Compression check 59 AB

B

BlueSunoco

Well-known member
See my post in the '6V vs. 12V ' Hard Starting thread I already started. Did a compression check and wondered if these numbers look OK to you guys--------

No. 1--85#
No. 2--90#
No. 3--85#
No. 4--85#
No. 5--100#
No. 6--105#
No. 7--95#
No. 8--105#
 
#120 is specs,your close, loose some power with those readings, but still will run good, go to VANPELTS Sales LLC for all the engine specs
 
WestCoast said:
#120 is specs,your close, loose some power with those readings, but still will run good, go to VANPELTS Sales LLC for all the engine specs
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Will do thanks guys. One Ford mechanic told me that 'flatheads won't start when they are tired' but he is a younger guy hasn't had much experience with flatties!!!
 
Just for future reference (based on what was stated on your other post) Ford cylinders are numbered starting with the right (passenger side) front to rear and then the left (driver side) front to rear. So, number 1 is the right front cylinder and number 8 is the left rear cylinder.
 
JSeery said:
Just for future reference (based on what was stated on your other post) Ford cylinders are numbered starting with the right (passenger side) front to rear and then the left (driver side) front to rear. So, number 1 is the right front cylinder and number 8 is the left rear cylinder.
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Thanks I should have remembered that from my years as a Ford parts manager!
 
Keep reporting on your progress. Many of use like these kind of stories, especially when we can see it through to completion.
Many times we only get to see the beginning of the mystery, not the end of the movie to find out "who dun it".
Just an opinion
 
BlueSunoco said:
Will do thanks guys. One Ford mechanic told me that 'flatheads won't start when they are tired' but he is a younger guy hasn't had much experience with flatties!!!
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I'm no longer a 'younger-guy', and I'd say the same thing. Working in a garage and used car lot back in the 50's, we pulled or pushed many a Ford to get them going the first time. If started daily after that, they would usually start on their own.

BTW, the spec may be 'up there', but my experience says your numbers are good. I've never seen a stock engine at 120.
Might have to define what a compression test is. Lots of definitions, with varying results. Still, good numbers, no matter how you did it.
 
Were those numbers obtained without adding oil into the cylinders ? What are readings if you add oil ?
 
Drbrown said:
Were those numbers obtained without adding oil into the cylinders ? What are readings if you add oil ?
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Good questions. I just did it the way my dad told me many years ago and didn't think much about it---- Did not add any oil in cylinders or such.

Started engine and brought it up to temperature. Then, I took the spark plugs out of 5-6-7-8 (left side bank one at a time and did the compression check. After cranking it to get those four cylinders I got the idea of leaving all the plugs out to make it easier on my starter and four year old battery. Then I did 1-2-3-4 (right hand bank) At this time I thought 'well, maybe that skewed my first readings so I went back and redid 5-6-7-8 and got the same readings I got the first time.

Started good cold but same no-start after warmed up. I'm going to recheck the coil and take the condensor over to Radio Shack and have it checked as a Fordbarner suggested earlier.

Will post the results of what I found. Has to be a pansy spark as when I hold the coil wire to ground it is a dribbly weak looking yellow spark. May also change coil wire that was a thought too. Pos. and Neg. wires to coil are in very good shape no broken insulation or anything of that sort!
 
Not related to your hard starting problem but your group of (slightly) lower (10 to 12%) compression test results on the right side MIGHT relate to a poor head gasket there. Probably not worth addressing unless those numbers decrease in the future.
 
Drbrown said:
Not related to your hard starting problem but your group of (slightly) lower (10 to 12%) compression test results on the right side MIGHT relate to a poor head gasket there. Probably not worth addressing unless those numbers decrease in the future.
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Thanks I kinda thought that too------------
 
BlueSunoco said:
Thanks I kinda thought that too------------
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I would find it odd that all four cylinders would have the same lower reading due to a bad head gasket.

Usually one of two cylinders are bad (leaking between them). I've never seen four cylinders go bad . . . and if bad, they are usually REALLY bad. Just my observations . . . not trying to step on toes.

B&S
 
Bored&Stroked said:
I would find it odd that all four cylinders would have the same lower reading due to a bad head gasket.

Usually one of two cylinders are bad (leaking between them). I've never seen four cylinders go bad . . . and if bad, they are usually REALLY bad. Just my observations . . . not trying to step on toes.

B&S
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Not stepping on any toes here;) I appreciate all the comments !
 
Just wondering why it seems that nowadays no one does both a dry and wet compression test,when i was turning wrenches my service mangr. would insist on both, as well as did the factory( jaguar and maserati)
 
robert dick said:
Just wondering why it seems that nowadays no one does both a dry and wet compression test,when i was turning wrenches my service mangr. would insist on both, as well as did the factory( jaguar and maserati)
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Robert, not familiar with a wet test I assume some motor oil down each cylinder?? Thanks.
 
That would be the case, the oil improves the seal of the rings and will increase the reads on an engine with weak ring seal.
 
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