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Discussion Starter #1 (Edited)
Ok, I finally have a problem I can't figure out. So, before I pull the motor,thought I'd throw this one out for you guys. I have a 400 small block new motor, just won't quit smoking.

It has a .060 overbore, total seal rings, wiseco forged pistons. It was assembled by the guy that has done the majority of the race motors in this part of the city, so I'm pretty well gonna discount any simple assembly error.
It, has a .674 lift solid roller, mega ported heads 2.065 intake valves,1.60 exhaust valves and an edelbrock victor single plane manifold with a 750 demon.

Ok, now the problem. Compression test= 175 lbs per cylinder +or- about 5 lbs.
Cylinder leak down test, about 2%.

With my vacuum pump unhooked the blue smoke from the exhaust lets up a little. But when it is disconnected, the motor pushes oil out the rear main seal. When the vacuum pump is reconnected (I have a check valve that limits vacuum to 10 inches) The smoking gets worse but the oil leak completely stops. Whenever I take the intake off, The bottom of the intake gasket is completely saturated with oil, and the entire sealing surface has some, as well as the entire intake runner being covered. But I can plainly see where the intake is sealing to the gasket just fine.

As far as the heads, I had them on another motor and had no problems, so that eliminates the sealing surface on them. I would think as long as the water passages are sealing fine that would eliminate the possiblity of the sealing surface on the intake. I have tried changing intake gaskets about four times but the same problem keeps coming back.

I have talked to the guys at total seal and they seem to think it is a ring seal problem, I'm inclined to agree. But, why is there so much oil on the intake gasket and in the intake ports, unless my vacuum pump is actually pulliing it from the cylinders and back through the intake? But I don't think that it is running that much vacuum.

So, there is my problem. Let's see if anyone has ever had any problem like this.

Thanks, David
 

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From the sounds of it you have the pump hooked up backwards!
It shouldn't push oil out of the seals if there is a vacuum in the crankcase. I'd independantly verify pan vacuum with pump hooked up. I'll bet you are pressuring the pan.
 

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interesting problem...does it push out the dipstick too...what if you take the dipstick out will oil shoot out. i've seen this kinda problem with boosted cars, but i don't see any forced induction goin on here. but it does sound like you don't have a properly ventilated crankcase, either with breathers, etc....
 

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Discussion Starter #5
No

It only pushes oil out the rear main seal, and bad too. If I let it idle for twenty minutes I bet it would push at least a quart out...NO KIDDING!
Like I said the really weird thing is it only does either after the motor warms up. Nope no forced induction, except for a big dose of nitrous.

David
 

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I can't add much to this but you might whant to get one of those old rubber oil fill plugs that push into the valve covers put a small hole in it and hook a vacuum gauge up to see how much your pump is pulling. It might not be enough to get all the pressure out.
 

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If the guy who built this engine is a professional engine builder, whats he saying? The shop I do my machine work at does nothing but build race engines. If they do a new motor they dyno it but a freshen up doesn't get dynoed usually but if the customer has a problem the motor comes back. There is something wrong with your engine for sure. The rear main shouldn't leak due to no vacuum and it shouldn't smoke or have any blow by if it was done right. I'd take it back to the guy who built it. JMHO, RM
 

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Discussion Starter #10 (Edited)
Machine shop

I agree in part with what you said McCoy. Here is my dilema, the problem with leak down testing total seal rings is until they get totally demolished they don't show hardly any leakdown. So when they do, they are definitely trashed, but if they don't it doesn't mean they're not. At least that is what the guy at total seal said...my machinist too. But if they just didn't seat correctly it may not show any negative readings on the leak down.

My machinist says either valve seals or rings......and he will gladly fix any problem, I'm just trying to resolve it without yankin the motor. Alas, the motor also has head studs, so forget yankin a head while the motor is in the car.

The rear main leak I can slightly understand, since without the vacuum pump being hooked up the motor has no way to breathe. But like I said, I also have a Moroso Check valve in the other valve cover that keeps the vacuum at 10 inches.....and it stays slightly open the entire time the motor is running.


I think the thing that really bothers me most is the inside of the manifold and the inside of the runners in the heads being covered in oil!!!!! I have never seen that before!!!! Do ya'll think the maching on the manifold surface could be off enough for the manifold not to seal off only on the intake ports????? There is no water in the oil so apparently there is no coolant leak around the manifold corners.

David
 

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NOTANOVA said:
I agree in part with what you said McCoy. Here is my dilema, the problem with leak down testing total seal rings is until they get totally demolished they don't show hardly any leakdown. So when they do, they are definitely trashed, but if they don't it doesn't mean they're not. At least that is what the guy at total seal said...my machinist too. But if they just didn't seat correctly it may not show any negative readings on the leak down.

My machinist says either valve seals or rings......and he will gladly fix any problem, I'm just trying to resolve it without yankin the motor. Alas, the motor also has head studs, so forget yankin a head while the motor is in the car.

