Head gasket coolant mod?
#1
Racer
Thread Starter
Head gasket coolant mod?
On the Lindsey Racing website, when you go to order a head gasket, they ask if you want their $10 coolant mod. I tried searching but couldn't find any info about it. Does anyone know what it entails and what it does? Thanks!
#2
Addict
Rennlist Member
Rennlist Member
It is a steam vent for the #4 water jacket. There is a tented portion of the head above #4 that easily develops air pockets. The mod is to drill and tap the head at this spot and run a plastic water line back to the reservoir. It works great.
#3
Nordschleife Master
The steam vent kit is $60, this “coolant mod” is $10, also on the steam vent product page they also say “In addition, if you're pulling your head, you would want Wide Fire or Cometic head gaskets with our Exhaust Port coolant holes. This, combined with our Steam Vent Kit, should give you that added protection you're seeking.”
Op could always call them and let us all know (405) 947-0137
#4
Rainman
Rennlist Member
Rennlist Member
not sure if LR is offering this as their service but on the 928GTS, Porsche added a few small holes on the exhaust side of the heads (and in the gaskets to accomodate) to allow for coolant to flow between the ports/valves.
can't hurt.
can't hurt.
#5
Racer
Thread Starter
Pretty sure that’s not what it is but I cannot think what it may be.
The steam vent kit is $60, this “coolant mod” is $10, also on the steam vent product page they also say “In addition, if you're pulling your head, you would want Wide Fire or Cometic head gaskets with our Exhaust Port coolant holes. This, combined with our Steam Vent Kit, should give you that added protection you're seeking.”
Op could always call them and let us all know (405) 947-0137
I'm imagining that there's a coolant port or two that the normal head gasket doesn't have holes for. Guess I'll find out when I call.
#7
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#8
Rennlist Member
LR adding coolant holes to the head gasket has been around for awhile, but not really utilized by most owners. I had one gasket with the modification done years ago. Can't attest to the benefits since I also installed the vent kit at the same time.
#9
Hmmm. I'm about to order parts from LR, including a Cometic gasket. If I'm understanding the conversation, without this mod, at least some coolant ports are blocked? That doesn't seem like a good thing.
#10
Rennlist Member
If you do not get your block and head machined I would think twice about the Cometic gasket. It requires a surface smoothness of 50 RA or less.
#11
#12
Rainman
Rennlist Member
Rennlist Member
lots of holes are 'blocked' by the gasket, only flowing up through the gasket behind #4 cylinder.
i cannot say with certainty what LR does as their coolant mod, which is different than the steam vent kit, but i speculate it is opening up some of those blocked holes.
#13
Drifting
Porsche at this stage of the game were not real proficient in water as a coolant. The cars they were producing were "air" cooled (really oil cooled) The designs in the water cooled engines leave a dead spot back by the #4 cylinder where a steam pocket can form preventing cooling of the #4 cylinder leading to head gasket failures among other things. I do not know how a couple of holes would alleviate this condition.
#14
Either some of the holes in the head are there due to the casting process and are not supposed to let coolant flow through or the headgasket is supposed to be exposed to coolant on both of its sides to avoid heat to build locally on "large" areas of the head surface. Or perhaps a bit of both.
The headgasket is not "holed" on the corresponding locations to avoid interfering with the flow of coolant, which flows backwards in the block from the water pump then frontwards after it went up in the head through the 4 triangular holes at the back of the head(gasket). There are still two small holes at the front of the headgasket which are so small that they should not alter coolant flow.
The headgasket is not "holed" on the corresponding locations to avoid interfering with the flow of coolant, which flows backwards in the block from the water pump then frontwards after it went up in the head through the 4 triangular holes at the back of the head(gasket). There are still two small holes at the front of the headgasket which are so small that they should not alter coolant flow.
#15
What I'm hearing seems to suggest that the head gaskets sold by LR are indeed specific to 951's, as opposed to generic gaskets that require modification for use in 951's. That they are copies of OEM gaskets. But they might (or might not) be improved if more ports were exposed.
When do we get to the easy, straightforward stuff??