdi and kiss the suspect seat. If there is a crack I will hear a click. I have looked on line and there are various articles on tuning an EXPAG and one from Australia for a XPAW. They all appear to use Blower's recommendation and I will carry out the Stage 2 work. Machine 3 mm off the head to give a thickness of 73.575 mm (9.31 compression) and fit 36 mm inlet valves and 34 mm exhausts. Has anyone carried out such a modification Cheers Jan  |
| J Targosz |
| Jan. I think its the inlet side of the head that we would like to see please. I followed the usual recommendation of rounding off and slimming down the inlet port divider a little, but it would be very interesting to see what Mangoletsi have done. The head thickness you propose will give 9.3:1 on a std TF head, but only if the bore size is std (+0.00). If its been rebored at all the CR will be higher than you may want to go. Dave H |
| Dave Hill |
| Hi Dave,
It is difficult to get a good pic of the inside of the port but I attach one showing the divider in the inlets. If you want further pics just let me know. I have cleaned the head and had a good look at the possible cracked seat - the magnifying glass was in the grandchildrens' toy box. I am not convinced there is a crack. Cleaning up the seats and fitting A Series oil seals would be a simple job but the head is 73.55 mm thick and pistons are +20. This is 0.02 mm over the max. If there is no crack I will be tempted to reuse the Mangoletsi head. The problem I had been having was a smoky exhaust caused by the lack of any oil seals. Cheers Jan  |
| J Targosz |
| Jan. Thanks, that's a nice image and useful. They have removed less material than I expected but its very nicely done indeed. Sounds like you need a better magnifier. If clear of a crack and it were me, I would reuse that head but install a slightly thicker head gasket from Cometic and ARP studs. Even if cracked I would want a second opinion on repairing it. Peter Burgess was a good suggestion. Dave H |
| Dave Hill |
| As usual, I 100% agree with Dave Hill - have the head re-examined by a knowledgeable XPAG man, and see if the seat really is cracked. It takes an awful lot for a head to be junk. I suspect that Magnafluxing would reveal the truth, even though it is the seat itself, not the head in question.
And I equally agree that if the head is OK, use a thicker gasket to lower the CR to a more manageable level, either a thicker Cometic or solid copper gasket (see my earlier post about CR). My ARP head studs are a significant contribution to securing the head in place; even if I did not sell them I would recommend them! Very interesting to see what M did to the head to improve breathing; not at all what I would have thought, as it is FAR removed from the factory recommendation. Have the intake and exhaust ports been matched to the manifolds? Would you be willing to copy/post the M information sheets? Many thanks. Tom Lange MGT Repair tlange@acadia.net |
| t lange |
| No matter for the step around the plug hole. The head of my car is stage 2. Puls hard and no knocking, no running on. This step is well described in different tuning books. And it needs to be filed a little to get a 1 mm minimum thickness around the plug hole. I'll try to post a picture later. Laurent. |
| LC Laurent31 |
| I agree with you Laurent
The only thing I would do is radius the sparkplug side of the chamber with a flapper wheel as has been done on the opposite side--This will help to stop it running on if there is a hotspot there- Also check to make sure the sparkplug threads don't extend into the chamber If they do you can machine the required thread off the plug body or opt for a shorter plug to suit-they usually go in 1/8" steps If you go the shorter plug just check that there isn't a stray head thread that needs cleaning up hanging in the chamber willy |
| William Revit |
| Jan, The radiused inserts for the intake manifold look interesting. Is that part of the Mangoletsi modification or are those available somewhere? Jim |
| J Barry |
| I'm sure that others know better than I, but they look to me like a device to exploit a resonance effect, the inlet manifold behaving like a plenum chamber. These days, inlet manifolds are their speciality. Could be completely wrong of couse. Dave H |
| Dave Hill |
| Hi Jim and Dave,
