New build engine smoke after 30 seconds, anyone?

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MK3HiluxV8
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New build engine smoke after 30 seconds, anyone?

Post by MK3HiluxV8 » Sun Mar 31, 2019 6:05 pm

Hello All
I've a newly built rover V8 SD1 engine start up question.
It's taken me a couple of years of spare time here and there but re built engine is in and running.
Starts and runs nicely, sounds good (second one I've built, other about 20 years ago).
After about 30 seconds to a minute it starts to blow smoke, couple of puffs from one pipe, like from one cylinder at idle, then general blue smoke, level building.
Plug threads seem to be getting a bit oily, but spark plug noses pretty clean.
I've run it three times to this point.
I wondered about crankcase ventilation so fitted the big rover flame trap into oil filler hole on rocker cover and straight through pipe to webber four barrel center pipe as a test.
It wanted to die (possibly as no PCV valve in pipe?) but it began to smoke again.
Any thoughts anyone?
I replaced the valve stem oil seals in re build, and bores and rings (new) all seemed good.
How long it's sat on bench may be a factor (all internals well lubed throughout).
Thanks for any suggestions, Sim



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Re: New build engine smoke after 30 seconds, anyone?

Post by DaveEFI » Mon Apr 01, 2019 8:19 am

Did you de-glaze the bores?
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Re: New build engine smoke after 30 seconds, anyone?

Post by MK3HiluxV8 » Sat Apr 06, 2019 8:45 am

Hi Dave

Thanks for reply

Yes did some de-glazing, looked about right.
I'm currently on the loose rocker trail as I fitted what I thought would be better aftermarket alloy ones, but after reading some posts and wiggling them they are a pretty loose fit. Running with a rocker cover off there was oil starting to pour from the shaft in a steady stream, which coincided with smoke starting at exhausts. No smoke until this level of oil reached.
other posts have suggested valve seals (new) becoming overwhelmed by the oil flow, producing smoke, and this being resolved by properly fitting rockers, so will at least rule that out before I dig deeper.
Rockers should arrive end next week.

Sim

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Re: New build engine smoke after 30 seconds, anyone?

Post by sidecar » Sun Apr 07, 2019 9:53 am

It sounds to me like the valve guide seals need looking at. The very early engines did not even have any seals on the exhaust, the later engines had 'umbrella' seals and these were pretty useless.

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Re: New build engine smoke after 30 seconds, anyone?

Post by Ian Anderson » Sun Apr 07, 2019 5:42 pm

New engine, rings not bedded in so lots of blow by on the rings.

Is POV connectors to top of rocker cover, and are the pipes clear?

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Re: New build engine smoke after 30 seconds, anyone?

Post by MK3HiluxV8 » Tue Apr 09, 2019 9:45 pm

Thanks for thoughts Sidecar and Ian Anderson (a local perhaps).

I fitted new well lubed valve guides and cranked engine minus plugs to get oil pressure up a couple of times before first start up so hoping valve stem seals are good.

I ran it briefly with flame trap (large type) routed to center manifold vac pipe on webber 4 barrel so definitely no crankcase pressure and the same, no smoke until nearly a minute when it starts to build.

I ran it with a rocker cover off and oil quantity coincided with beginning of smoke. Flow of oil from rocker equal to pouring from a cream jug.

Found some posts on here about poor quality fit of aftermarket rockers and oil quantity overwhelming valve guides, so figured I'd eradicate that possibility first.
Some rockers on the way. My current new brit part alloy ones are definitely a sloppy fit.

Will fit 'quality assured' ones when they arrive and run it for a bit to see what happens.. Plus fit an oil pressure gauge first so I can see what's going on there in case relief valve stuck or similar.

Will post results..

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Re: New build engine smoke after 30 seconds, anyone?

Post by ged » Wed Apr 10, 2019 8:33 am

I ran it briefly with flame trap (large type) routed to center manifold vac pipe on webber 4 barrel so definitely no crankcase pressure and the same, no smoke until nearly a minute when it starts to build.

Have you checked that pipe for oil ingress?

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Re: New build engine smoke after 30 seconds, anyone?

