R32 Rb25 Powered Gtx35R Build

[nick81xd]

The fun begins again.

After finishing a 26/30 engine build for a mates 34 GTR, another project began today.

Going to be a full forged bottom end, Tomei poncams, 6Boost manifold, Greedy intake, GTX35R setup

Not many non-workshop people building with the GTX turbos so can be a bit of a read for those interested

Story.

Car is a r32 with a 25 engine and box. It was brought from a guy from SAU in Brisbane pretty much as it sits driveline wise.

The Setup contains:

Greedy intake

GT2871r turbo

Ross Racing forged pistons

ARP Headstuds

N1 oil and water pumps

NPC lightened flywheel

Excedy Cushion button clutch

760cc injectors

Link G4 ecu

Was making 351hp on 19psi being very responsive down low to mid but hit a wall at 130kph and became very boring after that.

Ever since not long after buying the car its shown that the engine has been built very poorly, massive amounts of blowby, heavy piston rattling cold and hot and just generally not a nice engine so with mid to top end power being wanted for better fun while at events simply bolting on the turbo setup and cranking it up wasnt a option willing to be taken.

A tighter smoother engine rebuild has been chosen so can utilize the GTX turbo on big boost to make nice power.

Today after pulling engine out and stripping down its apparent either the previous owner got ripped off by workshop or the current owner got fed lies when buying. The engine was rebuilt with the bare minimum parts. At a guess its popped a few stock cast pistons at some point so all the rebuild consisted of was a set of ross racing forged pistons and a MLS head gasket all the rest standard.

The reason for the blowby and noise is the block has been overbored for the pistons and the ringgaps are way too big. Got some measuring to do but its ALOT of skirt clearance.

Needless to say pulling it apart has probably saved alot of dramas down the track with failures.

Photo time

How the car sat as of this morning

The mess that plenums hide below

The baby turbo hiding there

The nasty damage done to all pistons, wonder why it was rattly......

Crank collar and Flywheel

GTX35R VS OLD GT2871R

6Boost Art

Much prefer when its back from machine shop all clean

The worst of the bore damage. You can see the thrust scuffing from the piston skirts

How the car sits now at the end of the day

Hopefully going to be a 3 month turn around for build will be slow updates at first.

[Col-GTSX]

Nice detailed thread nick... Keep us up to date...

[DR 32R]

Good project, will follow with interest!

[nick81xd]

Had a few measurements sorted today.

Turns out there is 7 thou piston to bore clearance and 1 thou being wear. No wonder it was rattling like a old diesel tractor.

Going to bore out the block to 40thou get it all acid dipped etc.

Will be ordering a set of CP pistons, unsure of rod choice yet, Acl Race bearings, NPC clutch, Ross metal harmonic balancer, usual ARP studs.

Getting all the rotating assembly balanced as a whole that way cause rev the bottom end to whatevers needed (providing the heads up to it),

Got some money to send no we have a path to take.

[Mick_o]

Liking the look of this build nice detailed start keep up the good work mate Good to see somebody else taking the punt on the GTX range like I did! They have copped a bit of a kicking in here as there havent been too many crash hot results. I'm personally stoked with my setup and hope you get the same results with yours.. Will be watching this thread with GREAT interest. best of luck Nick

[nick81xd]

Liking the look of this build nice detailed start keep up the good work mate Good to see somebody else taking the punt on the GTX range like I did! They have copped a bit of a kicking in here as there havent been too many crash hot results. I'm personally stoked with my setup and hope you get the same results with yours.. Will be watching this thread with GREAT interest. best of luck Nick

Im just building it for a mate so i just get all the fun parts of building not the driving part unfortunetly.

Yeh hopefully the GTX proves itself to be a good choice and does what the owner wants (3rd gear pouring smoke while skidding at QR events).

With all the little stuff planned for the engine to help reliability it should work out to be a fun hassle-free(ish) skid car.

[Mick_o]

That's a bummer mate lol! But that won't be a problem because even my little 3071 on E85 with a 100% stock as a rock 25 will smash 3rd with good 255's tyres & a kaaz 2 way he should be aiming for 4th gear smoke shows with a GT35R

[Tyranus]

This thing is going haul major arse.

[nick81xd]

Been shopping today. spending other peoples money is fun

Ordered:

CP pistons 87mm

SCAT/PRECISION MOTORSPORT forged rods

ACL race series big end and main bearings

ATI Balancer

COMETIC head gasket

ARP main and head studs.

Parts will be here later this week, then the block maching can begin

[DR 32R]

Great start! Impressed with your thorough and detailed approach. Interested in how thi \s turbo gos attached to a well built engine.

