smoke after engine rebuild

Post Mon Jan 20, 2014 10:03 pm

Hi everyone, i just rebuilt a m20 eta high compression bottom with 2.5i cyl head with new rings, bearings etc. Seconds after starting it began to smoke. Block was honed and cyl head was recently rebuilt and was in use for a short time. the engine the head was on was smoking, head was removed and new valve seals fitted but still smoked. Any ideas?

Post Mon Jan 20, 2014 10:15 pm

What colour smoke? Where from?

Ben

Post Mon Jan 20, 2014 11:49 pm

Leave it run for a little bit, it's probably excessive oil left over from the build process that needs to be burnt off.

Post Tue Jan 21, 2014 8:55 am

As Ross said, it is hopefully oil used during the rebuild that needs to burn away. I have had this a lot when rebuilding Triumph and MG engines. They usually smoke quite a bit until warm, then it disappears.

I did have the issue once when a TR6 engine wouldn't stop smoking, and I quickly found out that the engine block was cracked, and water was falling into the oil sump. But that was an engine that had been standing for over 25 years, so it had probably frozen at some point.

Post Tue Jan 21, 2014 9:40 am

coul be just condensation from the exhaust mate or hopefully same as the above just some oil on the manifold or something daft.

let it run for a bit,best of luck .

Post Wed Jan 22, 2014 2:10 am

Thanks guys. White smoke from the exhaust. So far I let it idle for over 20mins. also rev to 4000rpm and less for short periods. no overheat, no sign of water in oil or oil in water. I was advised to take it for a drive which I'm planning to do next Monday and Tuesday to put some miles on the engine.

Post Wed Jan 22, 2014 3:30 am

Just another note, compression check is good. I did not write the figures down but they are higher than 10-11 bars as stated in Haynes Manual

Post Wed Jan 22, 2014 1:16 pm

turbocharge1962 wrote: White smoke from the exhaust.

They all do that, sir.

At this time of year it takes a long time for the exhaust to get hot.

Take it for a run and keep an eye on the temerature gauge.

Ben

Post Wed Jan 22, 2014 1:33 pm

Location: Jamaica. Don't think the temperature is the problem Ben

Post Wed Jan 22, 2014 1:41 pm

ross_jsy wrote:Location: Jamaica. Don't think the temperature is the problem Ben

Oops. Maybe he's got an air conditioned garage.

Ben

Post Wed Jan 22, 2014 1:47 pm

Must have left his stash in the back box...

Post Sat Jan 25, 2014 9:33 am