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MG TD TF 1500 - lifters worn differently
| Dear all
5000 miles since I changed the lifters (Moss). They are +020. I did a test and I cut the groove on all but one, Number 8. 8 and 6 don't rotate. 8 shows a mark near the bottom hole. Others have similar marks but do rotate. 8 has different color. Metal grey. The others are black. This is probably related with the lack of groove. But what does it mean ? Whilst they don't rotate, they are among the less pitted.5 is perfect.3 and 4 are very pitted. The cam lobes all look perfect and shiny. I did the running in procedure with cam lube and so on. I'm using Dynolite oil (1164 ppm phosphore, 1245 ppm zinc). The engine has the strong springs. And the cam is the late one. What can explain such a difference between the lifters ? I had a look at the old set. Pitted but no correlation between the two sets. I'll buy a new set. I'l try Peter Edney's. Shall I cut the groove ? Laurent. .   |
| LC Laurent31 |
| It is sometimes necessary to space the camshaft locating plate. The followers must be offset to the cam to ensure that they rotate. I have heard some new cams are machined with a slight taper to rotate the followers. Ray TF 2884 |
| Ray Lee |
| I have a Crane cam in mine and all the cam followers rotate. I did have a pushrod problem, but that was because the rebuilder used the original type of pushrods which were too long, I changed them to Crane pushrods of the right length and all is well! PJ |
| PJ Jennings |
| I got sick of problems like this and went to a roller cam on both my cars. |
| B W Wood |
| Buy them direct from the manufacturer - Newman Cams. They have two versions, standard and hardened for use with a higher lift Sports cam. Dave H |
| Dave Hill |
| Laurent, What can explain such a difference between the lifters ? I was advised many years ago " If you can not see the part from the outside of the car do not purchase it from Moss"
Ray, the cams that have no taper must be offset from the center line of the lifter to make the lifters rotate.These lifters are flat with no convex lifter face. Crane now CompCams have a .0003-.0006 taper and must be used with a convex lifter. Moss lifters for the Crane-CompCams have been on Intergalactic back order for a few years! I have testimonials from many of my customers who were dissatisfied with the cam and or lifter wear regardlass of who produced / sold them!! They then purchased one of my Abingdon Performance Ltd.Roller cam kits. A roller cam has no taper and must be used with a roller lifter. Roller cams and lifters last indefinitely! Len Fanelli https://abingdonperformance.com/  |
| Len Fanelli |
| Hi Laurent,
I run the original set-up in my road TC and race TC. The cam followers should have a slight positive radius on their bottom surfaces. If you put a straight-edge across the bottom faces, what does that show? It is hard to see in your first image, but the image shows that possibly your followers have flat or concave surfaces. Yes, the followers should rotate, but I have had some which don't rotate yet still give good service. The followers are not case hardened but "chilled". That means the hardening is very thick and can withstand being resurfaced a few of times. I guess there would be a site which can verify the radius which is ideal for cam followers. I cannot say, because my method of re-surfacing is a very crude, "don't try this at home", type of thing. I believe that some people never use more than 5000 RPM, but run valve springs capable of withstanding 7000 RPM. Strong valve springs put more load on followers. Lightening followers and valve-gear is a better alternative in my opinion. There is a lot of weight in the valve-train which is easy to reduce. Cheers from South Australia, Bob Schapel |
| Bob Schapel |
| Unless I'm mistaken shouldn't the grooves run from the upper hole down to the bottom hole and not just around the base perimeter? |
| Gene Gillam |
| Thank you all,
Bob, I think the lifters "were" a bit convex when new. But difficult to appreciate now. Len, If I were in a complete rebuild of the engine, I would think about your roller cam of course but This is not the case. The engine is in the car which is stopped only for a while. Sure I will purchase the new set from Peter Edney. The lightened version is not available. So I'll try to enlight them on the top with my lathe. As Peter's. I was also thinking about going back to the normal springs. I don't race the car and the axle is 4.3/1. So 5500 RPM is a maximum. Other thing I realized. The cork gasket of the side cover is so distorted that it touches the push rods. I can even see marks from the top of certain lifters. It may be possible that the cork wipes off the oil coming down along the rod. And a certain amount of oil goes directly to the sump by the big holes between the lifters. Laurent. |
| LC Laurent31 |
| Hi Laurent,
Can you tell me about the "groove" modification? I don't think I have heard about that. I am constantly learning new things from this forum. I have attached an image of a lightened follower, showing where there is a lot of metal which can be removed. The bottom could also be chamfered a bit. The follower in the picture is a bit rough. Perhaps it was a practice effort? It was lightened on a grinding wheel. The valve spring retaining washers can also be lightened. Their outer diameter can be reduced slightly, and the top "face" can be ground down to be smooth (where there are usually concentric rings). Good luck with the job. Bob Schapel  |
| Bob Schapel |
| Here are two pictures of a 50's lightened tappet from my Wall o' Speed. It is definitely a flat tappet, modified very much like Bob's version. I have also heard that a Studebaker tappet is the same diameter as the MG, and was often used in lightened form - sometimes called bullet-tappets.
