All Small Six Mahle head gasket compressed thickness

[clochard68]

Hello,

I'm new to the forum and at the moment rebuilding my 1968 small log cylinder head. Since I am going to mill the head I wanted to know if anybody knows the compressed thickness of the MAHLE head gasket? On summitracing they stated something between .042 to .044, on youtube I heard from mechtrician1 it is .044.

I ordered one and will compare it to the felpro I have already, was just wondering if anyone had measured it already.

Thanks, Martin

 

[bubba22349]

HI Martin, by chance I was also doing some researching on head gaskets last night and then found out that there is now a third composition head gasket available for the 144, 170, 200, and 250 small six'es. Before we only had the FelPro and Victor Reinz as choices so i was also very curious when I seen that Mahle is now making gaskets for our small six'es their parts quality is also reported to be quite excellent.

1. I think the FelPro Head Gasket was listed as having a .050 crush thickness, though I haven't verified this recently on their factory web site to refresh my memories and then update it here. These are the head gaskets I have been using for decades now.

2. The Victor Reinz Head Gasket listed in sales info as having a manufactured thickness of .049 and these head gaskets are said to have a .044 crush thickness by our site member "Bill wsa111" so that's a very good sorce of info. Again I also haven't verified this on their factory web site yet and really don't know if they accually list a crush thickness or not.

3. The Mahle Head Gasket I found last night was listed as being a .045 thickness nothing else on its crush thickness. I think this is going to be right on or within + .001 to .002. I don't know yet if they have this kind of info posted on their factory web site but I will try and find out. But like you I am quite curious about their head gasket thickness. Best of luck and please post here what you find out as to its manufactured thickness. Up date today Aug. 3, 2021 contacted Mahle and they verify'ed the crush thickness of their head gasket # 3910VC is .045 and is their only head gasket for the Ford Six.
.

 

[wsa111]

Who sells the Mahle head?

 

[bubba22349]

I found them on RockAuto.com last night!

 

[clochard68]

Hey,

From what I heard Mahle bought Victor Reinz, so .044 crush thickness for the Mahle gasket might be a good guess. I should have the gasket within the next two weeks, then I will have a brand new Felpro and a brand new Mahle gasket to compare... is it possible to get usable measurements with a vernier caliper to compare the two out of the box?

The head will not be installed before fall because of porting and machining I am doing to it. Till then I have time to test the crush thickness, so if anyone has good testing methods for me to try out (without ruining my gasket) I will sure try them and post the results!

@bubba22349 I should definitely step up my research game, you found more info in one night than I did in several!

On a side note I am also porting the cylinder head (1968 small log with unbored thermactor humps), and will post a little about that in another thread. I got my car bone stock on the dyno before I changed anything and got something around 70 rear wheel hp out of it, so there is a lot of potential for a little more power. I will bring it to the dyno after I have done all the mods and keep you all updated.

 

[bubba22349]

Hi clockard68, yes you should be able to get usable measurements using a vernier caliper as long as you use a light touch so it doesn’t compress the gaskets in anyway. There is no way I know of to get a crush thickness without installing the head gasket and torquing the head bolts to spec were it would than be used. By the way if you still have a stock steel shim head gasket that still looks to be in good condition you might be able to reuse it using some copper coat. They are about .022 thick sometimes you can find some NOS head gaskets but it’s getting quite rare to see them. I am going to be looking for good used one for a drag car project and the look into getting some copper ones made off the steel patterns.

On porting the 1968 log head (last year of the small log heads) you will be much better off if were to look for one of the later 200 or 250 large logs heads like a 1977 to 1983 their as cast intake ports are substantially bigger than a small log head. So after you get done porting any of the 1963 1/2 to 1968 200 small log heads it still wont even flow as much as a stock unported large log head does. And then if you port one of the large log heads you got even greater potential. Best of luck on your 1968 Mustang!

 

[clochard68]

Hey, thank you for the tips.

Unfortunately I can't get my hands on a later head, haven't found one in the past 18 months I was looking for it.
I decided to try my best on the small log head, I already did a kind of 2V conversion for my weber 32/36 and I found that someone before me already put hardened seats for both exhaust and intake in it. So I keep the stock valve sizes and the original camshaft, but I am in contact with rocker arms unlimited to get the 1.65 roller rockers. I have a pacemaker long tube header to a single 2.5" outlet with a flowmaster 50series muffler.
For the carburetor I fabricated an adapter plate that will be welded onto the stock air filter housing with a snorkel I got from a 351 air filter. I will route that to the right wheel well as cold air intake. For the ignition I tried to get a DUI unit but had to wait almost a year, so I got a progression ignition instead (so I can play with the advance a little easier). Hopefully all that will wake up the engine a little more...

