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MG MGB Technical - Unleaded question.
| Hi, I've bought an MGB the P/O told me it was unleaded but I have no proof one way or the other. I found an empty bottle of additive in the boot when I got it home, so I have my doubts. I'm using unleaded (no additive)and just going to see what happens. Question is...how long will the valve seats last before burning out? I reckon a maximum of 1500 miles. What do you fellas reckon? I've done about 800 miles up to now with no problems. Colin. |
| c caygill |
| Unless you use consistantly high revs, I doubt you will harm it at all. BMW reckoned than an engine that had covered 35 k KM/Miles had enough lead memory to be fine. In any event it will be in the order tens of thousands of miles before anything much shows. That said Valvemaster or Valvemaster plus is not that expensive given the mileage most of us do. |
| Michael Beswick |
| X2. RAY |
| rjm RAY |
| Just keep am eye on your valve clearances, if you're worried. |
| Dave O'Neill 2 |
| why spend £250-£300 on something that probably won't need doing. if it burns the seats out further down the line its not going to cost you any more. i think its a load of old cobblers. another money spinner. never had any of my cars done or used additive.. just my opinion. bob |
| bob taylor |
| I suppose it depends on how hard one drives ones car and what to do when it comes time to recon the head and /or engine. To be honest I cannot remember the last time an immaculate used head came in that showed no sign of seat recession. So, even if someone wasn't bothered about leadfree conversion the heads we have seen all need ex seats in to return the seat height to standard. Pre leadfree conversions we actually had slightly larger exhaust valves (34.5mm) made to address the problem of seat sinkage. That was way back in 1987, plenty of time for unprotected valves to recess since then! If a head is overhauled, even to the extent of a good hard valve lapping the fresh metal is not up to the job to offer full seat protection with no lead in the fuel. Various heads wear out faster than others, A series tend to 'die' quicker than B series. In answer to your waste of money and a load of old cobblers Bob, the cost of installing and supplying inserts is not very great, especially when I have stated ex seats need inserts to restore the seat to OE height. Even our basic leadfree heads sport three angle valve seats which increase bhp or increase fuel economy depending how the car is driven. The increase in economy will, at some point, pay for the conversion work. I get to see 3-5 B heads a week so have seen a fair few since 1987 to get an idea of wear and tear! This includes one owner from new 15000 mile Bs showing recession to poor old heads with starship miles on them! We have even come across 'perfect' heads which turn out to be leadfree and the 'new' owner didn't know! Peter |
| Peter Burgess Tuning |
| I became aware of the BMW statement not long after leaded started to disappear, and you have to bear in mind that the FBHVC tests involved brand-new A-series engines (considered the worst at the time for recession) run constantly at maximum load on a test rig. I've been using Castrol Valvemaster (it came out best in the FBHVC tests) since unleaded came in, purely as cheap insurance. My valve clearances don't vary from year to year (since I started checking at the point of largest gap), and when I changed the head gasket last year there was no sign of damage on the seats or valves, I just gave them a light lapping-in. This is a car that will do several hundred miles on a long weekend, including motorways at '70' mph, and other fast road trips on a regular basis. Ignore it, keep using the additive, and even with enthusiastic driving I doubt you will see a problem - that's assuming your head was used during the leaded era. And even in that case JFDI until you get a problem, then deal with it at the time. There was a lot of angst about unleaded when it first came in, now it tends to be ethanol. America has been using unleaded and ethanol for 40 years, and it doesn't seem to be a problem for them. |
| paulh4 |
| It depends how you look at things Paul, year on year, as the ethanol content percentage increases we meet new problems with the effects of extra heat/change in fuelling and burn characteristics. After around 20-25 mins flat out racing the 165 bhp FIA full race B engines have, at times, lifted the head enough to low the gasket and/or blow out all the water. Continued driving rapidly 'kills' the engine. To overcome this we are running Cometic MLS head gaskets which are very difficult to burn across and ARP head studs down at 70 lbs/ft. Which BMW heads run CI inserts? There seem to be very few ally heads which are factory fitted with low quality non leadfree compatible inserts. Lancia and Fiat come to mind as well as the P6 Rovers. Range Rover and MGB GT V8s were leadfree inserts as are all the SD1 heads. The Jags also have leadfree compatible inserts. We have only seen CI inserts recess with leadfree fuels. It may be as you look after and maybe molly coddle your engines you get long life. I seem to recall you shun rolling roads, even ultra low stress modern inertia dynos as you feel they will damage or unduly stress your engine/s. Our race Bs would die rapidly if we didnt dyno prep them, for instance wrong grade of plugs can kill an engine in a lap or less! Peter |
| Peter Burgess Tuning |
