Colin Cutts Posted January 8 Share Posted January 8 I have a 82 standard tr7 I am constantly resetting the valve clearances at about 2500 mile intervals could it be due to wear in the cam followers I have never looked at these just reground and refitted the shims Quote Link to comment Share on other sites More sharing options...
Clive Posted January 8 Share Posted January 8 Which way round are the clearances changing? getting tighter or looser? Quote Link to comment Share on other sites More sharing options...
Colin Cutts Posted January 9 Author Share Posted January 9 Looser Quote Link to comment Share on other sites More sharing options...
glang Posted January 9 Share Posted January 9 Out of interest what does regrinding the shims involve? Quote Link to comment Share on other sites More sharing options...
Clive Posted January 9 Share Posted January 9 1 hour ago, Colin Cutts said: Looser So something is getting smaller. Cam lobes, that would be obvious. Shims compressing, cam buckets wearing or valve stem tip. When you say regrind, I assume you are taking oversize shims and reducing their thickness to suit? I am certain those shims are hardened, not sure how they would respond to being refaced. Quote Link to comment Share on other sites More sharing options...
glang Posted January 9 Share Posted January 9 But surface hardened only? Quote Link to comment Share on other sites More sharing options...
Amy Wade Posted January 9 Share Posted January 9 1 hour ago, glang said: But surface hardened only? If they're OEM, they're hard all the way through, when I was in the trade doing engine reconditioning we would frequently load up the magnetic chuck with shims & send them through the surface grinder. That was last century, the modern ones are probably made out of soft chinesium & could well be the problem. 1 Quote Link to comment Share on other sites More sharing options...
Colin Cutts Posted January 11 Author Share Posted January 11 Yes I have used a surface grinder to reduce the shims to the required size thought such a small shim even only case hardened would be hardened to quite a depth on a small shim . Quote Link to comment Share on other sites More sharing options...
Amy Wade Posted January 11 Share Posted January 11 You can tell by the sparks if it's hardened - whilst grinding hardened steel you will get small, quite dark red sparks, should you break through the hardening, the sparks become more orange and sparkling. Quote Link to comment Share on other sites More sharing options...
glang Posted January 11 Share Posted January 11 Through hardened can make things quite brittle which is why surface hardening is used. However this only goes to thousanths of an inch depth. If broken through it might explain why Colins gaps keep opening up.... Quote Link to comment Share on other sites More sharing options...
Colin Cutts Posted January 12 Author Share Posted January 12 Ok will try again(when it’s warmer) and use all new shims we’re is the cheapest place to get them from Quote Link to comment Share on other sites More sharing options...
glang Posted January 12 Share Posted January 12 Well first how about looking at the existing shims? If they are soft you should see an indent in the side operating the valve where the stem has been impacting - otherwise theres no problem and the cause lies elsewhere... 1 Quote Link to comment Share on other sites More sharing options...
Amy Wade Posted January 12 Share Posted January 12 1 hour ago, Colin Cutts said: Ok will try again(when it’s warmer) and use all new shims we’re is the cheapest place to get them from Where are you based? There might be someone local that has a selection. Quote Link to comment Share on other sites More sharing options...
Clive Posted January 12 Share Posted January 12 1 hour ago, Colin Cutts said: Ok will try again(when it’s warmer) and use all new shims we’re is the cheapest place to get them from I have managed to swap shims with people when I needed them. They are common to stags and dolomites, so people often have a jar full of them. But it is worth checking the shims you ground have changed thickness in use, the issue may be elsewhere (but my brain is struggling to work out where) Quote Link to comment Share on other sites More sharing options...
Colin Cutts Posted January 14 Author Share Posted January 14 I live near Newark on Trent or just recently in Trent Quote Link to comment Share on other sites More sharing options...
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