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I have broken in my new camshaft (see my other thread) successfully and now i drove the first few hundred miles with the car and she runs great.
BUT today, i discovered a major problem:
When i was driving, i saw that my oil pressure gauge went close to zero pressure under hard acceleration, so i knew that there was not enough oil in the engine. Back home, i checked and the oil was only reaching the tip of the dipstick. After break in i filled oil to "full" on the stick. No leaks on the garage floor.
then i pulled the plugs and some of them are more, some less black of burned oil. When i look through the plug holes on the pistons, some of them are wet from oil.
What can be the reason for this?
the engine was rebuilt with new pistons (speed pro).
The heads are #7 with new valves and umbrella valve seals from comp.
because of the fact that the decks of the pistons are wet from oil, i suspect that the oil comes from the valves and hopefully not from destroyed piston rings or so.
Can this be because of the umbrella seals?
this is cyl. Nr. 2., you can see the black umbrella seal from comp. I have them on every valve.
i have a new set of silicone umbrella seals from Enginetech lying around, maybe they would be better?
ive already pulled the PCV valve and breather to check if the engine makes vacuum if i plug the both holes with my thumbs to check if the intake seal is bad, but theres no vacuum. The engibe pushes the oil fumes out and is bot pulling them in.
Try to look in the intake runners with a borescope for sealing problems. Did you seat the rings after the cam break-in?
Yes valve seals can cause large amounts of oil consumption, remove one to see if there is excessive oil on the stem between the bottom of the seal and the top of the guide.
No, i havent seat the rings, because i havent built the engine, the previous owner ran the engine just with another camshaft. I only sticked another cam in.
what is the best way to do a compression/leak test on the cylinders? 🤔
Yeah, this consumption is way too high! I was very shocked when i took the plugs out!
maybe anyone had same troubles with umbrella style valve seals?
A cylinder leak down test requires a leak down gauge. You can find other posts in here where members talk about them. I was just looking at your other thread where you describe your new camshaft/lifters/valve train. You mention using a high volume oil pump. I wonder if you are now pumping more oil up into the cylinder heads than can return to the oil pan. The stock Oldsmobile head does not have a great oil drain back design and if you are pumping more oil up there now than can drain off it may be the source of your oil consumption. Did you use oil restricted pushrods when you replaced the camshaft and valve train? I have had no problem with using factory style umbrella valve stem seals so doubt that is your problem here. As SugarBear noted above, check your intake manifold to cylinder head seal also.
A cylinder leak down test requires a leak down gauge. You can find other posts in here where members talk about them. I was just looking at your other thread where you describe your new camshaft/lifters/valve train. You mention using a high volume oil pump. I wonder if you are now pumping more oil up into the cylinder heads than can return to the oil pan. The stock Oldsmobile head does not have a great oil drain back design and if you are pumping more oil up there now than can drain off it may be the source of your oil consumption. Did you use oil restricted pushrods when you replaced the camshaft and valve train? I have had no problem with using factory style umbrella valve stem seals so doubt that is your problem here. As SugarBear noted above, check your intake manifold to cylinder head seal also.
Ok, i just ordered a cylinder leak down tester and will test all cylinders as soon as i get the tool.
My oil pump is a Melling M22F, i think thats standard volume/pressure. At cruising at about 1500 rpm i have about 40 psi oil pressure. At idle its ~ 25 psi. I think the problem is not the slow drain back/fast pumping up of the oil, because the oil was just gone. Or is it normal if too much oil is being pumped up, the engine burns it?
the pushrods in the engine are looking same as the ones i have in my stock engine.. so i dont think that theyre oil-restricted pushrods.
I will check the intake to head sealing as best as i can. I just dropped the intake on the engine about 4 weeks ago. I used the original style valley pan gasket and the black engine seal silicone on each port. Maybe i have to lift the intake again.
For my understanding, umbrella style valve seals always let a bit oil through the valve guide into the cylinders?
the #7 heads on my stock 1971 engine which was originally in the car do not have umbrella style seals, they have the type of seal which is fixed to the valve guide/head.
I just took a look with one valve cover off, to check how much oil is coming up to the rockers. And its a lot.
