OK, let's start by saying that I consider myself to be a pretty bright guy and most seem to agree unless I **** them off. My first career was land surveying so I'd like to think simple addition and subtraction are pretty easy stuff compared to some of the other things I've done with numbers.
In an earlier post I mentioned not being able to measure the clearances on my exhaust valves because they where too tight, my smallest feeler gague (.0015in/.038mm) would not slide into the gap between the shim and cam. Using the zip tie method I pulled and reinstalled each of the shims individually, checking their specs with both reading 2.55
Joined the shim club and passed along this same info. It was suggested that I purchase a thinner shim and thinking toward the future, I chose a 2.30 thinking that might work for at least one or two more checks in the future. Once I knew which ones I needed I could then make the swap with the club.
The shim arrived today and I replaced the 2.55 with the 2.30 on my first cylinder. The gap was .012 in or .305mm. Sure enough, the other one was also .012 in. Good enough, time for a cup of coffee and some good old fashioned cypherin'.
2.30mm + .305mm = 2.605mm.
Hmm, now if that where the case the 2.55 shim SHOULD have had .05mm of clearance and my thinnest feeler gague should have fit in there, yet it was completely tight.
Go back, check the work. Recheck the manual and follow the instructions again. The clearance is to be checked with the cam lobe facing 90? to the cylinder head where the valve cover mates up OR with the cam lobe in line with that same surface. Both positions are offset 45? from where the cam lobe would be pointing straight up opposite the shim. Yep same results!
So, something isn't making sense or I'm not doing something correctly. No, I don't have a caliper to check things so perhaps the old adage "It's a poor Craftsman that blames his tools" may not apply here. Any insight would be appreciated, I'm headed to the liquor store!
In an earlier post I mentioned not being able to measure the clearances on my exhaust valves because they where too tight, my smallest feeler gague (.0015in/.038mm) would not slide into the gap between the shim and cam. Using the zip tie method I pulled and reinstalled each of the shims individually, checking their specs with both reading 2.55
Joined the shim club and passed along this same info. It was suggested that I purchase a thinner shim and thinking toward the future, I chose a 2.30 thinking that might work for at least one or two more checks in the future. Once I knew which ones I needed I could then make the swap with the club.
The shim arrived today and I replaced the 2.55 with the 2.30 on my first cylinder. The gap was .012 in or .305mm. Sure enough, the other one was also .012 in. Good enough, time for a cup of coffee and some good old fashioned cypherin'.
2.30mm + .305mm = 2.605mm.
Hmm, now if that where the case the 2.55 shim SHOULD have had .05mm of clearance and my thinnest feeler gague should have fit in there, yet it was completely tight.
Go back, check the work. Recheck the manual and follow the instructions again. The clearance is to be checked with the cam lobe facing 90? to the cylinder head where the valve cover mates up OR with the cam lobe in line with that same surface. Both positions are offset 45? from where the cam lobe would be pointing straight up opposite the shim. Yep same results!
So, something isn't making sense or I'm not doing something correctly. No, I don't have a caliper to check things so perhaps the old adage "It's a poor Craftsman that blames his tools" may not apply here. Any insight would be appreciated, I'm headed to the liquor store!
