Burning Oil w/New Motor - Can't Diagnose

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Burning Oil w/New Motor - Can't Diagnose

Post by btwick »

Hi,

Fighting an issue with a new motor blue smoking when cold. Motor has approx. 140 miles on it, and approx. :45 more run time in testing and tuning.
At startup, get too much blue smoke. Tapers off as motor warms up, then is mild. Oil levels do not reduce noticeably, but clearly seeing blue, not black/white smoke.

Motor is 383 SBC, with OEM rollers, Comp cam, 10.5:1 compression. Paid a shop to assemble the short block with an Eagle rotating assembly and install cam. Running ProMaxx 2169 heads.

Carb is Holley 700 double pumper on Edelbrock manifold. Two jets down on primary (to 67) and one down on secondary (to 78). Have not yet done AFR but have consistently been fighting overly dark plugs.

After 100 miles, assumed problem was valve guides or seals, so took heads to a machine shop. They confirmed both were good. Second thought was intake leakage and was running the suboptimal standard blue FelPro gaskets. Reinstalled intake with the black Felpro 1206s, which is apparently the recommended gaskets for those heads.

Now a bit worried the rings were not installed correctly. Machine shop advised me to run the motor for awhile and he’s seen motors resolve oil issues like this after sufficient break in. Not fully convinced of this.

Now it’s running again with the same problem and thinking it might be an oil ring issue that resolves itself when the engine heats up. Know a compression or leak down test won’t tell me anything, as that doesn’t measure correct oil sealing.

My initial rich condition (with previous issues with carb) might have washed the cyl walls, but when pulled the heads, cyls had expected crosshatch and if that did happen, imagine that would resolve with more miles on motor and correct tune.

Running out of ideas here. Does this sound like an oil seal issue that will resolve itself with miles, or is that wishful thinking? Anything else I can check or do, short of pulling pistons?

Thanks in advance!
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by BillK »

Does the engine have a pcv system on it ? look in the hose that goes to the pcv valve. It should be perfectly dry. Is the blue only on start up ? Have somebody follow you down the road and accelerate and de accelerate a few times. Its VERY hard to see exhaust smoke when you are driving.
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by Lizardracing »

Are those heads with screw in studs? Studs could be leaking oil into the intake port
Oil can also get past the intake bolts to the intake port.


Places oil can be pulled into

PCV
Valve cover baffles
Intake gasket
Intake bolts
Valve guides/seals
valve studs

A bore scope is handy here. You can use it too look for oil trials in the intake ports without disassembly.
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by btwick »

Thank you. Checking off the list..

* PCV - pulled hose and not enough oil in the hose to smoke like that
* Valve seals and guides - Had them checked by an engine builder, so likely not them
* Intake Gaskets - Just replaced them with the 1206 gaskets, so should be good there..
* Intake bolts - used black RTV on all the open-holed bolts, so should be good there
* Valve cover baffles - Hmm. Please explain how the baffles (which are good on the motor) could get oil into the intake

So, besides pistons, the studs are left. The previous owner was a bit of a hack, and I wouldn't be surprised if he pulled the screw in studs for some reason, and didn't reseal them back in. Called Promaxx and they do seal both intake and exhaust studs during assembly. Had no idea the studs threaded into the ports on the heads.

Will be pulling them and sealing the threads this weekend. Truly hoping that solves the issue. Thanks again for the advice.
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by ProPower engines »

btwick wrote: Tue Jul 27, 2021 2:16 pm Hi,

Fighting an issue with a new motor blue smoking when cold. Motor has approx. 140 miles on it, and approx. :45 more run time in testing and tuning.
At startup, get too much blue smoke. Tapers off as motor warms up, then is mild. Oil levels do not reduce noticeably, but clearly seeing blue, not black/white smoke.

Motor is 383 SBC, with OEM rollers, Comp cam, 10.5:1 compression. Paid a shop to assemble the short block with an Eagle rotating assembly and install cam. Running ProMaxx 2169 heads.

Carb is Holley 700 double pumper on Edelbrock manifold. Two jets down on primary (to 67) and one down on secondary (to 78). Have not yet done AFR but have consistently been fighting overly dark plugs.

After 100 miles, assumed problem was valve guides or seals, so took heads to a machine shop. They confirmed both were good. Second thought was intake leakage and was running the suboptimal standard blue FelPro gaskets. Reinstalled intake with the black Felpro 1206s, which is apparently the recommended gaskets for those heads.

Now a bit worried the rings were not installed correctly. Machine shop advised me to run the motor for awhile and he’s seen motors resolve oil issues like this after sufficient break in. Not fully convinced of this.

Now it’s running again with the same problem and thinking it might be an oil ring issue that resolves itself when the engine heats up. Know a compression or leak down test won’t tell me anything, as that doesn’t measure correct oil sealing.

My initial rich condition (with previous issues with carb) might have washed the cyl. walls, but when pulled the heads, cyl.s had expected crosshatch and if that did happen, imagine that would resolve with more miles on motor and correct tune.

