scottv8

Hello all,

Hoping those wiser than me might be able to impart some ideas please.
I realise a diagnose over the web is not ideal but i am a little stumped on this one.

Olds Holiday 88 fitted with original 324 Rocket motor.

I bought the car a year ago, was told that the engine had done 4k miles on a rebuild, all was well (now done around 14k).
Did not use the car for three months over winter, had the original Rochester 2gc carb cleaned and rebuilt, changed the oil / filter changed but not done anything else to the engine.
Started using the car again this year and I now have Blue smoke.
Starting from cold with the auto choke on, there is no smoke at all!!
Fast driving / high rpm, there is no smoke at all either!!
When warm (choke off) at tickover i don't get any smoke, i get a heavy mist (not dense) of blue smoke from both independant tail pipes (although the left more than the right) when revving or pulling away and up to around 30 mph, then it clears to nothing.
A mate followed me for over 100 miles yesterday and he said on the motorway the exhaust is clear, even with kick down overtaking!!

I originally thought there was smoke all the time so suspected the rings, but not now i know its clear at higher revs.

Thought maybe valve stem oil seals, but surely that would smoke on cold start up!?

Rocker breather is clear and there is a little smoke from the block breather but nothing heavy.

Any ideas or suggestions, greatly appreciated.

Thank you in advance, Scott

pmathews

It sounds like, when under high vacuum, it's pulling oil into the cylinder that is being burnt upon acceleration. I was thinking 'valve guides', too, but like you said, it's not burning upon cold startup.

How about this theory: the oil drain back holes in the heads could be partially plugged, maybe with pieces of broken valve stem seals, so the oil could empty back slowly into the oil pan at night. But, during warm idle, oil is pooling on the heads and under vacuum, it's leaking past the valve guides?

If that's the case, it would be an easy fix, just pull the valve covers and clean the drainbacks. You can add new valve stem seals without pulling the heads using compressed air.

That blue smoke is coming from somewhere.

scottv8

Thats sounds feasible and a good idea.
Im just about to make sure the breathers are clear and while im there, i will check the drainbacks.
I have done seals on a Rangerover before with compressed air, I made a tool from an old spark plug by drilling the centre out and welding on a air line coupling.
Im sure ive still got it but I bet its not the same plug thread though :-(

Thank you for your time and suggestion, I will let you know how i get on.

scottv8

Ok......so the plot thickens!!!!
May have uncovered a secondary problem!!

Oil filler cap breather clear, can't get to the block breather without removing the inlet and valley pan but a light wisp of smoke does come out of it on hot tickover so i suspect thats clear.
Any breathers i've missed?

Took the rocker covers off, oil ways clear, no debris and valve train all clean and looking like a recent rebuild.

So, decided to do a compression check, all good bar one cylinder:
2 = 140lb 4 = 80lb 6 = 151lb 8 = 160lb
1 = 155lb 3 = 158lb 5 = 158lb 7 = 161lb
Obviously there is an issue with number 4 and maybe number 2, rings? valve seats? Wont know till im in there.

Now, here's the rub.......the low reading side of the engine does not smoke as much as the high reading side.......so im thinking the low number 2 and 4 are not the cause of my smoke, rather an issue on thier own......

So basically, im still stumped :-(

Next step for me i think is to change the valve seals as that's easy to do now, and see if that stops the smoke. It's got to be something common with both banks as i get smoke from both exhausts (they are totally independant) although i get more from 1, 3, 5, 7 bank than the other side.

Obviously a complete strip is now definitely on the cards for the winter, hardened valve seats, valve guides, bore hone and a set of rings.........something to look forward to... :-(

gs72

If it has a vacuum modulator on the trans (if it is an automatic), the diagram could be ruptured allowing trans fluid the be pulled into the intake. If the trans fluid is low that could be the source of the smoke. The low compression on #4 is another matter.

scottv8

Yeah, im ignoring the number 4 thing till the winter, its the smoke that is really embarrassing, so to stop it would really make my day.

Not sure on the modulator, its got the Hydramatic box, i can't see any inlets to the intake, apart from the obvious ones that go to the vacuum tank under the driver's floor, to the wipers, via the fuel pump and to the distributer.

Would the modulator one be as obvious if its there?

scottv8

Valve stem oil seals and rocker gaskets ordered, gonna be a couple of weeks as there aren't any on the UK.
Once installed and driven, I will update.......hopefully with a cheery smile and an all is well......fingers and everything else crossed :-/