Sudden Increase in Blow-by

[choppedtop]

Ha ha John. When I worked at Detroit Diesel years ago, the field mechanics would put very small amounts of Bonami in the blower if the rings wouldn't seat pretty quick after field quickie overhaul. Opps, to much was a real bad word.
Lee

 

[one finger john]

Yeah, that's it. Bonami. I think I remember mechanics feeding it to Indy car 4 cylinders (Offenhausers) to seat the rings. Chrome rings on a chrome plated bore. Head was integral with the block. No head gasket. Course that was in the 1930s.
Screaming Metal would know all about that. Probably taught them how to do it.

John

 

[Lee_in_KC]

By "rattling the engine" do you mean detonation? Not that I'm aware of. No obvious signs. I run the carbs on the rich side specifically to avoid detonation. Timing is mechanical advance only, IIRC 18* initial, 34* all in by 2600. I only put 93 octane in the tank!! All the BP stations have it.

The little "rock" is a piece of thread sealer from a head bolt that I knocked in there when wiping off the head gasket.

I have never run the motor without K&N filters in place. The blower rotors look brand new... not a scratch or wear mark anywhere. Same with the parts of the case I can see from the top and bottom.

I've decided to head over to Indy tomorrow for the rest of the T-bucket event, so I won't be working on the motor until next Monday.

I appreciate everyone's help and advice.

 

[one finger john]

Enjoy the experience and take the pictures of your engine for other peoples opinions on what might be wrong. Its a good conversation starter.

John

 

[Screaming Metal]

OK, on your head that fed that cylinder, look into the intake port and see if you have alot of oil on your valve stem. Probably where the oil fed in.
Or the runner right there on the intake runner, look at where that gasket sealed. if there was a leak there, you'd throw some exhaust gas in there possibly....
The bores and pistons look good....look at your rings on the one cylinder and see if you can get a really small fine wire, if you go past the top of the 2nd ring.... then there is your problem.

Normally, on a 10,000 mile motor, the bores are alot slicker....rings might have not seated correctly....
Give us a good closeup of the middle of the bore on #1, 2 places, 90 degrees from one another....

 

[Screaming Metal]

Also, check the guides in that cylinder....either a seal is gone, got oblonged, for that much oil to get on top there. It being right there on that piston notch, its either coming in thru the port on the intake cycle, getting pulled past the guide....
If its sucking oil past the guide seal, chances are on the exhaust cycle your getting some base pressure.
(The last one that I had that was like this one, there was a low spot on the blower intake manifold passage, was sucking oil there...)

Did you have the valve guides Knurled?

 

[Screaming Metal]

Around that oily mess on top of that piston, are those bb's stuck to the top of the piston? If so, possibly preignition. Did you wipe the top of that piston off any?
Reason being, right at that valve notch on top of the piston, all the carbon, soot and oil is blown off right at the edge of that notch.

You are right, there is excess oil in the cylinder. Either from the rings or valve guides or both.
Don't forget that well lit shot of no. 1 cylinder wall. Could you have rattled the engine at one time in the past?

Kinda looks like that....or slight case of preignition.

Give us a shot of the chamber on that cylinder, also....

 

[Lee_in_KC]

OK, finally got a chance to spend some more time checking things out on the motor. The "BBs" on the top of the pistons are just little globules of oil. They are very sticky... not yet baked on. I can rub them off with my finger. The other rough areas are baked-on oil. I can scratch it off with me thumbnail.

The intake valve stems on ALL of the cylinders have a baked on oil coating on them. The tops (intake side) of the valves have a sludge build-up on them. This is #1, but they all look like this...

Here is #1 combustion chamber...

I'm starting to wonder if I even HAVE valve stem seals!! I can't see for sure because of the damper springs inside the valve springs. I bought these heads built-up from Jeg's. They are Dart Iron Eagle S/S heads with springs as spec'ed by Comp for my cam.

There is a coating of oil in all of the intake runners, but there is no oil in the intake manifold under the blower. The head-to-intake gaskets looked well-sealed when I pulled them off. No obvious oil traces across the blue "print-o-seals."

I ran an .008" feeler gauge around the top ring of #1 and did not feel any gaps or abrupt changes in ring position (i.e. displaced piece of ring). It was dead smooth all around.

Guess I need to run down a valve spring compressor and take a closer look at the valve stems and guides.

If the valve stems/guides are the source of the oil getting into the cylinders, then what is causing the excessive crankcase pressurization that's blowing oil and steam/smoke out the breather? Could it be that the poor ring seal has gotten so bad that it is overcoming the PCV system?

 

[RPM]

However none of that will make you have 70% leakage into the crankcase.

 

[one finger john]

Lee, I love you like a long lost brother.

Drop the pan and pull no. 1 piston & rod.

We will all feel better knowing the truth.

John

 

[one finger john]

It's looking like one worn out engine after 10,000 miles.

The only thing that kept it going was the MSD ignition.

Beginning to look like diesel.

Sure this wasn't one of those VW diesels?

EPA gonna git ya!