The very best way to tell if tappets have been crowned is to hold the faces of two tappets against each other. Flat tappets will contact perfectly, while crowned tappets - even very worn ones - will rock. I have Delta Cams re-grind my cams and tappets, and ask for 1 degree off on the cam lobes, and a crowned tappet face, to encourage rotation. The fit of the tappets in their bores is crucial, as many are tight and do not allow the tappet to rotate at all. Tom Lange MGT Repair   |
| t lange |
| Thanks all Bob, look at my second picture. On tappet N°4, the groove can be seen from the bottom hole to the bottom face. It also allows the oil flow whilst the tappet is in up position. But my trial shows no evidence of efficiency. Tom, good method. I found at least a pair which rock so my tappets were crowned. Laurent. |
| LC Laurent31 |
| There was a big discussion about cam followers in this thread: https://mg-cars.org.uk/cgi-bin/or17?runprog=mgbbs&access=&mode=archiveth&subject=8&subjectar=8&thread=2013012517095627678 Also, this is a photo of the way the MG racing community modified their followers to allow oil to drain to the cam.  |
| Gene Gillam |
| I do not understand the extension of the groove to run between the holes. Regards, Tom |
| tm peterson |
| Tom, The upper hole fills up before the lower hole…the extension allows it to drain quicker and also provide more lubrication to center of the tappet as it rotates (at least that’s how it was explained to me). |
| Gene Gillam |
| Thanks guys,
You (and the archives discussion on the topic ... thanks Gene) have got me thinking. Next time I rebuild an XPAG I will probably do something along those lines. One week ago (19th November) was the 50th anniversary of the first time I drove my TC Race car in competition. (Approaching 300 competition meetings since.) I have been driving my TC road car from four years before that. I have never had any "major" issues with cam followers. However, some mods suggested are certainly worth trying because I have had to reface cam followers occasionally. I always enlarge the holes but maybe more is better, and standpipes at the low level sound promising. Maybe the grooves stopping just before the bottom face? Incidentally, very early Morris 10 heads did not have the central oil drain. I think that was added before the first TBs. As I have said before, I learn lots from this forum. Bob Schapel |
| Bob Schapel |
| Bob, the original idea of the grooves was to get oil on the face and then cam lobes. Stopping short does not accomplish that. Regards, Tom |
| tm peterson |
| Hi Tom,
I was thinking that the grooves could go beyond the wear mark so the oil could get through. However, I see your point, because the oil would then be directed (and have momentum) outwards instead of downwards. I have slightly chamfered/rounded the bottom "edge" of my followers, in an effort to reduce weight. I had never considered that the right shape of chamfer/radius might help oil drain around to the bottom face instead of being flicked off at the "corner". Maybe I have been doing my followers a favour without realising it. Cheers, Bob |
| Bob Schapel |
| If you reduce the diameter of the bottom of the lifter, you change the cam timing and duration... |
| J Stone |
| This'll be interesting- |
| William Revit |
| Some of you may know that I am interested in the EX176 racing engine, a dry-deck XPEG engine, from which the tappet I show above came (I just remembered the source). Factory documents note "Tappets - Standard Flat face but lightened at top by machining." This matches the tappet I show above. Tom Lange MGT Repair |
| t lange |
| Additional information : I measured 2 spring pairs
N°6 which does not rotate and shows little wear and N°3 which shows excessive wear. Both springs are close to TD specs with 6 slightly greater. I though I had the strong spring. I was wrong. These are standards. And it does not explain the wear out difference. About groove efficiency. I think we could get an answer with the N° 8. This one has no groove and has really a different color on its body. But I can't conclude about this color difference. Anywone can ? Laurent. |
| LC Laurent31 |
| Laurent
you mentioned early on that your followers were .020" oversize---Maybe when the block was drilled/honed for these the bores were left a bit tight on one or two (read 6-8) I think it would be a good idea to check for free movement of the followers in their bores, maybe if you're going to replace the lifters, check the new ones for fit and if you have one or two that don't drop under their own weight in the hole you could polish them up a bit to get a good fit or being new try them in a different hole I like Bob's idea of radiusing the bottom corner of the follower to let oil sneak around the corner--You'd be able to see on your old followers how far you can go before effecting the working area Also ,Ray mentioned spacing the cam retainer plate-It's weird ,some xpag blocks seem to have the lobe dead centre of the lifter bore and some seem to be very slighty offset forward---it'd help but I think your issue is more likely tight lifters in their holes, six and eight don't appear to have spun at all-- Just thinking---rare----maybe when the grooves were cut in the followers there were some sharp or raised edges that cause a tighter fit in the block, it'd be interesting to get say, number 6 or 8 and have a feel how tight it is in it's bore and then try it upside down ,away from the grooved area and see what the fit is like that willy |
| William Revit |
| Eureka !
