Head Gasket Choice RB25det NEO GTX3076

[Finn_GT-T]

Hi guys,

i'm going to get off my stock turbo an put on a Garrett GTX3076.

Other mods like FMIC, 600 cc injectors, link g4+, DW fuelpump etc. will be or were already added.

So I took the head off and got it machined to have an even surface. I've cleaned the block with a razorblade to get off the rest of the oem headgasket. The machine shop took off 0.16 mm from the head to get an even surface. The oem gasket thickness is 1.2 mm as I've read, so if I add the 0.16 mm the replacement has to be at least 1.36 mm. Correct?

As I am from Germany, i've searched for a metal headgasket in the local online shops but just found 1.2 or 1.5 mm but no 1.4 or 1.3.

 

So which thickness would you recommend? Or would the oem Nissan gasket be good enough for my setup, keeping in mind that the block was only cleaned by hand?

[Dose Pipe Sutututu]

Tomei or Nitto o-ring gasket, avoid Cometic if your block isn't prepped as it won't seal.

[Finn_GT-T]

Ok, thnks for the info. Is this the correct one? https://www.tj-partshop.com/products/13009-Tomei_Headgasket_Zylinderkopfdichtung_Nissan_RB25DET

It is available with 1.2 or 1.5 mm. Which thickness would be the right choice?

[Finn_GT-T]

The Tomei compression rate calculator says that the oem gasket thckness is 1.1 mm and the compression is 8.97.

With the 1.2 mm gasket the compression rate would be 9.03 and with the 1.5 mm it would be 8.76. 

[GTSBoy]

How can a thicker gasket increase compression ratio?

[Finn_GT-T]

1 hour ago, GTSBoy said:

How can a thicker gasket increase compression ratio?

I've clculated the compression ratio value for the 1.2 mm including the 0.16 mm of material that the machine shop removed from the head.

When I use the 1.2 mm gasket it will be the same as 1.04 mm gasket with the cylinder head before machining it.

[GTSBoy]

Oh, OK. Well, either way, you won't notice any difference.

I'd be aiming for >9.5:1 on any build I was doing these days.

[Dose Pipe Sutututu]

11 hours ago, Finn_GT-T said:

Ok, thnks for the info. Is this the correct one? https://www.tj-partshop.com/products/13009-Tomei_Headgasket_Zylinderkopfdichtung_Nissan_RB25DET

It is available with 1.2 or 1.5 mm. Which thickness would be the right choice?

get 1.2mm

It's 2019 not 1979 where we have shitty ECUs  

[AngryRB]

Just get a stock RB25 head gasket and ARP studs.. 

 

[Dose Pipe Sutututu]

2 hours ago, AngryRB said:

Just get a stock RB25 head gasket and ARP studs.. 

 

You know a Tomei or Nitto head gasket is much more? Not to mention it's better than the stock composite head gasket.

 

[AngryRB]

1 hour ago, Dose Pipe Sutututu said:

You know a Tomei or Nitto head gasket is much more? Not to mention it's better than the stock composite head gasket.

 

I know my RB3025 has no issues at 350kw, is a simple oem RB26 gasket that was very reasonable cost from Kudos with ARP studs.. 

If the block surface isnt perfect then it could leak and after pulling engines out a few times recently im over that bullshit so id advice OP to keep it simple.

 

[Dose Pipe Sutututu]

1 minute ago, AngryRB said:

I know my RB3025 has no issues at 350kw, is a simple oem RB26 gasket that was very reasonable cost from Kudos with ARP studs.. 

If the block surface isnt perfect then it could leak and after pulling engines out a few times recently im over that bullshit so id advice OP to keep it simple.

 

You clearly missed what I said earlier about Tomei or Nitto head gaskets ?

[AngryRB]

3 minutes ago, Dose Pipe Sutututu said:

You clearly missed what I said earlier about Tomei or Nitto head gaskets ?

So he should get a Tomei or Nitto head gasket?

 

[PLYNX]

Either will do an excellent job and in the end it will come down to personnel choice, budget etc etc.

I went old school and opted for a copper head gasket, o-ringed the block and run head studs

[Dose Pipe Sutututu]

How I see it is you've spent that money/time to take off the head and skim it, purchased a larger turbo and going to run ARP studs (over the factory head bolts), then what's an extra $200 to the equation? not much.

Not to mention the Nitto OR Tomei headgasket will seal better and also will withstand the punishment as it's o-ringed. Every car workshop does the same thing. I also got told this advice from both MRC and Billtech (both reputable RB workshops).

I would only advise going with a Cometic or similar style headgasket if your block is prepped.

[GTSBoy]

23 minutes ago, Dose Pipe Sutututu said:

I would only advise going with a Cometic or similar style headgasket if your block isn't prepped.

Or perhaps the correct grammar version where you advise against it?

[Dose Pipe Sutututu]

12 minutes ago, GTSBoy said:

Or perhaps the correct grammar version where you advise against it?

FUUARK - this is proof Asian Males cannot multitask, was typing out an e-mail to a vendor at the same time about "advising" shit too LOLOLOL

(have edited the previous failed post)

Thanks @GTSBoy

 

[niZmO_Man]

On 28/11/2019 at 9:25 AM, Dose Pipe Sutututu said:

get 1.2mm

It's 2019 not 1979 where we have shitty ECUs  

C'mon broooo get VL turbo A8 block with 7.8:1 compression ratio

[Finn_GT-T]

Thank you all for the replies. This forum is much better than the german equivalent.

ARP studs are already in my garage waiting for me to screw them into the block. I think I'll go for the tomei gasket because of the small extra cost but higher (presumed) reliability compared to the oem gasket.

Will the higher compression ratio be an issue when mapping the link ecu because of the risk of knocking? Keeping in mind that the stock knocksensors will stay in the block.

[Finn_GT-T]

By the way, what do you think about applying permatex spay gasket to the tomei gasket before assembly? Does it help to get a better sealing, or is it just wasted money?

Edited November 29, 2019 by Finn_GT-T