2eighTZ4me Posted January 5, 2011 Share Posted January 5, 2011 Bore size is +/- 88mm. The JE pistons specs said 88mm on the box. I measured the cyl. bore and it came out to 89.5mm. I took a Fel-Pro and another HG that I had lying around and measured them. The FelPro was right at 90mm, and the other was 90.5mm. When I lay the gasket on the block, there is some "slop" in the dowels - such that I can move the gasket around a little bit on the surface. If I move it towards passenger side, I can run my finger up and down the bore and it won't catch on the head gasket. If I move it toward the driver side, my finger catches the lip of the gasket on the passenger side. The last thing I want in a high-boost turbo app is for the firing ring to be inside the cyl. causing detonation. My theory is that I have two options..... 1) Copper coat the HG and "stick" it to the block as far to the passenger side as possible, such that I can run my finger all the way around the bore and not catch ANY head gasket. 2) Buy a bigger head gasket. The measurements tell me I have about 1mm to work with, but spread across a 360 degree circle, that is a FINE line. What would you guys do? There used to be a 2mm thick overbored (91mm) HG on the market, but I think I got the last one from Courtesy for my stroker a couple years back. Does anyone know if there are any 1mm oversized bore HG's available? Quote Link to comment Share on other sites More sharing options...
Oddmanout84 Posted January 10, 2011 Share Posted January 10, 2011 The only one I've been able to find that seems to be in stock anywhere is the Tomei MLS, but its also 90.5 bore. Thickness goes up to 1.5mm or 2.0mm depending on where you look. Then there's Kameari, which is either 86mm or 90.5mm bore, up to 3mm thick... but man is it pricey. The strange thing to me is that this item is listed on MSA's website (along with all of their MLS head gaskets) as N/A only, apparently because "some oil passages get blocked". I'm a bit skeptical of that statement. Wish I could help better, I'm in a similar boat. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted January 11, 2011 Share Posted January 11, 2011 Ive got a used one. I believe its an HKS MLS. 2MM thick gasket. Bores are 90.1mm as per my Harbor Freight caliper. But at least with the metal gasket you could in theory file the edge for clearance. Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted January 11, 2011 Author Share Posted January 11, 2011 I was able to get a 91mm HG from Nissan through my buddy the parts guy. Compressed is .6mm - but since I have custom pistons for the stroker that don't protrude out of the cylinders, I should be in good shape. Doggiine $150 though... Quote Link to comment Share on other sites More sharing options...
z-ya Posted January 11, 2011 Share Posted January 11, 2011 I would double check your CR calculation. Bore +1.5mm over what you thought, and now a 0.6mm gasket. Also, is the head shaved at all? What is the piston dish cc? I would suggest a copper HG with the correct bore diameter and thickness for your target CR. Then shim the cam towers and align hone if you need to. Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted January 12, 2011 Author Share Posted January 12, 2011 Hey Pete - the pistons are custom JE pistons with a reduced pin height - designed to work perfectly with a stroker crank and provide a zero deck height. Pistons are dished even moreso than stockers. They were designed especially for a turbo stroker by a guy that is FAR more "advanced" than I. Head has only been cut just slightly to make it flat. Nothing major at all. What I lack in compression ratio, I can make up for with boost (I figure). My "measured" bore is 89.5mm at the top of the piston walls - and the stocker gasket came out to 90.5 - but I still didn't feel comfortable with that little clearance. I'm going to measure the 91mm unit when I get it in and go from there. Not terribly fond of the copper gaskets either, as I've had several racer friends develop leaks. I'm comfortable with a Nissan factory part. Worst case - I'll go the copper unit if this doesn't work. The fact that I'll have a low(er) comp. ratio regardless of which gasket I use - gives me a little leeway to experiment with the thinner gasket. Just rambling - what do you think? Quote Link to comment Share on other sites More sharing options...
z-ya Posted January 15, 2011 Share Posted January 15, 2011 Hey Pete - the pistons are custom JE pistons with a reduced pin height - designed to work perfectly with a stroker crank and provide a zero deck height. Pistons are dished even moreso than stockers. They were designed especially for a turbo stroker by a guy that is FAR more "advanced" than I. Head has only been cut just slightly to make it flat. Nothing major at all. What I lack in compression ratio, I can make up for with boost (I figure). My "measured" bore is 89.5mm at the top of the piston walls - and the stocker gasket came out to 90.5 - but I still didn't feel comfortable with that little clearance. I'm going to measure the 91mm unit when I get it in and go from there. Not terribly fond of the copper gaskets either, as I've had several racer friends develop leaks. I'm comfortable with a Nissan factory part. Worst case - I'll go the copper unit if this doesn't work. The fact that I'll have a low(er) comp. ratio regardless of which gasket I use - gives me a little leeway to experiment with the thinner gasket. Just rambling - what do you think? You could always goes with one of these: http://www.zccjdm.com/catalog.php/azcarbum/dt43033/pd858312/KAMEARI_L6_METAL_HEAD_GASKETS_ Price is crazy for sure. I plan on using a copper gasket on my build. $100 made to whatever thickness I need. Freshly surfaced deck and head, plus copper spray should prevent leaks. It's either that or a new set of forged pistons and stock head gasket with a orings. Either way, it's costing me. Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted January 16, 2011 Author Share Posted January 16, 2011 Yeah - I've seen those - and that was what I was trying to avoid!! I've seen a couple folks on EBay that claim they'll make you a copper head gasket for $x.xx - is that what you'll be going with? I always tend to question the integrity of "low cost" items on Ebay. Good things aren't cheap and cheap things aren't good! Tell me more about who's making your gasket..... Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted January 18, 2011 Share Posted January 18, 2011 The Kameari gaskets on eBay that come with ARP head bolts can be had for about 25% less with the best offer button on eBay. Quote Link to comment Share on other sites More sharing options...
z-ya Posted January 18, 2011 Share Posted January 18, 2011 (edited) Yeah - I've seen those - and that was what I was trying to avoid!! I've seen a couple folks on EBay that claim they'll make you a copper head gasket for $x.xx - is that what you'll be going with? I always tend to question the integrity of "low cost" items on Ebay. Good things aren't cheap and cheap things aren't good! Tell me more about who's making your gasket..... Hussey quoted me $100 for any thickness less than 0.100. http://www.husseyperformance.com/PDF/Gasket%20Catalog%20-%20Rev%2013%20-%2008.pdf Here are a couple Kameari gaskets on Ebay. http://shop.ebay.com/?_from=R40&_trksid=p5197.m570.l1313&_nkw=Kameari+gasket&_sacat=See-All-Categories Edited January 18, 2011 by z-ya Quote Link to comment Share on other sites More sharing options...
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