Reading the thread indicated by Gene, I observed how the top hole is open in down position. As they are most of the time down. Big difference. Some are entirely closed. Some are little open. And guess what? Direct correlation with the lifter worned or not. I first thought of the uneven surface of the casting of the block. But the culprit is the top holes of the lifters which are at various positions. See picture. The manufacturing of these holes is weird. It is of course part of the cast mould. First reason for differences. And the chamfer seems machined but in a very fancy way. Maybe manually by a underpayed human. However, all holes are wide open in up position but there is an oiling difference indeed. So the up position duration appears to be negligible regarding oil entering. Top hole little open makes a big difference with entirely closed. But remember, only 5000 Miles. So I will largely extand them upward in the new set. I can see no draw back for this. No matter the bottom grove or the standpipe if upper hole do not allow oil to enter! So I would highly recommend to check each lifter hole in its bore and in down position. Willy, yes they are all free to rotate when in position, engine cold. But you also highlight a key point. Even if they are free to move the clearance may not be enough. Wood's booklet says 0.0015". I'll check that with the new set. Not easy. I intend also to extand the grove between the bottom hole and the top hole to allow lubrication of the top part of the lifter. We always learn something when we gather several brains. Laurent.  |
| LC Laurent31 |
| Thanks Laurent.
It has been great to learn so much from this thread, the archives thread and your observations. I have been lucky because the way I lighten followers has probably helped lubrication in my engines without me realising it. However, I must pass on this information to my South Australian colleagues because I haven't heard discussion about it in nearly 60 years of involvement with XPAGs! I will acknowledge the source of course. Next time I have the opportunity I will certainly be doing the extra mod. There are a lot of versions, and I will think about which one to follow. I do like the idea of sending most oil to the "approach" side if that is achievable. Thanks to everyone for all the ideas! Bob Schapel |
| Bob Schapel |
| Other ideas of improvement.
The bottom groove is of no help for rotation of the lifter inside the bore. It is mainly below the bore. But, as the bottom hole does not extand very much (0 to 1 mm) below the bore, the bottom grove greatly improve the oil output from the lifter. The top grove shown by Gene is better for rotation but it only collects oil from the lowest part of the top hole which does not collect much oil itself. Moreover, the oil is probably lost in the upper part of the bottom hole So I had 2 ideas for this grove. Green lines in the pictures. 1) The groove is located between the holes and goes from top to bottom of the lifters. It always collects oil from the block. Whatever the position of the lifter. 2) The grove starts from the chamfered part of the top hole and run in a Y shape towards the bottom of the lifter. Less oil is collected but the chamfered part of the top hole may act as a reservoir. I think 1) would be my prefered solution and is easyer to machine. Any comments ? Laurent.   |
| LC Laurent31 |
| Just to throw in another view----
I wouldn't be machining a groove right up like in either of your options The lifter/follower needs lubrication to help it spin, If you are going to machine drains in down the length of it the follower might not be able to build up a sufficient lubrication film IF that top hole does clear the top surface which it would at some point in it's travel, lube oil will get into the cavity in the follower anyway My choice if you are going to machine grooves would be from the bottom holes down only and radius the bottom corner of the groove around to just short of the working area on the bottom face and also radius the corner of the lifer in to a similar spot to stop oil flicking off the corner- What do you think of that--------- willy |
| William Revit |
| Interesting thoughts Laurent and Willy. Perhaps the top of the follower needs to have a radius too? With the fast acceleration of the follower, as it rises, oil sitting on top is likely to be flicked off. I am suggesting a convex radius to the top "corner" of the follower, so that under vertical acceleration, oil will tend to flow around it to get to the side of the follower, from where it is more likely to get to the holes and/or grooves. Similar to the radius on my image of 23rd November above. (Whether or not the concave "lightening" radius is included.)
