rwdawg2 Posted April 15, 2009 Share Posted April 15, 2009 I have been searching around and can not find out what I want to know, so I am asking for some help. I have looked around for different head gasket options because MSA does not have the 1 or 2mm head gaskets for a while. So I found one at courtesy nissan but I do not know what would be the repercussions if I bought a head gasket that is 91mm bore when my motor is at an 87mm bore. So my question is, would it be okay to buy a head gasket with a larger bore? I realize it would not be smart to buy the OE bore (86mm) head gasket, but I do not know what it would do if I used a larger one. Any input on this would help me out a ton. Also if you have a better idea on where to buy a MLS head gasket I'm all for it. I would just like the head gasket at my house before May 12th. Thank you Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted April 15, 2009 Share Posted April 15, 2009 I have been searching around and can not find out what I want to know, so I am asking for some help. I have looked around for different head gasket options because MSA does not have the 1 or 2mm head gaskets for a while. So I found one at courtesy nissan but I do not know what would be the repercussions if I bought a head gasket that is 91mm bore when my motor is at an 87mm bore. So my question is, would it be okay to buy a head gasket with a larger bore? I realize it would not be smart to buy the OE bore (86mm) head gasket, but I do not know what it would do if I used a larger one. Any input on this would help me out a ton. Also if you have a better idea on where to buy a MLS head gasket I'm all for it. I would just like the head gasket at my house before May 12th. Thank you I can't give you all the resulting issues from doing so (I am sure the machinists will answer shortly), but the quick answer is it isn't a good idea. I have never seen such a substantial mismatch. I used a Fel-Pro gasket. They can be had in a day or two from many auto parts store chains. What are you doing with the engine? Quote Link to comment Share on other sites More sharing options...
Xnke Posted April 15, 2009 Share Posted April 15, 2009 The stock headgasket has an 88mm bore, you are find with a stock bore gasket. Quote Link to comment Share on other sites More sharing options...
rwdawg2 Posted April 16, 2009 Author Share Posted April 16, 2009 I did not realize that. Thank you Xnke. My thing is, is that I did not want to use a paper gasket for fear that I will have to replace often. Forged goodies, oversized valves, t3/t4 hoping to see a lot of boost and plenty of power. Didn't really want to spend my weekends changing out headgaskets. Quote Link to comment Share on other sites More sharing options...
Xnke Posted April 16, 2009 Share Posted April 16, 2009 As long as you keep engine killing detonation at bay, you won't need to change the headgasket. a stocker is fine, as long as you are tuned right. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted April 16, 2009 Share Posted April 16, 2009 What is your engine management situation like? What kind of fuel are you using? Quote Link to comment Share on other sites More sharing options...
rwdawg2 Posted April 17, 2009 Author Share Posted April 17, 2009 SDS individual coils. 440cc supra injectors on pump gas. Quote Link to comment Share on other sites More sharing options...
rwdawg2 Posted April 17, 2009 Author Share Posted April 17, 2009 Anyone just know where I can find a stock bore Metal head gasket? That question should be a little easier to answer. I need it relatively soon. Can't do anything without it at this point. Thanks Quote Link to comment Share on other sites More sharing options...
neotech84 Posted April 17, 2009 Share Posted April 17, 2009 Check rockauto..... the are a great place to start any parts search...... They have 2 HG listed not sure if they are steel or not...... Quote Link to comment Share on other sites More sharing options...
rwdawg2 Posted April 18, 2009 Author Share Posted April 18, 2009 Yeah I looked on there. It's just the fel pro and beck arnley paper gaskets. Really looking for a metal head gasket. The only reason I want a metal head gasket is for high boost. I hope to hit 20psi at some point in time and I know the paper gaskets aren't going to hold up to that kind of pressure. Thanks for all the ideas guys. A little more help though to get where I need to be. Quote Link to comment Share on other sites More sharing options...
cockerstar Posted April 18, 2009 Share Posted April 18, 2009 Running a felpro HG on a turbo motor is good insurance. When you get into the detonation it's going to be the first thing to blow, and I definitely favor spending my weekends changing a hg over rings. Quote Link to comment Share on other sites More sharing options...
