Small block engine issue HELP (408 stroker) headgasket? Broken rings ? Intake gasket? Or???

[sattydaddy]

I recently picked up a built mopar 408 stroker engine to drop into my 1973 Plymouth Satellite. The engine was purchased from a gentleman that said he had gone through the complete engine and that it was a running TurnKey motor. I installed the engine into the car and shortly after setting base timing and taking it on a very short 10 to 20 minute drive to the car wash I noticed smoke coming out of the driver's side tailpipe I cracked the hood of the car wash only to discover oil sprayed on the top of the hood and all over the driver side engine compartment the oil and smoke were coming out of the vented breather and the driver side valve cover and I noticed excessive Blow by at this time with the engine idling. I later found out that I had incorrectly hooked the PCV valve to a port on my Edelbrock LD 340 intake instead of the nipple on the front of the Edelbrock 750 carburetor. My father and I have troubleshooted everything that we can think of and we have since given it a compression test only to find out that cylinders 5 and 7 have low compression 60 and 90 PSI respectively. Immediately after removing all plugs and starting the cylinder compression test on cylinder one we were met with oil spurting out of cylinder 5 I would guess roughly a half a cup of oil came out. The gentleman that I purchased the engine from has mentioned that improper installation of the PCV hose to the Edelbrock LD 340 intake nipple may have caused hydrolock and broken rings on Pistons five and seven while my dad and I believe that a head gasket maybe the culprit as the engine may be pressurizing in the oil galley I'm having a hard time finding information about where the oil galley is and if there is anything close to cylinders five and seven they may be causing this issue or if there's a possible issue with an intake gasket leaking oil into the cylinder however that would not explain the low compression. After being told about the improper installation of the PCV system I corrected this and ran it several times since the issue did not go away but I would assume that any oil that had been pulled into the cylinder would have been evacuated also I think it's a good point to know that I am using the old style Mickey Thompson valve covers that have Shields above the PCV and the Breather so it is not like the PCV was directly immersed in oil so that it would fill up a cylinder to hydrolock it.. those are my thoughts at least... Please any help or ideas here would be appreciated thank you in advance for your time. Apologize for the long Post in advance just wanted to be thorough.

 

[snakeoil24]

Doa

 

[sattydaddy]

The odd thing is it seemed to run good while idling for 20 minutes or so after setting base timing. No apparent blowby oil smoke out of exhaust or breather etc.. it was only after the short drive the issue showed itself. Only thing noted at the time of setting base timing was low vacuum at the front carburetor nipple (15 inches vacuum) at around 700 rpm.

 

[pnora]

Do a leak down test and that will tell you the story.

 

[Mick56]

Does the port on the front of the carb have full engine vacuum? If so, there is no difference where the hose was connected, the manifold port and the carb port both see full vacuum.

 

[RemCharger]

There was a good nicks garage video of a blownout sbd headgasket.

 

[Geoff 2]

The PCV should be connected to a port that accesses both plenums on a dual plane intake. Hence the front nipple on Edel/Carter carbs for PCV. This ensures smoothest idle/highest vacuum. The engine sees the PCV as an air leak.
If it is connected to a manifold runner, that cyl will run leaner, all else being equal.

 

[Don Frelier]

I don't think the PCV valve connected to the incorrect spot had anything to do with cylinders 5 & 7 going to lunch.
That much oil in the cylinder is a real problem.
Unfortunately it has to come apart to figure it out.

 

[66Satellite47]

I find it extremely hard to believe that the PCV has anything to do with the issue. It's a broken motor.

 

[sattydaddy]

Does the port on the front of the carb have full engine vacuum? If so, there is no difference where the hose was connected, the manifold port and the carb port both see full vacuum.

Thanks for the responses!. @Mick56 I am unsure I find conflicting information about that edelbrock states that the front nipple is ported (pcv vacuum )and the rear is unported (brake vacuum. However a user on this forum (fugly) has convinced me that both are unported so unfortunately I cannot answer that. I believe based on fuglys picture they are unported vacuum.

 

[sattydaddy]

Thank you all for the help. Unfortunately I am out of town this week for work so I cannot complete the leak down test at the moment. As of now the guy I bought it from says he is willing to work with me because it was a running motor I am just trying to conjure up ideas of what may be wrong because I can't sleep at night thinking about it. From what he has told me the only thing he changed from when it was broken in at his motor shop which I have receipts for was he removed the cast iron heads and put aluminum speedmasters on which is why I thought initially headgasket. It had not yet been run with those heads until I installed the motor and the issue only presented itself after running for awhile.

