New Engine Help (Please)!

[nonstop]

Good evening everyone!

I am hoping you can help me with an oil issue. I just finished building my 383 for an OT car (Firebird). I fired it up today and ran it at 2000 rpm for 20 minutes. Everything went well with that. As I was bringing the rpms down, it started blowing blue smoke out the tail pipes. I messed with it for a bit, but it still is smoking. It smokes more when you goose it. Rather than a long description, here's what I've got:

PCV oily, still smokes when disconnected
RPMs increase when PCV valve is disconnected
Compression test showed 160-170 in all
All spark plugs are oily
Doesn't smoke on start up, but about 30 seconds into running
Heads were reused, but checked by shop and given the green light. It didn't smoke before the rebuild.

The block was decked. When I assembled the engine, the heads did not have dowels, but the head bolts held everything pretty well lined up (doubt this is an issue, just throwing it out there in case). The heads have new positive valve seals.

Would I be on the right track to assume this is likely a common area problem since all spark plugs are oily? Would it be safe to assume I'm sucking oil through the intake gaskets, or am I missing something?

Please help me with this one!

Thanks for any suggestions or guidance,

Nick

[Alex V.]

If all plugs are approx. equally oily, and the problem is intake gaskets, you'd have really had to FUBAR the intake gaskets - and you'd have very substantial crankcase vacuum. It's not necessarily abnormal for an engine to smoke as the rings seat - a possibility? Since your cam's had the initial break-in now, I'd take that sucker out and put it under a good load a couple times to get the rings under some stress and try to get them seated.

What's your break-in oil of choice?

[Marv D]

You didn't replace the dowels in the block.?? they are there for a reason.

I'd bet a dollar to a donut you have head gasket problems. The head moves around on the block even WITH the dowels as it heats and expands. intake gaskets will be next.

Your machinist should have put the dowels back in the block!!!

[nonstop]

Originally Posted by Alex V.

If all plugs are approx. equally oily, and the problem is intake gaskets, you'd have really had to FUBAR the intake gaskets - and you'd have very substantial crankcase vacuum. It's not necessarily abnormal for an engine to smoke as the rings seat - a possibility? Since your cam's had the initial break-in now, I'd take that sucker out and put it under a good load a couple times to get the rings under some stress and try to get them seated.

What's your break-in oil of choice?

I scoped the intake and found oil all along the inside. I can't take it out yet, the car is still apart and frontend is off. The block was decked, I don't know how much. I went back with factory Fel Pro intake gaskets. I installed them with it on the stand and took my time, but I guess I need to do it again. Going with thicker gaskets this time.

Oil of choice was Brad Penn break in oil.

[nonstop]

Originally Posted by Marv D

You didn't replace the dowels in the block.?? they are there for a reason.

I'd bet a dollar to a donut you have head gasket problems. The head moves around on the block even WITH the dowels as it heats and expands. intake gaskets will be next.

Your machinist should have put the dowels back in the block!!!

Well sh&t! So do I get the dollar or donut?

[68gmsee]

Before doing anything drastic check the easy things first. The pvc usually is hooked to manifold vacuum and if you have oil in the intake, it may be sucking in oil through there . Is there a baffle under the pcv to keep oil from being sucked in?

Intake gaskets would be the next easiest thing to check then head gasket. The aligning dowels are there for gasket alignment purposes but also to keep the head from sliding when bolting it up. Most machine shops have them.

Forgot to add: if heads not aligned properly with the alignment dowels, it could also affect the intake manifold alignment.

[SASROD]

If you are running an automatic, check the vacuum module for a leak, could be sucking transmission fluid in.

[mattfranklin]

Originally Posted by SASROD

If you are running an automatic, check the vacuum module for a leak, could be sucking transmission fluid in.

And make sure to top off the tranny bfore you run it too much if you find it low.

[mattfranklin]

Originally Posted by nonstop

Well sh&t! So do I get the dollar or donut?

Summit has the official GM/ACDelco ones for $2 each. Your labor may run higher.

[nonstop]

Originally Posted by 68gmsee

Before doing anything drastic check the easy things first. The pvc usually is hooked to manifold vacuum and if you have oil in the intake, it may be sucking in oil through there . Is there a baffle under the pcv to keep oil from being sucked in?

Intake gaskets would be the next easiest thing to check then head gasket. The aligning dowels are there for gasket alignment purposes but also to keep the head from sliding when bolting it up. Most machine shops have them.