John

 

[one finger john]

There is a possibility that the heads were assembled without guide seals for "performance" purposes.
If so, then the valve guides and valve stems might be perfect.

Just looking for a positive spin here.

John

 

[2old2fast]

If you would , give us some pics of the cyl. walls toward the top of the bore , especially any discoloration , it could provide a clue about ring seal ...
dave
AFA the "wet" area in the combustion chamber , if you leave the head sit a few days , that may "dry up " as in it's fuel...as for the tops of the valves , that's what mine looked like when the guides went bad... Brodix claimed that if the guides were not "pre oiled " during assy. then used "almost immediatly , , the guides would gall on initial start up .....yea, right ???

 

[one finger john]

I thought Iron Eagles came with 2.02 intakes and 1.65 exhausts. That looks like too much room between the valves for those to be 2.02/1.65s.

Am I wrong?

John

Also would like to both sides of the head gasket.

 

[2old2fast]

There's only 3 ways I can think of that would pressurise the crankcase, thru the rings , head gasket to valley , or in your case , pressure thru the intake gaskets..
dave

 

[Lee_in_KC]

Ron, my confidence in the accuracy of my leak-down tests goes down with every new discovery. I was taught how to do an airplane-type "compression test," which is actually a leak-down test, about 30 years ago. I've done maybe 2-3 on airplane motors since then, always with an A&P looking over my shoulder. I wouldn't bet the money in my pocket ($9.37) on any of the leakage percentages!!!

John, I feel the love... or something! I have already accepted that the bottom end has to come out, if for no other reason than to get a good fresh hone on the cylinders. I guess I'm enjoying our detective work. I'm waiting for the big "Aha!'. I have the 72cc, 1.94/1.50 versions of the head... they're what the race shop that built my short block recommended.

I looked at both sides of all gaskets... nothing obvious. A couple of the bolts holding the intake to the heads were pretty loose when I removed the intake... could be.

Dave, I will try to get better pix of the cylinders tomorrow.

Gotta fix supper and get ready to watch the Royals and Chiefs (thank goodness for picture-in-picture!!).

 

[one finger john]

MMMMMM ......... Are those forged pistons or hypereutectic (cast) pistons?

 

[Lee_in_KC]

All I know about the slugs is they are KB "blower" pistons.

 

[one finger john]

I know this sounds like a terrible inconvenience.

Could you list all the parts that went into this engine, along with part numbers, manufacturer, (if they are listed on the build receipt, please photocopy the receipts and send them in). This would be from pan to carbs, water pump to converter. Along with pertinent tune specs and blower ratio.

And all the machine work that was performed, along with any modifications to the block, heads, crank, rods, balancing, etc..

I know this will be a big job, but I think that it will clear a lot of things up and steer us in a better direction towards diagnosis and repair.

I remember you have told us about this engine in bits and pieces but to be able to view the whole build in one sitting, visually one bite, would be very helpful.

And last but not least, tell us what the conversation with the machine shop & engine builders was like.
Especially what your wants and needs were for the expected performance of this engine. Please include prices. Were you budget constrained?

I wrote work orders as a service rep at various Porsehe, VolksWagen, and Ferrari dealerships. I started as an apprentice English car mechanic at eighteen (including Rolls Royce, Aston Martin, British Leyland, Austin Healy, And little bits and pieces of other makes.

I finished my auto career working for two of the top Honda dealerships (Beverly Hills Honda and Honda of Hollywood (both in Los Angeles Ca) in the service departments.

When I ask these questions I am only looking for answers to solve this riddle. I hope you do not find them invasive or prying. If you feel I am being either and are uncomfortable, please let me know and I will bow out immediately.

Lots of times people will write in asking vague questions and describe even vaguer symptoms. And then become offended when they don't get the answer they want. Typical - what size carb on my 350 Chevy should I run?

Don't want to play that game no more.

John

 

[coops]

Lee,
I hate to hear about your misfortune and have been there myself when things seem to go wrong before a scheduled trip.From your pictures you have posted I believe a few things: the oil pattern around the valve came from the stem side of the valve and is concentrated more towards #3 more than likely due to puddling and negative degree your engine sits front to rear. I like to use a led light to examine the runners after removing the blower and it is usually clear to see.The intake gasket was likely leaking on the bottom side and with the surface contamination the intake valve not sealing off completely. If your luck is anything like mine this more than once was when I parked it was as usual and the next time started it has excessive blow-by and a hardly noticeable twitch at idle not present before. The lines in the cylinder look to be in the 1/2 to 3/4 upper cylinder area and if not able to be felt with a nail are usually the result of loading with hardly any cylinder temp, excessive idling with hot engine, or in my case very slight aluminum contamination due to lean cylinder and usually have no effect. If the stem side and port of exhaust (dry) along with compression was consistent and appears as pictured then the short block should not have been pushing oil and rings good to go.No more time than what it took to take apart, go through clean and inspect valves,seals,seat areas, reassemble and install.I would then retest leak-down and see. Or if you play it right could be used as a excuse ticket for more cubes,stroke,boost , or all the above, lol. Best of luck!