I have been chasing a poor idle on my 455 since I purchased it.
At idle and low RPM's it is running very lean so I enlarged the idle tubes twice, now up to .036", the idle down restrictors and the base plate.
There are no obvious vacuum leaks on top.
I pulled the aluminum manifold tonight to check for cracks or a gasket problem.
Everything looks OK, just old. A couple of things I did see was oil weeping from some of the intake bolts and oil in the intake runners and head ports.
Also the lifters seem to be depressed too much. I used a .045" bent wire to check the distance from the clip to the plunger and I had closer to .080" clearance.
So my questions are:
Should I use the bathtub metal gasket or some other style
Any idea where all this oil could be coming from
Do they make adjustable rockers for the 455
Thanks,
Joe

 

Do you have any idea why there is oil buildup in the intake runners of the head? I recenlty freshend up my engine and after a year of not alot of use I am getting a simmuler buildup like you have on your intake runners. Any opinions would be appreciated from all. I want to take care of the issue before the build up gets too bad.

 

Think I'd be having both those manifolds cleaned and checked for cracks!
Do the aluminium version of magnaflux - zygloed, if I remember right.
Never seen that much 'oil reversion' in anything!
Make sure they check the whole bottom!!

 

I had the same problem with a W30 intake. Check, with a good straight edge the intake flanges, these old aluminum manifolds can warp, and will suck oil from the lifter valley. Get rid of the turkey tray and buy a quality intake gasket like SCE, or similar, if you want to keep hot oil of the bottom of your intake, several vendors offer an alum. tray that mounts in the lifter valley. Are you running an adjustable valve train?

 

I have an aluminum tray in the valley and I am using harlend adjustible rockers with regular hydrolic lifters. I did notice that the gaskets where also almost wet oiliy looking almost like they soaked the oil up. Could be I did not use a good enough gasket. It is in every port of the head consistantly not just in some ports like it was warped unless tht is how it warps.

Thanks for your reply.

 

I also wanted to add that when I took the engine apart to freshen it up I had no buildup whatsoever. I am using the same intake that was on the engine so I dont feel there are cracks or warping due to previosly there was not an issue. What is the best gasket setup to get for the W30 intake?

 

On my 72 W car. I use the Mr. Gasket turkey tray gasket. The key to sealing is to use RTV red gasket sealer around the ports. You don't have to use much, just put a small bead around each port. Set the intake in place after 10 minutes of setup time. Install the bolts. Hand tighten only. Let set for 30min. Then torque them to 25 ft lbs. This will prevent the oil leak. With bad idle, the intake leak is from underneath. I have been using the W30 intake on my car since 1996 when I rebuilt the motor. There has been no leak issues since. I have had the intake off in 2001 for a came change and still no leaks.
regards

 

The tray in your pic looks like the factory stamping, if so it won't keep oil off your intake. Have your heads been milled? Search "lifter preload" on this site and others for concise info on how to adjust your valve train.

 

You could also check that the pvc valve doesnt suck in oil maybe.