Less Depressed

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Posts: 32
Joined: Mon Oct 01, 2018 2:08 pm
Location: Calgary

Less Depressed

Post by steveO » Fri Oct 11, 2019 3:21 pm

Changed the head and base gaskets on both barrels as slight oil weeping. (1985 ish G% engine)
The bores and heads are virtually unworn as they should be at only 11,000 km. Some wear on one valve stem, but not enough to need replacement.
I was expecting some valve seat recession from previous owners not using leaded fuel or an additive, but none at all. Guzziology states no lead additive is required as standard valves and seats are hard enough to withstand. One inlet valve does have a ridge above the seat area, I believe this is recession and will change the valve at a later date. All valves lapped in ok. The worst issue was the amount of carbon build up on the heads of the inlet valve. I had to file it away and then polish all in a lathe. I did one barrel at a time and started the engine after each barrel was completed. This enabled heat soaking cycles and the head bolts to be retorqued. Quite a lot of gasket compression resulted from the heat cycling.
The car now sounds so much crisper. It will need a retune of the carbs as the carbon build up was chocking the intake. I use an old colour tune I have had for years and works really well. Balance with an electronic balancer. Will also check timing (electronic from Germany, no distributer) while at it.

One thing I got from Guzziology is the rocker can be wrongly installed on early round barrel engines. The rocker must be against the lower support of the cradle with the spring above and then the bronze washer against the upper cradle support. Apparently many are assembled wrongly.

Guess now I will have to check my MG Convert for inlet carbon and do it all again.


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