I found another set of bell mouth spacers in one of the boxes of bits that came with the car and thought they were original. I have just been to check, and the spare ones I have are only 1 1/8" diameter so are either from a very early MG or an old time accessory. I do suspect though the ones fitted to the TF are courtesy of Mangoletsi. The "A Series" stem oil seals arrived today and the engineers at the rebuild shop suggested 2m/m be taken off the top of the guides to ensure the collet retainer doesn't touch the seal. We checked the clearance with un-machined guides and with a 9m/m valve lift there was clearance but not much and I was concerned about possible bounce. The seals do require a shallow groove to be turned in the guide to prevent them rising with the valve. I have also cut off part of the tubes that locate the inner spring and act as crude splash guards. They would certainly have rubbed on the outside of the seals. They are hardened and I had to use an angle grinder and they are now level with the bottom of the collet retainers. They still locate the inner spring perfectly. Message for Tom. I don't have a scanner but can get the docs copied at the library. The stuff I have is more promotional but is still interesting Jan T |
| J Targosz |
| The 'performance' Mangoletsi business went bust in the 1960's. The current one is simply a car dealer set up by a relative, with no family member now involved at the management level. This makes interesting reading: http://www.mangoletsimanifolds.com/history.html |
| Ian Bowers |
| They still seem to make manifolds so perhaps more than a car dealer, but I take your point that there is a disconnect with the original Mangoletsi Co. Perhaps that insert we see on the inlet is the original Mangoletsi manifold modifier intended to improve atomisation. Dave H |
| Dave Hill |
| Sorry, I tried and failed to make it clear! Mangoletsi Manifold still has a Mangoletsi working and is carrying on the original inlet design tradition. The easier to find Mangloetsi is simply a car dealer. |
| Ian Bowers |
| To promote the best flow with the big valves, the XPAG experienced machinist machined the outer edges of the combustion chambers. Attached is a picture of my cylinder head where the work is visible. In a later stage the rough edges where smoothed out.  |
| Willem van der Veer |
| I didn't believe in coincidences but one has just happened. In the Octagon Club Magazine which arrived today there is an article on the various versions of the EXPAG engine. These range from the early Morris 10 Series M through the MG T/Y Series to the Wolsley 4/44. There is also a marine version. Can someone confirm that the replacement head I have, which has round water holes, is a late TD/TF/Wolsley one. I think all earlier ones had oval holes. Jan |
| J Targosz |
Jan, FYI: There are two basic design types.The "early" "Banana Head" with short 1/2-inch spark plugs. Then starting with XPAG/TD2/22735 a round water hole head with used with longer-reach 3/4-inch plugs. The thickness of a stock TC head is 76.65mm (3.018-inches) TD and TF XPAG 75.16mm (2.959-inch) TF XPEG 76.75mm (3.021-inch) (Source: MG Racers News Letter Code 106 by Mike Lewis, Bayou Racing) You have a "late" XPAG head. Jim |
| James Neel |
| Jan - I'd be interested to know what the casting number is on your XPAW head. Thanks. Tom Lange MGT Repair |
| t lange |
| Hi Tom,
I am not certain the head is ex Wolsley. The only evidence I have is that it was painted green. It is not a Morris one since it has circular water holes and 3/4" reach plug threads. The casting number is 168422 and the inlet throats are 30 m/m and the exhaust 26 m/m. The thickness is 76.66 m/m. I have spoken to the owner of the machine shop I use about facing the head and fitting larger valves. He is currently working on an E Type, two Mustang and a Cadillac engine and certainly knows his stuff. He has pointed out two issues with following Blower's stage two tuning instructions. Firstly if you machine the chamber around the inlets to 38 m/m and open the throats to 33 m/m (to take 36 m/m valves) this doesn't leave much meat for inserts at a later stage. The same applies with the exhausts. Secondly if you skim the head by 1/8" to give a compression ratio of 9.3:1 the thickness will be 73.575 m/m. This is the absolute minimum but we are unsure if this is because of compression, valve lift or head strength. If it is strength and the head distorts in the future further skimming will not be possible and the head will be scrap. We have agreed to take off a wisker over 3/32" to give a ratio of about 9.0:1 which will be more suitable for modern petrol. I have tried to photograph the Mangoletsi documentation for you but the writing was illegible so I will have to get it scanned next week. Cheers Jan |
| J Targosz |
| I don't know that you can differentiate between a late XPAG head and a Wolesley head - they are all numbered 168422, as I remember. The thickness of a stock TD head is 76.75mm (3.022"), so you are pretty close to stock; it could be a measuring error or the head could have been skimmed once.
