My 428 has less than 300 Miles on a full rebuild. It was burning oil from #3 and #7 cylinders. The spark plugs from those cylinders were oil fouled.
A compression test revealed 160# on all eight cylinders. I was told that even though I have good compression i could have a oil ring problem. is that possible?

I had the intake manifold gasket replaced. A Felpro gasket was used with right stuff sealant in the front and back of the intake/block junction and around the placed where oil could get sucked into the intake to head ports. By the way Victor Reinz intake gaskets are not available according to Clevite the needed part numbers are no longer being manufactrured. Believe me, I looked all over the country for them.

I still have blue smoke coming ourt of the tail pipes after a 45 minute run while parked and a 15 mile drive home. So I don't thibnk it is oil residue in the exhaust. The engine has a police interceptor (PI) intake and C6AE-R heads a AA Holman Moody solid lifter cam and Holley 750 FCFM ntake. The mechanic who replaced the intake gasket was not the builder of the engine. He has worked on FE engines for many years. I feel confident that he knows what he is doing. He conferred with the original engine builder (his shop is 75 miles away) about the build and the oil burning problem. Thsy have known one another for years.

I called the original engine builder today. He said that the intake may have low spots at the ports on cylinders 3 & 7 and that the intake may need to be milled. I think he should have checked that (I'm not sure how other than with a straight edge) when he built the engine. My thinking is that the original builder should replace the PI head either with another GOOD PI intake or one that is comparable and that will port match to the C6AE-R heads. I'm leary about having the intake milled. What do you guys think about milling the intake to fix this problem? What other intakes would work with this setup? Thanks in advance for your guidance / experience on this matter.

 

I had to have my intake milled due to oil leaks. You can check by dry fitting the intake and check the clearances, top and bottom at all 4 corners. If there is any difference between the top clearance and the bottom clearance..say more than 0.002", something isn't straight.

I have to admit, I havn't done the above check, so I can't guarentee it works. All I did was check along each side with a machinist's straight-edge and I found on mine, #1 port was out further than the others, so crated a bad leak on #2, less of a leak on #3 and #4 was OK. This sounds a bit like your issue where you have central cylinder problems vs end cylinders.

And of course that check didn't do anything to check the angles were all 45 degrees.

Intake manifolds can be more rare or valuable than cylinder heads. Also, heads sometimes need replacing where an intake doesn't. Due to those reasons, if the straightedge check works, you may want to think about trueing up the heads vs the intake. I think I'd fix whichever one was furthest from 45 degrees so no matter what happens down the road, a new part (head or intake) should match up with your engine.

A leak down test may reveal differences between cylinders that a compression test does not.

You also may have worn valve guides or possibly bad valve seals. I'd have to think it out more, but if you have more blue smoke at idle (where vacuum is highest), then it might be oil sucked down the valve guides.

Bad rings tend to pump out blue smoke when you accelerate putting a load on the engine.

 

Whether or not the tranny is a manual or automatic, put it in 1st or 2nd gear. Floor it. When the RPMs come up to say 4500-5000RPM, let off the gas, and let it rev down to about 1000 RPMs. Then floor it again.

If there is no smoke until you floor it the second time, or there is a BIG difference in the amount of smoke after that, the intake is leaking and sucking in oil.

The high vacuum during the down-rev from 5000 to 1000 will suck in a lot of oil, and then flooring it will burn it all off.

That won't happen with oil-control rings, or at least, it'll happen in a different way.

 

Argess and Krewat Thank you for the guidance. The guy who built the engine is supposed to come get it and the truck next week. If the intake is not straight then I'm going to ask him if he has another police interceptor intake in good condition. I don't know much about the highly technical aspects of engine building or machining of engine parts. However I don't get a real good feeling about milling the intake because it is an expensive and hard to find item and if it's milled it may not fit any future heads I may want to use on this engine. If it has low spots on #3 and #7 then I want a different intake. The heads went to a machine shop before they were installed. I would think that they would have checked the critical surfaces to see if they were true etc. This was not the highest dollar engine build, but I have several thousand dollars invested in it and right now it seems like a big mess.

I can't perform the checks that Krewat suggested because the rockers are out of adjustment (the guy who replaced the intake manifold gasket did something that caused them to be out of spec) and when I goosed the gas pedal bringing it home it clattered a lot. So I babied it home. I'm in over my head on this one. The guy who built the engine needs to stand behind his work.

