74 Restoration

[aj81spider]

Left work early today and spent the afternoon in the garage checking the valve shim clearances. Yet another reason to be cranky with the guy who rebuilt my engine and transmission. It looks like he set the intake clearances all at 0.013, when the spec is 0.017 - 0.019. Had some shims around and was able to get the intake side into spec.

The exhaust side was all set to 0.016 (spec 0.019 - 0.021). Less success there. Got two cylinders to 0.019. Didn't have a shim small enough to get #1 into spec, and need to get more mentally prepared to start grinding down my $50 tool to get it onto #4 - and procrastinated because I didn't have shims the right size anyway.

One minor disaster - when removing the plugs so I could rotate the engine both helicoils came out. Apparently high temperature thread locker was not the right thing to use. Off to the auto parts store, got two more inserts and installed them with red high temp RTV. On the plus side this is what the helicoil's instructions call for, and what the disturbingly unknowledgeable auto parts guy said to use. On the minus side the note on the RTV said not to use in applications that got exposed to gas. We'll see how this works out. RTV is drying and I'm going away for the fourth, so I won't know until Sunday if the shim adjustment fixed my ticking sound.

[ScotcH]

Shims being too tight should not be that much of an issue, and if anything, I'd think ticking would come from too loose ... and that spec gap seems HUGE (we run 8 and 10 on the BMW engines ... but of course that's a different application .... ).

As for the heli-coils, is it just me or does RTV sound like it would act like an insulator, preventing the plug from having a good ground? If you ever pull the head again, I would think the proper fix is a timesert ... they will not come out, and are a much stronger repair. If there is room of course (I haven't looked at the fiat head in detail yet).

[aj81spider]

Good news and bad news: put everything back together and started it up. Ticking seems to be gone. The horrendous clanking I could hear with the stethoscope on the intake side is now a purr!

Unfortunately there was a serious blow by sound on cylinder one. Pulled #1 plug and the helicoil came with it again! Sigh ... That will be tomorrow's project.

I looked up the timeserts, but the tools cost more than a new head. The helicoil's create a good metal to metal contact at a minimum at the top where the expander tool (supposedly) drives them into the head.