Re: Head gaskets--Fel-Pro or Cometic
 

We used to run copper gaskets on the Blown and Injected GP Hydroplane engines.They don't run a water pump so in order to warm the engine we would start the engine and after a few minutes turn the hose . If you turned the hose on before warming it up water would be everywhere.

Re: Head gaskets--Fel-Pro or Cometic
 

If anyone is so inclined, I do have used cometics, enough for two 4.560's and two 4.530 max bore sizes. These measure re-usuable. $20 a set.

Re: Head gaskets--Fel-Pro or Cometic
 

call PERFORMANCE GASKET COMPANY. They are located in Rockfield,wisconsin and the phone number is 262-677-4690--ask for Bob. Customers that use them are Innovation Marine, Richie Zull and Nortech just to name a few......LT

Re: Head gaskets--Fel-Pro or Cometic
 

I've been down this road myself pro-charged motor 7 lbs had a problem with the Fel-Pro gaskets. Water pressure took the gaskets out switched to Cometic this season after 60+ hours still running strong no milk. They get my vote.

Re: Head gaskets--Fel-Pro or Cometic
 

Which Felpros??????????

Re: Head gaskets--Fel-Pro or Cometic
 

So has any one used the Cometic C5330 ??
with a Gen V block and Gen IV head??
Don

Re: Head gaskets--Fel-Pro or Cometic
 

My engines are going to be N/A for awhile {$$} But will be Blown down the road. I'm using Felpro now. How many "points" in comp can i bring it down by using Cometic when the time comes for blowers ?

Re: Head gaskets--Fel-Pro or Cometic
 

2nd this, Bob is one smart cookie and his stuff works. HIs background was head engineer for Victor gaskets is what I have been told. A contact at Merc gave me his name years ago. His stuff is top notch. After that is Cometic, to quote a top marine engine builder located in FL,"best thing since sliced bread", as far as Fel pro is concerned. . .nevermind I won't go there.

Re: Head gaskets--Fel-Pro or Cometic
 

Anyone tried the Fel pro 1077?

Re: Head gaskets--Fel-Pro or Cometic
 

I am running the1075 at 10psi.I am fixing to tear down see what they look like :rolleyes:

http://www.offshoreonly.com/forums/s...ghlight=500efi

Re: Head gaskets--Fel-Pro or Cometic
 

On a 4.530 bore, you would want to use a 4.560 bore gasket.
No larger. Thanks,

Dean Gellner

Re: Head gaskets--Fel-Pro or Cometic
 

We have used O-Ring blocks with copper head gaskets for many years and have had excellent results with sealing. I use a gasket made by Performance Gasket in Wis. which incorporates graphite composition for sealing the water jackets. They work extremely well for an offshore application. The Cometic Gasket we are using more and more. They will save you money on some machining operations and they work great with higher static compression and lots of boost. I have even experimented with them in Nitrous Drag Racing applications where we are using 2-3 stages and they are very durable. Building from scratch...Cometic.

Best Regards,

Dean Gellner

Re: Head gaskets--Fel-Pro or Cometic
 

I had used a Felpro on a trouble prone 2.5L plymouth 4cyl about 10 years ago. It was a Permatorque gore-tex gasket. I have not seen this type of gasket since. Does anybody know about this material ? Or if there is a big block gasket of it's type ? Just wondering... BBB :eek:

Re: Head gaskets--Fel-Pro or Cometic
 

Oh , Also beware that most of those 4 numbered felpro gaskets are not marine and have steel rings that rot. Sometimes we get so caught up in dimensions, cc's gasket thickness etc. and build our motors with automotive gaskets. They could last a few seasons, and I guess wouldn't matter on a motor that comes apart every 2 years or every 200 hours. :cool: BBB

Re: Head gaskets--Fel-Pro or Cometic
 

The 1077 is FelPro's version of the MLS, suposed to be stainless. 4.640

Re: Head gaskets--Fel-Pro or Cometic
 

It is my understanding that Felpro went to the OEM suppliers for gaskets on the import and domestic aluminum headed engines. Since the Europeans and the Japanese had been doing it alot longer, I think it made perfect sense.

Gaskets for Heads
 

not sure if this is the right place here, but i have a couple of questions maybe you guys can help me with, i have this block i was told a 502 marine block casting numbers 14096859, i looked it up just says 502 4 bolt HO. is there a way i could no for sure?? i do know that it has to outlets right next to the oil filter i am assuming are for external oil filtering or cooling, at least i used it for cooling, This motor is in a car, 1923 ford t bucket it is stroked to 540 with a 4.550 bore, oh ya i also am running 2 yes 2 671 Don Hampton Blowers, wish i could post a picture it is a site to see. Ok question, head gaskets is there a difference between marine and auto as far as head gaskets?? i have on there now 17049 fel pro, but not real sure if there right, i am pulling the Dart heads that are on there now as they were used with Alcohol and are pitted real bad and leaking water, so i bought a new set of Pro Comp heads with 320cc runners and 115 cc chambers, with dished pistons, i really need to lower my comp. a little more as with the 115cc i will be about 9/9.5, does anybody make a thicker gasket and will the cometic c533 .65 gasket work ?? guys i really apprecaite any input you could give me here and if someone would give me there email address i could send them pictures of this wild car, strickly show and local cruzes.
thanks again.