As I noted above, I would be cautious not to remove too much from the head. I stand by what I wrote above: "...when you start getting into the 9's you are asking for harder starts, rougher running, using premium gas, and some more power. The run-on you experience is indeed very probably from the sharp edge at the plug hole AND the high compression ratio." Tom Lange MGT Repair |
| t lange |
| From Hal Kramer's data an xpag with +0.020" oversize bore. 75.159mm gives 8.26:1 74.371mm gives 8.81:1 73.584mm gives 9.46:1 Just in case its useful. Dave H |
| Dave Hill |
| Looks as though a thickness of 74.40mm is about right. This should give a ratio in the high "8s" and still leave some meat on the head for a future truing up. This means machining off 1.25mm or 50 thou. With the fly cutter head surfacing machine you can take off 2 thou per pass for cast iron. Looks like I will have to stand over it for quite some time. Jan |
| J Targosz |
| I wouldn't worry about a CR of 9.1. Don't forget that when the TD came out and later, the Tuning Manual for the XPAG, that petrol in the UK was probably rated at less than 90 octane (sorry about the American standard) and a CR of 9.1 would probably be an upper limit.
Today, most regular gas is at least 92 Octane, so a CR of 9.1 can almost certainly be tolerable. If you get any pinking, you have choices: either try a higher grade fuel, retard the timing, put in short reach plugs (will reduce the head volume by a bit), or as a last measure, put in a thicker head gasket. Most current vehicles use 10:1 or higher. Irrespective of your choice, you should nonethelss be using a solid state ignition and a good, healthy coil. I imagine you'll be OK with 9.1. Gord Clark Rockburn, Qué. |
| Gord Clark |
| In the UK pool petrol / gasoline only was available until early 1953, with an octane rating of about 72. This was soon after replaced with fuel having an octane rating of 85. Dave H |
| Dave Hill |
| Have gotten a bit more interested in this now as a mate just dropped off his TD-1 head for some new valves and port work The plan is TF size valves into a multi angle seat job and aim for around 9:1 to run on 91 octane (std) fuel- match the manifold to the head and open it out for 1 1/2" carbs Which also made me think- With the M. manifold, do you think that might have been opened right up to suit larger carburettors and those rings are sleeves to match smaller sizes willy |
| William Revit |
| The same thought crossed my mind, but why reduce it down again, which is what the inserts do. The increased velocity (venturi effect) followed by expansion would help atomisation of the fuel. Dave H |
| Dave Hill |
| Hi Wiily and Dave,
The bore in the carbs is 1.500". The bore through the rings is 1.304. The bore in the manifold is 1.530. If you place the rings over the carb flanges and feel inside there is a perfectly smooth curve from the bore of the carb to the 1.304" diameter of the ring. Place the ring in the manifold and there is a ridge from the ID of the ring to the bore of the manifold. I believe some tuners engineer such a step to prevent backflow of gasses but I thought this was more relevant to the exhaust e.g. exhaust manifold ports slightly larger than those in the head. Willy don't know if you have the Eric Blower tuning info, if not you can find it by Googling tuning the expag engines. Gives you all the machining dimensions. Jan |
| J Targosz |
| Jan, I don't know if you have this document, it seems to give some very useful information on XPAG cylinder head tuning. Even mentions the Serdi machine. http://www.vintagemg.com/articlepdfs/tech110.pdf John |
| J Scragg |
| Yes, that is sometimes done on the exhaust side for the reason you give. On the inlet side I am fairly sure its about ensuring better fuel atomisation. Dave H |
| Dave Hill |
| Here is a picture of my stage 2 TD head. It shows the file work around the plug hole. Laurent.  |
| LC Laurent31 |
This one shows the machined outer edges of the combustion chambers.Blurred. Look at the third cylinder from left to right. |
| LC Laurent31 |
| I have now bead blasted my spare cylinder head and have been able to properly compare it with the original. There appears to be two differences. The flat surfaces that the rocker pedistals sit on are oval shaped rather than oblong and there is a screwed plug behind the rear water jacket blanking plate which can be removed to clean out the banjo oil gallery. The valves are smaller than the original stage 2 head but the combustion chambers will take my larger valves without modification.