 

When you find out what the problem was, report back, we'd be interested to hear how it all turns out ...

 

I will definitely report back and let everyone here know what happens with the engine.

 

66_in_ky,
I hope this gets to you before you tear your engine down. Put a vacuum guage on your dipstick. If you have an intake leak you will get a vacuum reading. If you get pressure the intake is sealed. You'll see approximately 1 1/2 lbs pressure. Most vacuum guages will indicate pressure also. Make sure you tape off any vents, oil fill, pcv, road tube etc. before you do the check.
If you get good cranking pressure and still get oil that means it's comming down the valve stem on the intake valve. Jim

 

Jim,

I appreciate the suggestion. I'm not sure I understand it completely. Should the engine be running when I perform this test or just crank it over a few times? I understand that I would pull the PCV and hose from the valve cover and tape the hole on the valve cover. Same thing on the other valve cover where I pour in the oil. What about that same PCV hose going to the back of the carb should I plug the hose and what about the power brake vacuum hose and line that runs to the transmission modulator? I'm sorry about all the questions. I just want to make sure I understand how to do this.

Larry

 

Larry,
Yes, Pull ALL hoses and plug them off. Plug the Pcv at the carb so the engine will run. Stop up all holes. Then put a vacuum guage on the dipstick outlet. Yes, the engine has to be running. Let it run for a while at different speeds.
I've got to figure out how to get mail notification from this website. Jim

 

Interesting concept....connecting a vacuum guage to a dipstick tube to check for intake leaks. I suppose the leak would have to be bad enough the vacuum was stronger than the blow-by in order to confirm the leak.

 

I like my method better - it'll tell you if you have an intake leak, and take care of mosquitoes at the same time

Side note: I wonder how much blow-by a not-so-broken-in-engine will produce?

 

Guys,
The idea is to see if you've got vacuum. If so, it's a no brainer. Now doesn't this sound a lot easier than pulling the intake apart, having it milled and THEN find out the valves stems have taper or too much clearance. Jim

 

Guys,
P. S. Do a compression check on the cylinders also. The cylinders should all read about the same except for the cylinders that have oil. If they are good cylinders they should read about 10 - 15 lbs more because of the oil. If they read the same or less with oil in them that means the rings are suspect. Jim , ASK ME HOW I KNOW ALL THIS _ _ _ _. Well, I'll tell you anyway. I just went through this with my new engine. The machine shop used intake valves from another head I had to save money. They checked the top of the valve stems, put new guides in and called it fine. I ran the engine and had two cylinders fouled out with oil. The information I provided here is what I used to pinpoint the problem. We didn't have to wonder what was wrong with the engine, we knew. Jim

 

I just performed the test that Jim recomended. I taped off the following possible vacuum escape points: PCV hole in passanger side valve cover, PCV valve still in the hose that connects to the back of the carb, brake booster vacuum hose, transmission modulator line, oil fill hole in top of drivers side valve cover, vacuum advance hose coming from carb to distributor. The vacuum guage has a male extension on the end that fit tightly over the oil dipstick tube. The guage measures vacuum or preasure. The needle sat on zero. I know the guage works. The engine was warmed up prior to the test and I watched the guage at various throttle points (various RPM).

Prior to having the intake manifold gaskets replaced I could hear a high pitched whistle sound coming from the engine if I turned the carb idle adjustment screw to where the engine idled at about 750 RPM in park. Since the gaskets were replaced I hear that same whistle sound all the time. I put a funnel to my ear to try and isolate the source. It seems to be coming from the top of the engine. I don't know if this sound is related to the oil burning or not. I suppose it could a vacuum leak. That may explain why their was no reading on the vacuum guage during the test.

I stuck my finger down the hole in the passenger side valve cover where the PCV valve goes to confirm that there is a baffle in there. The baffle is there. I'm going to try the test that Krewat suggested nest.

When the engine first starts up I don't see blue smoke at the tail pipes. After it warms up a few minutes (3-5) it smokes a little at idle while in park. When I press the gas pedal and quickly release it there is a lot of blue smoke coming from both pipes.

Thanks to all who have offered their guidance.

 

Intake gasket leak. All the same smoke symptoms, PLUS, I had the same whistle when the engine got warmed up, UNTIL I had the manifold trued up.