We had the engine running for about 10 seconds and there was so much oil coming up that it was difficult for me to keep it from draining all the way down to the headers. I guess, if the valce covers mounted, my whole valce train is drowned in oil.
Even, because cylinder #7 and #8 (the 2 rearest) have the worst oil-burning symptoms.
Is my thinking true, that if my valve covers drowned with oil (when it reaches the valve stems), the umbrella style seals cannot seal? So that its like the engine is running without any valve seals?
I guess i have the infamous oldsmobile poor oil drain back issue 🤔
Are these a factory style, hard nylon umbrella valve seals on your heads? The other style in your pic to fit tightly on the guide may need machined, I have two sets of iron heads with that done so they don't just float around. Sorry to hear this, these old cars are supposed to be fun, not a headache.
Are these a factory style, hard nylon umbrella valve seals on your heads? The other style in your pic to fit tightly on the guide may need machined, I have two sets of iron heads with that done so they don't just float around. Sorry to hear this, these old cars are supposed to be fun, not a headache.
No, they are from Comp Cams and are pretty soft.
Ok, i thought the ones from engine tech on my 2nd Picture are umbrella style seals too and arent sitting fixed on the heads.
I ordered an borescope/endoscope camera too to take a look into the intake manifold to check if the sealing to the heads is bad.
yes, your right! i was really happy, because everything went well and the car runs very good, getting ready for tuning my q-jet and looking for the best performance i can get out of it, and now this large step back 😒
I think from what you have described that too much oil is going up to the heads and not draining back sufficiently. Although pricey, oil restricted pushrods are probably the easiest fix here without tearing everything down again. You can try to increase the oil drain back by careful opening up the drain back holes in the heads. I have never done this but have heard of it being done. Maybe others with experience here can chime in.
Yeah, so the 501-12 from comp are similar to the stock size just rubber instead of hard nylon. The Felpro nylon factory replacement may work better. It looks like those might be lifting and maybe letting all that oil in the valves. Check your drain back holes and make they aren't filled with filings from the machine work. Funny a stock volume oil pump pushes that much oil up top. Yeah, the oil restricted push rods may be your easiest solution to reduce oil up top.
There is a good chance old 307 and 403 just identified the problem, I had this occur on a SBC, the seal rides up on the stem. The SBC that did this literally had wet oil soaked exhaust pipes. Get a look in the intake when you receive the borescope and if that looks good I'd be going after the valve seals. Try to find seals that hold onto the guide via spring tension.
My first thought was in direction of intake leak to valley. Double check mating surfaces of intake to heads. Install intake w/ no gaskets, loosely install bolts and check alignment of surfaces.
Check PCV line for “excessive” oil, could be getting sucked through PCV system, I’ve had that happen w/ unbaffled valve covers, not sure what you have.
Last edited by bccan; April 13th, 2021 at 05:10 AM.
My first thought was in direction of intake leak to valley. Double check mating surfaces of intake to heads. Install intake w/ no gaskets, loosely install bolts and check alignment of surfaces.
🤔 its an edelbrock performer aluminium intake which i had mounted on my stock 350 before.
I used a fel pro valley pan gasket and around every port, i degreased the mating surfaces of the heads and intake before installation and put not too less, not too much of the black RTV silicone around the ports. A bit more around the water ports.
I worked very properly and careful but, for sure, there can be a leak! The borescop will tell the truth.
Sorry. There is no such thing as a liquid being a gas. It is one of three phases only: Solid, Liquid or Gas.
Yeah, i know what youre meaning, but it takes a while till fuel is vaporized, and these puddles are smelling like fuel and arent oily.
BUT, i put a rag on a thin wooden stick to check if the wet stuff on my pistons is oil, and it is. It smells like oil and its greasy, so theres definitely oil getting into my combustion chambers.
I cant wait to get the borescope.
Last edited by 71OldscutlassS; April 11th, 2021 at 07:59 AM.
Odd sense of reality has overcome my reasoning. The OP means to suggest it’s gasoline in the liquid phase as opposed to a “gas” (gaseous substance). I read everything like a fricking chemistry equation.
But it looks further as though it’s oil I guess from the rag and stick.
With "gas" i meant "gasoline", "fuel", in german "benzin" - whatever.