I was concerned about Blower's instructions to tune to stage 2. If the combustion chambers had been small and required machining as per the instructions, this would have reduced the compression ratio and I wonder if the head thicknesses as Blower suggests are correct. JanT |
| J Targosz |
| You CAN readily differentiate a Wolseley 4/44 Cylinder Head,a TF XPAG Cylinder Head and a TF XPEG Cylinder Head. Authors of XPAG motors in particular often get this wrong.
Firstly,Wolseley 4/44 have the numbers CAST in 168422. All,ORIGINAL TF Heads were numbered 168425 with the first five(5) numbers cast in and the (5) stamped in to indicate the larger valve sizes. The XPEG TF1500 Cylinder Heads were lettered/numbered AEF118. BOTH the letters and numbers were STAMPED IN.( The water holes on one side of the 1500 Head are slightly off set compared to the XPAG). The above information has been indicated in many Threads in the past on BBS TD TF. I guess many Cylinder Heads on T type MGs have been interchanged over the years(from what was originally Factory fitted) and hence the myths that can evolve. The TF XPAG originally had an Exhaust Valve head size of 34mm. and an Inlet Valve head size of 36mm. A few years ago a TF friend used a Wolseley Head with great success on his TF 1250. Planed the Head,machined out the valve seats to take the larger TF valves and had no problems at all. Cheers Rob Grantham TF3719("Aramis"),TF9177("Athos"). |
| Rob Grantham |
| You CAN readily differentiate a Wolseley 4/44 Cylinder Head,a TF XPAG Cylinder Head and a TF XPEG Cylinder Head. Authors of XPAG motors in particular often get this wrong.
Firstly,Wolseley 4/44 have the numbers CAST in 168422. All,ORIGINAL TF Heads were numbered 168425 with the first five(5) numbers cast in and the (5) stamped in to indicate the larger valve sizes. The XPEG TF1500 Cylinder Heads were lettered/numbered AEF118. BOTH the letters and numbers were STAMPED IN.( The water holes on one side of the 1500 Head are slightly off set compared to the XPAG). The above information has been indicated in many Threads in the past on BBS TD TF. I guess many Cylinder Heads on T type MGs have been interchanged over the years(from what was originally Factory fitted) and hence the myths the can evolve. The TF XPAG originally had an Exhaust Valve head size of 34mm. and an Inlet Valve head size of 36mm. A few years ago a TF friend used a Wolseley Head with great success on his TF 1250. Planed the Head,machined out the valve seats to take the larger TF valves and had no problems at all. Cheers Rob Grantham TF3719("Aramis"),TF9177("Athos"). |
| Rob Grantham |
| Rob - But can you differentiate between 4/4 and late TD heads? Aren't both late round-hole TD heads and 4/4 heads numbered 168422? I was not sufficiently specific above; I should have said late TD rather than late XPAG. Since the 4/4 head had lower compression that a TD head, the main difference between the two 168422 heads would be in the head thickness. And since most heads have been milled more than once, that might be difficult to determine. Tom Lange MGT Repair |
| t lange |
| So when exactly did the larger valves start The head I have here is off a TD Round water holes 3/4" plugs small valves and has 168422 cast onto the rh front corner It's going to get the larger valves but just wondered when they started being factory fitted Got stuck into some port work and couldn't believe how far out the match of the inlet manifold was, I reckon I've gained 700HP there already- lol willy |
| William Revit |
| I am pretty certain my spare head is ex Wolsley. I will start a new thread and call it Wolsley Head Pictures and attach photos showing differences to the MG one. A new thread will make archive searches easier. Jan T |
| J Targosz |
| Tom, A good question re the comparison of the 4/44 and late TD heads. I wonder if the MK2 TD had the same valve sizes as the TF 1250 and TF1500 Heads ? No doubt a TD Guru will comment. Cheers Rob Grantham |
| Rob Grantham |
| Hi All Thanks for all this valuable info, what spark plugs should be used on a XPAG engine that is fitted with a XPAW cyl. head machined to give a 8.5 compression ratio. rgds Trevor Burnett(TC/7196) |
| t burnett |
| Trevor - I see nobody has replied to your last question. May I inquire how you know it is an XPAW head, and not an early TD head?
