Got lots of miles and dont know what to do next?

PKRWUD · 09-01-2001, 07:26 AM

Jeff is right, partly. The very first thing you should do is to check the compression, twice. Dry the first time and wet (add three oil can squirts of motor oil into each spark plug hole just before testing each cylinder) the second time. If there is a big difference between the dry readings and the wet readings (25psi or more), your rings are going bad. The higher the psi difference, the worse your rings are. If the difference is 35 psi or more, it's time to rebuild. If the difference is 25 psi or more, do not install new heads. Doing so will tighten up the top end, which in turn will put more pressure on the rings, and accelerate their wear. This in turn will allow for oil contamination, which will accelerate wear on everything the oil touches, including your new heads, valve guides and rockers, not to mention increase the cylinder's out-of-round, which, when combined with the added pressure, will lead to cracked piston skirts (see below). If your psi difference is below 20, then heads and an intake would be fine. A cam and a new timing chain set would be nice too, but with that many miles, you may want to opt for a set of 1.70 rockers instead.

Take care
~Chris

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09-01-2001, 07:26 AM	#1
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Jeff is right, partly. The very first thing you should do is to check the compression, twice. Dry the first time and wet (add three oil can squirts of motor oil into each spark plug hole just before testing each cylinder) the second time. If there is a big difference between the dry readings and the wet readings (25psi or more), your rings are going bad. The higher the psi difference, the worse your rings are. If the difference is 35 psi or more, it's time to rebuild. If the difference is 25 psi or more, do not install new heads. Doing so will tighten up the top end, which in turn will put more pressure on the rings, and accelerate their wear. This in turn will allow for oil contamination, which will accelerate wear on everything the oil touches, including your new heads, valve guides and rockers, not to mention increase the cylinder's out-of-round, which, when combined with the added pressure, will lead to cracked piston skirts (see below). If your psi difference is below 20, then heads and an intake would be fine. A cam and a new timing chain set would be nice too, but with that many miles, you may want to opt for a set of 1.70 rockers instead. Take care ~Chris ------------------ Retired Moderator MustangNet My site: JimPorterRacing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!!