Intake manifold off again...Crap

[DAVID GAGNARD]

Originally Posted by tortuga

Well FACK it blew again today: Its always from BIG throttle to off throttle: Solved the oil leak and now back off again (i am getting quick at it): My confidenc in this motor is quickly dwindling to zero...need to check the manifold and heads for flatness, and use the best gaskets i can i guess: Its a small block making a crap load of power...

One thing i am wondering about is tapping into the back coolant passages and plumbing them back to a return? Seems weird having a stagnant passage back there? i would suspect that the cause is likely a big sudden vacuum spike off throttle at high rpm...

Gonna do some research before bolting this ***** back together yet once again...

Exactly what blew this time???? a picture or two would be great.....
Do you have any or what kind of PCV system on the car and any valve cover breathers????

Something seriously out of wack,never heard of or seen one blow repeatedly without some major flaw in the system.

David

[tortuga]

Originally Posted by DAVID GAGNARD

Exactly what blew this time???? a picture or two would be great.....
Do you have any or what kind of PCV system on the car and any valve cover breathers????

Something seriously out of wack,never heard of or seen one blow repeatedly without some major flaw in the system.

David

I was all ready to take photos but there isnt really anything visible to the naked eye...What i did find that i failed to mention was the intake bolts all seemed a bit loose, thoe one aft on the passenger side very much so? I think it may be very very critical to follow the stepwise torquing and a post relax torque?

I,ve cleaned the whole thing and test fitted the manifold and ther is no preceptable 'rock'...

Are these big stroked 351s in need of very special intake sealing? Gong to talk to the builder tomorrow.

Really frustrating.

I am thinking studs would be better?

[jeffgrice]

Originally Posted by tortuga

I was all ready to take photos but there isnt really anything visible to the naked eye...What i did find that i failed to mention was the intake bolts all seemed a bit loose, thoe one aft on the passenger side very much so? I think it may be very very critical to follow the stepwise torquing and a post relax torque?

I,ve cleaned the whole thing and test fitted the manifold and ther is no preceptable 'rock'...

Are these big stroked 351s in need of very special intake sealing? Gong to talk to the builder tomorrow.

Really frustrating.

I am thinking studs would be better?

Sorry to hear this...my 427sr intake let go last year. Bolts were loose.

When I fixed...I torgued the intake bolts in the proper sequence likely 20 times before they didn't need a touch up of torque. And didn't drive super hard until the torque was stable.

I used a thread compound that is suppose to help keep torque (not lockite). I can try to find it for you.

Jeff

[jeffgrice]

Originally Posted by tortuga

I was all ready to take photos but there isnt really anything visible to the naked eye...What i did find that i failed to mention was the intake bolts all seemed a bit loose, thoe one aft on the passenger side very much so? I think it may be very very critical to follow the stepwise torquing and a post relax torque?

I,ve cleaned the whole thing and test fitted the manifold and ther is no preceptable 'rock'...

Are these big stroked 351s in need of very special intake sealing? Gong to talk to the builder tomorrow.

Really frustrating.

I am thinking studs would be better?

One more point...did you use the steel reinforced intake gaskets?

If not please do when you r&r

Jeff