Going to do a leakdown test this weekend but suspense is killing me. Car smpkes pretty good. Particuliarly at start up and heavy excelaration. After startup and normal driving not too bad. Has 70k original on 351c 4V. Sat for about 10 years until body restore. Runs pretty strong other wise. Hoping just selas - Any bets - seals, guides, rings?
Valve Stems Selas or Worse?
- Thread starter palerider94
- Start date
-
Sponsors (?)
TD68302
New Member
JDS68Stang
New Member
Could be all of the above, especially if it has set a long while. I had a 76 Monte Carlo that had the symptoms you descibe, I bought new seals, popped off the valve covers and the drain holes turned out to be clogged really bad. Cleaned them first, reinstalled the covers and she didn't smoke no more. Didn't need the seals after all.
Sticking rings I would try an additive first in the oil and run it real hard, take it up on the highway and wind it out about 4-5 times. I cured a Dodge vans sticking rings by doing this in the past as well. Other heavy smokers I wasn't so lucky with but these ideas have worked for me in the past with a few.
Sticking rings I would try an additive first in the oil and run it real hard, take it up on the highway and wind it out about 4-5 times. I cured a Dodge vans sticking rings by doing this in the past as well. Other heavy smokers I wasn't so lucky with but these ideas have worked for me in the past with a few.
Shade tree mechanic 101:
1. Smoke under acceleration...............rings
2. Smoke under decceleration.............valve guides
3. Engine knock under acceleration.....BOSS-302 broken piston noise
4. Engine knock under decceleation.....wrist pin
5. Engine knock all the time................big-end rod bearings
StangDreamin'
Founding Member
Seen any "lumps" in old oil as you drain it? Investgate the lumps to find they were very brittle "half-cylinder" shapes, that were never more than 1/2" long? Do your rocker cover gaskets leak - a lot?(Like the oil isn't draining out of the top of the heads very well?)
One last one, does she belch out a puff of smoke on startup?
You said smoke on decelleration; couple that with any one or two of the above questions; and I bet "stem seals +2".
Been there, done that. Not that hard a fix on the Cleve, as I remember.....
One last one, does she belch out a puff of smoke on startup?
You said smoke on decelleration; couple that with any one or two of the above questions; and I bet "stem seals +2".
Been there, done that. Not that hard a fix on the Cleve, as I remember.....
ratio411
Founding Member
I would say valve seals (umbrellas).
They can dry rot even when the car sits idle for a couple years.
After 10 years of sitting, they are probably toast!
Keep optimistic and swap those out first.
There is probably smoke from valve guide wear too, but it is only heavily magnified when the seals are bad. Might clear up 80% or better with umbrellas.
They can dry rot even when the car sits idle for a couple years.
After 10 years of sitting, they are probably toast!
Keep optimistic and swap those out first.
There is probably smoke from valve guide wear too, but it is only heavily magnified when the seals are bad. Might clear up 80% or better with umbrellas.
Valve seals, the stock umbrellas are notorious for rotting in place after sitting idle. Even running, they eventually "cook" and do the same thing. The 68 Merc I had unitll last year sat for long periods (it had 58K on it when I bought it back around 02-03) When I took the heads to the machineshop after it popped a head gasket and ran 300* all they needed after 34 years was new seals.
Similar threads
- Locked