280SL White Smoke on Warm Starting and Acceleration

[w113abudhabi]

Dear all

I am hoping that some knowledgeable members may be able to assist me.

My mechanics are working through a number of issues with a 1970 280SL which I imported from the US to Abu Dhabi approximately a year ago, but have so far hardly driven. Whilst cosmetically and structurally excellent the car was running terribly when I received it. Recent work includes sealing the fuel tank with POR 15, replacing the spark plug leads, replacing fuel injection pump gaskets, replacing the brake booster, replacing the timing belt, replacing the transmission vacuum diaphragm and working through the throttle linkage.

The car now runs well with a steady idle and drives well. However, an issue exists with white smoke, particularly on warm starting and acceleration. This is rather an unsightly look for such a beautiful car. My mechanic also feels the car is slightly down on power with other w113s that he has driven.

I would like to know if there is any way for oil and fuel to mix together from within the fuel injection pump which could cause the white smoke? What checks might be made to identify the cause of the white smoke and therefore to move towards a solution? My fear is that we may need to pull the engine and undertake a complete rebuild in which case I will send the fuel injection pump for servicing while this is being done. If a full engine rebuild is required can members direct me to good parts suppliers; I am aware of sls, niomoeller, pelican etc and the general lists on other areas of this forum.

Many thanks to all for their valuable contributions.

Pierre

[Benz Dr.]

It sounds like valve guides and or seals. I have found that even though repairs have been made that should stop all smoking there can still be a fair amount of oil left inside of the exhaust system. This can take a while to burn off before it clears away.
This doesn't sound like your problem but keep it in mind after you make repairs.

[w113abudhabi]

Thanks for the reply Benz Dr.

I should have included in the original post that this is a low mileage vehicle with 59K miles from new and had spent most of its life sitting. We have also seen evidence of internal corrosion that appears to arise from a lack of coolant being used in the car which spent 44 years prior to my ownership in Florida.

I have purchased the car with a long-term ownership intent (30+ years) and am thinking if we have to rebuild the head to do the whole engine rebuild now and fuel injection pump so I move forward from a known position rather than my current position of working through previous ownership issues.

All recommendations are much appreciated.

Pierre

[kampala]

"White" smoke typically means water is getting into the cylinder.  Usual suspects that I know of are head gasket allowing coolant to get into the cylinders or moisture in fuel.

[Benz Dr.]

I would remove the cylinder head and see how it looks. Odds are it will have a lot of corrosion around thee water ports. Removing the head is part of a rebuild so you aren't wasting your time if you end up pulling the whole engine.

[watson2]

"White" smoke typically means water is getting into the cylinder.  Usual suspects that I know of are head gasket allowing coolant to get into the cylinders or moisture in fuel.

Hi Pierre.
My opinion is certainly not as authoritative as that of the members who responded so far, but I quote the answer of Kampala. I think that, if the smoke is white, we can deal with water. Before opening the engine you could take a look at water level; if it decreases more or less rapidly and forces you to top up the level in a few tenth of miles , then you have to think that it is water that leaks into the cylinders.
Another test could be to take a look inside the cylinders, passing through the sparkplug hole with an optical fibre like these http://www.amazon.com/gp/product/B00JERRES6/ref=pd_lpo_sbs_dp_ss_2?pf_rd_p=1944687542&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B008DYHY04&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0BCFV631NDGDGNACB6P8.

You have to look carefully if you see signs of infiltration, especially if you can put under slight pressure water circuit. Then look at the cylinder surface if you can see corrosion (an example in the image), as you said that the car was not used for a long period.

[w113abudhabi]

Many thanks to all that have provided responses.

Can anyone please provide a response to the following that was included in my original message:

"if there is any way for oil and fuel to mix together from within the fuel injection pump?"

Responses seems to be focused towards both oil and water issues - I guess removing the head and inspecting will help us to know much more. When done I will upload photos here for members review and further feedback.

I have also read an additional thread on this forum where Joe Alexander advises that it is possible inspect the lower end of the engine from below in an attempt to identify wear and damage. This also seems a wise route forward in the case of my car. Again we can try to photograph in this case and the probe camera suggested by Watson may also be useful in this regard.

Many thanks again to all,

Pierre

[ja17]

Careful examination of the spark plugs may provide a clue to your smoke problem. Do several examinations of the spark plugs first. Oil contamination of the fuel system is unlikely, but possible. I am dealing with one situation like this right now. Get back to us with the results of the spark plug examination.

