Head Gasket Questions

[Anonymous]

Hi!
I know some of this has already been covered, but from everything I read I still have a few questions about changing out a head gasket on an 200ci six. I gather that since the thickness of the old gaskets mic out thinner than the new replacements there will be a loss of compression. My question is as follows -
I have a head gasket leak and wish to replace the gasket. Since horsepower/etc is not an issue, will the loss of compression that results from useing the thicker replacement gasket be noticeable enough to cause a problem? I cant afford to modify the head in any way at the moment, and if the difference would be that drastic, I will just wait until I can afford either a new head or the modifications needed. I do know that the current head has never been removed from the vehicle and it is the original head gasket.
Thanks!!!

James

 

[CZLN6]

Howdy James:

No, a thicker composite head gasket will not cause any problems. Just a noticeable loss of power and economy. The Victor brand from NAPA is just a little thinner than the FelPro from other parts houses. Both will seal much better than the factory OEM shim type gasket.

What has caused your head gasket to leak?

Adios, David

 

[Anonymous]

David,
Thanks for that info, that will help alot. As for why it is leaking, I am not sure, it was that way when I bought it. I know the original owners though and I know it is the original factory gasket. Its just leaking a little oil and there is no water in the pan or anything, I just want to stop it now as a little problem before it becomes something of a bigger, more expensive one. I am not losing any oil from the pan (the level never goes down) but I change my oil and filter once a month and only drive an average of 30-40 miles a week tops.
And I honestly dont like the little oily trail it leaves down the side of my motor...lol.

 

[MustangSix]

One advantage of the composite over a steel shim gasket is the ability to be more forgiving of surface irregularity and slight warpage in the head or block.

With a steel shim, you cannot always get a relaiible seal on parts that have not been remachined true. After several decades, and many heat/cool expansion cycles, it's a rare piece of metal that is still as straight as originally machined. The composite gasket may be the better choice if you are not remachining the deck and head.

 

[Anonymous]

David mentioned a noticeable decrease in performance and economy - how noticeable ? Although horsepower is not an issue, fuel economy is. As it sits right now, with the stock carb and points, etc. I average about 26 mpg. I could accept as low as 20 mpg but that would be about it. Out of curiousity, what would it cost (roughly) to have the head milled (? proper procedure name?) the .025" to compensate for the thickness of the composite gasket? I dont want to do any special perfomance stuff, just keep her moving (even if somewhat slowly) down the road.

Thanks again!!!

 

[Anonymous]

James,

I found an NOS shim style gasket from www.marxparts.com

Just use a good copper spray gasket adhesive. I did no machining, just good cleaning of the surfaces.

Duane

David mentioned a noticeable decrease in performance and economy - how noticeable ? Although horsepower is not an issue, fuel economy is. As it sits right now, with the stock carb and points, etc. I average about 26 mpg. I could accept as low as 20 mpg but that would be about it. Out of curiousity, what would it cost (roughly) to have the head milled (? proper procedure name?) the .025" to compensate for the thickness of the composite gasket? I dont want to do any special perfomance stuff, just keep her moving (even if somewhat slowly) down the road.

Thanks again!!!

 

[Anonymous]

Duane,
Thanks for the site info, I couldnt get their online thing to work so I am going to give them a call. I can actually see my car NOT leaking oil...and its making my eyes leak..lol

 

[Anonymous]

I just changed my head and head gasket. When I removed the head it already had a Victor gasket, so I know it had been replaced at some time. But it had failed badly between the water and oil jackets and the outside. Oil in water, water in oil, oil and water outside. But all cylinders psi good.

Since I drive 100 miles a day a decided to replace the head with a rebuild with hardened seats. I ended up using "American" head from Kragen.
But I wanted to point out that the deck of the block was not good. There was appreciable tool chatter during the original head surfacing and there were several machine tool ridges approx .010 to .015 high right in the area where it had leaked. This was like a wavy surface that flowed with the machine marks. I took a fine flat file laid down flat and dragged it over these peaks and worked them down flat;they were actually high-spots.
I didnt go too far but enough to where I couldnt feel the waves with my finger tips. I have NOS-type steel gasket but was afraid to use it due to this condition. I went with the Victor , because I couldnt stand the thought of having to redo it right now. And I was already use to the performance level.