In another thread, i read that sometimes its necessary to retorque the intake manifold bolts when using ab aluminium manifold after the engine was running for some time. I havent done this yet, but i thought with the thin steel valley pan gasket, this makes not really sense? With thick composite gaskets i can understand.
For whatever reason, #7 or #8 also the cylinders I had issues with fowling and losing compression as well. What valve covers are on this motor? That could be mix of oil and gas in the intake, the PCV could be drawing in excessive oil. I find ethanol blends almost white and a much weaker smell. Straight gasoline is the more yellow, which would explain the colour and may be mostly gas.
Last edited by olds 307 and 403; April 12th, 2021 at 06:38 AM.
Not trying to side track this thread, but a nice borescope with dual lenses offering a side view to see the valves is the Teslong NTS500.
Wish I had one.
For whatever reason, #7 or #8 also the cylinders I had issues with fowling and losing compression as well. What valve covers are on this motor? That could be mix of oil and gas in the intake, the PCV could be drawing in excessive oil. I find ethanol blends almost white and a much weaker smell. Straight gasoline is the more yellow, which would explain the colour and may be mostly gas.
I will do i leak down test on all cylinders as soon as i will get the tool. What is the proper procedure for this test? I mean, in what time, which pressure lost is acceptable?
I use the regular "super 95 ocatane" fuel we have here in europe, i have no clue if or how much ethanol is in our fuel, but the stains in my intake definitely have the smell of gasoline, so it has to be mostly gasoline (i hope my well plugs in the q-jet havent started leaking 😶, i really dont need more problems currently).
The valve covers on the engine are stock olds covers with the long baffles. I really cant tell if my PCV valve is good or bad, but when i take a look at the grommet, there is some oil visable.
here are some pictures:
as you can see, theres a bit oil on the pcv valve, is this normal?
i cut my PCV Valve hose which is connected to the carb to take a look inside, this is the end of the hose on the valve cover-side:
this is the cutted end of the hose at the carb side:
Is it normal that the hose is that wet from oil? Or is my PCV valve shot and the engine is pulling too much oil through it in the carb?
my stock engine has different, higher valve covers, maybe they would be a better choice? Left is the higher one, right has the same dimensions which the ones i have on the 355:
BTW, when i swapped the Aluminium Intake after 3 years from my stock engine to the 355, it hasent had these Puddles inside. It looked like brand new and clean inside, so maybe really the valve covers and/or the PCV valve are the reason for the engines oil consumption 🤔.
BTW2, i recognized that the valve covers i was using have holes in the baffle. My stock covers havent. I suspect oil is splashing around from the rockers through these holes and being sucked in by my PCV valve. 😮 heres a picture for comparison, left is the higher, stock valve cover of my stock engine, right is the cover ive been using on the 355:
BTW 3, i stuck my hand down in the intake 2 minutes ago into the puddles and its really oil. Just mixtured with gasoline. So i really now think that my oil burning issue is coming from the top (pcv).
i really appreciate your all help and ideas! Great Forum!
Last edited by 71OldscutlassS; April 12th, 2021 at 10:34 AM.
Yes, use the valve covers with the tighter baffles. A combination of a valve cover change, new valve seals and new PCV valve should make a very big difference.
Yes, use the valve covers with the tighter baffles. A combination of a valve cover change, new valve seals and new PCV valve should make a very big difference.
Today i cleaned the intake as best i could and installed the other, new painted valve covers.
I got my borescope too and checked all mating spots of intake and heads from the inside. The whole intake is wet from oil on the inside, but the intake ports of the heads are looking more wet, so i guess the intake is not sealing properly to the valley.
Damn, because of the puddles under the carb, i was sure that the PCV valve sucking oil.
I cleaned the plugs and let the engine run warm for about a half an hour. It never really stopped smoking out of the tailpipes. I pulled out the PCV valve from the valve covers, but it made not really a difference. After the test i recognized that some plugs and pistons are wet again from oil.
I recognized too, that when i pull the pcv and the breather and plug the holes with my thumbs for a while and then take the thumb off the pcv grommet, oil fume is slightly whoooshing out, so i have a slight pressure on my crankcase. In my thinking, if the intake is not sealing properly to the valley, there should be a vacuum? Its confusing.