| Just having a look at cost effectiveness of lead free conversion versus valvemaster, Sandra is playing with her new Brother CM900 ScanNcut thingy so I am now fedup with being an art and craft widower. A B on 23 mpg with valve master+ costs 22.7 p per mile I work out, if a B does 23 mpg then improves to 27 mpg with head mods ( usually better than this but lets keep it less to be on the safe side) and doesn't use valvemaster any more then costs are 18.5 p per mile so I reckon 6714 miles is break even point to pay for head work. From then on it is all money in the pocket at 4.2 p per mile at current costs. £84 per year on 2000 leisure miles. I also copy info from Opie oils about valvemaster+, note the sentence about racing or arduous use. Also says 'likely' to be adequate! Castrol Valvemaster Plus is a lead replacement fuel additive with octane boost for use with lead-free fuel. One millilitre of Castrol Valvemaster Plus treats one litre of fuel, making it very economical. Castrol Valvemaster Plus is suitable for pre-1992 vehicles which possess soft value seats requiring protection against valve seat recession, and which require an additional octane boost in order to be able to run on 95 RON unleaded petrol Castrol Valvemaster and Castrol Valvemaster Plus are endorsed by the Federation of British Historic Vehicle Clubs. Castrol Valvemaster Plus has been subjected to a valve seat recession test by an independent test house on behalf of the FBHVC and was shown to offer the highest level of protection against valve seat recession from all the products tested. The results of the test indicate that the level of valve seat protection is likely to be adequate for all normal driving, but not including racing or other exceptionally arduous uses. Valvemaster basic is 10% cheaper so add 10% more miles to break even. Peter |
| Peter Burgess Tuning |
| All very interesting fellas. I'm happy to just run it and see what happens. I won't be using any additive. No big deal if she needs doing in time. I was just interested in opinions of longevity. Cheers Colin. |
| c caygill |
| Like the proverbial piece of string in one's pocket Colin :) Maybe valvemaster left in boot apres leadfree head fit! Peter |
| Peter Burgess Tuning |
| Peter, one thing I have noticed is that once the inserts are fitted, if a valve does for whatever reason burn out in a big way the seat doesn't crack underneath. In A series heads in particular you can count on mayber having to throw the head away if a centre cyl exhaust valve has burnt out badly due to generating a crack across the seat and propogating further. Or is it just that we are all bad guys here or something in the water?! So the extra protection the unleaded inserts offer to the head in this way is a real benefit on its own. What's the typical cost to suply and fit a set of inserts to a 4 cyl, if the head is already off the car for some other reason and the owner is doing the strip/reassemble? |
| Paul Walbran |
| Hi Paul I think the problem is worse with A series, you are quite right though the seats do have added 'crack' protection with inserts fitted in the ex seats. The seats let us rescue a fair few heads from the scrap pile from det damage as well. My old Mini 850 used to burn out number three ex valve with alarming regularity!!! Peter |
| Peter Burgess Tuning |
| Steady on Peter. You talk about race conditions which is hardly 'normal' use for the vast majority of us, then imply I molly-coddle mine after I indicated the use it actually gets. As for saying I shun rolling roads as I fear they will damage my engine, it's true I've never had either of mine on one but that because I'm not really interested in squeezing another couple of horsepower out of it. Both run extremely well, I won't admit to how far I've seen the speedos go round, but when not doing that I've also seen mpgs of 40+ from the roadster and 30+ from the V8 so I don't feel the need. Let's not forget, you are in the business of selling sessions on a rolling road and performance enhancements ;-) |
| paulh4 |
| I am also in 'the business' of looking after folk so don't usually charge what time I have put in! Rolling road tuning isn't just for bhp it is for fine tuning to get the best in terms of mpg as well. I have spent years without a rolling road and years with and understand that without I knew not a lot for how the engine was actually running. I have about one car a year that is set seat of the pants about spot on. This is usually someone who has spent a lifetime in racing a particular model. With regard to carrying out leadfree conversions, at some point the head will need reconditioning whether it is lead free or not so will cost money if reconditioned to new specs with new guides, valves and springs so the investment is not horrendous. Peter |
| Peter Burgess Tuning |
| Paul, I think you are being more than a little hard on Peter. I've had two cars on his road and had some engineering work done by him. His knowledge and experience is way up there with the best. I use the road; partially to confirm my ear and "seat of the pants" tuning, because it is an interesting experience, it improves my knowledge base, it gets the engine up to peak efficiency (or confirms it was already there!!) and is a most pleasant hour or two with nice blokes in a "proper" workshop!! Peter is not a slick salesman and neither does he guard his knowledge, a visit to him is just an all round positive experience. |
| Allan Reeling |