I have already 600 miles and it seems to hold fine.

I am runniing a 7 lb cap since my previous problems. Anyone know what is standard?

Frankie

 

[CZLN6]

Howdy James:

The loss in power and economy will be somewhere between 2 - 5%, estimating a .4 loss in CR. The variance is dependent on many other variables. In conservative driving with an automatic trans it will hardly be noticeable. Possibly a greater loss in economy than performance.

The cost to disassemble the head and mill it to conpensate for the thicker head gasket varies from shop to shop and area to area. Check with you local shops. If you are choosing to go this way consider a valve job at the same time. A three angle valve job with new valve stem seals would include a truing cut of the head surface. Talk to you machinist for details and $. The irony is that a head gasket alone is in the $25 -$30 range, while a valve job gasket kit is about $50. The kit will include the valve stem seals.

If I were in your shoes, I'd try- 1- Retorquing the stock head (seldom works, but free and worth a try), 2- Living with it 'til I could afford to do a complete valve job. 3- Buy a spare late model head and get it ready at your leasure and as you can afford it, then have a swapping party- heads that is.

Please reread the sticky post at the top of this forum for details.

Adios, David

 

[Anonymous]

I am doing #3

I am going to try to get a late model head and do it correctly

until then, I am gonna tinker

 

[mugsy]

James,

Milling a head should be in the $20 range. All professional auto machine shops can do this quickly and cheaply. Personally I wouldn't trust the gasket to seal without milling the head. You stand a better chance with the thick composite gasket versus the metalic OEM one. And yes I understand your desire to save money on the valve job etc, but if you just put back the head and it leaks again you will have to buy another head gasket PLUS the milling and the time to re-do. My $0.02.

 

[Anonymous]

WOW! I didnt know there was that much involved in just changeing out a head gasket....Think i am going to follow the " buy a late model head and rebuild it at my own pace" route. This is obviously something I should investigate alot further before making a decision on...

Thank you all very much for your input and ideas!!!

 

[Anonymous]

James, I have one other "in between" option still available - the FoMoCo "C" series head gasket (2 left). These composite gaskets were Ford's answer to the leaking steel head gasket. They are only .027" thick, compared to the steel's .018"-.020" and the Victor's .040"-.045" thickness. Ford used these in warranty situations where leakage due to slightly warped head surfaces. They're even rarer than the steel gaskets. If you need one of these, drop me a PM. They're not as cheap as the Victor, but good stuff seldom is.

 

[Anonymous]

James,
I guess this opinion is pretty unpopular, but if i was in your shoes i would sit on it and do nothing. 26 MPG is GREAT. i average probably 18, but i know there are a few things wrong with my car. Man, if I got 26 MPG i wouldn't even think about changing anything. As is, i gotta go rebuild my transmission again tomorrow. A small oil leak is nothing. My transmission right now leaked a quart on an 8 hour drive. That is a leak worth doin something about. You not being able to notice the level dropping puts you in real good shoes. If you take off the head you open up a whole can of worms. I know the grass is greener on the other side, but im tellin you you are ON the green side now.

-Dan in Atlanta

 

[Anonymous]

Thats what I kinda figured to do...I dont ever plan on doing the high performance thing ( not something I am into) just want it to run as the factory designed it too. I guess its kind of odd but I bought my Falcon for the same reason my folks bought theirs new - They are reliable, easy to maintain, and very economical. I do plan on rebuilding the engine at some point in the future (135000 and no smoke yet!) but I am not going to tackle that until I have enough to do it right and all at once. I kind of thought 26mpg was good too, and wondered if I was going to lose that economy by changing out the head, and since I have no water in the oil etc, I think in this case my best course of action at this time is no action at all...
Thank you all for saving me a bit of cash and teaching me ALOT about this !!!
James