Inlet Manifold Gasket Compression

Pulled the engine out of my car to check it over prior to upcoming endurance race. Bearings etc checked out fine so pulled inlet manifold to check lifters/lifter spiders etc.

Was surprised to find that the inlet manifold gaskets had compressed and extruded to the extent that on two ports there was an obstruction of over 1/8" of an inch into the port flow area. Great way to toss away a bunch of hp.

http://i427.photobucket.com/albums/pp355/NZGTRA/InletManifoldGasket-28Feb09.jpg


The gaskets are Ford Motorsport 'composite style' gaskets and factory torque loadings were observed on initial assembly and on post race retorques.

I will be looking for a better inlet gasket set (Felpro), may be something to look out for in your engines. Bring on another 10+hp with this addressed................!!

great find!

I may be wrong, but I don't think those gaskets are intended to be installed with sealer, except at the corners. That may be why they creeped into the intake ports. I've never seen that before, so it's hard to figure it out. You obviously have a motor that breathes! You could try a blower and see if the boost pressure would push them back in place :biggrin:

Mike

I may be wrong, but I don't think those gaskets are intended to be installed with sealer, except at the corners. That may be why they creeped into the intake ports. I've never seen that before, so it's hard to figure it out. You obviously have a motor that breathes! You could try a blower and see if the boost pressure would push them back in place :biggrin:

Mike

Hi Mike, gaskets were installed dry with a blob of sealant in each corner as you have suggested. Cant say I have ever used intake gaskets with this type of material before. Most of the ones I have used on my race engines have had a perforated steel core.

Like the blower idea. Have considered this but fuel use could be an issue over 6 hours. We expect to use around 450 liters as it is!!

great find!

Cheers Eric. We will be badly outgunned in the race as there will be many cars running significantly more power than us and the 6 hour circuit is a hp circuit. Every little bit of power will help. In fact next job prir to the race (along with lights and dry break fule system) will be to make up a sealed cold air system to try and scrape up another 15 - 20hp..............!!

Good to see that you car survived its 'low level flying' incident unscathed. These things happen with racing, thats for sure.

Kel,
Those gaskets are definitely poorly made, I'll remember that went the time comes.

Show us some photos of your cold air system, lights and dry break!

Mike

Same Thing !!! :headshake The mechanic that helped me is a Master Ford mechanic w/ many years under his belt ; he stated that Ford had a different gasket set for ( 2 ) years in the 5.0's which caused confusion ... My engine had the wrong ones ... The manifold end-damn gasketes gone & who ever just gobbed a silicone mess in place ... Also was ingesting a little coolant , nice ... Installed a Trick Flow upper / lower & 75 mm Edlebrock ; plus roller rockers ... Got a solid mid-range improvement , top end still flat @ 125 ish ...
QUESTION ... Has any one done any re-flashing / mapping or mass air improvements for more HP ???

Thanks / Paul M. Winship
Chassis # 37 GT-Ra

top end still flat @ 125 ish ...


Thanks Paul.

I am convinced that if you want to get any reasonable power increase out of the 5.0 you need to upgrade the heads/cam/exhaust in combination (and bump the compression up as much as local fuel allows).

The inlet manifold side will help but you need to get the air/fuel in and out efficiently. I was pretty amazed at the small size of the ports in the std 5.0 heads that were on my engine, definitely not the GT40 heads that were supposed to be on it thats for sure..........(they were actually E7TE heads, the worst flowing Ford head made for the 5.0).

Driving the car after this upgrade was like night and day. The car picked up around 1000rpm in 5th gear down the back straight of my local track. It went from being a slug to a quite reasonable performer.

I think what Paul and Kel both said makes great sense. If you upgrade the intake side, you can improve midrange, but the heads and exhaust will max out flow at about 5000 rpm. As Kel said the only way to get more top end is open up the whole flow system, especially the heads, cam and exhaust to remove the restriction. With some more compression and opening it up, you can use the cam and carb (or computer) to tune where the gains are and how wide the power band will be.

About the intake gaskets: There are a number of 289/302 gaskets out there. Fel Pro has/had at least four. The port size is the primary difference, but water cross over holes and sealing around the ports also vary.

About using silicone (usually orange Permatex) to replace the cork or rubber end seals: this is a very common procedure as the end gaskets have a habit of squeezing out or leaking. If the head or deck has been surfaced, this is even more likely. Peening the block and intake surfaces is also used to try to keep them in place. If the sealing surfaces are properly degreased with acetone or lacquer thinner, a nice even bead of the silicone works very well. Silicone will eventually succumb to the exposure to the hot oil under the intake. Whatever, never put silicone on the intake gaskets, especially rubber or cork end gaskets (guaranteed to squeeze out 99% of the time), except a SMALL dab at the corner joints. I can offer these opinion based on personally averaging about 2 intake gaskets per intake manifold install and having surpervised tech's who got it right the first time at least 95% of the time! I keep waiting for someone to design a one piece intake gasket with a wire insert on the ends to prevent this whole problem. Similar to the one piece pan gasket. I guess with the phase out of the SBF motors, not likely.

Mike