compression test looks bad, HELP

gingerbreadman · Jan 19, 2004

GaPonyFarm said:
If it just smokes when you start the car, it could be as simple as valve stem seals (a really simple repair). Does the car begin to smoke at very high rpms also, but not under normal conditions? This is also a sign of valve stem seals. The recommendation for a leak down test was a good one. The cylinder pressure test results looks pretty good, I'd start looking beyond the rings, to the heads.

Your compression numbers are very adequite in my oppinion, The valve seals are very cheap and easy to replace. i would try that,

My 85 f150 300 i6 with over 220,000k on the rebuild was burning a liter of oil every 1000 km thats roughly about what yours is burning... i replaced just the seals and it knocked the oil consumption down to 3/4 of a liter every 5000 km thats less then a quart every oil change.... dont need to add oil between changes.......

it will cost you a set of valve cover gaskets and a set of seals, maybe $20-$30. give it a try...

you do realize you can do it with the engine in the car and heads still on right??? ill explain the process to you if you need.........

-gbm-

GaPonyFarm · Jan 19, 2004

Probably wouldn't hurt to pull the heads for a fresh valve job. Its one of the cheaper things he can do and with some porting, some power is to be gained. You're right about checking the valve guides. Years of unleaded gas may have taken its toll..

gingerbreadman · Jan 19, 2004

GaPonyFarm said:
Probably wouldn't hurt to pull the heads for a fresh valve job. Its one of the cheaper things he can do and with some porting, some power is to be gained. You're right about checking the valve guides. Years of unleaded gas may have taken its toll..

its gonna cost ALOT more then just valve seals..... in my oppinion if you start doing a "top end" rebuild you mide aswell do the engine cause the bottom end is not far off..........

valve seals are cheap and easy to do........ to pull the heads and have them rebuilt its gonna cost hundreds apposed to maybe $30 to do the seals when chances are pretty darn good the seals are the culprit.........

-gbm-

68GEETEE · Jan 19, 2004

GaPonyFarm said:
If it just smokes when you start the car, it could be as simple as valve stem seals (a really simple repair). Does the car begin to smoke at very high rpms also, but not under normal conditions? This is also a sign of valve stem seals. The recommendation for a leak down test was a good one. The cylinder pressure test results looks pretty good, I'd start looking beyond the rings, to the heads.

The unfortunate story in all this is that the heads were rebuilt 2000 miles ago. The car at the time was at a shop and the guy working on it recommended doing the heads as there was a burned valve. I have no idea what kind of rebuild they did, they sent them to a machine shop, but the car now smokes on startup, it goes away in 15-20 seconds. I would have thought a rebuild would have included new seals and guides, I did ask for hardened seats to run unleaded gas. Like I said I have no idea how good of a shop did the repair. All the spark plugs are normal, no oil residue of any kind, another indication that the rings are ok, isnt it?

I have a spare set of 1968 4v 302 heads. Maybe I should have those rebuilt with the 3 angle valve job and such. ALso, the car has some type of performance cam in it, not sure which. Does a different cam affect the length of pushrods in the engine? Meaning do they need to be longer or shorter to work with a lumpy cam? Maybe whomever had the car before me didnt do the job right. Should this be a concern?

mustangracer · Jan 20, 2004

Most cheap head rebuilders just knurl the valve guides instead of replacing or resleeving. Knurling reduces the ID and then they ream it to size, but the knurling doesn't usually last very long.

SadbutTrue · Jan 20, 2004

those #s are fine

compression test looks bad, HELP

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compression test looks bad, HELP

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