Assuming that the XPAW head uses 1/2" reach plugs (I'm not sure of anything any longer...), the right plug can be a Champion L86. I don't think it is, but if a 3/4" reach, then a Champion N5. To check, bend a piece of wire with a small right-angle bend at the end, and fish into a plug hole against the end of the threads, and measure the exposed length. If you use a short plug in a long-reach hole it will be recessed and have a shrouded spark, and may foul the threads when you try to put in a long-reach plug. If you use a long-reach plug in a short-reach hole, you run the risk of the piston hitting the end of the plug, damaging both and/or closing up the plug gap. Hope this helps. Tom Lange MGT Repair |
| t lange |
| The following is from Neil Cairnes: "How to be an
Engine Expert on MGs MG Engines from 1935 to 1998" http://www.mg-tabc.org/special-files/how-to-be.pdf " For the more powerful midget TD Mk2 the engine had its waterways improved to help cooling.Whilst the TD Mk2 had both the new head and block, the normal TD and YB had to use up existing stocks. The new items are termed ‘round-hole’ blocks or heads, and carry casting numbers for the head of 168422 head and 168421 block. There is no octagon cast into these blocks, as they were also used on the Wolseley 4/44, and have an extra boss for the 4/44 dipstick. This was undrilled on the M.G. ‘oval hole’ heads are casting number 22952, and M.G. XPAG oval hole blocks are 24146 and 24445 with octagons. (See casting number identity for more.) The round hole cylinder blocks were now being fed onto the production line, the oval hole ones all used up. Alas there were still lots of oval hole heads left. At SC2/17463 and TD2/17969 the round hole block was fitted to the YB and TD, note how the TD numbers are now ahead of the YB, the TD was selling rather well. With an oval hole head and a round hole block, or visaversa, an oval hole head gasket must be used, part number X24481. Round hole head gasket is part number 168423. " |
| Gene Gillam |
| It's important to get the plug length correct as Tom says, but also for proper cooling of the plug's tip. Plugs need to shed head to the head to avoid burning it up and pre-detonation. |
| MAndrus |
| I greatly respect and value Neil Cairns' magisterial contribution on XPAG engine history, but I am not at all sure what he means with the statement, "For the more powerful Midget TD Mk2 the engine had its waterways improved to help cooling." Is he saying that ALL Mark II cars had round cooling passages? This is patently incorrect.
The first Mark II engine was XPAG/TD/1257 in May, 1950, and the parts book reports that round water passages were introduced at engine XPAG/TD2/22735, on about Nov. 26, 1952. There were probably nearly a thousand Mark II cars produced between these dates, and while some later cars may have had round water passages, the majority were oblong, bearing early head numbers 168422. Am I mis-reading something in Cairns? Tom Lange MGT Repair |
| t lange |
| Cairns still has the incorrect TF cylinder head number listed ! Under the section on " Known 'X' Engine Casting Numbers," he lists the TF Cylinder Head No. as 168422. The correct TF1250 number IS 168425. Cheers Rob Grantham TF3719("Aramis"),TF9177("Athos"). |
| Rob Grantham |
| Another conundrum. My Wolsley Head is now back from the machine shop and I am cleaning out all the threaded holes with a plug tap. Most are the standard EXPAG metric fine M8 x 1 but the four lager bolts that secure the rocker pedistals are M10 x 1.25. The 1.25 pitch is the same as current metric threads. Why are are the pitches different. Jan T |
| J Targosz |
| I guess it's a bit like most fasteners, the bigger the diameter gets the further apart the threads get, your M8s are 1mm apart and the M10s are 1.25 Having said that, M10 sounds too big for the pedistal bolts, aren't they 5/16" and 1/4" (8mm-6mm)ish. willy Any pics of the head job yet---interested to see the result |
| William Revit |
| Jan, metric bolts tend to come in two forms, standard and fine. M8's standard is 1.25mm, fine is 1mm. M10's standard is 1.5mm and fine is 1.25mm. M10/1mm are called super fine. Bud https://www.boltdepot.com/fastener-information/measuring/metric-thread-pitch.aspx |
| Bud Krueger |
| Just thought I'd add a few notes - I have written and rewritten the following several times, and posted it using copy and paste, so I hope it is clear.