| Allan said "Peter is not a slick salesman and neither does he guard his knowledge, a visit to him is just an all round positive experience." I completely agree. I have had an 1800 MGB and my current V8 at Peter's place and he is tremendous value for money. He works with the engine until he and the customer are happy, however long it takes. He will not try to sell you things you don't need and if it is possible to make existing components work better, then that's what he does. For example tweaking the distributor weights and springs to get a better advance curve rather than selling you something fancy. I just wish he wasn't so far away from me!! |
| Mike Howlett |
| I have to say that I've always been a bit bob-each-way on this. In my experience the benefits of fitting unleaded inserts are unquestioningly positive, both economically and in reliability and have done so to all my own vehicles. Even in my fully modified B head with 1.75" inlets and 1.44" exhausts, where the conventional wisdom is that it won't work as there's not enough between the valves. (Solution was to insert the inlet valves as well. with the two seats abutting each other and eliminating the crack area completely. Done originally to reclaim seats of an awesome flowing head, it's been that way for 30+ years, no problems.) But when a customer ask me Colin's original question on this thread, my response is monitor it for now (via tappet clearances), and do something if they are reducing ... until the next time the head is off. At that stage it is an absolute no-brainer to fit unleaded seats, very quick payback not to mention insurance against cracked seats. As Peter noted, more prevalent in A series, but I have come across B series so-afflicted. Herewith a tale: The incident which sold me on this happened 20+ years ago, we had an old Austin 1300 as a family runabout, fairly tired but I had given the engine a refresh and fitted unleaded seats due to the fuel change imminent here at the time. Me being me I fiddled the engine a bit, mainly raised CR tweaked cam and extractor (that car would sit on 75mph all day, up hill and all). I hadn't had the time to set it up properly (last minute drama as usual) before we set off on a promised trip to Wellington 400+ miles south. Turned out the spark plugs needed to go down a grade or so as shortly after starting the return journey on one very long uphill climb (about 2-3 miles and admittedly passing most others) the car started to misfire a little from what proved to be overheated plugs, and by the top there was the unmistakable feel of a burnt valve. Being committed to having an event to run the following day I resigned myself to a dead head and kept going. On reaching home, I stripped the head and looked at the seat underneath the errant valve with the classic V-shaped chunk burnt out of it. Looked good, to my surprise. Crack tested ... OK! Dropped a new valve in and with a 10 second lap-in there was a perfect seat. An original head under a valve that bad would almost certainly have been cracked. That's what I mean about protecting the head! |
| Paul Walbran |
| My B Head has had the 'Econotune' teatment from Peter. It had been around the clock and was burning oil really badly (500 miles to the pint). I dont have the facilities to get the engine out so I rebuilt what I could in the car - glaze busted the bores and fitted new rings. Hey presto oil consumption stopped. I have a marked improvement in low end torque with the Econotune, but havent noticed a massive improvement in fuel economy - it does high twenties. I dont do a lot of town driving. I've renewed everything in the valvetrain, but I get a clanking at low rpm, so I'm suspecting either piston slap or a little end. It gets better when the engine is hot and disapears luckily above 1000 rpm. The car owns up to having done 137000 miles on the original engine. I'll keep an eye on it. |
| Paul Hollingworth |
| Paul, were you able to measure the bore when you had the engine apart? It does sound like piston slap since the noise goes away once the engine has warmed up. The pistons and block have expanded just a little bit, taking up the slack. RAY |
| rjm RAY |
| Hi Paul mpg will be dependent on getting it tuned cirrectly then not using the extra power, we usually find ffolk go quicker for same amount of fuel to start wiyt then settle down as they get used to the engine and get the mpg improvements. Peter |
| Peter Burgess Tuning |
| The piston slap on my V8 only started as it warmed up. FWIW. |
| paulh4 |
| I'd just like to affirm that the statement "and neither does he guard his knowledge" is true. My knowledge of the BMC B-Series engine expanded considerably due to Peter's willingness to share both his knowledge and his insights with me. One could not hope for a more generous or honest mentor. |
| Stephen Strange |
| A true scholar and a gentleman to boot. RAY |
| rjm RAY |
| Ray - I didnt have the means to check the size of my bores, but there was a noticable ridge at TDC. I put the new rings into the bore and the end gaps were smack in the middle of the tolorance. Peter - I pride myself with being able to set the ignition precisely with dwell meter and strobe. I have the advance curve so it set it at 1000 rpm where it runs more smoothly. I have added a couple of degrees advance from the factory settings using the vernier. I'm also pretty sure that my carbs are well balanced for air flow (at least at no load). The problem I have is mixture setting. The plug condition is less of a good indicator with un-leaded petrol. I have recently found myself richening a couple of flats to get it to idle stabley and pull cleanly below 2000 rpm. I put it down to the dreaded Ethonol. The exhaust pipe is dark grey in colour. We have to bear in mind this is a 45 year old engine with 137000 miles on the clock. I don't know if any work was done on the carbs before I bought it 16 years ago, but we have to assume that the needles, jets and spindles are pretty worn. Having said this the car performs well against its contempories and I dont think 25+ mpg is that bad for a sports car of this era. You may be right that I'm driving in a more spirited manner now that its not burning so much oil. I for one am a very satisfied customer. Paul- its normal for piston slap to get better as the engine warms up as the piston tends to expand more than the bore, closing the clearance. |
