Header gaskets

[Stang951]

Has anyone tried the copper header gaskets? I have to change mine already (only been a little over 2 years), and I dont want to keep this up every couple years.

[Strim91GT]

I ran the copper head gaskets that came with my mac longtube headers for about 2 years on my old supercharged 302 and never had any problems... i would suspect that the copper gaskets with the sealing ring around the ports are the best choice. I think they are a little more expensive than other header gaskets but i never had any problems with mine.

[Kevin Price]

Header gaskets would usually last me about 1 pass. I use the red high temp RTV sealant. They don't leak a bit until I remove the headers.

It is a bit of work to remove the old sealant and apply new but I doubt you would have to unless you purposely removed a header.

If you do this, coat the header flange liberally with the sealant and tighten to the head at once. Do all eight and let it sit overnight. Then, start it and bring it to running temp and retighten the header bolts.

Works good and is cheap.

[drudis]

I tried the EAR- 29D03A Small Ford: header seals 302 Exhaust gaskets $35.99

They are expensive, but came highly recommended, and I think they are the best gasket out there!

[jim_howard_pdx]

Copper is what we use for racing, allows simple disassemby and reassembly at the track. When you win a bracket they often have you pull a head for verification, so copper is a great facilitator.

I use Felpro Steel and Graphite gaskets for my highway car with TrickFlow heads and they last a minimum of 2 years.

I plan to try the new Mr Gasket graphites if they decide to make a set with an oval port to match the headers I use. Right now they only have rectangular, and that is not a good match for me.

Kevin, I have never tried silicone on an exhaust header flange before. Just how long have these silicone gaskets worked for you?

Exhaust temp is between 1100 and 1500 degrees f. Most silicone is rated at 500 to 575 degrees??????

The coefficient of expansion between the head, the header, and the silicone is all wrong. But if it works, I would like to try it next time I blow a gasket and the shops are all closed down. Too bad you have to wait overnight though.....that is a pain.

[Kevin Price]

Jim-

It's worked for me for over a year now. I believe the red is of a higher temp. I just went back and checked but couldn't find anything.

There are a lot of people who use it around here, mainly racers. I was skeptical but I tried it and it's awesome. You might not have to wait overnight, the stuff sets up pretty quick. My headers are just a MAJOR PAIN so I don't mind the wait.

Good luck

[jim_howard_pdx]

Hey Kevin, this message is primarily for you. On those Yates heads you are running, you must have custom headers to make these NASCAR heads fit in your Mustang.

You said the gaskets would only survive a single pass but that has not been my experience with the Yates head.

Take your header to a shop and have them surface the bead so it is 100 percent square and flat to the overall flange. It also makes for a slightly wider mating flange and allows you to add additional clamp force without over torquing the gasket material.

Most headers come with a quarter inch flange stock, then the primary tubes are interior welded to the flange plate, then they surface these weld beads to create the mating surface of the header.

I have all my custom header pipes welded on 5/16 steel flanges. I like to get the flange plate from the shop, and do my modifications first. I drill the holes extra wide, and I chamfer the inside edge that mates to the head.

Then I have the flange heat treated. Then I let the guys weld on the primary tubes. Then I check their surfacing and the quality of their mating surface. Get them bead blasted and then ceramic coated.

I demand 5/16 plate steel because some of the mild steel 1/4 inch flange material was so soft that I could bend it and form it without much effort. The header guys will say that this is so you can individually torque each tube.

This is total nonsense. The gasket makes the seal, not the flange. A soft bendable flange will not hold up to high torque launches. Make sure the flange stock is hard and SOLID.

Another reason to harden the flange plate is so they will be prestressed to enhance their expansion and contraction rates to better match the thinner tube material.

This would be overkill for 99% of the guys on this site. But Yates Heads are not stock, are not a street design, and are definitely in the 1% class where attention to detail is demanded.

Kevin, I hope this helps.