Has anyone ever suggested grooving the follower bore instead of the follower itself? That could be done on the side which encourages oil to get to the cam-lobe "approach" side, where I reckon it would be more benefit? It could be done with a slight spiral which might assist turning the followers. There seems to be such a big selection of choices! Maybe one of us should do four different treatments in the one engine? That would be a cool experiment. However, I bet we all select the option we think is best for the whole eight followers. I haven't yet selected my favourite option, although there are a couple of aspects I am pretty sure I will include. I wonder if some of the XPAG racing guys in USA and Europe have tried all of the suggestions and have some conclusions. As I said earlier, I don't think the issue has been very well investigated in Australia YET. Bob |
| Bob Schapel |
| Probably all or most of the racers in the uk would most likely be running with the gun drilled cams with oil feeds to each lobe----maybe Thing is though ,if the lifter isn't spinning it's going to die earlier than one that is, nomatter how much lube it's getting, I think checking for a nice free fit in the block is probably the most important issue really. willy |
| William Revit |
| Willy, you may be right. Total groove may act more as a drain than as an oiler. Now I don't know what to do ! For sure, the best mod would be the helix on the bore with an output just where we need. But it is much more difficult than modifying the lifter. Racers may have different solutions than road drivers. Racers want as much power as possible. Road drivers just want a reliable engine whith a long life lifters and cam. Laurent. |
| LC Laurent31 |
| As Willy said, I think we must not worry too much about oil for rotation inside the bore. Rotation is at very low speed and there is no strength when it rotates. I noticed that the lifter rotates only when the springs are almost released. When valve is open, springs are so heavy that they prevent rotation. Especially if the cam is well lubed.In my block, I can still see the marks of the boring machine. It is probably 20000 Miles old. So I think that lubrication is OK. Even for sliding which puts radial stress on the lifter.
Anyway, to cope with the drain effect What about stopping the grove so that it always remains inside the bore ? Permanent reservoir. Laurent.  |
| LC Laurent31 |
| Having seen the amount of oil thrown off a crankshaft while running, I suspect this grooving may be a solution in search of a problem!
Lifters should be ground convex and mounted off center from the lobe thus inducing spin. Which worked well until the removal of zinc (ZDDP) additives from motor oil to preserve catalytic converters. Zinc is today available as a separate additive which is a good thing, a little goes a long way. It seems to me the zinc additive in oil was a simple and inexpensive solution to 'less than optimum' materials. The mandated removal of zddp became a big problem for high lift and high spring pressure competition cam assemblies about 15-20 years ago and was largely solved by aftermarket roller camshafts and followers. The oem camshafts, and lifter materials were likely of better suited alloys than aftermarket products. It's difficult to find those parts today where many alloys and products are manufactured offshore by the lowest bidder. |
| J Stone |
| Couple things, All oils still have ZDDP. I have a set of lifters only run on oils with the higher level of ZDDP that look like they were hit with a scatter gun.
ZDDP additives appear to be an untested solution to solving a problem of other causes. The only claims of how well the additives work are by the mfg of those same additives. Seems to fit the definition of snake oil. As a now 50 year mechanic, (where did THAT time go?), the closest independent professional trade publications get to an endorsement of ZDDP additive is to say “there maybe a possible benefit to slightly higher levels of ZDDP than found in current oil formulations in highly tuned engines running extreme valve spring pressures in flat tappet applications.” Regards, Tom |
| tm peterson |
| ZDDP has always been an oil additive, it has known and proven benefits.