Marine would be stainless, Fel Pro just switches the number to 1067 for auto. You would probably be better off with a MLS gasket for your application. Depending on how thick you make the head gaskets, you may need thicker intake gaskets, and longer pushrods.

The guys at summit and jegs told me this number
what do ya think, FPP-1075-1 dang these things are pricy,

if you want to check out the car and the first start up go here.

http://www.youtube.com/watch?v=fUIqzmoL0Fk

4.580 bore, .051, should work well, you might check CV Products, they used to be cheaper.

I've got a set of MK IV cometics and 502 GenVI cometics brand new for $160 a set. Will post pART# IF INTERESTED

Part# on the cometics is c3 h1177spa-040s. The bore size is 4.560. will work up to a.060 overbore on a 502.

post part number, i have a 4.550 bore.
and guys thanks for the help.

Although I like the Cometic over Fel-Pro while freshening this season the Cometic's did blow between cylinders. We are O-ringing it this year. Pro-Charged 7lbs boost.
Bob

Since I cut the timing back, I've run two seasons on the same 1077s with 15lb of boost and no problems. The Felpro's have one wide crimp between cylinders where Cometic tries to put two.

I'll get them tonite.

Part# on the cometics is c3 h1177spa-040s. The bore size is 4.560. will work up to a.060 overbore on a 502.

man thats a long part #:eek::drink:

Ive never bought conetics before, I wonder how it breaks down?

We run Cometics- 14-71s with 14 to 16 lbs of boost zero problems.

Others run Cometics beyond 20lbs of boost with zero problems.

If you do have detonation what would you rather blow, your gasket or your piston?

Because if your running copper you just lost a piston or worse!

If your not detonating, 20+lbs of boost in it self should not take out your Cometic gasket!

Cometic back ordred these on me and I went with the FelPros because I could get them locally. Machinist couldn't get his money back so I told him I would try to sell them for him. Anyway, that was the # he gave me.

I thought I would revive this thread and see if anybody's
changed their minds. lets hear your opinions

Cometic or Felpro MLS ?
Gen 6 502 4.466 bore AFR heads 10psi boost.

should the MLS be sprayed with anything??:food-smiley-007:

the felpro allready have black sticky stuff on them, they do say they want the deck slick,RA

I dont have any exp with Cometics,though they have more choises on thickness.

Cometics all the way. Put them on dry.
Eddie

call bob at perfomance gaskets he will help you out !262 677 4690. HE supplies merc with 75% of the gaskets they use.

How about on a non blower application? I am refreshing two Mercury 525's and ordered fel-pro high performance gasket kit (17207). I originally thought that that was a direct replacement for what was on the engines but turned out that that was not correct so I ordered the gasket from Mercury that was listed (811546A04). This turned out to be a cometic MLS gasket and both the engine builder and machine shop that I have talked to say that they have had nothing but problems getting the MLS gaskets to seal. I called the distributor and Mercury and they both said that it is a new part number (old was A03) and this is what they recommend.

Any help would be greatly appreciated.

From what I've seen lately, the Cometics are standard issue from Merc Racing and for good reason.
I have never heard of nor had any sort of problem getting the Cometics to seal. I wouldn't use anything else personally.
Dave

Hey Dave...I guess what the issue is is that only the head had been finished by the machine shop and we couldn't the block clean enough to meet the recommended specs for the Cometic to seal properly.

I am not real familiar with all that goes into the rebuilding of an engine but thats what friends are for and I am certainly learning. I also may not have explained everything correctly for the same reason.

We ended up using the fel-pro high performance marine gasket (#17048 I think).

Thanx,
Smitty

I have run BOTH in my turbocharged 69 bird.

I had failures with both, if you detonate the engine either will go bad. The cometics IMO need hylomar on them or they can weep water unless the decks are perfectly falt and polished like mirror.LOL

I run the cometics because I feel they will hold a little more combustion pressure than the felpros.

But the felpros seal water way better.

Old thread indeed, but I have to make this same decision. I talked to tech support for both companies this morning to get part numbers for my 489 build.

First, FelPro:

Interestingly enough, he said that neither the 17042 or the 1037 is a MLS gasket. They do both have a stainless steel core, with the only difference being that the 1037 has a fire ring that the other one does not have. Either will work for my Gen VI block. He recommended against any of their MLS gaskets for a raw water cooled marine engine because they are not SS.

Cometic:

PN for a Gen VI 4.280 bore is C5817-040, which is a SS MLS gasket with a .040 compressed thickness. The Cometics can be special ordered in .027, .030, .036 thicknesses also.

My engine builder has run both, but he thinks the FelPro's will be fine for my application since I am only running 8.7 - 9.0 :1 CR with no plans to supercharge. For supercharged applications or aluminum head motors he prefers the Cometic.

Cometics will cost about $100 per side. I have found the Fel Pros online for as little as $34.00 each.

The Felpro 1075 and 1077 MLS are definitely stainless.

The Felpro blue teflon composite gaskets are fine for just about any n/a performance use. The Cometics would be a waste of money in your case. The Felpro's are definately a better gasket than what Mercury put in all of their HP500's in the past few years.