Spit2 Posted December 28, 2017 Share Posted December 28, 2017 Hi, I have just purchased a 1980 Spitfire 1500 and need to change the head to unleaded. Does anyone know of a relable engineering outfit on Merseyside or Wirral / Cheshire that can be counted on to do the job properly. Anyone have any idea of an approx cost with new valves,gides springs etc.RegardsPhil Machttp://club.triumph.org.uk/blahdocs10/Smilies/cool.png Quote Link to comment Share on other sites More sharing options...
efp Posted December 28, 2017 Share Posted December 28, 2017 This has been discussed oft before, but are you sure you really need to do the work? Do you have low compression? Many of us have run unmodified heads quite happily on unleaded over many years before, if ever, seat erosion make inserts necessary. Quote Link to comment Share on other sites More sharing options...
thescrapman Posted December 28, 2017 Share Posted December 28, 2017 Evening PhilAny specific reason for wanting to change the head?If just for the use of unleaded don't bother, Triumph heads are not like A-series ones and will run on unleaded almost indefinitely with no Lille effects.Only get it done if it breaks is my advice, and that of some of those in the know.Cheers Colin Quote Link to comment Share on other sites More sharing options...
efp Posted December 28, 2017 Share Posted December 28, 2017 My reply overlapped with Colin’s to the same effect. The unleaded head thing is something of a myth. Unless you have money to burn, I’d humbly suggest that you’ll soon find more pressing areas on a Spit on which those kind of funds can be more urgently be spent.. Welcome to the world of money pit Triumphs. Quote Link to comment Share on other sites More sharing options...
Tim Bancroft Posted December 29, 2017 Share Posted December 29, 2017 Sorry to be a devil's advocate, my Saloon's head suffered from massive seat erosion caused by the lack of lead.I'd inspect the valve seats and if you see evidence that they are diminishing, then think about getting the exhaust seats changed.Also, check the valve guides. Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted December 29, 2017 Share Posted December 29, 2017 Quoted from timbancroft61 Sorry to be a devil's advocate, my Saloon's head suffered from massive seat erosion caused by the lack of lead.I'd inspect the valve seats and if you see evidence that they are diminishing, then think about getting the exhaust seats changed.Also, check the valve guides. Yes, cars that are well used (and hard used 🙂) will eventually wear through the surface hardening/lead memory. Although it will probably take many thousands, even tens of thousands of miles to get there, once through, seat recession of the exhaust valve will be fairly rapid. Even then then you'll be able to compensate for it by adjusting the tappets for a while. IMO, this is the point to get it done and the work involved for cure is the same as prevention.If you have the head off for any reason and need to lap the valves in, this will remove some or all of the lead memory/work hardening effect and I'd recommend get hardened seats fitted in this scenario too. Having said that, we didn't do it with our recent Spitfire build and are now 2,500 miles in with no hint of recession.Nick Quote Link to comment Share on other sites More sharing options...
efp Posted December 29, 2017 Share Posted December 29, 2017 Interesting Tim. After how many miles running on unleaded ? But I’d stand by the suggestion of if it ain’t broke, don’t fix it. (As opposed to my usual practice, of if it ain’t broke, fix it until it is...)As a point of reference Mr Spit2, and if you hadn’t already looked, Canley’s do a complete reconditioned head for £285, and you’d know the job had been done right. Quote Link to comment Share on other sites More sharing options...
thescrapman Posted December 29, 2017 Share Posted December 29, 2017 Quoted from timbancroft61 Sorry to be a devil's advocate, my Saloon's head suffered from massive seat erosion caused by the lack of lead.I'd inspect the valve seats and if you see evidence that they are diminishing, then think about getting the exhaust seats changed.Also, check the valve guides. Ah Tim, It may well have done so, but only after you drove it like a lunatic for many 1000's of miles.... They started to recede on one of my engines, but only after 20,000 miles and I had also lapped them in when I rebuild the engine (Just as unleaded became common)It was a cracked valve that did for the head in the end, and only then did I fork out for a rebuild on the head. CheersColin Quote Link to comment Share on other sites More sharing options...
mattv spit Posted December 30, 2017 Share Posted December 30, 2017 Hi Phil im the one you bought the spit off.The head was skimmed and new valves fitted and bedded in by a good engineer.Hope this helps Matthew Quote Link to comment Share on other sites More sharing options...
69vitesse Posted December 30, 2017 Share Posted December 30, 2017 The iron in the Triumph heads is a harder grade than the Austin rubbish. Taken 8 6 cylinder engines apart in the last couple I’d decades. No sign of recession on any engine, but one head scrapped for a cracked seat.The Americans have been using unleaded for ever and didn’t have the issues claimed in the UK motoering press when unleaded came in. ‘Valve recession’ is up there wirh Y2K windows hysteria. Very few people actually had a problem, avd it was just as likely down to a soft seat as a lack of lead just like back in th3 days if 5 star leaded. Quote Link to comment Share on other sites More sharing options...
Dogsbody47uk Posted December 30, 2017 Share Posted December 30, 2017 I'm just ignoring the supposed problem and running my 13/60 on unleaded. If it becomes a problem, if ever, then I'll do something about it! So far... no problems... Quote Link to comment Share on other sites More sharing options...
69vitesse Posted December 31, 2017 Share Posted December 31, 2017 Quoted from Dogsbody47uk I'm just ignoring the supposed problem and running my 13/60 on unleaded. If it becomes a problem, if ever, then I'll do something about it! So far... no problems... ‘Lead memory’? SnortThe amount of lead in Petrol halved between 1965 and 1974, then dropped again in the early 80’s to a trace amount. Any car running on ‘leaded’ Petrol in the 80’s was only getting 0.1gpg lead vs 2.5 gpg in the 60’s.Triumphs sold in the USA after 1975 had to use unleaded gas, and no, no hardened valves seats were fitted to iron engines. One TR250 has ran up over 200,000 miles on its original engine. Quote Link to comment Share on other sites More sharing options...
efp Posted December 31, 2017 Share Posted December 31, 2017 A Christmas miracle! Rare unanimity (almost) on a forum post! Quote Link to comment Share on other sites More sharing options...
JohnD Posted December 31, 2017 Share Posted December 31, 2017 Unless ..... (can't let that message of peace and love go unchallenged)You're going to cane it, motorways or competition. THEN, steel exhauist seats.John Quote Link to comment Share on other sites More sharing options...
efp Posted December 31, 2017 Share Posted December 31, 2017 There’s always one... Quote Link to comment Share on other sites More sharing options...
RobPearce Posted December 31, 2017 Share Posted December 31, 2017 I ran my Toledo on unleaded for many miles with no apparent ill effects. Then I entered it for the RBRR, serviced it with a dodgy float valve, and proceeded to give it 1000 miles of hard driving with a lean mixture, followed by another 1000 miles of thrashing to catch up after Dale diagnosed the problem. That caused terminal recession of all four exhaust valves, at which point I took the head to Cambridge Rebores (one of the two local engine rebuilders) for conversion. Quote Link to comment Share on other sites More sharing options...
69vitesse Posted January 1, 2018 Share Posted January 1, 2018 Yes, running an engine hard with a lean mixture will burn out your valve seats - even if it was running on 5 star leaded.Lean mixture burns slower - more heat transfer to valves and head - mixture still burning when exhaust valves open exposing seats of valves and head to the very hot flame front and eroding them. Quote Link to comment Share on other sites More sharing options...
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