dallasite21

Ok, so im tired of trying to use the standard felpro valley pan style intake manifold gasket. I cant ever seem to get them to sit right and I have problems after wards. I looked up some of the performance types by various makers, but they all seem to be the two piece variety. I am ok with using them, but is ok to use the two piece style? I have an after market edelbrock performer intake. Your input would be greatly appreciated.

442Harv

What problems are you having? If it is just the fit, I also have had some problems, but I just dry fit it first, and get the 4 locating post to line up and fit, you may have to tweak it some. I don't use the end rubber seals but use a good RTV type sealer.If you don't like the factory I would use a after market valley tray, to keep the oil off the bottom of the intake.

droptopron

I have a two piece on my car & have had no problems.

dallasite21

Well, I keep having leaks, and I thinks its because when I think I have it all lined up either its not actually lined up, or it shifts when I put the intake down on it. Right now I hear a hissing sound and the car runs fine a Idle, but when put it in drive and try to get on the gas it will die. I also have a rough idle so Im sure there is a problem in there somewhere. I have an edlebrock performer intake, and they recommend the Felpro MS96027 gasket, but most of the parts stores carry the MS96009 which is what i used. Is there any significant difference between the two?

442Harv

Are you using sealer on both sides of the gasket on the intake and water ports? You need to. Also if you are replacing the intake, while in the car, it is a two man job. Also do not state it up till it sets over night.

D Appeldorn

i'm with 442harv,

use a sealing compound on the water ports.
and retorque the intake several times.

mine i retorque 3times after putting a new seal or intake, the 3th time is just in case.
and i agree it is sometimes not easy to mount the intake with this type off valleypan if you are alone.
if you are with 2 guys one can hold the valley pan down and the other the intake.

Destructor

The manifold has to sit on the gaskets parrallel to the head while being torqued down. They can crook slighly while setting and yes retorque a few times. I've used plain ol' Mr. Gaskets without problems.

dallasite21

OK.. sounds like I need a new intake gasket and a friend. I hate to change topics but I have posted a couple of videos on youtube with the vacuum gauge at idle. You can see the guage jumping around at idle but it is steady at higher RPM. The electronic meter is the RPM's. It really starts jumping around at the higher RPM. I sprayed carb cleaner all around the intake and could not find a leak, but I guess it could be internal. Here are the links to my videos.


Idle
http://www.youtube.com/watch?v=fBV9qITcgqY

Idle over 200 rpm
http://www.youtube.com/watch?v=hNJkNRKVBKc

Railguy

A cam with a lot of valve overlap will have very low vacuum at idle.That's why some people run a vacuum pump for vacuum assist brakes and such. Also if your pulling air from under the intake,you'd most likely be pulling oil also,is there blue smoke?
railguy

boondocker

I used Permatex High Tack Sealant sprayed on both sides of valley pan as well as the felpro rubber gaskets that came with it, I've had no issues although I used a stock manifold.

dallasite21

There is no smoke, but I let the engine get hot turned it off and squeezed the top coolant hose and I could here a sizzling sound through the top of the carb? Like the sound you would hear is you poured a little water on a hot intake. Im no mechanic, but I would think I shouldnt be hearing that from inside the intake? sounds like some water may be escaping from the water ports into the hot intake. Does that sound like a logical yet troublesome diagnosis?

joesw31

Do you have a radiator pressure tester to pressurize the system? The steel intake gasket is harder to seal when using a aluminum intake as the intake is softer than the gasket to an extent. It takes a while to form the steel gasket to fit.

dallasite21

No I dont have one, but I can got rent one from autozone... How much pressure should I be able to sustain?

Railguy

If you got water going into the intake that will make steam it will look like white smoke out the tail pipe.But will disappear as the steam turns back to water.Do you have a performance cam?My 350 has low vac. at idle too it's normal.The intake valve is opening before the exhaust valve is completely closed.That's what makes the rough idle too.Makes for a better top end.
railguy

MDchanic

With the engine fully warmed up, you should have 15psi in the cooling system, and the upper radiator hose should feel hard (and HOT) when you squeeze it.

If you can squeeze the hose after turning off the warmed-up engine, you've got a problem somewhere, with or without a pressure tester.

