steve260z Posted March 14, 2011 Share Posted March 14, 2011 I have the 90.5mm metal Stoker Gasket. The coolant holes are not lining up. In this picture the gasket has small circular holes verses the "L" shaped (sort of) holes on the P90. Should I have the circular holes enlarged? On a drill press? On these next two pics there are no coolant holes in the gasket to match the head. Whats the best procedure here? Thanks for the advice. steve Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 14, 2011 Share Posted March 14, 2011 Look at your block and see what you got... (cough) "You may have something with that observation." (cough) I have been sworn, I can say no more. Quote Link to comment Share on other sites More sharing options...
ctc Posted March 14, 2011 Share Posted March 14, 2011 If that is the KAMEARI head gasket, it looks like it has cooling passages for an N42 Block. Which would make sense based on most high power JDM builds using the N42 block instead of the F54. I just verified a picture of the KAMEARI gasket against my N42 block and it looks correct. I don't know the best way to modify that gasket, someone else will have to answer that. Quote Link to comment Share on other sites More sharing options...
steve260z Posted March 14, 2011 Author Share Posted March 14, 2011 First, thanks for the responses. Block is the F54. The only passageways in the block which don't have a matching hole in the gasket are circled. See below: Quote Link to comment Share on other sites More sharing options...
steve260z Posted March 17, 2011 Author Share Posted March 17, 2011 Bump............... Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 19, 2011 Share Posted March 19, 2011 (edited) what about the head? Have you looked at the available resources yet? Just Asking, it's at the top of the page, after all! Edited March 19, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
steve260z Posted March 19, 2011 Author Share Posted March 19, 2011 Tony, Thanks...I was searching/looking in terms of "gasket" verses head cooling. Duh......... Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 20, 2011 Share Posted March 20, 2011 WHACK! Oh, thanks! It happens some times. Quote Link to comment Share on other sites More sharing options...
zxtman Posted March 22, 2011 Share Posted March 22, 2011 First, thanks for the responses. Block is the F54. The only passageways in the block which don't have a matching hole in the gasket are circled. See below: Here's some good email correspondence with my Nissan guy that I would like to share. Me... "I'm having sealing issues with the 1mm HKS metal head gasket, so I have decided to o-ring the block and use the factory head gasket instead. The question is which is the correct gasket to use?" Nissan guy... "I have attached some pics so you can compare the gaskets." "The part numbers referenced in the pics are: 11044-91MM1 is the HKS metal headgasket that Nissan Motorsports and others including myself were selling- it is now NLA. (You will notice that the metal gasket is pretty much identical to the early OE gasket in the oil and water passages) 11044-N4221 is the factory non-turbo gasket that was used from 1975 to 02/1981 11044-P7911 is the factory non-turbo and turbo gasket that was used from 03/1981 thru 1983." "The HKS gasket is just a big-bore, metal version of a 75-80 (N4221) gasket." "The thing about metal head gaskets is that the head and block surfaces need to be a near-mirror finish(low Ra or RMS numbers) for best sealing. I have kinda always had heartburn about using the (early style) metal gasket on the later blocks/heads." "You are probably on the right track with the o-ring+OE gasket setup, however, the turbo engine(P90 head+F54 block) calls for the P79 headgasket, so if you are going with OE, be sure to use the P79 one." "I remember when Nissan made the changes to both the P79 & the N42 & also the 240Z gasket back in the early 80's and arguing with the mechanics that Nissan would not have made the changes if they weren't necessary, and to trust that the Nissan engineers know what they are doing. It was something about keeping the water in the head longer for better heat transfer to the coolant." Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 23, 2011 Share Posted March 23, 2011 The dyno testing we did under load says otherwise, increasing flow to the head seemed to carry more heat out more efficiently than the original gasket configuration with restricted flow to the head. The gaskets restrict flow INTO the head, not out. That causes spot-boiling---look at any industrial exchanger and you will see unrestricted FEED side lines, and any throttling for temperature control is done on the OUTLET of the heat exchanger! Same goes for the L-Head: get as much water as you can into it, then play with getting it out. Restricting flow on the inlet side is not good as it can contribute to cavitation, etc. Quote Link to comment Share on other sites More sharing options...
zxtman Posted March 23, 2011 Share Posted March 23, 2011 The dyno testing we did under load says otherwise, increasing flow to the head seemed to carry more heat out more efficiently than the original gasket configuration with restricted flow to the head. The gaskets restrict flow INTO the head, not out. That causes spot-boiling---look at any industrial exchanger and you will see unrestricted FEED side lines, and any throttling for temperature control is done on the OUTLET of the heat exchanger! Same goes for the L-Head: get as much water as you can into it, then play with getting it out. Restricting flow on the inlet side is not good as it can contribute to cavitation, etc. There's an obvious difference (# of holes for coolant) between the early N42 gasket and the later P79 gasket. So what is sounds like you're saying is that the N42 gasket is more beneficial (more holes to allow unrestricted flow) for the later model head/block combinations over the P79 gasket??? Increasing flow to the head seems to make more sense; so, why did Nissan change it? Quote Link to comment Share on other sites More sharing options...
