Question regarding the 351W
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Senior User
Joined: Nov 2010
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Question regarding the 351W
I have located the 1984 351W HO that I have been on the hunt for and my question is what would be an exceptable compression check. I dont want to rebuild unless it is absolutly a must. I thought in the range of 120#s + would be exceptable especially if the readings were with in 10#s of one another.
Any opinions appreciated.
Any opinions appreciated.
Cargo Master
Joined: Jun 2001
Posts: 2,571
Likes: 22
From: Oxford, Indiana
I agree completely with Wayne, but I will add that compression is but one indicator of an engine's condition. Knowing what the oil pressure is both hot and cold is also a major indicator. I've seen a few with good compression and worn bearings. If you can hear it run and watch the oil pressure on a good mechanical gauge, then that's ideal. If not, I wouldn't feel quite right about putting it in without pulling the pan and havintg a peek at the bearings.
Lead Driver
Joined: Aug 2006
Posts: 8,093
Likes: 652
From: Brentwood, TN
Years ago I invested in a Snap-on leak down tester and have never regretted the purchase. With this tester you apply air pressure to the cylinder and then monitor how fast it leaks down. Not only do you get an indication of the condition of the rings but also the seating of the valves. If the leak down fails but the compression looks reasonably good then you know that you have a top end issue. I agree with BOR, I seldom will install an engine without first pulling the pan and inspecting the buildup in the pan and taking a look at the bearings. Even if the bearings look good you can always check the stamping on the backside and see if they are undersized indicating some rework in the engine's past life.
Senior User
Joined: Jan 2011
Posts: 369
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From: Indiana
In my opinion, as cheap as bearings are I would say get some new ones anyway. It is cheap insurance. The leak down test is a good one. Compression test only tells half the story. 10%...that could mean up to a 15lb difference. If this is an original setup to the best of your knowledge, it probably has some miles on it, so 10% is realistic, but know it probably will need gone through in a few years. Just my opinion and experiance.
