Rover V8 engine smoking

[chris52]

X8Matt said:

I had the same problem on an SBC engine. If the Rover V8 layout is the same you will find that the inlet manifold actually performs three sealing jobs.

Firstly, it allows seals the route from the carbs to the cylinder head.
Secondly, it seals the lifter valley (the gap in the middle of the VEE) from the outside world, stopping oil leaking out.
Thirdly, it seals the lifter valley from the cylinder head

You might think that it is doing the first two jobs correctly, i.e no oil is leaking out and there are no obvious intake air (vacuum) leaks. However, if the manifold isn't quite 100% sealed against either of the cylinder heads, then oil mist can enter the cylinder head directly from the lifter valley. The engine literally sucks oil direct from the lifter valley, and of course will suck most at idle when manifold vacuum is highest. If you have had a new or refitted manifold then I would suspect this is the problem. Took me bloody ages to work this out, and fixing it wasn't straightforward either!

Very interesting and certainly worth investigating, thanks for the input every bit of help is appreciated.
Chris

[Steve_D]

If the heads were skimmed as part of the rebuild and the machinist did not get it square then the manifold will have difficulty sealing.
Looks like you may need to invest in a tin of Engineers Blue.

Steve

[chris52]

Bit of an update. Removed the rocker covers and although the rockers were OE they were dripping directly onto the valve springs and tops of the stem seals around 2 drops a second oil was literally pouring down the head and nearly overflowing. So I changed the rockers and shafts and the difference is like night and day only 1 drop every 10 seconds and only a slight flow of oil in the head. Smoke seems to have cleared a lot while just left idling but give it a rev and you still get a plume of blue smoke from the tailpipe only had it running on idle for about 30 minutes with the odd rev up to 3k hopefully this is only a build up of oil and crap that will just burn off over time.
The only thing I can think of is that either the shaft had been replaced with an aftermarket one or the rockers were just worn out.
Chris

[Steve_D]

But the only way that 'excess oil from the rocker shaft' can get burnt is if the valve stem seals are duff in which case you have still not 'solved' the problem just reduced it.

Steve

[Boosted LS1]

I think the OP may be implying that there's still oil in the exhaust system which needs to be burned off/out.

[chris52]

Steve_D said:

But the only way that 'excess oil from the rocker shaft' can get burnt is if the valve stem seals are duff in which case you have still not 'solved' the problem just reduced it.

Steve

Not necessarily the fact that the valve stems were being drown in oil is hopefully the reason more oil than should be is getting past them. Fingers crossed it's all sorted now.
Chris

[chris52]

Further update all cured no smoke whatsoever today. Been out for a good drive to get it up to temp and left it idling all clear.
Very happy
Thanks for all the help
Chris

[Pupp]

You'll probably have increased your effective oil pressure a tad too

Excessive clearances on shafts and rockers bedevilled a lot of aftermarket components a few years ago with the rocker chests getting flooded, causing smoking and leaks. Glad it's sorted

[chris52]

Pupp said:

You'll probably have increased your effective oil pressure a tad too

Excessive clearances on shafts and rockers bedevilled a lot of aftermarket components a few years ago with the rocker chests getting flooded, causing smoking and leaks. Glad it's sorted

Yes jumped up about 5psi on hot idle

[chris52]

Pupp said:

You'll probably have increased your effective oil pressure a tad too

Excessive clearances on shafts and rockers bedevilled a lot of aftermarket components a few years ago with the rocker chests getting flooded, causing smoking and leaks. Glad it's sorted

Yes jumped up about 5psi on hot idle