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Discussion Starter #1
Dears,



I have problem with head block, it's always opening after drag race (2 runs or 3 runs), I changed the head bolts from RB25DET ARP bolts to RB26DET ARP bolts but still the same, The Head block is removed from the block after 2 runs or 3 runs, also I changed the Head but still the same.



Please see the following is my car engine info:



Horse Power: 1380

RB26 Head with RB30 Block

Cometic Head Gasket Kit – RB26DET - Thickness: 1.3m

RB30 CP Pistons 87m with 8.0 compression ratio

250HP Nitrous

RB26 ARP Head bolts (I tighted the head with more torque)



I don't know what to do?????




Please this is for those who reached 1300HP and above.

Thanks!
 

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would this not be caused by loads of boost rather than the BHP the engine is making?

So would the chap not need to use bigger/stronger head bolts? I presume he is stretching the head bolts?
 

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Discussion Starter #6
Thank you for your replies.

I am running with 3.3 bars.

I don't know why the head is moving (Head lift: best translation)

My torque sequence is:
30 ft
55 ft
75 ft
125ft

I heard that HKS has special head gasket for 3 bars boost or more.

I think the problem is with head gasket, maybe I have to use another brand. (I am using Cometic head gasket)
 

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It's a tuning issue. Rips is making more power than you and have never lifted the head. Heat treatments make a huge amount more than you and they don't lift the head much anymore. It's all in the tune mate.
 

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3.3 bar of boost for 1380hp with 250 of NOS? something isn't right there, you shouldn't need anywhere near that much boost to make that much power, what turbo do you have and why so much boost?

I've used normal 11mm RB25 head studs and a tomei head gasket and done 100s of runs from low 8s to low 7s and we never took the head off or had an issue so there's definatly something strange going on with your setup.

I'd be happy to try to help if you can give me more info.

Rob
 

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Discussion Starter #9
3.3 bar of boost for 1380hp with 250 of NOS? something isn't right there, you shouldn't need anywhere near that much boost to make that much power, what turbo do you have and why so much boost?

I've used normal 11mm RB25 head studs and a tomei head gasket and done 100s of runs from low 8s to low 7s and we never took the head off or had an issue so there's definatly something strange going on with your setup.

I'd be happy to try to help if you can give me more info.

Rob
Thank you Rob for you reply

The turbo is Garrett GT47- Compressor is 88mm - T6 with turbine 96 A/R

The Transmission is TH400 thats why high boost to get more HP.
 

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Thank you Rob for you reply

The turbo is Garrett GT47- Compressor is 88mm - T6 with turbine 96 A/R

The Transmission is TH400 thats why high boost to get more HP.
This car is TH400, 1350kg and runs an old GT45 @ 2.2 bar and 75 of NOS:

YouTube - RIPS 240z 7.86 177.4 Worlds quickest and fastest 240z and RB30

It seems there is way too much boost for the power you are making so something doesn't seem right to me and this may be part of the reason your lifting the head.

I'm pretty sure Reece is up around 1800-1900hp with a GT47 @ 3 bar boost on a RB28.

Rob
 

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excessive cylinder pressure the engine is seeing due to boost levels, nitrous, ignition timing, cam events, poor surface prep, gasket installation procedure etc can all contribute to the head lifting. Ive built a 1350hp engine recently and only had lifting issues when excessive ignition timing was introduced. An under cammed engine can also contribute as it will have insuficient overlap. Is the tune-up backed off for the spray? What camshafts are fitted? What fuel are you using? What sort of logged data are you seeing?

Id suggest ditching the spray and backing off the tune-up to get it down the track a few times and collect some data. Then creep up on it slowly and keep track of where its at. One step up in a certain area will tell you why its lifting and allow you to make the changes needed to run it reliably down the track. Logging your coolant pressure will give you an idea when you are getting close to the edge.

hope this helps.
 

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I agree, use the spray to build boost on the transbrake if you must, then log some runs at 2 bar, 2.5 bar etc without NOS and see whats going on.

If you've run 184mph as you told me, you clearly do have some hp, you just have to know exactly whats doing what so you can find, then solve the problem.

Rob
 
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