North American Turbocoupe Organization

Full Version: Major blowbye. Is it the rings?
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Hey guys after pulling off my head and having it completely checked from top to bottpom and pressure tested and also putting in the best pcv on the market, it leads me to believe the problem is my rebuilt short block. I looked at my rebuild receipt and the guy put in Sealed Power Chromoly rings. I went to a local parts house and the guy told me I had the wrong rings. He said I should have used Moly rings instead because they seat better and faster. Is he correct? If so, what brand is best and seal the fastest? Thanks
Chromemoly rings do take longer to seat. They are harder due to the chromemoly surface on the ring face. I have always used moly rings. Because they do seat faster. As for sealing better, once the chromes are seated they should seal just as good as the molys. If I were you I would put some more miles on the engine and see if the rings are going to go ahead and seat. Say at least 1000 miles. If they have not seated by then, then I would be looking at a tear down and replacing the rings. Hope this helps...Tommy

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Tommy Moore

Code 33 Silver Blue Clearcoat Metallic 1987 Turbo Coupe, Shadow Blue interior, 5 Speed, Gillis valve, Hurst shifter, 140 mph speedo, Auburn Posi unit with 3.73 gears, Flowmasters, KYB struts, shocks , and quads, 2nd and 5th owner of the car. I just had to buy it back.
Tommy, I cant wait that long. My car is a daily driver and when I drive it just 30 miles, my oil catch cam is 3/4 full and I have oil blowing all over my motor from the dipstick tube. I already have the head off and the macine shop has agrred that it is the rings. I just want to make sure I get the right rings and they seal quickly.
Just curious -- at a warm idle what happens when you take the oil filler cap off the valve cover?

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-asi

1986 TC, 132k pretty well taken care of miles. k&n, gillis@16, timing @ 12 (spout out), A/C delete. 3" Downpipe (no other exhaust... Whoever described that sound as a "pissed off tractor" hit the nail on the head)

[email pics to asimov at forced-induction org for sales/id/showoff purposes (free hosting)]
I get suction at idle from the valve cover at idle.
Most bang for the buck on a daily driver would be a good set of molys, like Speed Pro, TRW, or Sealed Power. Hope this helps...Tommy

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Tommy Moore

Code 33 Silver Blue Clearcoat Metallic 1987 Turbo Coupe, Shadow Blue interior, 5 Speed, Gillis valve, Hurst shifter, 140 mph speedo, Auburn Posi unit with 3.73 gears, Flowmasters, KYB struts, shocks , and quads, 2nd and 5th owner of the car. I just had to buy it back.
Do a leak down test
The guys at Turbord are kind of confusing me. Is there Chromoly and Moly rings or are moly and chromoly the same thing?
Quote:Originally posted by RDOG:
The guys at Turbord are kind of confusing me. Is there Chromoly and Moly rings or are moly and chromoly the same thing?

They are 2 different type of rings. One having a chrome face on the rings and one having a moly face on the rings. The chrome is much harder and takes longer to seal than does the softer moly. At least that has always been my understanding of it. I do know that they look different. I have seen molys and chromemolys side by side, and they are different...Tommy
Quote:Originally posted by RDOG:
The guys at Turbord are kind of confusing me. Is there Chromoly and Moly rings or are moly and chromoly the same thing?

Here is a link describing the difference between the rings and what they said...
www.customrodderweb.com/tech/cr1101_enginerebuildb/

Honing: This process establishes a pattern in the cylinder walls to hold lubricant and help the rings seat. There are three types of rings: cast, chrome, and moly, and each require a particular cylinder wall finish. Cast rings break in fast and are good for less than perfect cylinders, often these are the only type available for older engines. Chrome rings are best suited to dirty environments but can take a long time to break in, these were once considered "performance" rings, and may be found for some older engines that were commonly hot rodded. Moly rings (called that because the face of the top compression ring has a groove filled with molybdenum disulfide) break in fast and provide excellent sealing but have limited applications for older engines.
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