I already purchased the yellaterra roller rockers with pushrod/lifter kit (when the plan was to change the cam) that I have no use for now. If anyone is interested I will give them away for really cheap. I also have an ACP maxcore 3 row radiator brand new that I don't need because I installed a champion one to clear the stock waterpump fan, if anyone has use for it.

Regarding the gasket: Unfortunately I didn't have the steel shim gasket on the block, there was a felpro on it. I cc'd the combustion chamber and measured 55cc, so the head hadn't been milled when rebuild. That must be why I have so low compression and I hope to change that with the mahle gasket and shaving a few hundrets off the head to get hopefully near the 9.5:1 compression ratio (with stock 7cc measured dished pistons).

So thank you for your help, as soon as I get the gasket I will post some numbers and pictures!

 

[bubba22349]

That's a shame you can't even find a 1969 to 1976 log head I guess these parts are disappearing much faster now, and I understand your needing to stay with your small log head. Those are some very good parts for your combo i will be curious on how well that distributor works out for you I think it's should be excellent. So doing some of the numbers of what is needed to get you to a 9.5 to 1 (compression ratio CR) this is what I came up with not knowing all the details.

Is the short block staying stock?

Typical Stock 1963 1/2 to 1968 200 short block some California Emissions engines had a larger dish CC.
Bore 3.680
Stroke 3.126
Piston Dish 6.5 CC
Deck Height .019 Piston down the hole, stock Ford 200 piston compression height (CH) is 1.511. Note The Replacement cast oversize pistons are a shorter CH at 1.50 which then gives you an increased deck Height of .030 on a typical stock block that's not been milled before.
Gasket Thickness? Victor Reniz .044
Gasket bore opening is 3.820

So without milling the block deck to zero you will need head combustion chambers that measure in at about 46.5 CC’s this could change a little if the head gasket thickness measurement is a different + or - a .045 mill cut to the head surface should get you really close to your desired 9,5 to 1 CR. This engine will also have a .063 quench distance that's not ideal for good detonation resistance. Better still would be to at least zero deck the block or even more for Pistons to be out the hole .005 to .010 to tighten up the quench some more, and then you would only need a 50 CC combustion chamber (for Zero decked block) a mill cut to the head of .025 and that would also give you a good .044 quench distance that's nicely in the sweet spot of .030 to .050. Best of luck Edited

 

[chad]

R U located Down Under?

 

[clochard68]

@bubba:
Yes, the shortblock is staying stock for now, all I changed was the damper-pulley. For now I focus on the head, exhaust, carburetor and ignition.
Thank you for also running the numbers for me! I was planning on milling the head .050 at max, I don't want to go much higher not to weaken the head too much (although .090 is possible from what I read) since it's not going to be a performance engine anyway

Is there a rule of thumb as to how much milling will reduce the chamber cc to what extend with a standard D-shaped combustion chamber? Something like "if I mill the head .010 I will loose ...CC of the original, unmilled chamber"?

@chad:
Hi chad, no I am located in Austria/Europe. But I bought the Yellaterra rockers directly from the manufacturer, didn't know vinageinlines at that time!

 

[bubba22349]

Yes you can get real close by using this formula a reduction of 2 CC's for every .010 mill cut you do. Best of luck

 

[clochard68]

Thanks bubba, I will take that as my guideline for the calculation!

 

[chad]

...rule of thumb as to how much milling..."
no, we "CC" the head just as we measure the deck. A 50 y/o motor (how many previous owners? how many mods done? what kind?) is an unknown till doing so (disassembly is a great time as it's still 'together').
If not getting a copy of 'the Handbook' the time is late for that:

The Ford Falcon SIX Cylinder PERFORMANCE HANDBOOK | Vintage Inlines

The Ford Falcon SIX Cylinder Performance Handbook has 107 pages of History, Facts, and Information to help you get more power out of your small Ford SIX. This engine was used in Falcons, Mustangs, Fairlaines, and Comets in the 60’s. It was the FoMoCo workhorse in Mavericks, Granadas, and...

www.vintageinlines.com

I believe a ford6 member included the method for this when writing the Handbook. The tech archive above is nother