There is not and never was a separate Wolseley cylinder head. The Wolseley 4/44 XPAW engine was basically the YB XPAG/SC2 engine (different sump, bellhousing and gearbox, not sure about the front engine mount) with the same 7.25:1 compression ratio as the XPAG/TD2 engine. Thus the round water hole head casting 168422 was used for both engines, machined to the same 76.75mm thickness and using the same size valves etc. All the engine casting, machining and assembly work was done by the Morris Engines Division at their factory in Coventry, which is about 70 miles away from Abingdon and about 20 miles away from the Wolseley assembly plant in Birmingham. Any slight variation in the castings would likely be due to wear and tear, or slight differences, in the casting moulds, including those for the internal sand cores, which had to be remade for each casting. The machined 168422 head casings would be assembled with valves etc and fitted on whatever XPAG or XPAW engines were being assembled at the time. Once the XPAG/TD2 engines reached MG at Abingdon, those destined for the Mark II had the cylinder heads removed. Then the valve throats (to the combustion chambers) would be opened up for the larger valves, including recutting the seats and machining the combustion chambers to clear the valve heads – the head thickness was also reduced to (beginning Dec 1952) 75.16mm. Then the reassembled heads, with large valves and stronger springs, would be put back on the engines with no change to the casting number, although the engine code was changed to XPAG/TD3. The owner of a standard TD could also convert his engine to Mark II specification, but changing the head casting number would not be something he would even consider. However, when the TF was introduced, the complete XPAG/TF engine would then be supplied by Morris Engines Division, so the cylinder head work to TD Mark II, or TF, specification would then be undertaken at the Morris Engines Coventry factory, which was still making XPAW engines and reconditioning XPAG engines. Thus to distinguish those 168422 head castings which were machined to take the larger valves and have a thickness of 75.16mm, the last 2 of the casting number was ground off and a 5 stamped in it’s place. This would also help during head assembly to know which valves and springs to fit, and also during engine assembly to correctly build up XPAG/TF engines. Later on, when the XPEG engine was introduced, in the cylinder head there were slight changes to move some water holes and improve the combustion chambers and inlet/outlet ports. Thus for casting, the moulds for both the external form and the internal sand cores were altered to accommodate these changes, but it seems that a new casting number was not included. Instead, from an examination of XPEG cylinder heads, it appears that the 168422 number recesses in the moulds were filled in to leave a plain area after casting, and this area was then stamped AEF118. The castings were machined for the larger valves, although the thickness was changed to 76.75mm The early oval water hole heads had the casting number 22952, and were fitted to the Y and T type, including the Mark II. Neil Cairns is correct, the actual head castings were 168422 – only after the valve throats were machined for the larger valves, and reduced head thickness of 75.16mm, was the last 2 ground off and replaced by a stamped 5. The 10mm diameter threads are not ISO metric, which have pitches; fine = 1.25mm, coarse = 1.5mm, but the predecessor SI metric, which has pitches; fine = 1mm and coarse = 1.5mm. The four large pedestal bolts are SI 10mm coarse, so 1.5mm pitch. Thus the wrong bolts have been forced in as 10 x 1.25 is ISO 10mm fine. |
| R A WILSON |
| Roger, Thankyou for the agreed confirmation that TF 1250 Cylinder Heads were in fact 168425. Neil Cairns is not correct in that he currently lists the TF 1250 as having the numbers 168422. Cheers Rob Grantham TF3719("Aramis"),TF9177("Athos"). |
| Rob Grantham |
| Well, perhaps I was trying to be generous. The castings were 168422, but became 168425 heads when they were on the XPAG/TF engines. Also may be of interest, all 22952 heads had 1/2" thread lengths for the spark plugs, and all 168422/168425/AEF118 heads had 3/4" thread lengths for the spark plugs. It was reported at the time that the increase in length allowed 'a greater range of spark plugs'. |
