Gtr And Gtst Pistons

[MJTru]

Happy new years everyone.

My year has started bad. my built motor just died, and a little part of me too.

Can GTR pistons work in a GTST, i ask because i bored my stock block to .40, 1mm 87mm over size, but now the pistons are damaged do to detonation. So i would like to bore it ,to get the bore clean again, to .50 or 1.5mm over stock so that will bring the bore to 1.5mm, 87.5mm

Now everytime i look for gtst pistons it goes only to 87mm, and the GTR goes all the way to 88mm. I'm looking for 85.5mm bore.

does anyone know if it will work????

[The Dan]

The GTR piston has a shorter pin height so you will also need to run a GTR crank. Anything more than 0.040 and you run a very high risk of splitting the block. The 87.5mm and 88mm pistons have to be used in an N1 block that has more block material to cope with the larger bore.

Is the damage that bad that you can't just do a finish hone and run the same size? Often piston manufacturers make pistons in various sizes but all in the same size (if that makes sense). We often search through boxes of pistons at the supplier to get a set that is 0.001 or 0.0015 larger for that very reason

[MJTru]

The GTR piston has a shorter pin height so you will also need to run a GTR crank. Anything more than 0.040 and you run a very high risk of splitting the block. The 87.5mm and 88mm pistons have to be used in an N1 block that has more block material to cope with the larger bore.

Is the damage that bad that you can't just do a finish hone and run the same size? Often piston manufacturers make pistons in various sizes but all in the same size (if that makes sense). We often search through boxes of pistons at the supplier to get a set that is 0.001 or 0.0015 larger for that very reason

I dont feel that its that bad, but i can feel it when i rub my finger nail on it.

Do you think i can order some new pistons .015 over ther .40 bore. so i'm guessing here it would be .415 bore over stock. Then do as you say, a finishing hone.

thanks.

[tm_r33]

yer agreed. going 50 thou over is running a high risK of splitting the block. i seen some pretty shitty looking bores get a hone and work fine. still running

EDIT (typo's fixed)

Edited January 2, 2011 by tm_r33

[MJTru]

ok i made my mind up here is what i'm going to do.

I will buy a long block from ebay.

Bore this block to 86.5mm bore, leave somthing for later if this happens again.

Eagle rods cp pistons 8.5:1 insted of the old stock compression ratio.

ACL bearings Main and Rod,

Head gasket Tomie

Main and head Studs ARP

N1 or GReedy oil pump, May use greddy, i have a new one.

N1 water pump new.

Use back hks timing belt.

For the head

Suptech +1mm o/s valves solid in and ex

Supertech dual valve springs and retainers.

Supertech valve seals

Supertech solid lifter conversion kit

Tomie cams dont know lift yet (any recommendations)

Tomie cam gears.

Crank coller

Jun oil restrictors in block.

This list isn't including parts that was on the motor before like split fire coils, HKS twin power, Haltech PS2000, 6boost manifold, Tial 44mm wategate, AMS GT950R turbo, Custom 100mm intake and TB, top feed 800cc injectors. External fuel pump rated at 1000hp. and a whole lot more. My mistake with my last engine was to much boost on pump gas. My friend detination came knocking. lol. It lasted for about one and a half years at 26 psi on pump 91 octain if that. This time only 15psi on pump gas and 30 with c16 in the cell.

I will take pic's of every step and up date everyone.

Thanks guy's

Have a good year mates.

Want 500 to 600 hp

any recommendations When i first built this motor, i never herd of SAU. But now that i now of this site please give me your recommendations, you guy's build this motor. Just tell me and i'll do it.

One part of the build i'm lost about is the cam specs, what you you all think i should do. What duration lift and degree should i run for this hp. ??????

thanks again guy's

[blind_elk]

I believe you have 2 options. First, the machine shop would ordinarily sleeve the cylinders back to standard bore.

Second, get the machinist to bore the cylinders over by the smallest possible amount, then get someone to make a set of pistons to suit the new bore size (I used Australian Precision Engine Parts in Wantirna (Vic) to make me a set of forged os pistons for my RB25).

[MJTru]

this is about 8000k project starting from sratch. I've lernt so much about these engines over the last years reading topics from this site. This i'm truly greatfully

i bow thank you.

Edited January 2, 2011 by MJTru

[BoostdR]

Don't waste your money on a new block!

