Pressure or vacuum testing 426 hemi intake manifold and rocker oiling issues

[Beekeeper]

Was thinking of trying to do a pressure or vacuum test on intake manifold gaskets on the 426 hemi. I have all the pushrods removed so all valves are closed so if I make block off plates for the carb flanges on the manifold would it be possible to get an accurate test? I figured there would be a small amount of pressure or vacuum get past the valve stem seals but not sure.
Has anyone ever tried this type of test to verify the intake to head gaskets are sealing correctly?

 

[Mick56]

A smoke machine would work good for that

 

[Fran Blacker]

Buy some prussian blue from an art supply or amazon. Put on a thin coat on manifold or gaskets not both. Put studs in each corner of heads. Drop manifold on as even as possible maybe tighten the nuts on studs a little. The prussian blue will transfer to which surface you didn't coat. Might want to use only 2 studs and put spacer on end rails until your ready to go the last 1/4". Probably nice to have helper to drop that last 1/4". The prussian blue drys very slow so you have time.https://www.amazon.com/M-Graham-Art...id=1633820338&sprefix=prussian,aps,185&sr=8-4

 

[famous bob]

Was thinking of trying to do a pressure or vacuum test on intake manifold gaskets on the 426 hemi. I have all the pushrods removed so all valves are closed so if it make block off plates for the carb flanges on the manifold would it be possible to get an accurate test? I figured there would be a small amount of pressure or vacuum get past the valve stem seals but not sure.
Has anyone ever tried this type of test to verify the intake to head gaskets are sealing correctly?

If I still had a hemi , I`d pull the heads , if worried , and not squirrel around with it !!

 

[Beekeeper]

If I still had a hemi , I`d pull the heads , if worried , and not squirrel around with it !!

What would pulling the heads accomplish?

 

[HEMI-ITIS]

With the diagnostic tools available today I would NOT be so fast to yank a head!

 

[WileERobby]

Why not just squirt starter fluid on the intake flanges while idling to see any difference in rpm ?

 

[Beekeeper]

Thanks for all the replies. I did check the the fit between the intake and heads with feeler gauges with the intake setting on the studs and no gaskets in place. The gap was the same top to bottom and front to back I think it should be good. I just had a thought on some type of pressure or vacuum test but then realized that there would be some loss around the valve stem seals. I will proceed with installing the intake and firing it up and see how it goes it’s on a run stand and want to fix any issues before it goes in the car.

 

[HEMI-ITIS]

A leakdown test could be in order.

 

[Beekeeper]

@HEMI-ITIS on a different subject i noticed when i oil primed i am getting more oil to the rockers on the driver side than the passenger. the intake rockers on the right side get a good amount of oil but the exhaust rockers get very little.
any ideas what to check? Stage V rollers with mancini shafts and purple stands.

Well actually #2 exhaust is getting plenty of oil.

 

[Hemirunner]

What a horrible design (the wedge valley pan gasket isn’t much better).... if the faces aren’t parallel, the intake won’t seal, if the intake won’t seal, the engine can possibly suck oil, if the intake is over tightened, it’ll attempt to lift the heads. I modified mine to use a valley cover that’s independent of the intake. I use ultragrey RTV on the gaskets, snug the bolts, then a little more once the rtv sets up.

 

[HEMI-ITIS]

@HEMI-ITIS on a different subject i noticed when i oil primed i am getting more oil to the rockers on the driver side than the passenger. the intake rockers on the right side get a good amount of oil but the exhaust rockers get very little.
any ideas what to check? Stage V rollers with mancini shafts and purple stands.

Well actually #2 exhaust is getting plenty of oil.

Very Little or NONE at all? Banana grooves face down......

 

[Beekeeper]

Very Little or NONE at all? Banana grooves face down......

View attachment 1178047

I did check the banana grooves are down.
it is getting oil to to the exhaust rockers just about half the amount the driver side is. just puzzles me why #2 exhaust is getting plenty and #4,6,8 are minimal. this is all with 60psi
from about 300 rpms with a battery drill turning the pump.

 

[Hemirunner]

I did check the banana grooves are down.
it is getting oil to to the exhaust rockers just about half the amount the driver side is. just puzzles me why #2 exhaust is getting plenty and #4,6,8 are minimal. this is all with 60psi
from about 300 rpms with a battery drill turning the pump.

Are you rotating it while you prime?

 

[Beekeeper]

Are you rotating it while you prime?

yes cranking it over with the starter

 

[beanhead]

What a horrible design (the wedge valley pan gasket isn’t much better).... if the faces aren’t parallel, the intake won’t seal, if the intake won’t seal, the engine can possibly suck oil, if the intake is over tightened, it’ll attempt to lift the heads. I modified mine to use a valley cover that’s independent of the intake. I use ultragrey RTV on the gaskets, snug the bolts, then a little more once the rtv sets up.

I agree. I've never had very good luck getting perfect sealing out of the wedge valley-pan setup....I started cutting the runners off and folding them under the heads so I could use just one paper gasket on each side, which worked pretty well...then I decided to stop being cheap and got one of Finkbeiner's aluminum plates...
But I wish I had these Hemi problems!!

 

[beanhead]

I did check the banana grooves are down.
it is getting oil to to the exhaust rockers just about half the amount the driver side is. just puzzles me why #2 exhaust is getting plenty and #4,6,8 are minimal. this is all with 60psi
from about 300 rpms with a battery drill turning the pump.

Did you scrub the shafts out real good before installing and look down them? I was surprised at how much crap can build up in there...

 

[Beekeeper]

I did clean the shafts out and it’s looking like I’m gonna have pull at least the exhaust shaft and see what’s up. Just really puzzles me why I get lots of oil out of the #2 exhaust rocker and only minimal out of 4,6,8 since they are are on the same shaft.

 

[beanhead]

I did clean the shafts out and it’s looking like I’m gonna have pull at least the exhaust shaft and see what’s up. Just really puzzles me why I get lots of oil out of the #2 exhaust rocker and only minimal out of 4,6,8 since they are are on the same shaft.

If clogged holes aren't a possibility, that leaves maybe side clearances or the bore diameter of the rockers themselves?

 

[Beekeeper]

Here’s another interesting thing i’ve found.
on the drivers side when cam is in the correct position i get oil to all rockers no matter if the rocker is up or down. when the cam is positioned to oil the passenger side I
get flow to all intake rockers no matter if they are up or down. on the passenger exhaust rockers I get good flow when they are in the down (valve open) position but when up no flow at all.