Just finished installing Chevy 454

[VileZambonie]

^^^This

After you shut the engine off and remove the check valve from the booster, do you hear a whoosh of air?

[josh0325]

I've isolated all sources of external vacuum components.  The only two that need manifold vacuum are the vacuum modulator for trans, and the brake booster.  Capped off all vacuum ports at manifold, and carburetor, besides the pcv valve.  I know I can't rely on the vacuum gauge, but it is not running correctly either.Talked with tech support at Erson cams, and he advised that tohe cam should provide plenty of vacuum and  have crisp throttle response.  I know it is on an 110 degree centerline, but it really isn't that radical of a cam.  I tried to post a video of engine running, just to give an idea of what I'm talking about, but it won't let me attach, says file is too big.  Video is only five seconds long.

[josh0325]

If the valves were improperly adjusted, could it give me the symptoms I'm experiencing.  I normally adust by  moving pushrod up and down until all slack is out, and then go another half turn.  I didn't adjust though, builder installed and adjusted everything other than the intake manifold.

[josh0325]

I finally found time after an 80 hour work week to investigate further into the issues with my engine.  I took everyone's input into consideration and started by hunting through possible issues.  Cam is where it should be, valves are lashed to 0, and another 1/2 turn lashing both valves in firing order sequence.  Went through all vacuum connections no improvement, tightened carb to base a little more, no improvement.  Lastly, just as an attempt to humor myself, I yanked the intake.  Sure, enough there were visible signs intake was leaking coolant on driver's side head.  Even though it was leaking internally, would that also cause a huge vacuum leak???

[bd]

An internal leak from the corner coolant passages will dump coolant into the oil through the valley, but shouldn't introduce coolant into the runners.  While you have the manifold off, make sure the gaskets properly fit the intake and heads to provide an effective seal around the ports.  Pay particular attention that the gasket seals along the lower edge of the flange where it meets the valley.

Did you ever verify that the vacuum check valve at the brake booster is holding vacuum inside the booster?

[josh0325]

Yes, brake booster is holding vacuum, did a simple test by using a bicycle pump with pressure gauge and manually pressurized it to about 5 pounds on gauge, and it held pressure until I removed gauge and undid my psycho-rigging of a valve stem and barbed fitting to seal hose to check valve.  Oddly enough when I placed the intake gaskets on the heads they fit the ports very well, and also the ears rested on the top of both China rails.  I placed a bead starting at the ears and across the rails on the front and rear.  Also put a small bead around each water port, and a small dab in the center of each to help hold it in place.  I let the permatex set up for a few minutes,then installed imanifold straight down.  I think the reason it leaked was because of improperly torquing them down, as I just snuvgex them and gave them a good cinching down.  Hopefully, the intake is not warped, but haven't checked  it for flatness yet.  Also, forgot to put permatex on threads of I take bolts which is why I think I leaked a small amount of coolant into the lifter valley.  Waiting on weather to permit, and I will reinstall intake after checking mating surfaces to be true.

[josh0325]

Yes, brake booster is holding vacuum, did a simple test by using a bicycle pump with pressure gauge and manually pressurized it to about 5 pounds on gauge, and it held pressure until I removed gauge and undid my psycho-rigging of a valve stem and barbed fitting to seal hose to check valve.  Oddly enough when I placed the intake gaskets on the heads they fit the ports very well, and also the ears rested on the top of both China rails.  I placed a bead starting at the ears and across the rails on the front and rear.  Also put a small bead around each water port, and a small dab in the center of each to help hold it in place.  I let the permatex set up for a few minutes,then installed imanifold straight down.  I think the reason it leaked was because of improperly torquing them down, as I just snuvgex them and gave them a good cinching down.  Hopefully, the intake is not warped, but haven't checked  it for flatness yet.  Also, forgot to put permatex on threads of I take bolts which is why I think I leaked a small amount of coolant into the lifter valley.  Waiting on weather to permit, and I will reinstall intake after checking mating surfaces to be true.

Finally got everything installed and fired up today.  Still same problem.  Just repainted heads and intake so leaks would be easier to find.  After shutting engine down, I noticed rust spots around where the manifold meets the heads on drive side, and same rust spots on front of intake.What the heck is that from???  Intake still leaks, Why???

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[bd]

Were the heads or intake manifold milled?  Did you check the dry fit of the intake manifold gasket flanges against the cylinder head gasket rails to verify that the sealing surfaces are parallel and achieving full contact, before tightening the manifold bolts?  How much gap is there between the top of the china walls and the underside of the intake?  Did you install end gaskets between the intake and china walls or discard the gaskets in favor of silicone sealant?  You really need to post pics with your responses to help clarify.

[roundhouse]

If the block has been decked or the heads have Been cl shaved it can make the intake really hard to seal up

But of its dumping water into the cylinder it should show up on the spark plugs

Or on a cylinder leak down test

Also your pressurizing the brake booster won't show of its holding vacuum
It should have a check valve that will hold vacuum but won't hold pressure

Although the water leaking into the engine shouldn't affect the vacuum at the brake booster

Sounds like two separate problems

[Rattler12]

A faulty seal between the water jacket and cylinder will result in pressuring up the coolant system and water being ejected out the overflow in a relatively cool engine. Compression blows by the head gasket into the water jacket. This happened on a 305 I had. I bought a "small block" head gasket set with said gasket's having a diameter of 4.10 inches. The 305 bore size is 3.76 inches. This difference in diameter resulted in very little sealing surface between the cylinders and lower water jacket openings. Pressure in the coolant system got so high the over flow couldn't handle it and it blew the upper radiator hose off. A set of 3.76 inch gaskets fixed the problem. You don't have to look at the plugs to see if they are wet.  You'll know from the "explosion" Scared the crap out of me.....

[josh0325]

Thanks for all the responses, intake is not leaking, and brake booster I'm pretty sure is not the issue either.  I was turning the engine over by hand to watch the valve operation.  I found at least three rockers that I could push down quiet easily by hand.  The engine has ran for a total of maybe 40-45 minutes, including the 25 minute initial break in.  Do you think that the lifter are collapsed, or if they were just adjusted to tight to allow them to pump up???  Really trying to avoid engine damage.  I know I can find out by starting engine and then allow it warm up, andreadjust with it running.  Back off rocker nuts until it chatters, and then tighten it until noise goe away, and give additional 1/2 turn.  Is this a good idea, or am I risking engine damage.

[bd]

...I was turning the engine over by hand to watch the valve operation.  I found at least three rockers that I could push down quiet easily by hand....

Toward the pushrods or toward the valve springs?  Unless you have the strength of a locomotive, you shouldn't be able to budge the rockers in either direction with your bare hand.

[josh0325]

Towards the pushrods, but I figured out the problem.  The engine builder installed the lifters dry, and adjusted the valves too tight. It took about two hours of adjusting to get the lifters to pump up.  Vacuum is at 14" and the needle is pretty steady.  Thanks for all of your help, this site is great!!!

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