Rover V8 blue smoke

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gilps
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Rover V8 blue smoke

Post by gilps »

This is on a car I recently purchased. The engine was rebuilt 200 miles ago don't know what was done to it as all I have is a copy of the bill for over £2k which just says full engine rebuild but should have been pretty comprehensive at that price. Anyway the car starts great has great power very smooth no noises etc. Start up from cold and no smoke whatsoever it only starts smoking (blue smoke) after its warmed up for a good ten minutes. There is no really noticeable smoke while driving but leave it idling for a few minutes and it gradually gets worse and worse give it a rev and loads of smoke take it for a spin and it clears but comes back as soon as it's left idling.
My thoughts were valve stem seals but I would have expected it to smoke on start up as well and it doesn't. Tried with breather off and no difference.
The engine is a 3500 circa 1986 with Edelbroke inlet and Holly four barrel carb.
Pulled all the plugs and they are a medium sandy colour on the tips and a light sandy off white colour on the ceramic centre that was after a run. Leave it idling for a while until its smoking badly and a couple were a black sooty colour but not wet.
I will be working on the car this coming weekend and before I do I will try the running the car down a long hill on over run to see if the smoking gets worse which then should pint to the stem seals. but just thought it worth posting here to see if anyone had similar issues and found remedies
Would appreciate your views on this.
Chris



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Post by DaveEFI »

If the £2000 included labour and all done at a garage, it's not enough for a full engine overhaul to good as new which would involve removing the engine. Sadly, full overhaul means a different thing to different people.

At idle, you have high vacuum, so oil is being sucked into the cylinders past either pistons or valve stems.

However, if the bores were honed, and new rings fitted, it will take some miles to bed in fully. I'd run it to a couple of thousand miles before worrying further. Try and do this over varied driving - not just cruising on a motorway.
Give it plenty revs once in a while, when fully warmed up.
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gilps
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Post by gilps »

Cheers appologies for the lack of info, the rebuild was £2000 plus labour for removing the engine etc total bill was just short of £3k the invoice says full engine rebuild.
I see what you mean about running it in but the amount of smoke coming from the exhaust is a lot more than you would expect litterally clouds when its been sat idling for a few minutes. The strange thing is I would have expected to see oil fouling on the plugs but nothing visible. I did its first oil and filter change yesterday oil level was spot on the max mark in fact it was a little over but nice and clean with no smell of fuel mixed in. was wondering if it could be running really rich on idle (sooty but dry plugs after long idle) could this cause blue smoke?
Cheers Chris

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Post by ChrisJC »

Is the brake fluid going down?

Chris.
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Post by JP. »

DaveEFI wrote:...
However, if the bores were honed, and new rings fitted, it will take some miles to bed in fully. I'd run it to a couple of thousand miles before worrying further. ...........
Pistonrings should bed in within 400miles. Especialy the first 100 miles are important.
If they haven't bedded in within those 400 miles, they wont bed in anymore and the bores are glased.

Thats why its inportand to properly break in a fresh engine. Floor it WOT on a regular base the first 400 miles..
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gilps
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Post by gilps »

No oil in the brake servo pipe and no loss of brake fluid.
The car has only done about 250 miles since rebuild but only 50 of them have been done by me so no idea how it was first broken in.

This car does not have a pcv just a fire trap breather going into the air filter pan. I have been told this may be the issue and simply adding a PCV will help as it will pull a slight vacuum in the crankcase.
Any thoughts on this

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Post by DaveEFI »

Poor crankcase breathing usually shows up at higher revs, rather than idle.
But you could simply remove the oil filler cap at idle and see if that stops the blue smoke from the exhaust, as a quick check.

The colour and smell of the exhaust will be different if it were excessive fuel rather than oil.
Dave
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gilps
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Post by gilps »

Thanks for all the help and advice. As said before I want to try and get this resolved this weekend or at least rule out certain things. I have been advised that it also may be the rocker shaft letting in too much oil and basically drowning the valve tops in oil which is then getting sucked in down the valves on high vacuum. Ive had a look on youtube and found this video. My question is, is this the right amount of oil that should be coming from the shaft to compare to mine when I test it.
I did take the rocker covers off the other day and I had a lot of oil sitting in the lower edges much more than you see in this video even after the engine had been off for a few minutes.


Cheers again Chris

gilps
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Post by gilps »

Just managed to get hold of the chap that I bought the car off. Apparently the engine was rebuilt due to burning oil he couldn't remember everything that was done but says he knows for sure that the heads had new guides (bronze) and stem seals all bearings were changed but he can't remember if it had new rings and a hone or if they were just checked and deemed to be ok but he is going to contact the engine builder and try and find out. He was told that the smoking was down to excess oil just burning off in the exhaust but I guess this is why he sold the car on not that I am complaining I bought it as a project at a fair price and as seen.
So knowing this information now it's unlikely to be the heads guides or stem seals I guess that leaves rings will do a compression first and if that shows ok I will have to invest in a leak down tester.
Chris

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