I did this test today with my OLD PCV valve, just because im still waiting for the new one.
how can i recognize if the valve itself is bad? I just know that its rattling when i shake it.
sorry for my long posts, but i never had an oil burning issue on a V8, just on my DR650 😃
Last edited by 71OldscutlassS; April 13th, 2021 at 12:21 PM.
The crank case pressure could be unseated rings, your leak down test will tell you that. On a motor where milling occurred, really any rebuild, the intake will actually fit tighter. Don't be in a hurry to remove the intake, the PCV valve looks like it was pulling in some oil. The Turkey tray gasket usually seals without issue. I use Aviation sealant around the intake ports, whether it does anything, who knows.
The crank case pressure could be unseated rings, your leak down test will tell you that. On a motor where milling occurred, really any rebuild, the intake will actually fit tighter. Don't be in a hurry to remove the intake, the PCV valve looks like it was pulling in some oil. The Turkey tray gasket usually seals without issue. I use Aviation sealant around the intake ports, whether it does anything, who knows.
CAN the rings still be unseated? The previous owner already drove some miles on the engine, and even i did a few hundred miles since the cam swap. But maybe its no mistake to do the "ring seating procedure" a few times.
Even, my crankcase pressure isnt really high as i read in some "high crankcase pressure" - threads were oil dipsticks and intake front and read rubbers seals being popped out and oil bein pressed out of gaskets.
just a slight whoosh when i let the thumb off, and the PCV's job is to suck thoses fumes out and burn them?
Maybe i have to DRIVE the car some miles to eliminate the smoking completely and get the rest of the oil out of the intake/combustion chambers.
Because i just let it run on my driveway for about 30 minutes in hope that the problem was just the valve covers/pvc and the smoking will stop when the engine gets warm.
Yeah, i will not hurry to pull the intake again, but if the consumption/smoking will not stop, this is the next step to do.
I will do the leak down test as soon i have the tool here and let you guys now what i found out.
As far as oil drain back goes if you are getting that much oil il top and not going back down something is clogged. I run 6 qts with a deep sump pan and I spin the engine to 7k RPM. On my last sbo it had a stock pan stock style pump and I spun it to 6500 rpm with no oiling mods. Just fwiw.
As far as oil drain back goes if you are getting that much oil il top and not going back down something is clogged. I run 6 qts with a deep sump pan and I spin the engine to 7k RPM. On my last sbo it had a stock pan stock style pump and I spun it to 6500 rpm with no oiling mods. Just fwiw.
I have checked my drain back holes, theyre all open. Even, when my engine was warm, i spun the engine to so 3000 rpm while lighting into to pcv grommet to take a look if theres oil splashing around over the baffle but it wasnt. I think, with the old valve covers it was like this.
I drove the car yesterday first without PCV in the calve cover for a good while and i recognized when the car is warm, i have those oil fumes/steam coming out of the valve covers when the engine is running, when i block both grommets with my thumbs, there is building up slight "pressure". Its not able to feel on the thumbs, but as i told, when i let them off, it whooshes out a bit. With the pcv hooked to the carb as it should be, the car ran normal and without smoking.
But at home, i pulled plugs, valve covers and carb again to inspect it, and now there was a bit water mixed with slight oil in the pcv hose which made a small spot of milky sludge on the carb gasket.
Maybe it is condensed water which got in the crankcase when i was driving around with open grommets.
I took a look in the manifold again and now its dry under the carb, but i borescoped again in the intake ports of the heads and through the plug holes on the pistons, and there its oily-wet again. I assume, if the leaking HAD stopped, the combustion chambers should be dra or the rest-oil being caked?
Im getting more and more suspicious that my intake manifold isn't 100% sealed to the heads.
You have done the valve seals yet, correct? Unless there is a gap and air leak, the steel shim gasket should not allow oil to be pulled into the combustion chamber. A few on here have had that issue with the aftermarket fiber gaskets and no valley pan. I would check the Performer for straightness if you do pull it, It may need milled. Also try Gaskasinch or Aviation Sealant around the intake ports and either Ultra or Optimum Black around both sides of the water ports and tall, thin beads on the end rails when you put the new Turkey Tray gasket in.
