blue smoke when warmed up, new rebuild on engine

[Ron]

As some of you know, I've been trying to bring my 230SL back to life.  Purchased with engine out of car, I've gotten everything back together and it now has about 600 miles on it.  At about 500 miles I got most of the issues with the adjustments corrected and the exhaust ran clear for a few miles.  ( previous issues were: steam caused by under torqued head, black smoke caused by too rich IP) 

Now it starts with clear exhaust from cold.  About 20 minutes, when really warmed up, it runs blue.  Both pipes.  The engine had a professional rebuild from a machine shop by the PO, I have the paperwork: new rings (standard, Hastings), new bearings, cylinders honed, original pistons, head done with all new valve seals and with guides as needed.  One valve was replaced, the rest ground.

The car runs great. 

Where should I start looking?  I'm thinking maybe the IP, with the 20 minute delay.  Could it be that this IP pump, or any worn pump, would put oil into the gas?  I know this thing has a line to the oil galley from engine.  So maybe that is causing oil burning? 

This IP is the wrong pump: it has a R18 pump, it is supposed to be R11.  I hope to get a R11 pump, but wonder if this would help with the oil consumption issue.

Thanks,  Ron

[ja17]

Hello Ron,

Run the car and continue reading the spark plugs. If oil deposites show up on the spark plugs, the issue is the rings or intake guides.

I suspect it is a exhaust valve guide problem.  When an exhaust guide is loose in the engine or leaking oil, the oil never enters the combustion chamber. Oil drops through the guide and into the exhaust port of the head. The exhaust stream then carries the unburnded oil out to the exhaust. As the exhaust system warms up, the oil then burns off and leaves as blue smoke.

Remove the valve cover and take a flashlight and closely look at all the valve seals and guides, especially the exhaust guides and seals. I think you  will find your problem.

[hands_aus]

Hey Ron,

How does the injection pump get its oil supply from the engine and how does the excess oil return to the engine?

I ask because I see you say you have the 280sl Inj pump on a 230sl engine.

Thanks

[ja17]

Hello,

Good thought, on the injection pump. Most likely the oil is supplied to the pump as on a 280 and excess is still drained of fat the front end of the pump and into the engine block. Worth looking into.

[Ron]

Sorry, I've been away from the net. 

The injection pump has an oil feed from the block.  There is no return line, so I'm thinking it is what Joe said, oil is returned via the front of the pump. 

I did take the valve cover off, and had a look at the valve seals.  They look like white plastic, they all look like they are in the same place.  Am I looking at the correct thing?  Also, I noticed drops of water, about 5, in there.  I last ran the engine for only 20 minutes, but I don't think that's a good sign.  I'm beginning to think head gasket, since it takes 20 minutes from cold for the blue smoke to start.

So I've located an R11 pump from a salvage yard, but it'll be a while before that's done, I'll have to go through it before installing.  And I've got some head gaskets ordered.  My engine is made up of these parts:

block:  127 010 4100
head:   127 010 5020
pump:  R18

Should I start off changing the head gasket?  Ugh!

Ron




Where to start?

[Benz Dr.]

You have the wrong pump which is your first problem. Install the right one and see what happens.
You will be running far too rich so keep an eye on your oil level and if there's gas in your oil.
Most smoking on rebuilt engines will be caused from cylinder head problems. Improper valve geometry is the usual cause.
I've been tricked by smoking exhaust before. In this case the engine was rebuilt and the old exhaust was replaced. All of that oil that used to go into the pipes suddenly had to be burned away and it smoked a lot. It can take an hour or more before the smoke will clear away and the oil to get burned up.
The thing to look for is continued smoking long after this should or could be ant sort of issue. After 500 - 600 miles the engine should be broke in so you should have a clear exhaust by now.

[Ron]

Hi Dan, thanks for your comment.  The car did blow a lot of blue smoke when first started after putting back together.  But after the first couple of drives, it didn't have much blue smoke.  I think that initial start was the garbage stored in the exhaust pipe burning out.

I've about decided, after about 700 miles, that the head gasket is the problem.  It was probably not tightened correctly before I got the thing, the first start had a lot of water and smoke in exhaust.  Then there was water down both sides of the block from head gasket edges.  The first hot tightening did away with the water down the block.  I tightened again at 500 miles, hot, and that seemed to cut down on the water (steam) almost completely.  There's still a bit of "foam" and drops of water inside valve cover.

So my question is, before I take the head off, is it OK to re torque the head?  This would the the third (hot) time, since I got the car.  Are these head bolts stretch bolts?

Could this crack the head?  Or other damage?

Thanks,

Ron

[ja17]

Helllo,

No problem with re-toquing the head again. A 230 SL should be torqued at 58 ft. lbs.   As last resort I would take it up to 62 ft. lbs.

As Dan indicated, give it plenty of time to burn the fluids out of the exhaust. Brisk drives work best.

[Ron]

OK Joe, I'll try again.  Unfortunately, I may have messed this part up.  I took it up to 65 ft-lbs.  And my torque wrench is old an Sears torsion bar thing with not so accurate scale.  So I'll buy a new one and try it at 62 ft-lbs.  Ron

[ja17]

Hello Ron,

Ok, do not lower the torque setting. Keep it at 65 lbs is this case. Actually the beam type torque wrench is quite accurate. It is a little hard to read but it is pure physics. No moving parts to wear out or springs to get weak. It is a s good as its operator!

[jeffc280sl]

Ron,

Joe or Dan know far more than I but some moisture under the valve cover is not unusual.  I disconnected the valve cover outlet hose at the venturi and now have it routed to a small clear plastic container.  I've noticed a bit of water in the bottom of the container after driving the car.