Bore the old one to 87.5 or even 88 and get it sonic tested. Which ever bore/s are thin-sleeve them. Its usually number 3. I run a big bore RB30/26 (bigger then 87.5mm). With the sonic testing it takes the guess work out. Spend the money on more worth while things like balancing and a tomei oil pump that has an external pressure releif valve adjustment( just don't forget the 1.5mm(hydraulic lifters) block to head restrictor.

With the money you saved get a GTR crank and pistons ( I would use stock GTR rods for your power level and CP pistons)...with the extra capacity from the larger bore you would be rewared in response and torque. I wouldn't be to quick in dropping the comp level either...Your tune is what determines detonation, the comp level will effect when peak cylinder pressure is reached but the tune determine if it will det. Your off boost response and fuel econ will be better with a comp of 8.8 to 9. I wouldn't use any less than 98 octane for 500hpatw however. Make sure you get the head cc'd and piston dome cc's calculated properly so you can actually work out what the comp is. It does change with bore size also! The comp ratio stated with your new pistions is only a guide.

You won't need a crank collar on a 33 GTST or 33 GTR crank.

Supertech valves are fine, but if the old ones are fine, don't waste your money.

For drivability and good idle/Vacuum go low duration cams and medium left. Tomei Poncams 256's or some re ground GTR cams (to hydraulic profile)...but best to go with the pon-cams to keep the VCT and ease of installation.

Lastly get a good sump which has internal baffling.

Matt

[BoostdR]

Just noticed your comment about a solid lifter kit....for the cost of Valves, retainers, seals, springs, buckets and fitting it would be cheaper the buy a RB25DET NEO head which has solid lifters std.

Edited January 2, 2011 by BoostdR

[MJTru]

Just noticed your comment about a solid lifter kit....for the cost of Valves, retainers, seals, springs, buckets and fitting it would be cheaper the buy a RB25DET NEO head which has solid lifters std.

Wouldn't I need new intake manifolds to go with the NEO head. ???????

I've herd of the exhaust and intake manifolds have different bolt patterns.

If i can find a Neo head i would just get a Tomie Strocker Kit, with oil pump. Well its just a thought, buy the NEo head sound good. Its just if it shares the same manifolds. ????

Thanks again mate.

[The Dan]

Inlet manifold is different

[MJTru]

Inlet manifold is different

Hi are you dan from elite racing

i left a message for you at work.

[MJTru]

Sorry for getting of topic.

I can get a gtr engine for $2490.00 would this be a better option. I know that i will have to use new intake and exhaust manifolds , well i would use the stock intake and have Kyle from 6 boost build me a new manifold for the rb26det. The motor is from a r32 so i would need new water pump and oil pump, but here's the thing I have a new n1 water pump and Greedy high flow oil pump for a rb25det.

Can these pumps work on the rb26dett motors, and do i need to run a crank coller on the rb26 motor, also do i need the oil restrictor between the head and block.

Does anyone know what all mods i will need for this set up to get me hp goals of (about 600hpatw) This head is great from what i've hear, it uses the solid lifter set up, and as a add bonus i can make a gts power fc work on a gtr.

In the past, using a jumper harness i made a gtr power fc work in a gtst. just lost VCT.

But this option seems smart to me, I would just us some new supertech valve springs in the head and us some new cams as well. The block I can put rods and cp pistons in it.

Are all the main and con rod bearings the same from a gts to a gtr????? Because i have all new ACL race bearings for a GTST, and if its the same then i allready have some bearing. I would just need crank coller installed.

[discopotato03]

All too expensive , I'd buy an inexpensive RB30 bottom end and throw rods and pistons at it . Larger engine in a less stressed state of tune will make easier better power IMO .

20% bigger air pump and cheap/easy to get .

A .

[MJTru]

Its hard for me to find an rb30 block, the thought has crossed my mind, but i like the rb25det block as well, where i'm located its easier ti find all kind of parts for rb25 and rb26, the the 30 would also be a new learning curve for me as i know nothing about them.

I will pull the block apart and ask my machenist to see if he can rebore it as small as possible. The car was making 528hpatw on a stock head. Thats good for me., so as of right now i'm planning on a finishing hone and sonic test, then i will rebuild the block with the same rods, because the engine never knocked. The motor never stopped running i just, took it apart cause of a lifter noise, thats when i noticed that #6 piston had a small pease missing, this damaged the head, and lifters. So the rods are still good, some new bearings, pistons, main studs, oil pump, crank coller, and the block should be like new again.

[Rolls]

The other option is just troll the for sale section for a motor for sale, sometimes you see almost finished builds up with a reasonable discount, could save a lot of time and some money.