Burning Oil

[SteveWood]

Having just purchased a Javelin for Chris Spencer (the one for sale in Februarys Jowetteer - 1952 Jovelin Standard), as I wait for it to arrive I've been doing a little research on the site into replacing/fixing the issue with the Carb Breather Pipe - which Chris believes to be the cause of the oil problem.

I have restored/owned a few cars in the last 20 years and am pretty good at working on most things but of course the Javelin is completly new to me and a car I've been after for the same number of years!

Any suggestions of how to tackle this repair would be greatfully recieved as well as any advice on the articles I've read about replacing the breather pipe altogether with an external pipe?

cheers Steve

[Forumadmin]

Hi Steve,
Burning oil or at least smoke coming out of the exhaust can be caused by a few faults so you need to find out which one.
I would first check all the plugs and see if there is any difference between them. If they have a smear of oil on them and are also encased in black soot being black everywhere (except perhaps the electrode) then it is likely the oil is coming through the intake.
If any plug is different then it is probably not on the intake but more likely associated with worn bores or broken rings. One exception is if the oil is coming down from the tappet cover through a worn valve guide. This could be a fault on more than one cylinder and can be made worse by oil collecting in the tappet cover through a blocked return hole (usually caused by excessive use of sealant on head gasket).
For all these tests it is worth grit blast cleaning the plugs or fitting new ones and repeating the exercise. It is also a good idea not only to do this after idling but also after a hard drive with the engine hot. Smoking can get better or worse when on load and high revs. But of course, be careful if the problem is likely to be a broken ring!
There are ways to check for worn bores and broken rings. A simple way is turn the engine by hand and listen down the oil filler to see if there is blow by. You can also run the engine with the oil filler off and see if there is excessive blow by.
Diagnosing a balance pipe leak can be done in a similar way. By putting your finger over the pintel valve inlet just inside the oil filler, you can see if you are getting vacuum through the pintel valve. If you have a vacuum gauge you can also test the pressure inside the crankcase by modifying the filler cap with a test tube outlet. The pressure should be just below atmospheric when idling and at about 2000 rpm . If it is very low then the balance pipe seals have gone or the pintel valve is not closing and thus excessive purging of the crankcase is taking place. If this has been faulty for some time the inlet tract will be black.
You can see this using an endoscope which can now be obtained cheaply to work with a smart phone. The endoscope can also be used for looking at the bores.

To repair the balance pipe seals requires spliting the engine, so is not a quick job. Also it is possible the balance pipe was not fitted correctly, there are different sorts, Care should be taking in selecting the seals and in the orientation of the pipe when reinstalling. I also have a vacuum pump test kit that checks this seal after installation but this requires the heads to be off the block (which is not really necessary when you split the block to do this job).

[Keith Clements]

Using the JT search server with 'balance pipe smoking' found 22 results
This one Jowetteer1977-04.pdf explains the test kit. It is best to download the file as this is an extract of the OCRed text and is missing some words.

According to another result (Jowetteer1970-03.pdf) the test kit was in the Club Tools now with JCS.

TECHNICAL CORNER
' ' : ^ THAT B - PIPE
Bv B - Shaw
Never in the 25 years that I have run the Javelin and Jupiter have I ha^a
failure of the balance pipe seals, though I have had every other fault you can think
of.
My freedom from balance pipe trouble, I am convinced, is due to very careful
assembly and a prolonged vacuum test. Not only does my vacuum pump easily give 24 ,
I expect it to still read 24" overnight.
In fact, having once assembled a spare crankcase,- with a reground shaft, just
to ha^ fSLX assembly ready to hard, I forgot about it for
and was then somewhat amazed to find the vacuum still holding. _ . a-iimc?
I had one case where the seal collapsed suddenlyafter 2_hours, having given no signs
of failure up to that time.
I am'now in the process of assembling an engine for XMG 258 and it, therefore,
oame L“ SLrsSckPto find that when I tested the balance pipe seal the vacuum
dropped very slowly to zero over some 30 minutes.
Not only had I very carefully cleaned bott the pipe
Shine both with carbon tetrachloride, I had also smeared the seals with Loctite
plastic gasket both to lubricate them during assembly and aid the sealing process,^
The set up for testing is quite simple. It consists of two lengths of ^ h"
M Sbar drilled to clear the two studs adjacent to the balance pipe,^d four s
pieces of tube which are fitted over the studs and bolted down. Short pieces of cop-
per tube are brazed in holes to coincide with the balance pipes. One of these car
ries the vacuum gauge and the other takes the rubber pipe from the rotary pump.
(Incidentally, the input of a compressor produces quite a good vacuum.) A sealed
cS screws on the'crankcase breather pipe. Small li" squares of i" rubber sheet
with a small hole to match the pipe opening, fit under the bars.
No various Club members have borrowed the gear and in the process one of the
rubber pads had been lost, I looked around hastily and found an old water transfer
washer and used that.
Now,the balance pipe end is peened over as it leaves the crankcase^d the
transfer washer is large enough to fit outside the peening, and it was the leakage
through this that caused the trouble. So make sure your sealing washers have only
small Sholes and the peening is sealed off. It might save you needlessly opening up
the crankcase again