I'm just pointing out that perhaps we should try to select oils with higher levels of zinc for older flat tappet engines (This, the ppm, is still a guarded secret with many brands. It is not something that is labeled on the container, and is often listed proprietary on MSDS sheets) I still build a few engines with flat tappets (although less all the time) and once you have a cam failure you tend to be a bit gun shy and check all the boxes. If you do not have a catalytic convertor there is no reason not to use an oil w/say 1200 ppm zinc. There are oils formulated specifically for break in and continuous use flat tappet applications. "Zinc in Oil - Not a Myth ZDDP was first used in mainstream motor oil in the 1940's, primarily for its anti-corrosion benefits. Zinc in oil kept the lead-copper bearings of the day from oxidizing, but it was also found to significantly reduce wear. As a result, ZDDP additive levels in mainstream oil gradually increased up until the early 1990s, peaking around 1,200-1,400 parts-per-million. Starting in the early 2000's, hot rodders, race teams and automotive enthusiasts began seeing an increase in camshaft and lifter failures, particularly with flat-tappet cams. Issues with flat camshaft lobes became common place. Enthusiasts began scratching their heads trying to figure out why these failures happened. Valve spring pressures were checked, lifters were matched to the cam, everything was put together correctly, and brand-name oil was used - but there was still a failure. Significantly reduced levels of ZDDP oil additive in mainstream oil were to blame. Looking back, we know these things changed parts-store oil forever: Addition of sensitive emissions equipment like O2 sensors and catalytic converters Better fuel economy via more efficient engines (roller valvetrains, georotor oil pumps, thinner piston rings, etc.) Introduction of ethanol in gasoline (first E10, now E15) Increased levels of detergents, extending oil change intervals Modern parts-store oil is engineered with all of these things in mind. Obviously, your Eisenhower-era cam-in-block engine has a different set of engineering challenges. It needs different engine oil additives". https://www.speedwaymotors.com/the-toolbox/what-is-zddp-benefits-of-zinc-in-oil/30870 |
| J Stone |
| My point exactly, another article citing the “benefits” of ZDDP additives published by a company whose business is selling ZDDP additives. Seems like a snake oil method of marketing. PT Barnum is smiling somewhere.
The article has a kernel of truth in the statement that oils at the time the XPAG engines were produced had low levels of zinc..similar levels as to current engine oils. If you read vintage trade publications you do not find articles referring to premature valve train failures. The first attempt at connecting cam/lifter failure to oil formulation changes was made by Crane Cams just prior to one of their bankruptcies. A case of a failing company pointing fingers at others after its products failed. That coupled with the internet fueled a firestorm of, at best, questionable “data”. Regards, Tom |
| tm peterson |
| Perhaps the "data" found in the "SAE Automotive Lubricants Reference" would prove more convincing? |
| J Stone |
| Here's something for you to think about- Back in the mid 80's here when unleaded fuel was introduced the current Ford Falcon(on leaded fuel) was modified to run on unleaded----Different shaped combustion chambers ,cat converter, same otherwise ,same carby etc---The unleaded version ate camshafts and lifters |
| William Revit |
| Back to my lifters issue.
I received the new set. Again a poor manufacturing with differences about the hole from one another. But this makes me think of another hypothesis. If the top hole is not high enough in the bore block to allow oil in it, it could be because the lifter is too low in the block. Hence the cam could be the cause. The cam might be reground or the late camshaft (the one on my engine) is not compatible with the after market lifters. Can someone measure the distance from the back of the cam to the top of the block bore ? Laurent.  |
| LC Laurent31 |
| The new lifters have flat faces. I think that's better for rotation thanks to the cam off center. If they were crowned, what ever the position of the cam the contact is always close to the centre of the face.
Here is the lifter machined. Bottom and top holes are enlarged. Top hole is now at least 5 mm above the bore in low position. But even enlarged, the bottom hole does not allow oil flow in high position. Quite sure that the low position makes the most of lubrication. But anyway, I also added the grooves. And now, they are also lightened in the lathe. Original weight was 100 g and lightened is 90 g. Is it a sensible improvement fo performance ? Laurent.  |
| LC Laurent31 |
| Your experience will tell but it looks like you're on the right track. Keep us informed. |
| Gene Gillam |
| Looking good Laurent , and yes lighter is always better
Just a reminder, but i'm sure you've checked, A nice free fit in the lifter bores in the block, they should just drop under their own weight without having to 'push' them in and also--no need to say it really but any sharp edges where the slots are machined need polishing off. Good luck, and----nice job you've done there. One little suggestion--Do you think there might be a small advantage to just make a small shamfer or rolled edge on the bottom of each of the grooves to encourage the oil to sneak around onto the bottom of the lifter surface - just a thought, don't know if it'd help or not but now you've gone this far--- willy |
| William Revit |
| Hi Willy, Chamfering the groove could create a sort of cutting tool for the cam. I was affraid of this. Instead I chose to deepen the grove as much as possible to increase oil flow but still remaining outside the cam contact surface. A more shallow groove with chamfer could lead to the same oiling effect but with less flow. Just my opinion. Laurent. |
| LC Laurent31 |
| Yep -all good, I hadn't noticed you'd gone deeper with the groove willy |
| William Revit |
This thread was discussed between 19/11/2022 and 19/01/2023
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