numbers seem generally low. did you do it with open throttle?

 

Yes correct. Actually removed throttles off intake, left it electronically connected and allowed motor to Turn.
Would be interesting to know what other Mclarens 838 motors are getting. No one really posts the results…..

 

could be cam phasers increasing overlap to facilitate starting ? idk.

 

Yeah could be, engine defs would have had a cold start , almost impossible to get all plugs out and still have engine “warm” to test, I would be burning my fingers left right and center! 😂😂😂

but consistently all cylinders kinda same except 4. Doing leak down test today as well. Will post those results too

 

10% variance is permissible 25% is too high

 

Brad, can you also post a picture of the equipment you are using for your compression test? Are you using a single mechanic gauge per cylinder? Also have you tried an electronic 'relative compression' per cylinder method?

I'm assuming your using a mechanical gauge (the most accurate way), based on you said you removed the spark plugs.

Looking forward to finding your solution to this issue.


Kevin Prickett
Supercar Garage
Kennesaw GA

 

This is what I used… mechanical old
School

 

Do you have a video of the blue smoke coming out of the exhaust? Also need to know what exhaust system do you have on the car? OEM? Aftermarket? Brand? Style?

Some exhaust systems will have the left exhaust tip physically connected to the right bank of the engine, and vice versa due to an "X pipe" design. That might make it confusing to know which side of the engine is actually producing the smoke.

Also, you 'could' remove the turbo air inlet pipes and inspect for oil seepage in the housing to confirm if you have a failed turbo seal causing the blue smoke.

Keep us posted!

 

Do you have a video of the blue smoke coming out of the exhaust? Also need to know what exhaust system do you have on the car? OEM? Aftermarket? Brand? Style?

Some exhaust systems will have the left exhaust tip physically connected to the right bank of the engine, and vice versa due to an "X pipe" design. That might make it confusing to know which side of the engine is actually producing the smoke.

Also, you 'could' remove the turbo air inlet pipes and inspect for oil seepage in the housing to confirm if you have a failed turbo seal causing the blue smoke.

Keep us posted!

So I am straight piped. No blending of exhaust and down pipes are fully decatted.

video here , cold start, high idle, moment it comes down from high idle, smoke starts for about 1.5 mins.

Yeah so removed charge pipes, was expecting to see a ton of oil because of that smoke, but to be honest, there was oil on the left pipes, none on the right pipes, but not a lot at all, certainly a lot less than I was expecting. I could wipe it all out with 1 finger and one sweep of it.

 

Just watched the video. I noticed a bit of smoke out of the other tail pipe just after start up as well. Not as much, but still there.

What happens if you stop the car for 30 minutes and the then restart it? Same thing?
Or does the car need to sit over night or maybe a few days for this to happen?

 

Just watched the video. I noticed a bit of smoke out of the other tail pipe just after start up as well. Not as much, but still there.

What happens if you stop the car for 30 minutes and the then restart it? Same thing?
Or does the car need to sit over night or maybe a few days for this to happen?

Haven’t tried those experiments as yet, would have done it for you. But one turbo I just took off (the Smokey side) and sent to turbo shop to trouble shoot.

on the plus side, my leakdown test and compression test on that Smokey bank all came back 100%. So that bank doesn’t seem to have a block or head issue.
Unrelated, which I just discovered, is that cylinder 4 on opposite bank, had a bad leakdown test (37% loss versus all other cylinders at 14%) so when I applied pure air hose to it, I can literally feel the air coming back out through the intake manifold (I’ve removed the throttle bodies) so yeah seems like I have a bad left bank turbo and a bad intake valve on the right bank, cylinder 4.

LOVELY DAY TO BE ALIVE!!!!!
😂😂😂😂😂😂😂😂😂😂

 

that looks like turbo seals to me, also it stops. Which is good.

I dont think it will be valve stems. Much more likely to be a turbo. Also comp ratios are fine, cyl 4 looks a bit low but that could have just been a dodgy test.

 

Did the test on cylinder 4, 4 times, using doffernt O-rings and seals on the test pipe seal. Also did a leakdown test and got 14% loss on all other cylinders and then 37% loss on that cylinder. So just applied 90 psi direct pressure to cylinder at TDC compression and felt the air escaping out through the intake manifold (removed the throttle
Bodies) so yeah seems pretty strange that only 1 cylinder, but all indications are that the intake valves have a problem. Going to try a pick clean on the valve seat and head seat because a walnut shell clean only cleans the chamber and valve stems. Probably won’t fix the issue but rather try that than drop entire engine to access head to see WTF is going on there…..

 

Im interested to know too.