Running out of ideas here. Does this sound like an oil seal issue that will resolve itself with miles, or is that wishful thinking? Anything else I can check or do, short of pulling pistons?

Thanks in advance!
Not likely its an oil ring issue unless the builder used a low tension oil ring.
the 2nd ring is the oil control ring for the top ring so that could be the main issue here.
If the 2nd ring was not installed correctly or the bores had a very rough finish that wore the 2nd ring badly causing the oiling issue that would most likely be where the issue lies.
The fact that you always have smoke on start up says to me you either have loose guide clearance and badly worn seals rather then a ring issue.
I have seen this too many times to count where guys use a moly ring set and have no idea how to hone a block properly for them to seal.
Also the ring choice if it is using a 5/64 ring set may just be a std. Hastings or what ever ring pak using a narrow top ring that is not correct for the ring grove depth. Seen this many times in the last couple years where pistons are supplied with a stock rebuilder type ring set.
Depending on the 2nd ring design most are a reverse taper type or a Napier style ring.
The Napier style does not like a rough finish and will wear the scrapper land off in no time flat causing smoke issues.
If the oil return from the top end is restricted it will flood the valve train area and cause a smokey run condition but will also cause lots of smoke on start up with excess oil running down the guides.
On a new build there should be no sign of oil on the back side of the intake valves or in the ports but if there was oil that could be the issue you have causing the smokey cold start.

Sounds like it should come apart and get re-ringed and re-check the guide clearance.
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by dannobee »

Blue smoke on start-up is nearly always a valve stem seal problem. The oil drips down the valve stem and onto the back side of the valve. When you start it, that oil goes right into the engine and into the exhaust.

At the dealerships, we replaced a LOT of sbc valve stem seals back in the day for that exact complaint. A LOT. There was a tool kit made that allowed you to air up all cylinders on one bank at once, then a plate bolted down on a few rocker studs that compressed all 8 of the valve springs at once. Dunno if it would work on your valve springs though.
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by williamsmotowerx »

Why don't you pull the plugs, look to see if they all or some look like they're burning oil
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by btwick »

williamsmotowerx wrote: Tue Jul 27, 2021 8:53 pm Why don't you pull the plugs, look to see if they all or some look like they're burning oil
They all appear to be equally dark, and either rich or oil fouled through a bigger issue.

Considering this fact, the odds of oil leaking through unsealed rocker stud threads or an intake gasket leak appear to be less. Those conditions would probably be more evident in some cylinders and less in others. Will still check the studs in the next day or so for existence of adequate thread sealant, as that is a far easier next step than inspecting and/or replacing rings... Really hope I don't have to go there.
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by BCjohnny »

Now a bit worried the rings were not installed correctly. Machine shop advised me to run the motor for awhile and he’s seen motors resolve oil issues like this after sufficient break in. Not fully convinced of this.
I think you already might possibly know the answer

With a bad bore as the engine warms up the oil thins, obviously, and if there's a problem less of it usually gets past the rings
Tapers off as motor warms up, then is mild
Which is what you may expect to see
My initial rich condition (with previous issues with carb) might have washed the cyl walls, but when pulled the heads, cyls had expected crosshatch and if that did happen, imagine that would resolve with more miles on motor and correct tune
Seeing a cross hatch doesn't always equate to having a 'good' bore :wink:

Some simple 'fixes' already mentioned to try first, but don't rule out maybe having to pull the motor at some stage, unfortunately

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Re: Burning Oil w/New Motor - Can't Diagnose

Post by BOOT »

I was gonna post last night but saw someone mention rocker studs and figured I'd wait, since it's something that is often overlooked. What oil are you using? Is there noticeable crankcase pressure from the valvecover holes or oil leaking from the engine gaskets? What type of valve seals were installed on both int/exh. Did you perform a break in? Are you using a header evac?
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by steve cowan »

I have seen 1 x napier 2nd ring put in upside down cause a blue smoke initial start up issue, would not believe it if I didn't see it.
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by btwick »

BOOT wrote: Wed Jul 28, 2021 3:50 am I was gonna post last night but saw someone mention rocker studs and figured I'd wait, since it's something that is often overlooked. What oil are you using? Is there noticeable crankcase pressure from the valvecover holes or oil leaking from the engine gaskets? What type of valve seals were installed on both int/exh. Did you perform a break in? Are you using a header evac?
Yes, rocker studs tonight--will report tomorrow on outcome. BTW.. When pulled rockers after first 100 miles, noticed a bit of blackening and light bluing on exactly 8 of the rockers and guessed they were exhaust. Not 100% sure as made mistake in not recording which rockers were black as I was going to replace them and didn't notice the black until removal. No bluing on the insides of the rockers (Comp roller tip stamped steel 1.6) or pivot balls. Reason this is mentioned is if the previous owner pulled all studs and didn't reseal them, I might be getting oil through the intakes and soot/heat up through the exhaust studs (?). That would be the very best outcome.