[Benz Dr.]

White smoke is more often ATF or brake fluid. Water comes out as steam and usually you can't see it very clearly. Oil is more gray in colour while too much fuel tends to be black.

[w113abudhabi]

Thanks to JA and Benz Dr for the responses. I have asked the mechanics to remove the head, but will now ask them to pull the spark plugs, inspect, clean as necessary, drive, pull the plugs again etc prior to starting on the head removal and will report back here.

Thanks again

Pierre

[w113abudhabi]

There is little information to report back regarding the spark plugs. I had forgotten that they were recently changed along with the plug leads to help solve some of the previous rough running. My mechanic reports that they did not show any indication of oily deposits when changed. The new plugs have covered very low miles so do not provide any help. Changing the plus and leads certainly helped to achieve a smooth idle.

The mechanic has also disconnected and reconnected the transmission vacuum line which is connected to the intake manifold to make sure the gear oil was not going into the intake manifold. Unfortunately this did not have impact on reducing the engine smoking.

There is also an issue of excessive engine temperature issues but only if we use the dealer air conditioning at idle (noting that at this time of the year the daytime temperature here is in excess of 100F and can reach 125F). As soon as the car starts to move the temperature starts to come back to normal. I am aware of the retrofit cooling option (http://www.sl113.org/wiki/Cooling/RetrofitCooling) and that some owners have used 9 blade fans. We don't believe this is related to the smoking issue but I chose to mention it here in case others feel it is possibly relevant.

There is no sign of loss of coolant or loss of pressure in the cooling system during early morning starts suggesting that the head gasket is not leaking. My mechanic suspects the valve guides or seals and has not seen low oil pressure so does not think it would be necessary to open the bottom oil pan of the engine at this time to inspect.

The head will be removed this week and I will post photos and the head thickness back here to gather further feedback.

More to follow soon....

Pierre

[w113abudhabi]

My mechanic removed the new spark plugs to take a look and the findings are as follows:

The plugs from cylinders no. 6, 5 and 3 have shining oil deposits on them
The plugs from cylinders 2 and 1 have very faint oil deposits
Cylinder 4 appears to be working perfectly

They also put a camera probe into the intake manifold and were surprised to notice a lot of oil just behind the throttle body. There is also some oil on the boot which connects on the air filter housing to the throttle body.

Today they plan to examine the blow by vent pipe from the tappet cover to the intake system to see if it is sucking engine oil into the intake manifold. They have also removed the tappet cover again to have a second look at the valve seals and if possible the top portion of the guides. There is also a small oil deposit on the air filter rubber boot as shown in the attached picture.

Any thoughts please?

More to follow.....

[w113abudhabi]

Photo of the spark plugs attached from cylinders 1-6 from left to right. We inserted a camera into the pistons with the plugs removed, some with wet oily deposits within. Lots of oil in the intake manifold.... Even very minor traces of oil in and around the air filter...

My mechanic wonders if there should be any filter or restriction on the connection point shown on the tapper cover?

[w113abudhabi]

The cylinder head was removed today. A few photos attached with more to follow. All feedback much appreciated..... Individual cylinders from 6 down to 4 in order

[w113abudhabi]

And cylinder 3, 2, 1

[w113abudhabi]

Exhaust manifolds in order. 1, 2&3, 4&5, 6

[w113abudhabi]

The valve guides are loose some so loose that they can easily be moved by hand.

Time for a head rebuild and sneaky installation of a euro 02 camshaft

[stickandrudderman]

Your head gasket was leaking between cylinders 3 & 4.
Be sure to check your head dimension before having it overhauled.

[w113abudhabi]

The head measures 85mm but has quite a lot of corrosion....

[Benz Dr.]

That can be welded in and then the head can be lightly planed. You will need new water inserts.

[w113abudhabi]

Many thanks.

[Benz Dr.]

Your head gasket was leaking between cylinders 3 & 4.
Be sure to check your head dimension before having it overhauled.

Just wondering how you saw that. Care to share?

[stickandrudderman]

The lighter colour coupled with a dryness absent on the other cylinders. Effectively, those two cylinders have been steam cleaning themselves.

[Benz Dr.]

I saw that too but I didn't connect it to a leaking gasket. Of course, with all of that corrosion it's not surprising. I expect it ran mostly on water in the cooling system - a real mistake on these engines.

[w113abudhabi]

We assumed that it was due to the valve guides being loose on the other cylinders