flathead gasket question

[Nasser Almasary]

Hello everyone:
  Upon installing heads on the 346, I noticed that some water jacket openings are obstructed by the gasket, one of these openings is near the temperature sending unit and very close to the water heater outlet fitting. I compared the old head gaskets with the new ones and they are identical and these holes were obstructed by the old gaskets too. My questions are:
1- are these obstructions normal (intended)?
2- if normal, what is the purpose of these openings since they'll be plugged by the gasket?
3- do you recommend using a sealer on the head gasket? if yes, what kind? and where on the gasket? (I am using Fell Pro)

Thank you for reading and thank you for your reply, and great thanks for this forum and the marvelous keepers of it.
Nasser,

[Nasser Almasary]

Addendum:
4- do you recommend using sealant on the threads of the head bolts which go into the water jackets?
5- what kind of washers are used with the bolts?

Thanks.

[Nasser Almasary]

Hi Every One:
   My head is waiting to be installed, your input is greatly appreciated.
Nasser,

[Brett Cottel]

I'm not sure about the holes on your gasket but most head gaskets do not require sealant....check with felpro maybe.
HTH
Brett

[Otto Skorzeny]

I have never seen a gasket with holes that didn't line up that was supposed to be that way - especially in water jackets and oil galleys.

[Jose Gomez]

I'm not sure about the holes on your gasket but most head gaskets do not require sealant....check with felpro maybe.
HTH
Brett

Brett,

One small correction on your statement would be applicable when the two materials are different aluminum to cast iron or when both are aluminum. In cast iron application it is always recommended to use sealant i.e. cooper spray sealant or equivalent. At least that is what old machine shops folks and the Cadillac manual recommends. I can’ speak for flat heads but I would assumed the same applies.

[Jose Gomez]

Addendum:
4- do you recommend using sealant on the threads of the head bolts which go into the water jackets?
5- what kind of washers are used with the bolts?

Thanks.

Nasser,

4- do you recommend using sealant on the threads of the head bolts which go into the water jackets?
My reply is taken from the 1956 Cadillac manual as recommended; again I would assumed the same applies for the flat head in this case.

[Roger Zimmermann]

1- are these obstructions normal (intended)?
2- if normal, what is the purpose of these openings since they'll be plugged by the gasket?

In my opinion, I would say yes for the question 1.
The answer to question 2 has certainly to do with manufacturing.
About the sealer: I'm applying sealer too on my cylinder head gaskets if they are metalic. I don't know how the gaskets are looking out for the flathead; if they are metallic, yes apply a dealer. If the gaskets are like graphite, then: no sealer.

Roger

[Bob Schuman]

You definitely need a sealer on the threads of all of the head bolts on the flathead V-8, as all of the bolt holes are open into the water jackets. I have had good luck with Permatex #2 non hardening sealer, but there are lots of others that other people prefer. Just don't use a hardening sealer or RTV, because they will set up, and then when you retorque the heads(VERY important) you will break the seal and create water leaks.
Bob Schuman,CLC#254

[Nasser Almasary]

Bob, Roger, Jose, Otto, and Brett:
  Thank you for your insight and contribution, but one question remains about the water jacket holes that are going to be blocked by the gasket. There is one hole (triangular) on each side of the block and a corresponding hole in the head that the gasket will plug (gasket is not opened and coolant cannot go through). I compared the new gasket with the old one and they are fully identical, and blocking the same holes too. one of these holes located near the water heater outlet fitting near the temp sending unit. I am baffled about the wisdom of having two meeting water jacket holes (on the head and block) that are going to obstructed by the gasket. This is stifling me and stopped me from reassembling my heads and to proceed with my restoration. If you've noticed such thing in the past or have an old flathead gasket in your garage, please check it out to see if it has the some swelling areas indicating the blockage I am talking about. I hate to see something suspicious in my restoration and take it for granted. Best regards to all.
Nasser,

[Roger Zimmermann]

Probably I was not clear enough: there can be jacket holes covered by the gasket. I noticed that on my '56 & '57 Cads. As I wrote, this is probably needed during the manufacture of the block to let escape the sand, but not needed for the cooling. If you are looking at the head, there is maybe not passage at all at this (these) location(s).

