Ring gap

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Jun 8, 2006 | 10:16 PM

Ford_Six

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From: The Big, Oregon

Ring gap

Hey guys- almost done with putting my 300-6 together, except one thing-
What is the ring end gap supposed to be? I seem to have misplaced my specs on that-

Jun 9, 2006 | 08:00 AM

Silver Streak

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From: Broken Arrow, OK

The specs I have at work don't go back very far. The earliest specs I have say 0.010-0.020 on the compression rings and 0.015-0.055 for the oil rings. That seems pretty tight on the compression rings, but that's what all the years say. In later years the oil ring gap is shown to drop to 0.010-0.035.

Jun 9, 2006 | 02:52 PM

Ranger GT2

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From: Indiana

What year motor you working on? I have a Chilton truck manual that goes back to 65.

Jun 9, 2006 | 10:59 PM

Ford_Six

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From: The Big, Oregon

The lower end is from an 80 F-100 emissions engine.

Jun 10, 2006 | 02:30 PM

Ranger GT2

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From: Indiana

Sorry it took a while to get back with you. We have been working a lot of overtime.

For a 79 - 84 300 six motor the top and bottom compression ring gap is .010 - .020. The oil control ring gap is.010 - .035.

Do you also need the ring side clearance? It is .0019 - .0036 for the top compression ring. .0020 - .0040 for the bottom compression ring.

Hope this is what you need.

Jun 11, 2006 | 07:16 PM

Ford_Six

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From: The Big, Oregon

Ok, my ring gaps are a little on the loose side. I'll run this engine for now, but it won't be seeing boost. I'll build a whole new engine for that.

Jun 11, 2006 | 07:53 PM

kotzy

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Rule of thumb from Perfect Circle way back when, compression rings .003 to .004 of an inch per inch of cyinder bore. I think the cast iron oil ring was the same, it is impossable to check the three segment oil ring gaps. In most cases you will find the gaps greater, unless you pay for a semi fitted set and then file the gaps yourself. As I stated on one of the forms about gapless rings, I have a old Dykes Automotive Encyclopedia the various gaps tried to prevent leakage is hard to believe, and now 75 years later we still use the straight ended ring. They simply don't leak that much.