Why Model B Gaskets on High Compression Model A Heads? Pics

[fivefix]

Why do all the suppliers of high compression heads recommend Model B gaskets? I just blew my second head gasket in the first 2,000 miles since my AER rebuild with a Snyder's 6.0 head. I first blew my supplied B composite gasket and now have blown the Model B copper gasket. The rebuilder now recommends a Best Gasket Company carbon fiber gasket but it's still a B gasket.

I had a group of experts from my Model A club with me today as we pulled the head. It appears the B gaskets overhang into the combustion chamber of each cylinder as they are wider than A gaskets.

The first picture shows the gasket in the combustion chamber and the next are of the failure.

I took the head straight to a machine shop to true up the surface and ensure warping isn't the issue.

Snyder's is doing some investigation and I'll speak with Richard Fallucca tomorrow who has been great talking me through my concerns and questions.

Until then, any suggestions as to why A engines with high compression heads require the use of the B gasket?

 

[Ed Pitts]

What bore do you have on this engine? Ed

 

[fivefix]

What bore do you have on this engine? Ed

Ed,
1/1,000th over standard.

 

[Bob C]

Vince has some info on the A and B gaskets on his web site.
http://www.fordgarage.com/pages/brumfieldheadgasket.htm

Bob

 

[Pete]

It doesn't matter what gasket you use if the fire ring hangs over the edge of the cylinder or combustion chamber it will fail in short time.
Ideally the fire ring should sit back .010 from both the top and bottom edges.
Few if any gaskets qualify these days.
That's why many race engines use solid copper gaskets with wire O-rings.

 

[James Rogers]

First, the B gasket is the same size as the A gasket because the bore size is the same. The only difference I see in the basic design of the gaskets is the B gasket has 2 holes in the center that the A gasket does not. Pete is correct that the fire ring CANNOT protrude into the combustion chamber. It will cause a hot spot and burn through in short time. I always use a Best gasket for a Model A and have had no failures reported. There may have been some but no one has told me about it and that is in several years. I hate the modern type with the red sealant. It will fail and cannot be used but once. The original B composite gasket is as bad and for the same reasons. I have used copper Best gaskets, even on my own car, and have never had one to fail, and have reused them several times with great success.
That is my experience for what it is worth and, I put on a lot of head gaskets.

 

[kelley's restoration]

it also depends on how you drive it.
do you lug the motor hard with the timing totally advanced?
knock works in strange ways
tk

 

[freak]

I used a Best gasket once. Leaked water like crazy.

 

[Ed Pitts]

Here is a 7013 R3 with my 40 bore. This is a good head gasket. Ed

 

[Tom Wesenberg]

Here is a 7013 R3 with my 40 bore. This is a good head gasket. Ed

How come there is a number "2" on the number 1 piston?

 

[Ed Pitts]

Tom, that is just a sloppy 1. Ed

 

[Tom Wesenberg]

Tom, that is just a sloppy 1. Ed

OK, now I can see it.

When I was 18 I bought a 1956 Chevy 265 engine, with an overdrive ******, from a Ford dealership mechanic. 5 of the pistons had the notch facing the rear and none of the marked rods and pistons were in the right hole.

 

[tbirdtbird]

your gasket hangs way into the combustion chamber all over the place. what's with that?

.001 over std? You mean 3.876?

and I thought Felpro was up to a 7013 R4 gasket; where did Ed P get an R3?

The one Best gasket I looked at about a yr ago at a seminar on the Texas tour had the poorest quality fire ring I have ever seen. Having seen that poor quality I will never buy one

 

[southfork]

The Felpro 7013 C copper gasket was recommended to me for my 125 overbore. Is that the same gasket as either the 7013 R3 or 7013 R4 gasket mentioned above? if not, how are they different.

 

[jw hash]

Ed
if you have a B head lay your gasket on the head just like you did on the block and make sure the fire ring does not hang over into the combustion chamber

 

[H. L. Chauvin]

Hi Five,

FWIW:

I guess not too many today remember recommendations by vintage Model A mechanics born well prior to WWI who were already grown men working on all makes of vintage cars when the more modern Model A's came about.