Have ~140 miles on the project (71 corvette) and have already pulled the motor a second time to fix a leaky rear main as the horrible shop that assembled my short block didn't tighten the rear seal carrier for the one-piece seal. Another motor pull to fix rings with less than 150 miles on it would be challenging.

To answer your questions, running PCV and noticed some smoke (light) coming out the breather filter at a stop light (hood is still off). Surprised as believed vacuum would pull air into the breather filter, not let smoke come out of it. BTW.. PCV hose is not oily and have baffles in the v covers.

No leaking from gaskets. Valve seals are new from ProMaxx as I had to install their heavier springs with my hyd roller, and seals came with kit. As mentioned in initial post, first thought on this was typical seals/guide issues, and had a different (and better) machine shop inspect the heads after the second motor pull and they are good.

Running 2x zinc non-synth break-in oil, and break in procedure was routine. Roller cam, so did not run 20 mins at 2K RPM.

Hope this helps.
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by maxracesoftware »

Valve seals are new from ProMaxx as I had to install their heavier springs with my hyd roller, and seals came with kit. As mentioned in initial post, first thought on this was typical seals/guide issues, and had a different (and better) machine shop inspect the heads after the second motor pull and they are good.
sort of like something like you described in your Posts :
one of the weirdest things i seen from Dyno testing a SBC w/aluminum Heads
oil smoke at 1st startup ... with a little smoke out the Headers during a Pull

Engine builder comes back a few Days after Dyno tests
with bare unassembled Heads ,
says watch this : Look thru the Intake Port while i pour a little Varsol on the Spring seat around the solid bronze Valve Guides

results was Varsol leaking between the Guide and the Guide's hole in the Head
dripping into the Intake Ports

evidently when they pressed in the Guides they also galled the holes enough to cause grooves in the holes ??

he showed me 3 Cylinders on 1 Head were leaking there at Intakes
i don't know if they were more than 3 Cylinders with that problem, or if some exhaust guides had that problem too ??
he just showed me 3 intakes

Guides were not loose , i could not see a gap , but they leaked Varsol pretty easily between the guide OD and hole they were pressed into .
spring seats were milled by Factory , no mods after , i checked for spring pockets breaking thru tops of Intake Ports ... no problems there !

the engine is pulling pretty much vacuum at ideling or ideling around 1500-2000 RPM on the Dyno
then you shut the Engine down after a Pull , time-wise later you startup it up for another Pull
and by then pretty much oil has leaked into the Intake Ports behind the Intake Valves in the Bowls
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by btwick »

Thanks... Last night checked sealant on rocker studs and found:
  • Bad galling on the rocker pivot balls and darkening/heating on 8 of 16 rockers after just 40 miles. Very random, no pattern on side of motor, intake vs exhaust, etc. Clear top end oiling issue, but had run motor on stand with no covers and got pushrods "spitting" droplets. Apparently not enough. Running OEM (SealedPower) roller lifters. Have checked everything on this when motor was out. Thinking bad lifters, lifter channels not aligned in block correctly, dist channel not aligned in block correctly, or perhaps install an oil diverter plate over rockers. Perhaps due to the 145lbs closed, 325lbs open valve springs using pivot balls, not rollers?
  • Only 3 stud holes had any evidence of broken up thread sealant. Reinstalled all with black RTV. About half of intake and half of exhaust stud holes go through to ports.
  • All spark plugs were equally oil fouled, making it hard to tune.
To your last point, the guides are still suspect, as last shop inspected seals (fine) and did wiggle test on valves to check guides. Could be the galling you mention.

Back to the smoking issue. Hunch is if it was studs, or intake, the plugs would not be all oil fouled the same, as some would be affected and some not. Back to rings or guides. Got some advice to "just drive it more" (only 140 mi on motor) to get them to seat, but if plugs just foul, driving it more is not sounding a viable option.

Any additional help/advice with either of these issues is greatly appreciated.
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Re: Burning Oil w/New Motor - Can't Diagnose

Post by BCjohnny »

Got some advice to "just drive it more" (only 140 mi on motor) to get them to seat
If the bore is 'bad' ...... 'iron shell' burnishing etc .... you can drive it a 100k miles and the rings will never seat properly
Have ~140 miles on the project (71 corvette) and have already pulled the motor a second time to fix a leaky rear main as the horrible shop that assembled my short block didn't tighten the rear seal carrier for the one-piece seal
If the same 'horrible shop' that couldn't even successfully complete a simple task such as that, and assuming they did the machine work, what faith do you have in them accomplishing a much more challenging task such as getting the bore finish right ?

As said, do all the simple things first and if you still have no joy, yank the motor ...... which understandably is not what you want to hear

I think the rocker galling issue is likely unconnected with the oil burning issue

To help discount or validate the 'rocker stud' & 'valve guide' leakage theories, safely decelerate (as in snap the throttle shut) from speed in gear for several hundred yards without braking, and then sharply accelerate .... get someone to follow and film it on their phone if it helps

If on accelerating you get a big puff of smoke it's likely an intake related issue, 'leaking' studs or guides ...... if not it's usually something else

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