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Preparing cylinder heads for marine application

Old 12-03-2018, 02:38 PM
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Originally Posted by Full Force
guide, but some valves are machined a tad smaller like AFR valves.
Yes I've just measure my valve stems @ .341 and the guild @ .343-.344 across the board.
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Old 12-03-2018, 03:56 PM
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You using a split ball gauge and micrometer.
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Old 12-03-2018, 04:25 PM
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Originally Posted by getrdunn
You using a split ball gauge and micrometer.
Micrometer for the diameter and I have a set of ZZ class pin/plug gauges to check the guides, a slight variation in size but was amazed how parallel they where. Split ball would be nice but my smallest one is for the lifter bores.

Last edited by Camalot; 12-03-2018 at 04:28 PM.
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Old 12-03-2018, 05:48 PM
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Sounds like your on the right track anyway and at the very least understanding the importance of the clearance. The old school marine truck engines seemed to run flawlesssly without marine prep however that was before any real power stated to come into play. Then again at least some if not several didn't even have oil coolers. I ran over 60 miles wot at 4,600 with no issues. Bone stock 78 boat. Water temps 50/60 deg.
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Old 12-03-2018, 08:20 PM
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Originally Posted by getrdunn
Sounds like your on the right track anyway and at the very least understanding the importance of the clearance. The old school marine truck engines seemed to run flawlesssly without marine prep however that was before any real power stated to come into play. Then again at least some if not several didn't even have oil coolers. I ran over 60 miles wot at 4,600 with no issues. Bone stock 78 boat. Water temps 50/60 deg.
Yes I do understand importance of clearances but wasn't sure what the "marine" standard was. Funny you should mention your truck engine. This year I was trying cams and home grown risers on a stock 310 7.4 Gen vi, I had a simple RPM to 02 deta log on it. 40 hours at plus 5000 RPM and 15 hours at 5500 RPM. I'm not saying it would live a long and happy life but it did live and was happy or did it live and I was happy 😊. Either way it was great data to take for the new build and learnt a lot about reversion why it happens and how to stop it.
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Old 12-02-2023, 12:52 PM
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Originally Posted by dunnitagain
Ive always cut my seat widths to .040 on intake , .060 Exhaust . I also hit them real lightly with a lap stick and fine compound.
The powdered metal seats when cut that narrow with a dead pilot cutter , tends to not have real sharp defined angles .
With the good powdered metal seats they will spread .010 to .015 each after a few hours hard running , and seat in very well.
They also work harden as they break in. Powdered seats are a win/win system. Easy to machine, best to break in and seal.
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