Classic Inlines

probably under 'cyl head'. It takes just a plate of sorts, some colored liquid, a known measurer to gauge the upside dwn head's cubic inch volume. Far from the difficulty in setting up a rear end or tuning multi webbers...
aahahahaa
So, yes:
"...as my guideline..."
but this is a science of more precision (U C w/'compression thickness" above) & wrkin w/as many 'knowns' as we can, here so easily determined. Besides, I all ways look for an excuse to buy a new tool, here a 50cc turkey baster or graduated/lined medical (mine's a horse) syringe ~

 

[clochard68]

I already cc'd my chambers as well as the dishes of the pistons. I tried putting just the desired CC of liquid into the chamber an measure the distance to the gasket surface to measure how much I will have to mill the head, that gets me pretty close to where I want to get concerning chamber volume.
I have a copy of the falcon handbook, but I am always eager to hear what results other people get when applying the well known rules or what methods they use to get the desired results! I guess I will let the head be milled only once and live with the achieved CC, hopefully I get it close to what I have in my mind...

 

[chad]

oh, OK, kouwell. U may have said that already. I just don't re-read the whole thread usually and wanted to offer that as assistance...
Good. As we say on this side of the pond "Not his 1st redio", "not his 1st BBQ.", etc...

 

[Wayne clark]

Hey, thank you for the tips.

Unfortunately I can't get my hands on a later head, haven't found one in the past 18 months I was looking for it.
I decided to try my best on the small log head, I already did a kind of 2V conversion for my weber 32/36 and I found that someone before me already put hardened seats for both exhaust and intake in it. So I keep the stock valve sizes and the original camshaft, but I am in contact with rocker arms unlimited to get the 1.65 roller rockers. I have a pacemaker long tube header to a single 2.5" outlet with a flowmaster 50series muffler.
For the carburetor I fabricated an adapter plate that will be welded onto the stock air filter housing with a snorkel I got from a 351 air filter. I will route that to the right wheel well as cold air intake. For the ignition I tried to get a DUI unit but had to wait almost a year, so I got a progression ignition instead (so I can play with the advance a little easier). Hopefully all that will wake up the engine a little more...

I already purchased the yellaterra roller rockers with pushrod/lifter kit (when the plan was to change the cam) that I have no use for now. If anyone is interested I will give them away for really cheap. I also have an ACP maxcore 3 row radiator brand new that I don't need because I installed a champion one to clear the stock waterpump fan, if anyone has use for it.

Regarding the gasket: Unfortunately I didn't have the steel shim gasket on the block, there was a felpro on it. I cc'd the combustion chamber and measured 55cc, so the head hadn't been milled when rebuild. That must be why I have so low compression and I hope to change that with the mahle gasket and shaving a few hundrets off the head to get hopefully near the 9.5:1 compression ratio (with stock 7cc measured dished pistons).

So thank you for your help, as soon as I get the gasket I will post some numbers and pictures!

If you still have the rockers & pushrods & are intrested in selling contact me at wc4225@gmail.com. thanks

 

[clochard68]

Hello Wayne,

I sent you an email.

Regards, Martin

 

[bubba22349]

Hi clochard66, when your porting your 1968 log head be sure to open up the logs carb mounting hole to a least 1 3/4 inch that will help the flow some. If you want depending on gasket mounting surface area some go to as much as a 2 or 2 1/8 opening again this helps it flow better and using a 1 3/4 inch hole or larger allows you to bolt on bigger 1V carb's and or in using one of the 1V to 2V adapters. After you have it opened up also grind a radius on the bottom of the carb hole this also helps flow going into the lenght of the log. Good luck on your. Porting.

 

[clochard68]

Thanks bubba, that tipp with the radius is a good one. I have a 1/8" radius there atm which I ground, should I get it bigger?
I also plan on removing the plugs on both sides og the casted intake and round the short radius cormners of the 1, 6, 2, 5 cylinder as much as possible, has anyone experience with that?
I will open a new thread about the porting, I would really appreciate every input on dos and don'ts concerning porting the log head!

 

[clochard68]

Today I finally got the Mahle gasket in the mail. I took some fotos of both gaskets, on the left is the felpro, on the right the mahle.
Outer shape and bore seem to be identical, only the small water passages differ (they are smaller on the felpro). The felpro feels a little bit "stickier", the mahle resembles more the gasket I got with my transmission oil pan.

I measured the thickness just on the gasket material and also on the metal rings around the cylinder bores. I know it's hard to see, so I attached the measurements I got also.