[jim_howard_pdx]

Kevin,

You show 813 Hp on the chassis dyno.
813 HP at the REAR WHEELS?????
Dude, you have a missile not a car!!!!
I usually don't see HP like that on a Yates head without NOS. We can get 813 HP from a 504 cubic inch stroker with aluminum super cobra jet heads ported to the max.

That is flat out OUTSTANDING!

Are you using a piston coating?

Did you coat the combustion chambers as well?

[Kevin Price]

Jim-

Thanks for the info., definately some new, and very useful information. Kook's Custom headers did my headers originally for my 89. All I had to do was weld some extensions on 2 of the tubes to clear my steering rack on my 01'.

As far as the motor the 815 hp is actually at the flywheel, not the rear wheels. At the time that was all that was available.

Bennett Racing was very impressed/surprised by the numbers. We originally were anticipating around 740 hp, which is typical for a motor with Nascar takeoffs. I must have gotten lucky with the heads as it makes the $3000 I spent on the heads, Jesel J2K rockers, and intake seem pretty cheap to me.

Neither my pistons nor Combustion Chambers are coated and I don't have roller bearings either. With the right air and some more chassis and motor tuning I am really shooting for high eights before I put the nitrous to it. We shall see I guess!

Again, thanks for the info. VERY HELPFUL!

[Eric4Nitrous]

Kevin you'll never hit 8's..haha j/k figured i'd bust on you a little for all those little comments you made towards me a while back. hehe

[Kevin Price]

I know I know. Mr. Chevy boy.

[Eric4Nitrous]

Every time that nova starts up your little mustang runs and hides in the corner of the garage..hahaha take that.

[jim_howard_pdx]

Spend the money, spend the time and anyone can get into the 8's if they have the motivation. I have had 4 cars in the 9's and I had no real desire to go for the 8's because the car would end up being a trailor queen. I like being able to hit the streets and the car shows DRIVING IN.

Now that NOVA of yours sure is a looker.... Other than a Gremlin, the NOVA has to be the uglyest car ever built.

Why not put that engine in a 57 Chevy or a Vega, something with some class???? What fun is it to drive fast UGLY?????

NOVA's.......U G L Y ugly U G L Y ugly U G L Y ugly

[Kevin Price]

To each his own Jim. It's been my experience that you have a hard time keeping up with a daily driven race car/street car, such as your 9 second cars that you drive to the car show. Would you take your family across the country to Disney World in it? I prefer to have my race car and my street car separate. My old 89' Mustang was street capable and pulled 9.50's. What's so special about that? Guess I don't get my thrills impressing high schoolers on cruise night by spinning my tires for 4 blocks.

It is an accomplishment to get a 2900lb N/A motor into the 8's. Might not be a big deal to you but it is for me.

Don't know why your raggin' so much on a 66' Nova. Personally I like them better than the old Mustang Coupes.

Again, to each his own so chill out.

[Eric4Nitrous]

Kevin you'll get there for sure man. My nova may be ugly Jim..but it sure as hell runs quicker than 13.7..

[moc]

hey it's hit or miss sometimes with the copper !
I have a bran new set of felpro's .i'll give you
if your hard up for money ( they are the best)
give me your address ,you'll get them in 2 days !
rather see you use them than sit on the garage wall

[moc]

if i didn't own MUSTANGS for more than 30 years ! I would have a 1965 NOVA SS, 350 tunnel ram ,dual quad ,4.56 rear ,black .like the day it rolled off the assembly line interior ,verta gate shifter . dam . they are the only chevy i would own ! and every time i see one i wish

[Stang951]

Does anyone know if there is a pwer decrease, or if I should feel a decrease in power with a leaking header gasket?

[jim_howard_pdx]

First of all, I am really sorry for my comment about UGLY Novas.

(They really are UGLY, but I have never found a mother that didn't love her UGLY baby either.)

I guess I need sensativity training.