Noddle Posted March 23, 2011 Share Posted March 23, 2011 (edited) Question, having the water holes on the exhaust side of the head ( less on the spark plug side), will this increase the amount of the water moving past that side of the head, and thus reducing the chance of spot boiling, and helping reduce heat faster ? Nigel Edited March 23, 2011 by Noddle Quote Link to comment Share on other sites More sharing options...
zxtman Posted March 24, 2011 Share Posted March 24, 2011 (edited) Question, having the water holes on the exhaust side of the head ( less on the spark plug side), will this increase the amount of the water moving past that side of the head, and thus reducing the chance of spot boiling, and helping reduce heat faster ? Nigel ...that makes alot of sense, and to re-iterate what my Nissan guy said (with regards to the P79 gasket for the P90 head+F54 block combination): "Nissan would not have made the changes if they weren't necessary". Let me also add that the P79 gasket does not block coolant flow to the head at the (2) holes that Steve mentions in post #4. Edited March 24, 2011 by zxtman Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 24, 2011 Share Posted March 24, 2011 Regarding engineering decisions in the 70s and 80s - don't forget emissions requirements. They weren't designing engines just to run cooler or make more power. They were designing engines that would meet emissions standards. Retarded timing, EGR systems, etc. They might have been designing them to run hot to get a cleaner exhaust. Just offering something to consider when trying to figure out why things were changed. Their objectives were different. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 24, 2011 Share Posted March 24, 2011 The points mentioned, are all valid. Guys at a distributor mechanic level can surmise all they want about why whatever was done, they likely aren't engineers, haven't studied thermodynamics, and usually are basing their assumptions on very limited (bliners on) scope of problems they may be seeing. Of everything mentioned, NewZed likely has the best 'general' answer. MArk (OzConnection) I believe has some current NON-USA (Nissan OEM) "Universal L-Engine Head Gaskets" with FAR more holes on them, which are specified for universal application. They aren't required to meet US emissions outside the USA, take a look at 'universal fittment' replacment service parts outside the USA and you start realizing they did things here, and it wasn't for performance. REMEMBER: These gaskets were for low-specific output engines. Not high-performance engines (which I surmise is what we are talking about here... something more powerful than the average bear...) Long and short of it, if it seals and doesn't leak get as much flow to the head as you can get. Period. Quote Link to comment Share on other sites More sharing options...
steve260z Posted March 25, 2011 Author Share Posted March 25, 2011 One interesting side note since I posted this question. I purchased this .6mm, 90.5mm Kameari HG from Brian at Z car customs JDM (zccjdm.com). I sent these pics and basically asked the same question I did here. He contacted Mr. Miro, who, I understand designs many Kameari products and or founded Kameari...I'm sure someone here knows the story. Anyway, Brian at zccjdm forwarded Mr.Miro's response, to quote: "I designed the KAMEARI L6 head gasket so that F54(P90 HEAD) could share it with N42. When F54(P90 HEAD) compares the port of the gasket, there is a different place. However, there is no problem to use it. Please do not worry." Interesting. Steve Quote Link to comment Share on other sites More sharing options...
zxtman Posted March 25, 2011 Share Posted March 25, 2011 One interesting side note since I posted this question. I purchased this .6mm, 90.5mm Kameari HG from Brian at Z car customs JDM (zccjdm.com). I sent these pics and basically asked the same question I did here. He contacted Mr. Miro, who, I understand designs many Kameari products and or founded Kameari...I'm sure someone here knows the story. Anyway, Brian at zccjdm forwarded Mr.Miro's response, to quote: "I designed the KAMEARI L6 head gasket so that F54(P90 HEAD) could share it with N42. When F54(P90 HEAD) compares the port of the gasket, there is a different place. However, there is no problem to use it. Please do not worry." Interesting. Steve ...so what I'm reading here is that the Kameari gasket is a duplicate of the N42 gasket and that it's ok to use with the F54/P90 combination. If what Tony says is true: "...get as much flow to the head as you can get. Period." then why didn't Kameari make a 2nd gasket to match (F54/P90 combination) with more holes? ...or all holes opened up? Probable answer: Cost, make one gasket to be used universally (copy the N42 gasket and call it a day). Is it the best gasket for every combination? I don't know... So Tony, is the answer to use a gasket that matches the exact coolant passages for whichever block/head you are running? This would be a modified or custom gasket, of course. Quote Link to comment Share on other sites More sharing options...
z-ya Posted March 25, 2011 Share Posted March 25, 2011 Hussey makes two L6 copper gaskets in basically whatever thickness you want. See attached images. NIS-01 is the N42 style NIS-05 is the P79 style with some trimming to contour the cylinders The message I got from JR at GMT Racing (he worked on the Bob Sharp team), is pretty much what Tony is saying. Get as much into the head as possible, and then restrict the flow on the outlet. A flow restriction at the thermostat outlet is where they did it. 3/4" to be exact (from JRs memory). They ran a stock Nissan N42 gasket with an E31 head. They cut grooves in the block for copper wire just outside the gasket fire ring. They never blew a gasket running over 13.5:1 CR. Pete Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 25, 2011 Share Posted March 25, 2011 I think what Miro-San said has been twisted a bit. I don't see what he said was that he duplicated the N42, merely that he used it as a basis and designed the gasket to be interchangable. Again, Mark (Oz Connection) has 'universal fit' gaskets which have a part number from Nissan and they have FAR more holes than either individual originally had. Looks similar to the pictured N4221 above but as I recall the part number had some "XX" in it, which was strange. Regarding what gasket to use...I believe it was mentioned that someone had some $$$ tied up into a head gasket which is universal in application and isn't like ANY of those pictured. But there are block and head modifications (not rocket science here) that GREATLY increase the flow capability. What was the gas-ring Nissan Comp gasket made of? How easy is it to matchport a gasket... Quote Link to comment Share on other sites More sharing options...
zxtman Posted March 25, 2011 Share Posted March 25, 2011 How easy is it to matchport a gasket... Well said. That pretty much sums it up. Quote Link to comment Share on other sites More sharing options...
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