300 compression?
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300 compression?
Hi guys, I have an 88 econoline van with the 300 in it. I.m trying to do a compression test with one of those hold in testers. What should I expect for compression on this engine? Its got 230,000 miles on it. Thanks.
Elder User
Joined: Sep 2003
Posts: 926
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From: SE, Michigan
I did one on my 82 F100 with the 300 a few weeks ago, heres what I got:
1. 155
2. 155
3. 135
4. 150
5. 90
6. 140
So I know something is wrong with my #5 cylinder. This engine has over 314,000 miles, so there is going to be some wear. I'd say if your numbers are all
150 and over your good. Also if you want to go a little further with it, after you check all 6 cylinder if any are low, pour a teaspoon of oil into the low cylinder and see if the compression comes up. If it does then the rings are worn. If not its the valves.
1. 155
2. 155
3. 135
4. 150
5. 90
6. 140
So I know something is wrong with my #5 cylinder. This engine has over 314,000 miles, so there is going to be some wear. I'd say if your numbers are all
150 and over your good. Also if you want to go a little further with it, after you check all 6 cylinder if any are low, pour a teaspoon of oil into the low cylinder and see if the compression comes up. If it does then the rings are worn. If not its the valves.
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So... found a screw in type gauge and cold they all read about the same. 125-130. I'm tempted to let it go like that. Would there be much difference between a cold and hot test? Thanks for any replies, Ron
Postmaster
Joined: May 2002
Posts: 3,241
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From: Broken Arrow, OK
The teaspoon of oil test isn't very good on the EFI engines. At best it's inconsistent because little, if any, of the oil you put in will actually make it to the rings. The dish in the piston is 33cc and there is not a direct path for the oil to take to the rings.
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Thanks alot guys, I need to get this old van from the nw corner of wash. to east texas. I'm gonna do the clutch and change all the fluids, maybe a new radiator. A post I read on here has got me thinkin' about the timing gears too. Any suggestions with all that? How long can fiber timing gears last anyway? Thanks again, Ron
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