Gathering Cav Engine Fail Assistance

I saw it happen, and was gutted for you - I hope it easily fixed.

At the time it looked like clouds of steam from a blown head gasket, but thinking back it hung around, and steam dissipates really quickly. It certainly wasn't black enough to be a fuelling issue, but it didn't really look blue enough to be oil.

Are any of the fluids down from their normal level? If so, which ones? Do check the brake fluid - if the master cylinder/servo dies then brake fluid can find its way into the inlet, and I understand that it burns white. If the take-off is right at one end of the manifold then it might have gone into only one cylinder.

Another thought is that the crankcase breather might have chucked a whole load of oil into the inlet manifold in one go - again that could cause losing a cylinder and loads of smoke.

Unlikely to be a sticky valve, TBH - that wouldn't cause oil to find it's way into the cylinders.

Quick check - take the spark plugs out, noting which cylinder each one came from. They should all have a small amount of deposit on them, and that deposit should be light beige/tan in colour. Dry but black = running rich. Wet, oily and black = burning oil. Super clean = head gasket (steam cleaned).

I suspect that one plug will be black and oily, and another one or two a bit dirtier thanmight be expected.

As above a sticky valve wouldn't make it smoke but it could cause a miss, where as oil in the cylinder will do both, have you checked your not out of oil and thats why it stopped smoking ? or it could have been a stuck pressure relief valve on the oil pump failing to open at high pressure and sticking ?

Have you done the rocker cover mod mate?
Xe's in their natural habitat do seem to have oil surge issues and the mod is meant to help get rid of the problem

If its running right again and the smoke has cleared then id be tempted to run it around for awhile and see if you can replicate the problem again under similar conditions(obviously....on a private track )

Steve

Steve, good call, I havnt done the rocker cover mod. Il attempt to replicate similar conditions having reduced the amount of oil in the bad boy and see what happens

cheers Rich

I'd have to agree recon oil entered the head breather straight into the engine and oiled up the spark plug causing the misfire, probably due to giving it a lot of beans

I was wondering what issues were appertaining to the Cav.
We were stood halfway up the hill and there was a collective sharp intake of breath when it happened. It was an impressive smokescreen you created though
If this turns out to be a simple fix I'll be well chuffed for you.

I have to say, I had assumed you were running an LET and that the turbo had let go.

yep, no turbo here, just a well tuned xe lol!! still havnt had chance to look at it yet, its still under dust covers atm! hopefully il get chance to have a look soon. however the potential rebuild has enspired me to look a little left field, and i think I'm going to try and run it next year with a merc compressor on for sh1ts and giggles!! if nothing more it should go very well and make an awsome sound :-)

I bet this too. Common as hell on XE engines, oil comes down the breather, into the inlet and hey presto - mental smoke screen. If your oil was overfilled then thats why its so bad.

I'm really suprised that its taken this long to work out, Redtops are really well known for it - theres a mod you can do to one of the breathers on the underside of the cam cover, its called the breather mod normally, loads of stuff on the web about it.

MIG probably has a how too.

my fiat 2.0 20v does this every now and again, its the breather valve that has gone, its a £5 quid fix for mine, hope yours is the same buddy