Many were former common sense blacksmiths & old steam engine mechanics.

I knew many ........... & I learned that a Model A or Model B head gasket was a head gasket whereby they later either came with sheet copper top & bottom, or with bare gasket material lined with crimped steel at combustion chambers.

Both worked great on Police heads, or heads that were commonly shaved down 3/16" back then for increased compression. ....... & quite a few head gaskets, (even though never heard of today), were re-used after a valve job or a ring job after coating same with Permatex No.2.

Your head was re-surfaced; however, was your block surface checked for flatness. I would definitely check it.

Also, please call Mr. Ron Kelley who advertises rebuilding engines in the MAFCA for a report on the blocks he sees daily which are very much over stressed with guys following the 65 ft.-lbs. & more of torque recommendations while using Model A high strength bolts.

I used to subscribe to "Outdoor Life" years ago in the 1950's. I learned quickly that the guys who wrote about successful squirrel hunting, their feet were always on concrete in the city, & they never even saw a real shotgun being fired.

To me, a head gasket is a head gasket -- I do not need a blueberry gasket, a strawberry gasket, or one of pumpkin flavor with a touch of nutmeg whether placing an A gasket on a B engine or a B gasket on an A engine (with or without the (2) additional hoes in the B), when using Permatex No. 2 on both sides of the gasket which acts as not only a sealer, but as a "lubricant" to allow the gasket to "slide" into place when greatly compressed by so few head bolts, as opposed to being crumbled up like a crawling dry pair of underwear in a dry wool suit.

The last gasket I installed was a new modern silicon gasket recommended by Mr. Walt Bratton on an A engine with a Model A Police high compression head -- installed with new non-recommended "standard" head bolts as opposed to extra strong bolts, all torqued very carefully in 15 ft.-lb. increments to only 55 ft.-lbs. in lieu of 65 ft.-lbs.

Contrary to recommendations, I coated both sides with Permatex No. 2.

The bore was .125" overbore & like in the past with many head gaskets, I still have no problems with this set up.

Flatness of head & block, lubricant like Permatex No. 2, & incremental even torque works.

Hope this helps to quit changing so many different flavored head gaskets.

 

[James Rogers]

The A gasket and the B gasket are not at all the same size. They are completely different shape around the combustion chamber, in addition to the two added holes on the B. The holes makes them easy to sort, but the combustion chamber edge is several millimeters different in several areas on A's and B's to accommodate the the differences in the shapes around the valves. This is how you keep the edge or fire ring in the proper place.

Now in this modern age, I am not surprised if the questionable gaskets available have tried to evolve into a one size fits all regarding combustion shape, and bore size, but they were never like that originally. This is why there are so many blown head gasket stories. Somebody blows a FelPro 7013 R3 on every tour it seems, based on the stories I hear.

I have a fetish for NOS head gaskets and gasket sets, and have well over a hundred of them, all brands and style from the 1930s to 1960s, all new and NOS. No head gaskets made today impress me as much as most of the old ones.

This is the point I was trying to make.

 

[OL JENNY]

I have a similar setup, and this has been a great discussion with knowledgeable people providing good advice. But for a novice, the question remains, where do we start for securing the proper head gasket. Snyder's suggest the "Model B" gasket for the 6:1 head, and their "Model B" copper gasket appears to infringe into the combustion chamber. For those of us who do not have access to many different types of gaskets in our inventory, but need to purchase anything before we can set it on the block and head, where do you start with a suitable gasket that SHOULD WORK on a Snyder's 6:1 head and an AER touring rebuild. It may be necessary, but I hate to purchase 4 or 5 types of gaskets before finding one that fits. Thanks to all who are providing discussion on this topic.

 

[Ed Pitts]

Here are some measurements from 3 head gaskets that I have. The top one is a 7013 that dates back to the early 1970's with no R number. The second is a composition and the third is a 7013 R3. Ed

 

[Bob C]

I think this is what a B head gasket should look like.

Bob