| R A WILSON |
| A small Mark II note of clarification to R A Wilson's post above - the first engine numbered TD3 was XPAG/TD3/17030, in TD/C16811, made on June 4, 1952. All previous Mark II cars had engines marked either TD or TD2, all with the usual Mark II head modifications. Tom Lange MGT Repair |
| t lange |
| Roger, On 'the list' is also indicated that the "Late 4/44,round water holes" is numbered 168425 !? I am unaware of any original Wolseley having that Cylinder Head Number. TF 1250s were designated that number. Cheers Rob Grantham T3719("Aramis"),TF9177("Athos" |
| Rob Grantham |
| Regarding the Mark II, according to the June 1958 AKD834 parts list, the round water hole head assembly and TD3 notation was introduced with engine number XPAG/TD3/17029. However, the production records show that the engine was not installed in a car until the 9th June 1952. I agree about the W4/44, it was never fitted with the 168425 head, although owners may have wished it was. |
| R A WILSON |
| Jan Any pics. of your finished head that you would like to share A bit interested to see how it turned out willy |
| William Revit |
| Hi Willy,
I feel rather ashamed. When machining the Wolsley head was finished I couldn't wait to get the car running and got straight into reassembly. After all the interest and responses I should have shared photos of the head prior to fitting it to the block. I apologies but can say after fitting larger valves, skimming the face and installing Mini seals the engine is running faultlessly. No exhaust smoke and very quiet. Even though my porting work only involved smoothing the larger valve ports into the original ports the performance is exactly the same as with the Mangoletsi head. With a 9:1 compression there is no running on. The bottom line is the Wolsley head, with a little valve work and face machining performs exactly like the original MG one. Thanks for all the advice and responses Jan T |
| J Targosz |
| Hi Jan, Congratulations Jan re the Wolseley 4/44 Cylinder Head work. Top stuff. Your Thread also allowed for written inaccuracies to be highlighted and put right. Cheers Rob Grantham TF3719("Aramis"),TF9177("Athos"). |
| Rob Grantham |
| Jan
All good, thanks for the reply I've just finished a head for a friends TD Managed to get hold of some nice stainless valves and gave it a basic port job, matched the manifold to the inlet ports and followed your thoughts of staying around 9:1 He's on a .030" bore so ended up with 74.25mm thickness to get the result I stuck with the standard seals but finished the tops of the inlet guides into a bullet shape to stop oil pooling on top of the guides It will be a while before it makes any noise so just hope it turns out ok Good to hear yours worked out well willy Just out of interest, what sparkplugs are you running--I'm thinking BP6's |
| William Revit |
| All up I have found this thread subject very interesting and informative
The depth of knowledge of you guys is fantastic What I have taken away from here is that although there is heaps ducumented, there are no strict dates etc. more a guideline thing which has continued all through the years of MG production A prime example of which is here when from 1970 onwards all new cars had to have a compliance plate to comply with the ADR's (Australian Design Rules) I have seen 1970 model reverse grille Bs without plates as they started selling late 69 but have also seen a chrome grille 69 car with a plate and the car dated 2/70 which must have been an old stock vehicle that had to get plated in 1970 to be legally sold as a new car There must be heaps of overlaps in model and spec changes similar to this--all of which makes it more interesting Looking forward to the next exciting episode of what model did this come from------- Cheers willy |
| William Revit |
| I'm a bit late to the party and don't have much to add, but it's worth noting that you can achieve 9.1:1 compression with a stock head thickness by using hi-top pistons. I've had this setup in my TC for the past 30,000 miles with good results. The advantage is that you don't have to cut a cylinder head that is getting more rare every day. |
| Steve Simmons |
This thread was discussed between 08/08/2017 and 18/09/2017
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