low comp

[Anonymous-0]

I tried to relap the valves got better comp now but still not enough. I didn't put manifol on this time does it matter? old comp 30-35 lbs new comp {1}40 {2}50 {3}60 {4}70 all cylinders checked wet. anyone about how much it would cost for a mechanic to rebuild the engine? not sure whaat part of the country your in but someone should have a good guess..?? Thanks for the help Peace Shane

 

[Brian Bell]

When you had the head off, how did the cylinders look? Deep scratches, lots of wear? Also, are you 100% sure that the valves are sealing like they are supposed to? That could have be the issue...also did you replace your head gasket? What else have you done? Have you poured marvel mystery oil or ATF into the cylinders and let it sit to be sure the rings aren't stuck?

 

[Anonymous-0]

Yes I did all that I replaced rings and rod bearings, first time back together w/new gaskets I checked valve clearance, laped valves, ring gap ok, spacing correct, checked wet and dry comp 30-35 lbs took her down again double cleaned again, lapped valves again, they held fluid on top. exhaust valves are a little pitted but they looked to lapp good?? getting frustrated
with it Might have to take to a shop to cut new seats, all I can think of. Thanks for the help. Peace Shane

 

[Brian Bell]

How fast is the engine spinning? If the battery is weak, it will make a huge difference in the compression. Also, did you check to make sure that your head was fairly straight and not warped? I have seen them be so warped that they would not seal properly.

 

[Den N Ms]

Shane, what was the piston cylinder wall clearance?How much clearance did you have at the ring,piston ring land?It could be that the ring lands have too much ware.What was the ring gap clearance?

 

[Sean (TX)]

Want a new one?
http://www.agkits.com/index.asp?PageAction=VIEWPROD&ProdID=462

 

[duey]

I don't think I'd care one little bit about what the compression is until maybe it had 25 hours on it. And if it doesn't want to start, I'd PULL IT and get it running, several times if necessary.

And even then, if it starts and it runs and it gets the job done, well, who really cares what the numbers are? Shane, don't get "wrapped around the axle" needlessly,

My Opinion, duey

 

[Dell (WA)]

Shane.........first you write........."how much it would cost for a mechanic to rebuild the engine?".......and then you tell us........"I replaced rings and rod bearings, first time back together w/new gaskets I checked valve clearance, laped valves, ring gap ok, spacing correct, checked wet and dry comp 30-35 lbs".........What do you think an engine rebuild by a mechanic consists of??? And why is that "different" from yer shadetree rebuild???

You don't suppose there is a relationship to your low compression and the fact you didn't replace the worn-out engine dry sleeves, do you???? ($80, cheap) They are meant to be replaced every engine rebuild.

Would it surprize you to learn you just can't drop-in some new rings in ANY engine without checking the cylinder bore for wear??? and expect good compression???

You need good compression inorder for engine to start and run. Ford specs: 90psi (dry) min. And yer reporting 30-35psi. As a rule of thumb, new rebuilt 8N engine compression should be about 120-125psi from the gitt-go before break-in.

Bottomline, yer el-cheapo quick'n'dirty shadetree overhaul didn't. Now you are willing to squander $1500 for a mechanic to fix yer $80 mistake. And that is exactly what he will charge you. 'cuz iff'n he don't fixx it right the first time, yer gonnna be on his buttt to make it right for free.

Ain't no biggie to R&R drysleeves; -100F dryice is yer friend. (yellow pages) We're really on yer side and are trying to help you, but you've gotta help us help you. We'll answer yer questions, you just ain't supply us with all the details without playing 20-questions..........respectfully, Dell