Hey guys,

I'm looking into / researching head gaskets available for the VQ and trying to find what is best, and what to look for and what not to look for. Are they all pretty much the same? What kind of difference can the bore size make? Advantages/disadvantages to thickness?

BTW I have a 2006 with the Rev-Up engine. My mods are directed towards NA gains, and include JDM Trust GReddy Intake, Flashed/polished upper plenum, 3/8" Plenum spacer, Flashed/polished non-revup lower plenum, AP lightweight pulleys (Crank, idler, alternator pulleys), NGK Iridium IV Spark Plugs, BERK High Flow Cats, and a single exit 3" Exhaust which I haven't decided on yet (probably Agency Power or JIC).

These are what I've found so far that I could be interested in. Just wanting to know which route would be best! Thanks so much.



-Brian Crower
(?)

-Cometic
(96/97/100mm Bore x 0.7mm Thickness)

-Cosworth
(96/98/100mm Bore x 0.6mm Thickness)

-GReddy
(97mm Bore x 0.7/1.0mm Thickness)

-HKS
(97mm Bore x 0.7mm Thickness)

-Tomei
(96.2mm Bore x 0.7mm Thickness)


Thanks again guys,

-Paul

 

It would not matter for an na setup

the real question is why do you need/want to change in the first place?

As for bore size I don't mean this in a rude way but if you don't understand how that relates to the rest of the engine head gaskets are sorta the last thing to be concerned with. I'd suggest starting with a basic tutorial on engine internals. Barnes and Noble has some really good books and even sites like howstuffworks can give you a tin of basic info to help sort through your basic questions about the inner workings of an engine

 

So it wouldn't matter as in the thickness wouldn't make a difference? Or it doesn't matter which brand I'd choose versus OEM or any other factors?

I've read in some cases, the thickness can kind of work synergistically with compression ratio.

But I guess this was kind of more a feeler thread more than, "I'm ready to buy something so please help" thread. I just got a new engine through Nissan thanks to the Oil Consumption TSB. So new head gaskets are really not anything I need to be worried about right now, it was just kind of information that I'd like to refer back to further down the road.

I understand what bore is in relation to the pistons. But I just didn't know what kind of affect or necessities there are with reference to bore size on gaskets.

 

go for the thinnest material if you plan on staying N/A

after polishing the plenum did you notice any idle issues? polishing can result in POOR air/fuel mixture since the fuel is just being dumped rather than being atomized..
just curious since i was thinking of polishing my own plenum.. on 4 cylinder engines if you polish your plenum and intake runners it will result in poor idle since the fuel is being dumped into the combustion chamber

let me know man

 

I haven't installed all the polished/flashed manifold. I'm still breaking in the new long block and I still have to take the car back to Nissan one last time for them to give it a once over. But after the engine is broken in, I will be putting everything on the car. I'm actually still in the process of finishing polishing/flashing it all. And I'm to the point where I might just take the upper plenum to a powder coater and have it powder coated in some cool color. I was going to polish the thing to a mirror shine, but it's so much work, haha

As far as the idle thing goes...I've never heard of that. I've been kinda following this thread here:

https://my350z.com/forum/engine-driv...m-porting.html

I haven't seen anyone in there talk about idling issues. But I can't imagine that polishing the inside of the plenums would really make so much of a difference that it would cause to change the air/fuel mixture so much to result in a weird idle. In any case, it could be addressed with an ECU flash. With some sort of tune/flash on the car, I'm sure the mixture would go back to normal, and idle adjusted.

 

Gasket thickness really only comes in to play when you surface the heads or block deck surface, thicker gaskets are used to replace the material that is removed from the heads or block in order to keep the compression ratio the same and insure that piston to valve clearance remains in range.

So, unless you've had your heads or block machined I would recommend staying with a stock thickness gasket.

The bore size of the gasket needs only to be matched to the bore size of the engine, if you have a stock 95.5mm bore stay with a stock sized gasket or one just slightly larger. We typically use a 96 mm Cometic gasket on a stock bore build.

As far as gasket selection, on an NA engine the stock gaskets are more than suitable. We've started machining all of our short blocks to accept HR head gaskets and are now using OEM Nissan HR head gaskets even on our boosted builds.

I would just recommend staying with stock head gaskets in your case though.

 

Cool thanks for the info Bryan!^