Post by stevieturbo » Wed Apr 10, 2019 5:45 pm

ged wrote:
Wed Apr 10, 2019 8:33 am
I ran it briefly with flame trap (large type) routed to center manifold vac pipe on webber 4 barrel so definitely no crankcase pressure and the same, no smoke until nearly a minute when it starts to build.

Have you checked that pipe for oil ingress?
if the breathers are routed to intake vac....likely sucking oil straight in ?
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Re: New build engine smoke after 30 seconds, anyone?

Post by ged » Wed Apr 10, 2019 6:57 pm

stevieturbo wrote:
Wed Apr 10, 2019 5:45 pm
ged wrote:
Wed Apr 10, 2019 8:33 am
I ran it briefly with flame trap (large type) routed to center manifold vac pipe on webber 4 barrel so definitely no crankcase pressure and the same, no smoke until nearly a minute when it starts to build.

Have you checked that pipe for oil ingress?
if the breathers are routed to intake vac....likely sucking oil straight in ?
My point exactly.

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Re: New build engine smoke after 30 seconds, anyone?

Post by MK3HiluxV8 » Wed Apr 10, 2019 8:56 pm

Thanks for breather thoughts.
The one I built ages back I routed the two flame trap (small grey) pipes to the underside of the aircleaner which seemed to work fine.
Ran it on LPG/petrol and seemed to work ok for both.

This one I started out with two small k&N style filters on (P6 style) rocker covers but reading up it needs to be vented into aircleaner to create a slight vacuum.
Engine 'breathes' I read, so air in and air out.
It smoked with this set up (no vacuum at all) which was why I suspected that first.
I rigged up the 'rocker cover straight to inlet manifold' to get a big vacuum so I knew it wasn't engine pressure.
Understand oil drawn in point, noted 👍.

When I then ran it without the 'straight to inlet' pipe but rocker cover off there should have been no pressure in engine as I understand it, as cover was off.

I now have replacement rockers and an oil pressure gauge to fit when I can (sadly probably not this weekend as I have a show to set up, but asap as motor sounded great and keen to get it sorted).

It's run for about four/five minutes in total.

Will post results of rockers and oil gauge when fitted. All thoughts very much appreciated.

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Re: New build engine smoke after 30 seconds, anyone?

Post by DaveEFI » Thu Apr 11, 2019 8:27 am

When you assembled your new rockers, were they obviously a poor fit to the shaft?
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Re: New build engine smoke after 30 seconds, anyone?

Post by DEVONMAN » Thu Apr 11, 2019 6:33 pm

I'd be surprised if after only 30 seconds the valve guides are flooded sufficiently to cause lots of smoke. Maybe at full pelt with rocker covers on they may get flooded. Have you checked the oil level in the sump? Is the sump a standard SD1 item with matching dip stick? The worst case scenario is a cracked head which is allowing rocker feed oil to reach an inlet port but if it's both banks that's unlikely.
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Re: New build engine smoke after 30 seconds, anyone?

Post by MK3HiluxV8 » Thu Apr 11, 2019 9:00 pm

Hi Dave, certainly wiggling the old rockers off their shaft was a snug fit but I put the ease of fitting on new ones on new shaft to lack of crud build up.
I should have been a bit more critical perhaps.
I could get some sideways wiggle on the new rockers in situ (the ones not under load) with my fingers, quite noticeable.
It's been so long since I stripped it down I had a clear out of all the steel rockers (several sets) as figured my shiny new alloy ones where going to be the business.

Devonman, the oil level seems good on the stick and was a running unit when I got it (though with some issues, un seated rocker gasket allowing grit/gunk in so stripped it and cleaned everything, re ground crank, new bearings, lifters, cam, rings, timing chain set). Sump looks like standard other SD1's I've seen, plus in Haynes etc. hopefully the oil pressure gauge should tell me if this is up the creek.
I did think of lowering it to just above lower level to rule out being over filled, worth a go, esp if no joy on the rockers.
Oil smoke builds evenly across both sides at around a minute. It did coincide with the stream of oil starting from rockers, so as a couple of things there I wasn't convinced about it seemed a place to start.
No garage time sadly this weekend (by the looks of it) but will fit stuff and see what it does/says..

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