Advice on engine vacuum...or lack of..

[Alex Blair (RIP)]

Originally posted by Bob Carriere
To David...... Yes the 3 little intake rings have been iinstalled.

I have found that a hypodermic needle/syringe filled with gasoline is an effective way to find leaks in specific areas.... I have traced the major leak to be at the front first intake runner....dripping gas causes the engine to pickup in RPM....... and by using a piece of sheet metal to deflect the air blast from the fan..... found that the second last exhaust port is also leaking underneath........

to Bluebell...... the timing of the valves was done by the machine shop..... I am hoping that this woudl not be the problem. Engine runs relatively smoothly with no clacking or missing...... also the vacuum gauge needle is very steady at 9 inches and not jumping around as if valves were out ......

to Alex....... the distributor was totally disassembled, cleaned and back together.....making sure the bushings were good..... new points, caps,condenser, wires and plugs......lubrication cup cleaned and refilled. To the best of my knowledge the mechanical weights are working freely...... the vacuum advance is new..... I have run the usual test to check for diaphram leaks..... suck on it and hold it to see of it springs back leaking...... I have watched the distributor advance mechanism in action when I speed up the engine.....rpm picks up with no stumble....

Following a suggestion from the Stovebolt forum I have ordered a "special leaking manifold kit" from a US suplier..... gasket for exhaust and intake is all in one piece and thicker than usual to account for slight variations. According to some users it worked very well.

It may very well be that my biggest problem is the leaking intake.... so I will try to be patient until the parts arrive.

I may consider having the manifold milled at a machine shop if necessary......

One consolation....... I am glad I am finding this problem now and not after ALL the sheet metal is back in place....

Stay tuned....... any other comments suggestions are welcome.

BooBee

Hi Bob..
Those old intake manifolds are so long that any kind off heat will play hell with the machine surfaces for warpage..Were the manifolds dne or sent with the short block to the machine shop...??
If they were they would have been milled true and mated to the head..If not ,pay me now...or pay me later...
You know the old saying..
Throw andother fat gasket on it..do not get any oil on the gasket and torque the sucker using the proper torking pattern and torque specs as laid out in the MB-C2...that old beer stained copy in your shop..
Good luck..