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Posted by: MNnewbie Apr 13 2017, 04:05 PM

Looking for any advice I can get regarding a 1972 1.7 w 48k on the motor
It starts fine when its cold but once it has ran for 5-7 minutes and driven it starts blowing a lot of blue smoke. So much so that there are drop of oil coming off of the tailpipe. Have not checked compression yet -hope to tonight

Posted by: injunmort Apr 13 2017, 04:09 PM

need more. has it been sitting? comp check first, could be rings, valves etc, need more info

Posted by: Rand Apr 13 2017, 04:19 PM

Sorry for the dumb question, but asking to learn: How could blue oil smoke be valves? Wouldn't it have to be rings (or scarred cylinders)?

Compression and leak down test will surely reveal some answers, no question there.

Posted by: mgphoto Apr 13 2017, 05:45 PM

worn valve guides.

Posted by: Rand Apr 13 2017, 05:54 PM

Oof, of course. Thanks.
Back in the day when I was raising a family, we had a Dodge Caravan. It was of that era where they had valve guide problems. It would run clean, until you let it idle. Which was a nightmare at stoplights... It poofed a batman style smoke screen on takeoff.

Posted by: MNnewbie Apr 14 2017, 09:27 AM

The car had been driven last summer off and on for 4 months.
The last day I drove it last fall it had been running fine when suddenly the blue cloud appeared and I lost power. I figured that it was one of the problems that has been mentioned but when I restarted it this spring it ran- idling and revving the motor were ok, until I started to drive it.
Will do the various compression/ leak tests down this weekend and post results.

Posted by: mgphoto Apr 14 2017, 12:51 PM

Pull the spark plugs, check the condition, if oily black get a set of hotter plugs for the time being, she will burn the oil off.
Mike

Posted by: Perry Kiehl Apr 14 2017, 02:57 PM

Sounds like a broken ring to me, but anything is a guess.

I'd do a compression, leakdown, and vacuum test. One of those will point you toward the problem.

Posted by: injunmort Apr 14 2017, 03:36 PM

worn guides or mushroomed valves will allow oil into the combustion chamber, blue smoke to ensue

Posted by: MNnewbie Apr 24 2017, 09:28 AM

I finally got around to doing a compression check
120
120
120
90
Put a couple of squirts of in the 90 cylinder and got 95.
Which leads me to think its probably in the valve train.
Knowing what I am looking for and where to start should make it easier.
Appreciate the comments so far.

Posted by: Ansbacher Apr 24 2017, 09:36 AM

I had the same symptoms with my first 914 back in the eighties. Started good, ran good till hot, then smoked like a B-52 on takeoff. Turned out to be valve guide tube seals, as others have said here. Good luck.

Ansbacher

Posted by: The Cabinetmaker Apr 24 2017, 10:41 AM

Valve guide tube seals?

Posted by: MNnewbie Apr 24 2017, 10:51 AM

Thanks for the response

Posted by: Dave_Darling Apr 24 2017, 01:16 PM

No such animal.

There are pushrod tube seals, which leak oil down onto the heat exchangers and cause smoke to come up from under the car.

There are valve guides, which will generally cause smoke to come out of the tailpipe on overrun (throttle closed, coasting down from high RPM in gear). Other cars may have valve stem seals, whose failures would tend to lead to similar symptoms as this, but our 914s don't have them.

Smoke from under the car means an oil leak out onto the exhaust. Smoke from the tailpipe means a problem inside the engine.

--DD

Posted by: injunmort Apr 24 2017, 06:42 PM

there are no guide seals on a type IV. 90 is low and and adding 90wt brings up compression, i am leaning toward a ring issue not guide/valve. dosent matter though, to address either requires pulling engine and top end disassembly. to inspect and measure rings and piston/wall clearance. if the engine is not making any strange noise, probably rings, if it "ringing like a bell" maybe bore and piston.

Posted by: MNnewbie May 4 2017, 02:46 PM

I stalled out last weekend on removing the engine and tranny but have my confidence back and plan on doing so this weekend.
Any recommendations for a mechanic or machine shop in the St Paul Mpls area also appreciated.