| Paul Hollingworth |
| Yes, it is normal. I have this problem with my Suzuki Samurai. #3 cylinder is slightly larger than the rest and the piston makes a fair bit of noise until the engine warms up. RAY |
| rjm RAY |
| "its normal for piston slap to get better as the engine warms up" Indeed, but not with mine, going by the bores and piston skirts. |
| paulh4 |
| Ah Paul - your engine has an aluminium block, that could make a difference. I've heard tales that disconnecting the vacuum advance pipe on that engine cam make a difference, stacking up with the theory a regarding ingnition advance. |
| Paul Hollingworth |
| Unstable idle is often due to worn throttle spindles admitting varying amounts of air, depending on where they settle when the throttle is released. FX, AAU and ACD metering needles are all at the lean end of the window for 2000 RPM cruise conditions. If the needle has worn mostly in the idle position (as most do) and the jet wound up a bit to compensate, then the mixture will be lean on the less worn parts of the needle and a lean misfire will occur on cruise, especially at a steady 30-35mph. Richening up a couple of flats will correct the cruise condition, but make for a rich idle. |
| Paul Walbran |
| As an engineer, I would always "do it right" rather than take my chances - the B series in particular is built like a brick S**t house and will continue running even if falling apart - this may be fine for some people but I won't let anything out of the workshop unless it is done to my standard - which includes a PB unleaded head. Yes, I am back to annoy you all from time to time as I now have extra time on my hands after having a recent heart attack - however, there won't be any cars leaving the workshop from now on - the last PB head is sitting there ready to go, but the owner has the pleasure of fitting it! |
| Chris at Octarine Services |
| Yeay! Glad to see you back Chris. Peter |
| Peter Burgess Tuning |
| Chris, Good to see you are back, but don't neglect the rehab process we would much prefer to have you around annoying us mate ;-) Regards, Larry C. |
| Larry C '74 B/GT |
| Good news - Welcome back Chris - Take it easy man Cheers willy |
| William Revit |
| Great to see you back Chris. So are you closing the shop or just not going to do the work? |
| Bruce Cunha |
| Thanks for the welcomes back. Yes I am doing as the doc recommends but being me I am not a slave to a routine... so "exercise" might be walking the dog or doing some wallpapering - whatever I fancy at the time. I will still take on any jobs that fit in with my lifestyle - but since I have 3 "projects" that have been on the back burner for years, I will be getting on with them and, since my horse is now stabled out in Italy, I shall be spending more time out there with her! However, the heavy, dirty jobs are a thing of the past and I won't be doing anything to a timescale but I may build the occasional engine "on spec" and will advertise them for sale only when they are finished and ready to go. I have sold off a lot of my core stock now but still have an incredible number of boxes full of bits "that might be useful one day"  |
| Chris at Octarine Services |
| Chris, rest up while you can. I'm getting over open heart surgery, done on July 27, where one valve was replaced and another was repaired. Maybe I should send my heart to Peter for an unleaded conversion. None of us is getting any younger and maintaining our health, what little that we have left of it, is very important. RAY |
| rjm RAY |
| when it comes to spending on the MGB, i tend to justify the cost of parts & mods by comparing them to the cost of parts for my Volvo. .....so my MGB gets spoiled rotten! i think the constant thought of head failure just isn't worth a couple of hundred quid, plus the fact that the car can be underperforming whilst gradually failing. it's not a huge amount of money nowadays. couple of family meals out. i don't replace stuff for the sake of it, in fact i'm quite frugal but i haven't met many folks who don't think a good healthy engine is a bonus to driving enjoyment. all depends on how you view your car i guess. few hundred miles a year, or like myself, drive it every day. the volvo only gets driven for haulage, long family journeys or when it's p*ssing it down. G |
| Graham Moore |
| Graham, my thoughts exactly. I converted the head, on my '67 B, back in the late '80s. I purchased it in a salvage yard for $50. I replaced the intake and exhaust valves with stainless units and installed hardened seats on both the intake and exhaust valves. While I was at it, I also installed silicon bronze guides. The head has been on three different engines in my car over the years and still performs flawlessly. While I had the head apart, I also spent 13 hours porting and polishing it. RAY |
| rjm RAY |
This thread was discussed between 17/10/2016 and 17/11/2016
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