Roger

[Nasser Almasary]

Roger
  Thank you for the follow up. What you said is what I believe, but the oppening on the block has a passage correspods to it on the head, which is amazing. Any thoughts, Roger?
Nasser,

[Roger Zimmermann]

Sorry Nasser; I have no other explanation or idea. An engine designer/developper could certainly give an explanation; unfortunately I'm not.

Roger

[Otto Skorzeny]

Do you have any diagrams showing the oil galleries and water jackets?

By any chance do you still have the gaskets that came off the engine? Compare them.

[Brett Baird]

Nasser,

I can not tell you why manufacturers cast holes that will be blocked by the head gasket (it has something to do with the casting process itself), but it is normal for head gaskets to restrict or block those water jacket passages to control the flow of the coolant.  As I recall, the flathead gasket is symmetrical, and doesn't have a "this side up" or "front" designation, so you will be fine.  If it is a metal gasket, Permatex makes a spray sealer called Copper Coat that is recommended.  Never use sealer a composite head gasket unless the gasket maker specifically says to.  Use the permatex white teflon brush on sealer or permatex #2 for the head bolts.

[Nasser Almasary]

Roger
  Thank you very much, that is why I am stifled.

Otto

Do you have any diagrams showing the oil galleries and water jackets?

By any chance do you still have the gaskets that came off the engine? Compare them.

I have the shop manual and other literature that I consulted but no answer as it shows oil galleries but not water jacket passages. I do have the old gaskets and they are the same as the new ones and show the swelling done by the contact of the coolant with the gasket exposed to hot coolant from the water jacket holes in the block and the heads. These holes meet, if I cut the gasket, the coolant would flow from the block to the head or visa versa. I wish that some one in the forum has an old flathead gasket to inform us here if he can see these swelling(s) on the gasket. Frustrating, but I'll stay behind it till I find the answer. Regards.
Nasser,

[Nasser Almasary]

Nasser,

I can not tell you why manufacturers cast holes that will be blocked by the head gasket (it has something to do with the casting process itself), but it is normal for head gaskets to restrict or block those water jacket passages to control the flow of the coolant.  As I recall, the flathead gasket is symmetrical, and doesn't have a "this side up" or "front" designation, so you will be fine.  If it is a metal gasket, Permatex makes a spray sealer called Copper Coat that is recommended.  Never use sealer a composite head gasket unless the gasket maker specifically says to.  Use the permatex white teflon brush on sealer or permatex #2 for the head bolts.

Brett
  Thank you for jumping in this thread, I'll follow your advice for the sealer on the bolts and the gasket as you said. If I dont get  a red light at the end of the day on these gasket, I'll just mount them and go on my work and if something is going to fowel like over heating or coolant getting to places that it shouldn't, I will attend to it then, but, for now, I have to go on with my restoration. Best regards and big thanks to all contcontributors and to this forum.
Nasser,
P.S. I'll keep you posted.

[Mark Lowery]

Nasser,
I know this answer doesn't address the "why" part of your inquiry, but I'm looking at a copper clad asbestos head gasket that came off of my 37 LaSalle, and indeed the two triangular holes on the interior side (towards the center of the engine) are completely blocked off and both sides exhibit swelling that is no doubt the result of coolant exposure.  For the record, the gasket is stamped Victor-977-C, and though I can't verify it was part of the original assembly, I can tell you it had to have been on the engine since at least the mid-sixties.  It seems that there are three other holes that are similarly blocked on the outside of the deck and/or head surface.  One round near the center, and two oblong opposite the triangular holes you mentioned.

Mark Lowery, CLC#25216

[harry s]

Nassar, I have had the same question as to why the block/head holes are blocked by the gasket. I have done what Otto suggested, compare the old one to the new one and yes they match up. As to sealant on the gasket I have used Permatex Hi Tack spray. On the head bolts the Permatex #2 works good on the threads and also should be placed around the small shoulder on the bottom of the bolt head. Good Luck, Harry

[Brad Ipsen CLC #737]

Don't question Cadillac engineering.  I guess there is a possibility that repo gasket manufactures made a mistake but with all of the comparisons with old gaskets that show the same thing the possibility is extremely small.  Recently a friend's engine rebuilder wanted to match the water outlet size on the right head to the larger one on the left head.  My friend hestitated just enough to stop this action.  This would have resulted in a flathead forever having overheating problems.  The left side would have been way short of water flow.