Xnke Posted April 18, 2009 Share Posted April 18, 2009 ...except that many of our members here run 20PSI and the stock gasket. If you have the car tuned correctly, with no detonation, then the stock gasket is fine. Do some searching around here and you'll find reports of stock headgaskets doing just fine at 20PSI and more. A metal headgasket on a suboptimal tune is just a piston breaker/rod bender/main bearing masher. I'm not saying that a stocker is gonna last forever, you'll possibly blow several getting the tune right unless you are tuning on the dyno, in which you *might* still blow one. With a metal gasket, you'll be on the verge of piston damage or worse whereas the paper gasket will greatly lessen the chance of internal damage. If it was me, I'd get it tuned up on a stock gasket, then after I drove it for a while and did some datalogging, I'd turn the wick up some until I either got to my power goal, or blew that paper gasket out. Quote Link to comment Share on other sites More sharing options...
slown280z Posted April 18, 2009 Share Posted April 18, 2009 ARP studs and a stock style headgasket will easily allow you to run that much boost and more. MLS gaskets are for engines developing a LOT more horsepower using a lot more boost. Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 19, 2009 Share Posted April 19, 2009 Aside from a metal one, Nissan OEM gaskets are the best. They will blow, unlike a metal one, if something goes wrong. Ishino is the OEM for Nissan. I found one on thepartsbin.com for $24.95. This is a great deal as the dealers get around $75 for them. http://www.thepartsbin.com/catalog/?N=9285&uts=true&Ntt=W0133-1632596&x=14&y=13 Pete Quote Link to comment Share on other sites More sharing options...
rwdawg2 Posted April 19, 2009 Author Share Posted April 19, 2009 I appreciate all the input. I guess the availability of a paper gasket and not having to rebuild the motor if something goes wrong is probably worth it. Now the only thing I worry about is the compression ratio being to high for a forced induction vehicle. I had the block decked and the head shaved when being rebuilt, so my worry about the compression ratio being to high is the next concern. This was one of the reasons I wanted to go with a MLS gasket (1-2mm) to offset the high compression ratio. What do you guys think about that? Thank you again. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted April 19, 2009 Share Posted April 19, 2009 What is your comp ratio? I think the thing you need to fully appreciate is that a "paper" gasket will hold LOTS of power; it is simply a "fuse" if you get some detonation. Having a MLS gasket will make your bearings or ringlands the fuse. It would be "rated higher", but still fail. And fail quite expensively. The only realistic application where a (hard to acquire) MLS gasket is better is if you think you WILL detonate while tuning, but you are SURE that it won't detonate badly. That narrow range would make an MLS gasket more convenient since you won't pop the HG and not damage the bearings. Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 19, 2009 Share Posted April 19, 2009 OEM Gaskets are not "paper". They have a metal outer layer with some sort of fiber material between the metal layers. Quote Link to comment Share on other sites More sharing options...
tech9 Posted April 20, 2009 Share Posted April 20, 2009 Do you know how thick the Ishino gasket is? Great price on that gasket btw, I just might order 3 or so for tuning! Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 20, 2009 Share Posted April 20, 2009 It is the stock thickness as it is the OEM gasket. It's approximately 1.25mm thick. Felpro is 1mm thick. Pete Quote Link to comment Share on other sites More sharing options...
slown280z Posted April 21, 2009 Share Posted April 21, 2009 I'm surprised no one has said "headgaskets are not what you should use to choose CR ratio." (Unless the engine is designed to do so, like the Toyota 2JZ). But there, I said it. If the machining has taken away a lot of material to make this a factor, you might just have to get a set of custom pistons. Quote Link to comment Share on other sites More sharing options...
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