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I have white smoke coming from  the rocker cover vent and the exhaust.

Also I suspect low compression because the engine turns over very fast on the starter.

The engine was supposed to have been rebuilt when I bought it and it looked like it had a couple of new pistons and the head looked like it had been refurbished.Oil pressure is  good.

I thought if it was oil burning the smoke wouldn't  be white. Is this correct?

I haven't had the car MOTed yet so can't take it for a run.

Any ideas?

Thanks Eddie 

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John,smoke doesn't persist so I suspect it is water .

Rob, I don't know. I will check but can't run car on the road yet.

Looks like a leaking head gasket which is no real problem because I have a replacement UK head to fit sometime in the near future. Just need to make sure I buy a good gasket. 

If I  have the head off will putting oil in the cylinders and checking it leaking away be a useful check on ring sealing?

Many thanks for replies.

Eddie 

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Could be condensation burning off if the engine has not fully warmed up. I wouldn't jump to head gasket failure too quickly. May be best to check compression first. 

Tim

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I concur with Tim,

do a compression test first, dry and then, if you see low values followed by a a wet test. 

Cheers,
Waldi

 

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Steam can be condensation- after all petrol is combusted to CO2 and H2O with a Bit of CO and traces of other gasses. On a cool day you will see this water vapour condense quite quickly as it exits the exhaust and likewise from the crank case - blow by is essentially exhaust gases blowing past the rings into the crank case. Some blow by is to be expected and that’s why engines have breathers. It’s a matter of how much blow by. If compressions are ok and consistent across all 6 then that’s a good sign.

White smoke can also be brake fluid being burned. Oil tends to be blue and excess fuel tends to be black/sooty.

Run it to get it properly warm and do a compression test. If they are poor or uneven, remove the head and take a look. 

The mention of a rebuild including a “couple of pistons” does ring alarm bells. By and large an engine rebuild will be a case of a hone and re-ring of all  6 or a re-bore and new oversize pistons to suit on all 6.  

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I had a dempnstartion of 'oil smoke' yesterday.     The damp grass clogged the roller of my otherwise excellent, and nearly new, 4-stroke lawn mower, so I turned it on its side while I poked out  the impacted cuttings woth long screwdriver.      Usually easy to start, the Briggs& Stratton engine took several pulls and then started like an old diesel, smoking vigorously!      Initially white, the smoke hundg about for ages, blueing as it thinned.   

I think sump oil had seeped up into the chamber while it was on its side, imitating severe ring or valve stem leak.   It cleared rapidly, and ran much better, without the clogging grass!

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3 hours ago, john.r.davies said:

I had a dempnstartion of 'oil smoke' yesterday.     The damp grass clogged the roller of my otherwise excellent, and nearly new, 4-stroke lawn mower, so I turned it on its side while I poked out  the impacted cuttings woth long screwdriver.      Usually easy to start, the Briggs& Stratton engine took several pulls and then started like an old diesel, smoking vigorously!      Initially white, the smoke hundg about for ages, blueing as it thinned.   

I think sump oil had seeped up into the chamber while it was on its side, imitating severe ring or valve stem leak.   It cleared rapidly, and ran much better, without the clogging grass!

I hope it is the upright engine if not your warranty is shot

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Have some compression results,they  don't look good. 

             1       2    3    4    5    6

Dry      60   55  55  50  56   65

Oil        75    72  70  75  75  75

I don't know how accurate the gauge is but readings look very low. The cylinder head looked in very good condition when I put it on. Tappet clearances are OK.

Eddie 

 

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Eddie, 

The absolute value is of no importance - gauges are not precision instruments, or even like a rule!    The importance is on the relative values of the cylinders, and all yours are within 10% or so, so I'd say you're fine.

Edited by john.r.davies
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1 hour ago, Eddie Trickett said:

Have some compression results,they  don't look good. 

             1       2    3    4    5    6

Dry      60   55  55  50  56   65

Oil        75    72  70  75  75  75

I don't know how accurate the gauge is but readings look very low. The cylinder head looked in very good condition when I put it on. Tappet clearances are OK.

Eddie 

 

There's a big difference between the dry and oiled readings, which suggests that the rings/bores are not the best.

Pete

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4 hours ago, stillp said:

There's a big difference between the dry and oiled readings, which suggests that the rings/bores are not the best.

Pete

Disagree!    That difference is entirely to be expected, even with good rings.    The purpose of the oil is not to test the rings but if pressure will not rise then a valve is  leaking.

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8 hours ago, john.r.davies said:

Disagree!    That difference is entirely to be expected, even with good rings.    The purpose of the oil is not to test the rings but if pressure will not rise then a valve is  leaking.

How's that John ? ..when oil is added to the bore it runs around the rings not the valve.

Pete

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The numbers are very low both dry & oiled.  If you can find a second gauge to check the pressures then I would. Sure, they are not precision instruments, but they should not be that far out. Pressures should be in the order of 150 PSI to 180. for a standard engine.

 

Bob

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Bfg, if that were the case then there would be no oil smoke, would there?  Even without ignition, turning over the engine with oil in the bore will splash the valves.  

Eddie, how many times did you turn the engine for each reading?  I find that the guage climbs to a max in five or six revs.  And please describe your technique?  Wide open throttle?

John

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You mean an external oil line to the cylinder head?   That can flood the rocker cover with oil, but more importantly at the expense of oil flow to the mains!  

John

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I note Eddie said he thought the engine spun over very quickly on the starter.

That might well tie in with the low compression figures. Eddie have you ever had this engine running properly in your ownership? It is worth going through the basics like tappets which may be tight, firing order 153624 and timing, then trying to run it, but it doesn’t sound in good shape tbh.

Kevin

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7 minutes ago, boxofbits said:

I note Eddie said he thought the engine spun over very quickly on the starter.

That might well tie in with the low compression figures. Eddie have you ever had this engine running properly in your ownership? It is worth going through the basics like tappets which may be tight, firing order 153624 and timing, then trying to run it, but it doesn’t sound in good shape tbh.

Kevin

The fast spin over might just be a high torque starter and poor timing.

Stuart.

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Just a thought, but Are you sure you read the gauge correctly, some have two scales PSI, & Bar.

If you read the Bar scale, then 7.0 bar = 101PSI, which is a bit closer to what you would expect.

(but still low)

Bob

Edited by Lebro
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