 

[RemCharger]

Don't know if there's much point doing a leak down with 60 psi.

 

[pnora]

Don't know if there's much point doing a leak down with 60 psi.

That will at least tell you where its leaking. Which most likely will be ring s and piston lands.

 

[pnora]

Thank you all for the help. Unfortunately I am out of town this week for work so I cannot complete the leak down test at the moment. As of now the guy I bought it from says he is willing to work with me because it was a running motor I am just trying to conjure up ideas of what may be wrong because I can't sleep at night thinking about it. From what he has told me the only thing he changed from when it was broken in at his motor shop which I have receipts for was he removed the cast iron heads and put aluminum speedmasters on which is why I thought initially headgasket. It had not yet been run with those heads until I installed the motor and the issue only presented itself after running for awhile.

So what was broken on this motor? I suspect a very shoddy repair. Or something got dropped in and made the mess. As bad as it sounds I would leak down test and pull it out. Then do a full tear down.

 

[Mick56]

Where the pcv hose was connected did not have anything to do with your problem.

 

[sattydaddy]

So what was broken on this motor? I suspect a very shoddy repair. Or something got dropped in and made the mess. As bad as it sounds I would leak down test and pull it out. Then do a full tear down.

Im not sure pnora I was told/sold the motor pictured below was a fresh rebuild. I was given all receipts for the motor work as well as receipts and even the physical boxes for all of the aftermarket parts. I was told the motor was built for his duster and he decided he wanted a big block for more hp so he decided to sell this motor. He changed the heads out from the original cast iron heads to the aluminum and even provided all of the old parts including those heads. Engine supposedly has a full scat rotating assembly which he provided receipts and boxes for and that is even notated on the engine builders sheet as being a part of the build. I assumed and upon initial running it seemed the engine was good. It was only after the short drive that it exhibited the first signs of an issue.

 

[pnora]

Im not sure pnora I was told/sold the motor pictured below was a fresh rebuild. I was given all receipts for the motor work as well as receipts and even the physical boxes for all of the aftermarket parts. I was told the motor was built for his duster and he decided he wanted a big block for more hp so he decided to sell this motor. He changed the heads out from the original cast iron heads to the aluminum and even provided all of the old parts including those heads. Engine supposedly has a full scat rotating assembly which he provided receipts and boxes for and that is even notated on the engine builders sheet as being a part of the build. I assumed and upon initial running it seemed the engine was good. It was only after the short drive that it exhibited the first signs of an issue.

View attachment 1363578

Start taking it apart is all you can do. Something serious has gone wrong.

 

[sattydaddy]

Start taking it apart is all you can do. Something serious has gone wrong.

Agreed my logic is as follows.

1. Remove intake check or obvious oil leaks into cylinders 5 and 7.

2. Remove cylinder head and check for obvious signs of blown headgasket.

3. Last resort yank motor and pull pistons rods etc..

Thanks everyone for taking time to respond I appreciate it. Wish me luck.

 

[pnora]

Agreed my logic is as follows.

1. Remove intake check or obvious oil leaks into cylinders 5 and 7.

2. Remove cylinder head and check for obvious signs of blown headgasket.

3. Last resort yank motor and pull pistons rods etc..

Thanks everyone for taking time to response appreciate it. Wish me luck.

I would start with valve covers and crank it over making sure all is working. Then do it as you said. Once the intake is off look the cam and lifters over well.

 

[dvw]

First as others have stated the PCV hose location can be anywhere that pulls vacuum. Intake or carb doesn't matter as long as there is constant vacuum on the port that is being used. If the head gasket was blown pulling oil from the lifter valley, it would be smoking out the exhaust heavily. It is possible the gasket is leaking between #5 and #7. It's also possible the intake port in #5 is pulling oil from the valley area. Again, a cup of oil in a cylinder should be producing heavy smoke out the exhaust. I'd remove the intake and do a leakdown. Watch for air escaping into the lifter valley between the head and block. If it did break a ring. It wouldv'e been done during install, insufficient gap causing the gap to close and butt together, or from detonation. I've seen the oil ring fold up onto the side of the piston during installation.That woill cetainly draw oil. Also the 2nd ring intalle upside down will pull oil.
Doug