Thread: 72elk

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Originally Posted by States

Got the block back from the machine shop, washed out, squared, new Cam bearing, new soft plugs and a fresh hone. Machinest says for best reliability I should use cast iron rings, any thoughts? Also got in the Yukon Posi and Richmond gears to be installed on the 15th. Looking at getting a Scat crank and Speed Pro competition main brings as well. Any input on these selections would be appreciated.

Let's let Hastings clear the air for you concerning ring composition.....
https://www.hastingspistonrings.com/...ecommendations

You should also know that different compositions require different hone finishes on the bore. Cast iron requires a rougher finish and in my opinion, will not last as long as a moly-faced ring which requires a smoother bore finish. Ask the machinist for an estimate in his opinion of the service life of cast iron versus moly-faced. If he says the moly rings will last longer, but require a smoother bore and are more expensive, then it is up to you as to whether or not you want so spend the additional jack for additional service life. I would expect a cast iron ring rebuild to have a service life of 60,000 to 75,000 miles, while I would expect a moly ring rebuild to have a service life exceeding 100,000 miles. I'm not sure what the OEM's are using for piston ring material, but my 2004 Ford F150 SuperCab has over 235,000 miles on the little V8 motor, uses very little oil and still has good power.

As far as ring width, that is governed by the width of the ring grooves in the piston. In the past, you could order either 1/16" (0.0625") or 5/64" (0.078"). I have always preferred the wider ring for a daily driver and the narrower ring for a strip or street strip motor. The narrower the ring, the less tendency it has to flutter (and lose seal) at higher rpm's because of its lighter weight. The wider the ring, the more surface area it provides to effect a good seal against the bore. Current thinking is to go with narrower rings, which will lend a little extra horsepower and therefore, mileage. Of course, if you are not changing pistons, then you will have to use the ring width you have now.

Don't know anything about Yukon, but have used Scat parts since Noah was a teenager. And of course, Speed Pro has been around forever.
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