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.

 

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.

 

Thanks for answer. I don't trust the gauge I'm using, its too hard to use. I'm going to see if I can come up with something better and if I do I'll post results later. Thanks again.

 

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

 

The official Ford method is the lowest should be no less than 75% of the highest.
130 X .75 = 97.5 Youre in good shape. Also, the lowest they put on a schedule they published is 101, so again you're fine.

 

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.

 

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

 

Mine are at 173,000.