You have done the valve seals yet, correct? Unless there is a gap and air leak, the steel shim gasket should not allow oil to be pulled into the combustion chamber. A few on here have had that issue with the aftermarket fiber gaskets and no valley pan. I would check the Performer for straightness if you do pull it, It may need milled. Also try Gaskasinch or Aviation Sealant around the intake ports and either Ultra or Optimum Black around both sides of the water ports and tall, thin beads on the end rails when you put the new Turkey Tray gasket in.
No, i havent done the valve seals, since they came new when the previous owner rebuilt the engine. I took a look of them, and they also look brand new and are soft. Even, i want to determine everything else first before i do this.
yesterday i got my leakdown tester, and 15 minutes ago, i finished testing:
i think these results arent bad for a cold engine, my compression test results have been good too, so i doubt that my problem has something to do with pistons or rings.
today, i used all my senses to find the issue:
as i realised that its fuming/steaming out of my valve cover grommets and "whooshing" when blocked and let the thumbs off them and my pcv hose had also water/oil sludge inside after a 30 min drive with the car, i tasted a bit coolant, and tasted the watery oil stuff in the pcv hose.
Surprise surprise, its coolant.
After that, i took a look in my radiator, which i filled up a few days ago and the level rapidly lowered.
Now, im pretty sure that my intake is not sealing properly. I think its letting hot coolant steaming into the crankcase AND let the cylinders sucking oil from the valley too. I think, with the previous valve covers, the engine really pulled a lot of oil through the pcv valve, since my intake was flooded with oil right under the carb. This stopped with the new/old valve covers with the better baffle, and now, the coolant steam is visible better in the PCV since the oil sucking stopped.
I have to say that i guess that i know my fault:
I havent followed the CSM's torque sequence to tighten the intake manifold down AND, i used RTV not only for the water ports, i used it in a thin layer around the intake ports too. Since that you recommended aviation sealer or gaskasinch for the intake ports i assume that this is a mistake? AND, i used the rubber front end end seals which came with the turkey tray gasket. A lot of people in this forum are recommending not to use them.
I guess, its time for me to pull the manifold, check it for warping, and follow the CSM's procedure to install the intake again.
Thanks a LOT for any help! The learning process is never ending 😮
Last edited by 71OldscutlassS; April 15th, 2021 at 10:48 AM.
Look for unsealed areas immediately after removing the intake before cleaning anything, you might see the problem. After all the surfaces are clean but before reassembly, fit the intake dry sans gaskets and look/measure/examine it again.
No, i havent done the valve seals, since they came new when the previous owner rebuilt the engine. I took a look of them, and they also look brand new and are soft. Even, i want to determine everything else first before i do this.
yesterday i got my leakdown tester, and 15 minutes ago, i finished testing:
i think these results arent bad for a cold engine, my compression test results have been good too, so i doubt that my problem has something to do with pistons or rings.
today, i used all my senses to find the issue:
as i realised that its fuming/steaming out of my valve cover grommets and "whooshing" when blocked and let the thumbs off them and my pcv hose had also water/oil sludge inside after a 30 min drive with the car, i tasted a bit coolant, and tasted the watery oil stuff in the pcv hose.
Surprise surprise, its coolant.
After that, i took a look in my radiator, which i filled up a few days ago and the level rapidly lowered.
Now, im pretty sure that my intake is not sealing properly. I think its letting hot coolant steaming into the crankcase AND let the cylinders sucking oil from the valley too. I think, with the previous valve covers, the engine really pulled a lot of oil through the pcv valve, since my intake was flooded with oil right under the carb. This stopped with the new/old valve covers with the better baffle, and now, the coolant steam is visible better in the PCV since the oil sucking stopped.
I have to say that i guess that i know my fault:
I havent followed the CSM's torque sequence to tighten the intake manifold down AND, i used RTV not only for the water ports, i used it in a thin layer around the intake ports too. Since that you recommended aviation sealer or gaskasinch for the intake ports i assume that this is a mistake? AND, i used the rubber front end end seals which came with the turkey tray gasket. A lot of people in this forum are recommending not to use them.
I guess, its time for me to pull the manifold, check it for warping, and follow the CSM's procedure to install the intake again.
Thanks a LOT for any help! The learning process is never ending 😮
Looks like you found your problem. I would say with confidence that your rings are bad. That 22% is not acceptable in my opinion.
April 10th, 2021, 06:00 AM
