bigh

SteveE, I'm afraid your right, it seems that in the USA the consensus seems to be to me that the Cometic gaskets are pretty bad. Just to quote Greg Dupree from SpecialtyZ again incase anyone missed it earlier: Hi Howard, The OEM head gaskets seal the best, I run stock head gaskets on my 1000 HP drag Z. We also do all our builds with OEM gaskets. We have never had a gasket failure with factory gaskets. The only reason to go metal is for bore sizes over 88mm, or if the heads and block have been surfaced too far. Cometic gaskets are the worst available, I know lots of people that have had issues with those gaskets. Tomei are the best Metal gaskets, but it requires an extremely fine surface that most machine shops are not capable of providing. Most surfacing machines cut too coarse, they will still seal fine with a OEM gasket. And more from Greg Again I highly recommend FACTORY head gaskets as they are hands down the least likely to have issues. and finally regarding larger bore sizes The stock bore size is 87mm The factory head gaskets fit 87, 87.5, and 88mm We only use factory gaskets and bore 87.5 and 88mm all the time. I hope that this helps with anyone contemplating future rebuilds

Thanks Jaffa

Yes Jim has confirmed they are good. Jaffa any idea how SpecialtyZ run OEM HG ( 87mm)with 87.5mm and 88mm bores? Surely the 88mm piston would foul on the 87mm OEM gasket? I am awaiting an answer from Gregg, just wondering if you could shed any light on it?

Dan, Whatever you do don't use MLS (Cometic) I'm going with OEM HG

Taken from Z1 website; If rebuilding and your block has been decked and heads have been surfaced with-in Nissan specifications, chances are that around 5-7 thousandths of material has been removed between the block and the heads (8 thousandths being the factory specified limit). In this case the .051" thickness (6 thousandths thicker) will closely compensate for the amount of material removed. Decking block and surfacing heads (especially past factory specifications) without increasing headgasket thickness results in higher compression ratios, affects timing due to distances between crank and cam timing sprockets changing, as well as can cause problems with valve to piston clearances in extreme circumstances.

I hope not to Andrew. Re the plugs they are NGK I cannot remember the exact variant atm, will have to find the invoice.

Well Jim got the heads off the other day and you can see where the Cometic gasket failed No detonation damage

:thumbup:

Doh would have come, but that's my wedding anniversary. :blink:

Mine is going back to him on Monday for him to test on his own car.

Instructions no sticker

I don't think so mate, although he does appear on FB, Nismo and 300zx marketplace pages occasionally. " Lord-Rich Cropley"

Bloody hell, the cheek of the seller (semiconductor) saying that his are the real deal and putting a photo of the (fake) item on his page in order to get buyers into believing his are the genuine ones. Makes my blood boil Ffs. Thanks for the extra photos Noel, hopefully this will stop anyone else being shafted by the unscrupulous barstewards out there! And potentially seriously damaging their engine.

Thanks again Noel. I have been looking at a few so called genuine ones on eBay and some of the sellers even show the insides(circuit board s) saying that this is what a genuine one should look like. I opened up my one and the boards are identical, so these copies are pretty bloody good. Rest assured it won't be going in the car

Cheers for the heads up Noel. Seems like Mr Cropley isn't interested in doing the right thing.

Hey Pabs you enjoying the mud plugger? Have you been in the mud with Mr Isherwood yet? :nono: that's not the waving smiley:gun_bandana:

No problem they are the size of the Ashspec massive iirc. Good price I did post some photos of them on here, probably on my build thread

That's terrible, makes me mad how people just don't give a flying f#€} about other peoples property. Hope you find the little $#ts

Ash take a look at these. I have them fitted on my car and the quality is really good. Jimmer was very impressed with them as well. http://www.amsmotorsports.com/shop/ind/rs-performance-2-5-superflowz-sidemount-intercoolers-ash-greddy-z1-hks.html

Aesthetically I think the side mounts look better, as the FMIC always look like a poor retro fit IMO. As to which setup gives the best bang for buck and the best performance.......

Did you have any footage of the orange indicators flashing? - - - Updated - - - :lol:

Interesting read Noel, thanks

Thought I would share some more information that I have received recently from Greg Dupree. I asked him for his thoughts and experiences on OEM and Cometic gaskets. Below are his comments: Hi Howard, The OEM head gaskets seal the best, I run stock head gaskets on my 1000 HP drag Z. We also do all our builds with OEM gaskets. We have never had a gasket failure with factory gaskets. The only reason to go metal is for bore sizes over 88mm, or if the heads and block have been surfaced too far. Cometic gaskets are the worst available, I know lots of people that have had issues with those gaskets. Tomei are the best Metal gaskets, but it requires an extremely fine surface that most machine shops are not capable of providing. Most surfacing machines cut too coarse, they will still seal fine with a OEM gasket. Hope that helps Greg I then asked Greg what specification the heads in his opinion would need to be finished to (RA Rough average) if using metal gaskets like The Tomei set. Gregg, Regarding the fine surface finish for the Tomei gaskets, do you happen to know what RA grade of finish would be required to obtain a adequate seal? I recommend factory gaskets, but the few large bore we have used Tomei metal gaskets on, we did a 10 Micro inches RA. Typically the recommended RA is 20-30 micro inches, but smoother = better. Again, the equipment required for the ultra-smooth surfaces is not found in most machine shops. Interesting stuff eh? Well I have tried to find a machine shop that can carry out a finish of a 10-20RA and as yet haven't found one and I have phoned over 12 now! Some of them didn't even know what an RA finish was, which i found scary to say the least. So if you are thinking of going to using Tomei then find a machine shop first, and a good one at that. Oh and if you do find one make sure you let us all know, lol, as they potentially could get a lot of business from future builds. So as it stands at the moment I will be going for a set of new TT heads and OEM gaskets as this seems to be the most reliable and trusted set up even for high powered cars.

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Get a good quality oil temp gauge, that is the most important thing when it come to "warming" up the car to normal running temps. You will be surpirsed to compare a water temps gauge to an oil temps gauge, the oil takes a lot longer to heat up.