Forgot to add: if heads not aligned properly with the alignment dowels, it could also affect the intake manifold alignment.

Thanks. There is a baffle (or at least a plate) mounted under the pcv valve. There is oil in the line. I was thinking of changing to a fixed orifice pcv valve like the LS engines.

The intake gaskets are the blue Fel Pro ones that came with the gasket kit. I was thinking of changing to the performance style ones in an attempt to get a better seal.

The frustrating thing is I used the intake, heads, carb, valve covers, and pcv valve on the old engine and it was dry as a bone. The only changes (besides the block and innards) is that the block was decked and I used the blue gaskets (didn't use those on the old engine).

[nonstop]

Originally Posted by SASROD

If you are running an automatic, check the vacuum module for a leak, could be sucking transmission fluid in.

Thanks. When I saw the smoke, my fingers were crossed hoping that was the problem. Already had that issue before with this car and replaced the modulator. I actually pulled it off, and the line was dry.

[68gmsee]

Other possibility.

I've never had this problem and don't know how much you would have to grind off the block when decking to cause a problem but I've heard that it can change the angle of the head to intake manifold enough to cause an oil or vacuum leak.

[nonstop]

So I pulled a valve cover and checked my baffle. It's shaped like a trough. I'm wondering if this might be trapping the oil and can be part of the problem. I was thinking of grinding it off and replacing it with a baffled pcv grommet. Any thoughts, or is this a bad idea?

[nonstop]

Originally Posted by 68gmsee

Other possibility.

I've never had this problem and don't know how much you would have to grind off the block when decking to cause a problem but I've heard that it can change the angle of the head to intake manifold enough to cause an oil or vacuum leak.

That is what I am thinking as a possibility and will be focusing on next. I think I'll mess with the PCV system first. I pulled off the carb and there is oil in the bottom of the intake and on the bottom of the carb, leading me to believe (and hope) it's PCV related.

Thanks for all the help guys!

[geezer#99]

Originally Posted by nonstop

That is what I am thinking as a possibility and will be focusing on next. I think I'll mess with the PCV system first. I pulled off the carb and there is oil in the bottom of the intake and on the bottom of the carb, leading me to believe (and hope) it's PCV related.

Thanks for all the help guys!

Easy test!!
Clean it all up, then put a clear hose on it to see if the pcv is the source.

[DieselSJ]

Originally Posted by Marv D

You didn't replace the dowels in the block.?? they are there for a reason.

I'd bet a dollar to a donut you have head gasket problems. The head moves around on the block even WITH the dowels as it heats and expands. intake gaskets will be next.

Your machinist should have put the dowels back in the block!!!

This is a problem. Regardless of what you find elsewhere, pull your heads and install the dowels before you do anything else. Running it any longer without the dowels is just asking for failure. I am shocked that more people in this thread do not realize the importance of those and have you chasing things like PCV and trans vacuum modulators.

[68gmsee]

Originally Posted by DieselSJ

... I am shocked that more people in this thread do not realize the importance of those and have you chasing things like PCV and trans vacuum modulators.

No one has mentioned alignment dowels were not important. Marv D made it plenty clear and I mentioned that they're there for aligning the gasket and heads with the possibility of misalignment if not there. I'm sure nonstop understood the importance of this and there's no need to keep pounding the issue.

The baffle in the valve cover is easy to check and is needed to keep the pvc from sucking in oil if it not there. You should always check all possible problems areas.

[Dead Parrot]

If your PCV baffle is the simple bent flat plate it looks to be, that could be the problem. If you have good oil pressure, the oil coming out of the push rods could be squirting enough to splash into that trough and get sucked into the PCV valve. The factory baffles pull air from lower down between the rockers to avoid pulling splashed oil.

2nd on Geezer's clear hose test.

[nonstop]

Test one is out of the way! I didn't have clear tubing. I started it with the PCV valve disconnected. It smoked minimally for 45 seconds or so, then was smoking like before. I hooked up the PCV valve and the RPM dropped about 300-400 or so rpm. I put in a baffled grommet, figuring it can't hurt.

I am going to talk to my machinist on Thursday about the dowel issue and see what he's going to do for me.

I'm eager to try the intake gaskets soon, but don't want to jump the gun if I need to pull the heads!

Thanks guys for the help!