Just out of curiosity, I’m going to contact a local machine shop and get a quote for 10 thou off the piston tops …
That's probably better than VW built it originally, not as good as it could be be but not bad either and certainly safe. The imperial/metric thing is confusing, when you look at the CSP and BAS websites they convert imperial to metric. CoolAir shims must be imperial dimensions so 0.010” should give you 0.60mm+0.53mm+0.254mm (0.010”) = 1.384mm Machining 10 thou off the top of the pistons would result in the same deck and a slightly higher CR because the volume of the dish would be reduced, but the difference is insignificant for a road engine. I guess we're all happy.
I’m pleased that we’re all happy…. just the wait for the shims if the machine shop doesn’t want to know/ is silly money.
Been to see the local engine machine shop for a quote for 10 thou taking of pistons… quoted an hours labour, so £65. As they can have it done by next weekend, bearing in mind the uncertainty of obtaining shims and time scales quoted by some companies, I’m quite pleased with that. Need to double check all my measurements before I give them an amount to remove, which is…. ? I’m also thinking that removing shim “should “ improve chances of a good block to barrel seal.
Not sure if its been said, but machining will reduce the CC's (marginally) which should have a positive effect on your compression.
Finally ready to put engine back together, piston rings gapped and clocked etc. When the engine was taken apart, the middle two top cylinder head bolts came out with the nuts, so I ordered two replacements…. true to form, only one came and I fitted it in using the two nuts method, but it got half way and wouldn’t go any further unfortunately it refused to come out using the same method. When the second bolt arrived, I realised that the “stuck “ one was far tighter to screw in than the other. Any suggestion for removing the offending bolt? I’ve squirted PlusGas, but don’t think heat will be a good idea. Is it just brute strength and ignorance…if so, I’ve plenty of the latter!?
Sounds like the first one might have been the wrong thread or some threadlock stuck in there. Did you clean out the threads with a tap? Brute force and ali doesn't bode well.
Got it out, with brute force….. tested depth of hole, no obstruction…. haven’t got a suitable tap, although threads “look” ok, so thankfully I haven’t stripped anything. My mechanic friend suggested getting a bolt of the same size and cutting two groves in it to use as a tap…. but haven’t got a bolt of the right size that doesn’t look suspect. EBay for a tap I think.
Well the easy option, the modified bolt didn’t work…..the bolt only went in about 5 turns without starting to use a disproportionally large amount of force, so proper tap it is then. None of the usual suspects give the screwed part dimensions, but my Lidle micrometer says 12ish mm. Before I aquire one, is that correct?
Who knows? It does sound like the wrong thread. People even make their own case savers. It could theoretically be anything.
I was really referring to the actual bolt sizes…. I recall seeing the measurements somewhere, but searching on here and Google hasn’t helped.
Ah right, I thought you'd said some case savers came out with the studs and these were causing the problem. My bad.
Finally got out of DiY long enough to go in garage for a few minutes…..managed to run the tap down the bolt hole and get the new cylinder head bolt in…. might even get engine finally built up tomorrow. Then it’s the rounded drive plate bolt to sort next….. easy outs at the ready…tempted to use the new impact wrench, but considering how shallow the Allen bolt head is, I think it might be best with a softly softly approach. My friendly mechanic said that if that failed, I should drill out the bolt head and the remaining bolt should come out easily as it won’t be under any tension…..does that sound plausible?
