lots of smoke on decel-good used head out there?

[ceylove]

Well, so far put 400 miles on my "new" '75 with it's used -no history available motor. All the smog stuff removed, no air pump, etc. After rebuilding the distributor (vacumme advance was bad, weights frozen at full advance, swapping carb, etc we've finally got it running well-then the smoke started.

it's really bad on deceleration-full on blue oil smoke. Hate to ask the obvious, but do I need valve guides or to rebuild the head? No budget for this now, but need to drive it. Tips on locating a good used head to get by on? Thanks

[kbmb02]

I've got a known E12 head which came off a (my) running street '02, stock internals, didn't smoke. Email if interested and I'll shoot photos and check height, etc. -KB

[Napes]

Considering the things you've done to get it running good I assume it was not running good before. Therefore, you might take it out on a 50+ mile drive with the tach up in the 4500-5000 range and then see if it still smokes the same. Doing the above cleans up my wife's ' 76 for a month or so, 'cause she mainly drives it a few miles at a time around town, and that's not what these engines like best.

Bob Napier

[ceylove]

Thanks for input. I just drove it 95 miles at about 75 (3800RPM-I have a 5 sp)

and it just got worse and worse. I need to do a leak down test in the next few days, but for now still driving it. Running well, not over heating, just keeping an eye on oil consumption.

[c.d.iesel]

i agree with Bob N. change the oil now

with 20w/50 and filter, continue to drive it

and go easy on the decel. keep a light pressure on the gas pedal

instead of letting off completely on decel.

this troubles me ...." valve guides or to rebuild the head? No budget for this now, but need to drive it ?"

"guides" and "rebuild the head" is one and the same.

and i don't know how you do any of it for free.

[ceylove]

Guess I should have said "no more budget till I recover "-in last few weeks I painted the car, did interior, suspension, brakes, etc. Just took delivery of the car Christmas Eve- seller represented motor & mechanicals as good used & driveable. It's proving not to be the case -I'm at the beginning of a long term project. And...No-not expecting anything for free! Eventually-after I replace everything on the tired worn out car it will a good driver

[thehackmechanic]

Smoke on foot-off-the-gas is the classic symptom of oil getting sucked past the valve guide seals (that is, depending on where everything else is in the wear cycle, you might be able to get away with just the seals). I'm remembering that there was a nifty trick to changing these with the head in the car, but I can't remember what it is... any takers?

[FunkyLaneO]

Smoke on foot-off-the-gas is the classic symptom of oil getting sucked past the valve guide seals (that is, depending on where everything else is in the wear cycle, you might be able to get away with just the seals). I'm remembering that there was a nifty trick to changing these with the head in the car, but I can't remember what it is... any takers?

I know there are tricks for alot of other cars but I was always under the impression the heads had to come off our little cars to replace the seals, if there is a way I would love to know it.

[c.d.iesel]

the head does need to come off for

valve seal replacement - and also consider

wear , warpage, burned head gasket, carbon,

poor valve/seat sealing - all reasons for the head

to come off for 'attention'.

So you fix the oil smoking (just replacing the

valve seals and nothing else) and now you run the car harder

because of the regained confidence - but now you stress

the head and other details which are still in the old weak

condition - and now you have more work to do - head comes off

in the end

[Lars]

My old 75 had the same problem. Until the engine went, probably not caused by this, it just had issues.

Be careful when cruising along and you see a cop and let off, it is a dead give away. I learned to spot them well in advance and eased off.

If valve guides are worn, other things are probably worn too.

[nbristow01]

My unprofessional opinion is the valve seals. My mechanic says he does seals with head in place. Pumps the cylinder with compressed air and keeps it compressed while he doe sit. Never done it myself so no personal experience. My mechanic works on most of the Dallas 02s I know of, so he is reputable

[Duncan2Turbo]

My unprofessional opinion is the valve seals. My mechanic says he does seals with head in place. Pumps the cylinder with compressed air and keeps it compressed while he doe sit. Never done it myself so no personal experience. My mechanic works on most of the Dallas 02s I know of, so he is reputable

That is exactly right. I haven't done anything that dumb since I was a kid.

Roll the engine over until both valves are closed like you were adjusting the valves.

Unscrew the line off compression gauge attach to air line fill cylinder with shop air and if you have the right tool you can do it.

I used to have one for motorcycles but I wouldn't consider this anymore.

Learned a few things in 20 years.

[ceylove]

Ceylove here-Well, did leakdown test yesterday and the motor is just plain worn out. Presented to seller as "good running used motor" he did a compression test and was satisfied. I've never liked compression tests only as diagonistic tool. The leakdown, which we did on 2X for verification, showed #1 cylinder=16% leakage, #2-78%, #3-70%, #4-55%. So, basically I'm running on a one cylinder motor! most of the air escaping through the bottom end, but oil smoke on decell tells me there's plenty swimming by the valve seals and guides, or lack of them. I was given a rebuilt head as a band aid fix. I'll put it on and see what happens. I'll drive it till it fails, then start fresh and build the good motor I've always wanted. BTW -we did a compression test as well while we were doing the leak down test and got: 160-135-150-160 which the seller thought was fantastic! He said anything over 120 he considers a good motor, but I fear he's missing the point it's not just the highest number here that matter but the variance between cylinders-? I'm open to other POV if I've got all this wrong-Thanks

[TobyB]

most of the air escaping through the bottom end

bad rings will also cause smoke on decel.

t