I recently towed a John Deere 4630 home from across the divide with my '66 with a built 410. It was just shy of 33,000 gross but it pulled like a champ (as always). Coming down the long side of Homestake (2+ miles of 6%) loaded I was in second gear between 2500 and 5000 RPM trying to help the brakes all I could.

Once I got to the bottom I could barely keep it from sputtering out and dying and she was smoking a LOT of blue out of the tail pipes. It took almost a mile for it to clear up and come out of it. After that, it ran great.

I assume with the extended period of high vacuum I was just pulling a ton of oil by the rings? Is there any way to combat this? Would a set of exhaust brakes raise the back pressure enough to keep it from loading up on oil so bad? I know they would help out my brakes a fair bit...

 

Sounds like you either have an intake manifold leak, or oil was polling in the heads because of the high RPMs.

I'll post more later.

 

I've come to the conclusion FE's (and other engines) will use a little oil any time you drive sustained 3000 or so rpm's and pushing it down a long, long hill is definitely worst case for oil sucking. I rigged up a clear window for a valve cover once just to watch oil at various rpm's. At around 2500 the oil turns into a fog. I'm guessing the same thing happens down in the crankcase. In other words, the oil mist is easy to suck up into the chambers.

What brand and weight oil you using?

 

I have no input to help but wanted to tell you every time I hear what you tow it amazes me. Hopefully some day I can use the parts I have and turn my 390 into a 410.

 

Oh, and the other obvious thing to check - the PCV system. Make sure the PCV rattles when you shake it. Another thing to look at - the baffle in the valve cover for the PCV - it has to have one, otherwise it WILL suck up oil.

Is this even a PCV equipped engine? Or is it just a breather?

 

PCV, worn valve guides or bad valve guide seals

 

PCV valve rattles - AFAIK if they rattle then they are good.

Running 15W40 synthetic oil and have an engine oil cooler mounted in front of the radiator.

Intake manifold gaskets - the engine runs great with no symptoms of a vacuum leak at all.

Valve guide seals - Fel Pro with less than 25K miles and about 4 years old.

Valve guides - less than 25K miles

Oil pooling on the heads - I have the Holley jets under the rockers. If you guys really think this is the cause, the only thing I could do to help is swap in a set of long finger drain tins. With the jets in place, do you think this still could be the cause?

As for oil use at RPM sustained over 3,000 - I drive everywhere at a minimum of 70 MPH (3100 RPM) and have been know to cruise down the interstate at 80 MPH (3600 RPM) and it never uses more than 1/2 a quart in a 6,000 mile oil change interval.

Pulling the tractor home, I used about a 1/2 quart in 250 miles. This is the first time I have seen oil use like that (when starting from the proper level).

Since then, it is back to normal and not using any oil.

 

I try to use the semi whenever possible, but the tractor was way back in the sticks and I didn't want to have to jockey the semi back in there.

 

Due to the usage under load only, I have a few thoughts.

-If it was an intake leak sucking oil, it would always do it.
-possible valve stem seals or or excess oil under valve covers
-possible thinning of the oil due to high load/high heat

Seems a $10 deal to change the valve stem seals. Better yet, if ever rebuilding the heads, I'd have them machined to accept viton seals (they really are so much better). Obviously not worth tearing the heads off to do, but I'd keep it in mind for the future.

An oil cooler or a different oil, perhaps a little thicker synthetic that can handle higher temps without thinning.

Good luck,

 

5000 is winding a 410 up pretty good, same stroke as a 428, we use to limit them to not over 5200 to keep from breaking cast pistons, best to keep rpm's below 4500.
Most likely sucked oil up past the rings, not sure if heavier synthetic or dino oil would help.
Don't think a exhaust brake would be as effective on a gas engine as on a diesel but it wouldn't hurt to have one, I like the one on my diesel pickup.

 

There's a reason they only use exhaust brakes on diesel engines. They can take the insane compression, gasser can't.

 

It has forged pistons, ARP rod bolts, and the whole assembly was balanced. It was mostly in the 3k to 4k range but it did get up there a couple times.

 

It would be really cool to use something like this: (I bought one but haven't used it for anything legit yet)

It comes with a mirror attachment so it can "see" at a 90 degree angle. Remove the plugs, rotate the engine until the intake valve is open, and take a look at the intake valve and see if it's got oil on it. That would eliminate a vacuum leak or PCV system problem.

 

Most exhaust brakes only create 40-60 psi of back pressure which doesn't create insane compression pressures. A exhaust brake prevents fresh air from entering the engine thus preventing ignition, compression stroke without ignition causes a retarding effect, on the exhaust stroke the back pressure from the exhaust brake creates a second compression stroke thus adding to the retarding effect.
Engine brakes on larger diesel engines open the exhaust valve slightly just before the injection event dumping the compression eliminating the power stroke, with the cylinder now empty on the power stroke this creates and suction inside the cylinders thus adding to the retarding effect.

On gas engines when the throttle blades close it creates a suction inside the cylinders that have a retarding effect, something diesels don't normally have.
Because there less air entering the engine due to the closed throttle blades , there's less exhaust for the e brake to work with to create back pressure.

There forth a exhaust brake is not as effective on a gas engine as it is on a diesel because the closed throttle blades are already doing half of the job.
The lower compression ratio's of gas engines also takes away from the retarding effect.

The cost of two e brakes for a dual exhausted gas engine is also a deterrent.
Not saying a e brake on a gas engine wouldn't help, It's more of a cost verses benefit issue.

 

When I was driving an Isuzu NPR box truck in my early 20's, and the heat shield welds blew on the piece of pipe before the exhaust brake, it sure didn't sound like 40-60 lbs of pressure. It was a simple exhaust valve, completely closing the exhaust pipe. No exhaust valve operation. Besides, on a gasser with the throttle plates closed, there's really no exhaust anyway, and really no hope for cracking open an exhaust valve

Back to the original topic at hand.