Now to the power / header leak issue.

First of all, any exhaust leak will effect cylinder filling during the intake stroke. WHY? Because the Intake and the Exhaust valves are both open for a short period of time. On my street cars that event is about 36 to 42 degrees. On a racing cam it might be 110-120 degrees of overlap. The leak means that the cylinder will not purge during the exhaust stroke, and that means more burnt fuel in the intake charge. Since it is fuel density, not fuel mixture that creates horsepower, a slight decrease in fuel charge density can make big swings in torque and power production.

Your torque curve will reduce, and sometimes we see exhaust leaks in reduced ET times before we hear it from the engine.

To find an exhaust leak. Have a buddy fire the engine when it is cold, and run it up to 2200 RPM immediately, just as you would if you were breaking in a new flat tappet camshaft.

Take your hand and feel around each port. You are looking for puffing. You might have some initial leaks that go away immediately as the gasket expands due to the heat. This is normal. I usually check the exhaust bolt torque first to minimize this.

You will feel a leak before you hear it. By the time you hear a header leaking, the seal is completely gone and exhaust is now rushing past the gasket.

Many times a repeatedly leaky exhaust is the sign of exhaust system problems. If you are running a CAT it may be too restrictive. If you have small tubes and high power, you might need to go up in tube size to reduce the pressure on these gaskets.

I think this is one reason Kevin Price has such problems with his gaskets on his Yeats Head. At 800 HP he really needs a dragster type exhaust system. What I mean by this is that to develop full power, an engine needs the first 6 to 10 inches of exhaust flow to be a straight tube exiting the exhaust port. So on my Mustang with the first primary bend about a 1/2 inch off the exhaust port I am immediately giving up about 4-8 HP. That is what my shock towers contribute to my engine. NEGATIVE 4-8 HP!

I think Kevin is already running 4" primary tubes and large collectors.

Something that people don't know is why exhaust header leaks form in the first place. Actually the exhaust flow is like an explosion. The power rings back and forth against the sides of the pipe as it slowly moves its way down the length of the pipe.

Take some time to think about what I just said. The exhaust pulse beats side to side against the tube. It actually moves quite slowly down the length of the pipe. One reason that X tube exhaust systems are effective is that the X tube itself subjects this ringing pulse energy to a 45 degree angle that reduces its back pressure. That is the only reason why an X system exhaust makes more power than an H system exhaust. It reduces the side to side ringing.

What we did in the 60's and 70's to improve cylinder scavanging was to run a product called swirl tech mufflers and pipes. In fact our 427 AC cobra engines and GT 350 R cars were all fitted with swirl flow tubes. The had NO provision for muffling the sound, all they did is convert the horizontal energy of the exhaust pulse to a rotational energy created by the fins that created the swirl. We often picked up close to 20-25 HP on a big block, but we also picked up total MPH capability as well.

We ran this swirl tech system on a GT 350 R and got 370 HP from a car that was getting 338 HP on mufflers. It improved from a top speed of 148 mph to 157 mph. THIS IS HUGE!

The exhaust was so loud we were pulled over once driving 55 mph with a 98db reading. We did not tell the CHP officer that the reading would be 106 db at 80 mph and above. That was one loud Mustang!!! Just starting the car was an event all its own! That 289 in a 65 Mustang was almost as loud as the 427. The 427 AC Cobra swirl tech exhaust side pipes could set off earthquake alarms. I kid you NOT.

Hope this helps. I make all my friends fix exhaust leaks BEFORE I do any type of engine tuning. Fix the exhaust, and often your problems will go away. Then you super tune to get ET consistency and to equalize cylinder to cylinder power production to maximize your bearings life expectancy. I wonder what Kevin's bearings look like after 25 passes!!!!!

800 HP on a small block can make for some pretty hammered out looking rod bearings on a NOS car. His is naturally aspirated. Man is his engine "cooking."



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