The rear main leak I can slightly understand, since without the vacuum pump being hooked up the motor has no way to breathe. But like I said, I also have a Moroso Check valve in the other valve cover that keeps the vacuum at 10 inches.....and it stays slightly open the entire time the motor is running.


I think the thing that really bothers me most is the inside of the manifold and the inside of the runners in the heads being covered in oil!!!!! I have never seen that before!!!! Do ya'll think the maching on the manifold surface could be off enough for the manifold not to seal off only on the intake ports????? There is no water in the oil so apparently there is no coolant leak around the manifold corners.

David
I had a similar problem 2years ago with the motor thats in my car now. The intake gaskets pushed up and it started sucking oil into the intake ports. But the biggest problem I had was the total seal rings that were used, they were the low-tension gapless 2nd ring, the moron who gapped the rings gapped them way tight, you could barely stick a 16thousanths feeler gauge between the gap of the ring. It completely wore the rings flat and every single cylinder was shiny and no cross hatches, the motor probably had 200miles on it. I couldn't keep plugs clean to save my life. I pulled both heads off the motor while it was still in the car, every single cylinder was coated with gas/oil mixed. How your plugs look? Always black and wet? If so I would blame the rings for the smoking problem. I don't know what to say about your rear main, other than somebody put in wrong or it went together with no silicone to seal it.
 

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Discussion Starter #12
Plug condition

They are not always black....but they are always wet with oil. Of course I figure if the intake runner on the manifold and the head are both covered with oil then the plug should be expected.
I also uncovered a weird fact tonight when I pulled the intake, the ends of the manifold where the water ports are are coated with gasket material from a good squish when the manifold was tightened. However, around the intake ports there was almost no squish what so ever and no trace of gasket material. Looking at the gasket you can see where it doesn't squish down around the intake ports at all.

Could the manifold be that out of whack????? And the same on both sides???
And no before you ask, the heads are not angle milled.

David
 

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If this is an early 70s block and the mains have been align honed, you need to use a Fel-Pro 2909 rear main seal. A standard small block rear main seal usually will not seal well in this situation. It's worth a check.
 

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NOTANOVA said:
Could the manifold be that out of whack????? And the same on both sides???
And no before you ask, the heads are not angle milled.

David
But have the heads been milled at all? Depending on how much the heads were milled the ends of the (and sometimes the sides too) intake would need to be machined too so that it would seal correctly to the heads...
 

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NOTANOVA, Let me say again that the rear main should not leak on a new or freshened motor even if it has no vacuum on it. Also, you said the intake runners were well sealed when you pulled the intake off so why would you now think it was pulling oil into the intake? You mention not wanting to pull the motor out. That is the easiest thing to do with the problems you have with this. Whats it take to pull it? 1 or 2 hrs max? Buy a 12 pack and call a buddy or two to give you a hand with the hood. JMHO, RM
 

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Discussion Starter #16 (Edited)
intake

I thought it was sealed since there was no coolant leaking anywhere, but looking at the gasket it is sealing good around the water ports and not at all around the intake ports.

Yes the heads were milled,only 0.10. Yes the block was line honed and yes the seal is correct for that.

I didn't say pulling the motor was difficult I said if I didn't have to I didn't want to.

So, if there is no place for the crankcase pressure to vent no seals would leak???? What's the point of a PCV valve?

David
 

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Race engines don't have PVC valves, many just use vent tubes in the valve covers, and they don't leak at all. My motor has only got breather tubes on it, two years old and no leaks. PVC valves came out in the late 60s for pollution control, prior to that engines all had breather tubes. If you sealed the motor so pressure could build inside it gaskets might leak but not the rear main seal. If you didn't angle mill the heads flat cutting them .010 shouldn't be a problem. Not trying to give you a bad time about this just trying to help resolve the problem. Best of luck. RM
 

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Discussion Starter #18
It's ok

I didn't think you were giving me a hard time, I just expected a sealed up motor with no crankcase venting to push oil out somewhere.

I did put a set of thick intake gaskets on, using gaskacinch and a ton of silicone on the end seals. Seems to have gotten rid of my smoking problem.

Of course now I run across a killer deal on a set of big runner Dart pro 1 heads......Just gotta buy them, so I'll end up pulling the motor anyway.
I just hope they make a difference, sure would suck to spend 800.00 and not gain much. The intake valves are actually a hair smaller than what I have now, but I'm hoping that raising the compression (76 cc to 64cc) and the better design of the dart pro 1's will make a difference.

David
 

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sounds like you fixed it but...

i had the same problem with the smoking.. and i tried everything with jetting and fuel. but i checked my cylinder pressure at it was at 210-215 on all 8 so it wasn't blow by. so i pullled the intake off and the intake gasket was pushed up and was leaking oil into the cylinders.

i really dont like the vortec style bolts on the intake they suck with the 2 in each corner i think the old style worked alot better. atleast the bolts were perpindictular to the heads..
 
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