- Eric

dallasite21

Just to make sure I didnt have any head gasket issues I did a compression test, and here are the results. Do these seem like something that would cause a problem? They seem inline for a stock 71' 350 rocket

#1-150 #3-150 #5-135 #7-150
#2-140 #4-130 #6-140 #8-135

MDchanic

They look about right to me...

Maximum variation of 130 to 150 may be at the high side of "official" recommendations, but I see no problem for a well-used 40 year old engine.

- Eric

70Post

If using the Felpro metal "turkey tray" you need to remove part of the locator/"divot" metal on one of these locator spots (these are the outward-belled holes in the metal turkey tray that "snap" into a corresponding hole a the end of each cylinder head).

Typically, it's the P side front divot that needs to be modified. If you remove the outward/cupped lip from 6 o-clock to 12 o'clock (the front half of this cupped lip) or slightly more, you should be able to snap the tray/gasket into place without any need to distort the piece. Test fit it dry until you've clearanced it enough to snap in and have the metal gasket sit right (ie flush).

I've done this on 4-5 of these Felpro sets within the last few months. Some sort of manufacturing defect in the stamping. These Felpro sets have had this great "feature" for years.

You can use a good pair of tin snips to remove the lip area or a dremel tool and stone, etc. Just make sure to blow off and clean the whole gasket afterwards so there's no metal pieces or filings sticking to it.

Bunser

I had the same problem and had to modify the ''turkey tray'' as well.

dallasite21

Thank you all for the info... My next step is to re-install the intake gasket. Just to make sure that I do this correctly here is what I plan on doing...

remove old intake
scrape surface, sand lightly, and clean with solvent
snip divots on new turkey tray
coat ports on heads with rtv black
coat backside of turkey tray ports with black rtv
line turkey tray up and set in place.. allow to dry slightly so it will stay in place
coat top side of gasket and manifold ports and set manifold in place
torque to 10 or 15 lbs
let dry completely and re-torque to 25lbs


Am I going about this right?

70Post

No.

1) Divot....you only need to modify the ONE divot (you probably meant that but figured I would repeat that since you wrote "divots"). Test fit it dry and you'll quickly ID which divot needs the trimming. Trim and refit DRY until you're sure it will snap into place.

2) Sealers/etc...use RTV on the water ports and use a gasket sealer such as PermaTex Aviation Gasket Sealer on the intake ports of the gasket. Not sure if this matters but Felpro doesn't say to use any silicone type sealers on the INTAKE ports. In fact, they only include a VERY SMALL tube of the silicone(for use on the water ports....see the instructions) which wouldn't be near enough to deal with all the intake ports.

3)Drop it on and bolt it down. Don't wait for anything to set up or cure. By the time you get the silicone on all four cylinder head water ports and the Gasket Adhesive Sealer onto the cylinder head side of the turkey tray intake ports the silicone is already skinning over. Now you have to get silicone and Gasket Adhesive onto the intake side of the turkey tray (once snapped into place) which again takes more time (silicone skins over).

There's also no reason I know of to partially tighten and wait 'til the stuff fully cures before getting to final torque....In fact, this might lead to a leak. Think about it....."hardened"/cured silicone isn't going to flow into any nooks and crannies when you tighten things down. At some point it might actually prevent a perfect seal. Look at the instructions on the back of a tube of Permatex Ultra Black Silicone. I believe it says to "apply and assemble parts immediately". Doesn't say anything about waiting on a final cure before tightening things down. Yes, do the tightening process in 2-3 stages of increasing torques and follow the tightening pattern in the assembly manual....but no need to wait for anything to "cure".


Don't forget the rubber end seals and the application of a decent spot of silicone at the ends of the end seals (see Felpro instructions)....or eliminate the end seals and apply a good bead of silicone instead along the end rails (again with a little extra at each corner per the instructions).

That's my "take" on it and there are surely other ways to install the thing successfully.

dallasite21

Thanks alot.. this is exactly what I will do.

70Post

The cleaner the better on all surfaces. Take your time cleaning.....like many of these car related exercises, the prep work is usually the most critical (and most tedious, etc.)

Good luck Mr. Phelps.

joesw31

It should hold 15 pounds. And as 70post states take your time when test fitting the intake gasket. Just make sure it fits flush on the heads and does not touch the lifters.