Hi gents...little history..72 cut..455 swap..finally running...probably 4 hours run time including breakin(new motor) rebuild professional shop..while running a few days ago wouldn't idle anymore kept dying when throttle released...started looking around and saw oil running down the back near dist..further investigation showd the rear intake seal leaking..ok new seal..could not running pcv and only valve breathers cause the seal to blowout??also found alittle brown sludge on rad cap could this be a part of crankcase pressure putting vapor onto the coolant via the blown China wall seal???thanks crankit

 

Crankcase pressure inside the engine is very low, without a PCV creating vacuum; the breathers won;t let any real pressure build up. Your cooling system is around 10-12 psi. No way crankcase pressure is going into the cooling system, in fact the opposite is more likely a cooling system leak into the crankcase.

 

Thanks for the fast reply...I kinda thought the same thing..I pulled the intake to redo the China wall seal..hard to tell if any of the coolant was leaking into the crankcase did notice slight couple of brown gook on the valley bolts...could this be from crankcase vapors...gonna do compression check on all cylinders...hopefully it's not a head gssket... thanks for the reply........crankit

 

Got a picture?

 

Hey bang...intake is off but I can send a pic...gonna drain the oil today...

 



 

The little bit of rust is probably from condensation. I wouldn't worry about it. Same with the junk on the radiator cap. Do you have antifreeze in it or plain water ?

The intake gaskets do not look like the correct ones ? Unless they match the ports in the heads. Look way too big on the intake manifold.

Whats with the extra piece on the exhaust crossover passage ? Almost looks like it would hold the intake off and keep it from sealing properly ?

 

Hi bill..those are block off plates..not suppose to interfere with intake the gasket goes over them... and the ports are pretty much spot on...I have been running two breathers and no pcv??? So a little condensation I can deal with...already removed the intake leaking from (slightly)from rear china wall gonna redo and put in a pcv in one cover hopefully it's just condensation....rad was full...oil had no water on dipstick...gonna drain oil and do compression check..maybe get a better handle on things...running 50/50 coolant...thanks for the reply...crankit

 

It looks like there may have been leakage around two ports (gray areas on the red sealing beads).
The presence of the block-off plate many have caused this problem.


The silicone sealer on the china walls looks rough. That could be the source of your leak at the back of the manifold. Did you use old sealer? Did you try to pack it into the cavity after the intake was set in place?

It's best to measure the distance between the intake and the china wall during a dry setup with gaskets, lay a bead(s) of silicone to just a bit over that depth, set the intake in place, and then (if you want to be neat) smooth the silicone as in the picture below.

 

I dont see how it wouldnt cause a problem with as thick as it is. We always use a very thin piece of steel. Used to use beer cans back in the day

A couple of others have mentioned the china wall seal ? I have actually used the rubber seal a few times IF it looks like it fits good and isn't being squeezed to death. Otherwise I use either The Right Stuff or Permatex Ultra Black.

 

hi bill and vc...upon initial break in ..had 50 60 lbs oil pressure...and20 25 vac not to say heat cycles didnt cause china wall to fail...their was no indication of coolant leak after breakin or subsequent starts??it was only after several start warm up periods I noticed oil running from the china wall ..upon further inspection it seemed the oil was coming from center of bead...so I said I screwed up the intake placement which I did wiggled for and aft to line up bolts...but it did have excellent vac and oil pressure??? Guessing the heat cycles caused the wall to fail??? As far as the slight amount of goo on rad cap may just be crankcase vapors...the block off plates have been used for years and as far as I know dont cause intake leaks...that remains to be seen ..obviously something cause the China wall to fail...operator error or something caused it to fail...used the new tube of right stuff black..followed instructions .
hey alls I can do is try again this time one shot putting intake on no wiggling...thanks for the help I will follow up...crankit

 

Understood.

Use your great setup and you can place the intake perfectly the first time. Put on your lift plate and, when you are doing the dry measurement, align your lift device to position the intake perfectly.

Then lift the intake straight up to give work room. If necessary, take it off the hook. Position the intake gaskets, create the china wall seal, put the intake back on the hook if necessary, and lower the intake perfectly into place the first time.

 

Hi vc... iam such an idiot!!!.iam using a megshift pulley system...and have hinewerner cherry picker that I've used 100s of times pulling motors trans bodys and never thought of the intake...it would be so easy!!! When you said take your set up to maneuver intake!!! It hit cherry picker dumb ***!!!thanks vc for opening my eyes!!!!! Crankit...

!!!!!