[nick81xd]

Small update.

All parts are here except for the clutch. Unsure on how big to go for clutch just yet. Decisions need to be made as the crank assembly needs to be sent out for balancing as a complete assembly.

Block machining should be started next wednesday hoping to get a few photos/(maybe videos) while thats being done for your viewing entertainment.

Head is getting stripped this week to make a start on the port matching and bit extrathis weekend. Will get all the seats recut and valves refaced (all the usual repair work for head).

Once thats done it can be all systems go for starting to assemble it

Scat rods

Box of shiny slugs.

[nick81xd]

Theres been holds up with engine machine shop getting bit busy so work is slow going at the moment. These things happen when machinist works alone and theres a line up.

On a good note the twin plate clutch from NPC arrived today. Got pulled apart marked and ready to be sent with the crank to the balance shop. Just waiting on some new bolts for flywheel so everything can be spun up as a complete assembly.

[nick81xd]

Got the block and head back yesterday.

He knocked it all over in one day so didnt get a chance to get any footage of machine work unfortunetly

Block has had the usual acid bath and clean it has also been decked, bored and honed to .40 over.

The oil return galleries have been enlarged to help the head drain oil back to sump

Once bores were finished the skirt clearance again was checked for the final time and its just over 3 thou which should make a quiet (when warm) engine.

Machine work as always great quality thanks to Ben at Bundaberg engine centre

Head has been stripped down so can we massage the ports to match the gaskets and make the exhaust flow alot smoother and just a general clean up. All the valve guides are perfect so will be leaving them in. Once we have finished with ports then it can be dipped to make shiny again, skim'd, new valve seats cut (unsure what type of angle cut yet but have the possiblity for a 8 angle cut.....which would do shit all but it sounds good on paper ) most likely just do a 3 angle and then it will get reassembled with new faced valves, seals etc. Also throw in a set of baby poncams while at it.

The fun parts ahead

Can see how much extra material there is around the gasket to take off

The ugly exhaust port which will take up most of the time

Edited October 9, 2012 by nick81xd

[nick81xd]

head is 90% ported just have to do the finishing sanding but they have come up good.

Exhaust took alot of material off and reshaped the port to better match the manifold which will help get the gases out

BEFORE

AFTER

The intake not alot was taken off just matched it to the gasket, enlarged it a bit and made the divider more sharper to elimate a small turbulant spot

BEFORE

AFTER

Ignore the old gasket marks. It used to have a set of phenolic spacers which were oversized for some reason (read: cheap shit). Going a genuine intake gasket and it not matches that

Noticed a weird ""modification"" done by someone before car was brought, someone has drilled into the head with a 5mm drill bit diagonally into the water jacket in the spots circled in the photos. Now i cant see any purpose to doing this as the water gallery flows around to the same spot anyway.

It is stupidly close to the firing ring bite surface on a couple of cylinders so will have to get it welded up just to be on the safe side. Unless someone knows why this gets done?????. i can find anything about it

[nick81xd]

Dont know if people are watching/interested in the build but Started engine assembly today.

Spent a few hours cleaning the block and removing the grub screws in crank to clean out all the material from machining.

Had the very repeatative boring job of setting the ring gaps. The bit that everyone hates.

Top rings required most filing being .004 from required gap. 2nd ring was almost exact measurement. Oil ring was close to minimum which is good (not that can file oil rings anyway)

Dummy fitted the crank to measure end float, Very happy that its still within specs after having to linish the thrust surface. Forgot to get plasti-gauge out of toolbox so will be checking bearing clearances tommorow.

Unfortunetly the small end clearance on the rods are a little tight for my liking so will have to get them honed out on monday to suit gudgeon. Not a big hurdle just a set back.

Was aiming to have the bottom end bolted together by end of weekend .

Full backyard washbay

Matching each ringset to own cylinders

The crap still in there after a quick washdown before removing screws makes you realise how important removing the factory slugs is.

Dummy assembly for measuring

Edited October 27, 2012 by nick81xd

[brenton21]

Noticed a weird ""modification"" done by someone before car was brought, someone has drilled into the head with a 5mm drill bit diagonally into the water jacket in the spots circled in the photos. Now i cant see any purpose to doing this as the water gallery flows around to the same spot anyway. It is stupidly close to the firing ring bite surface on a couple of cylinders so will have to get it welded up just to be on the safe side. Unless someone knows why this gets done?????. i can find anything about it

I found this on my head too, but only on one jacket. I didn't have a head gasket to check against so i figured that l would just weld it to make it suit the others, like you said it seemed close to being able to creep under the head gasket. So l'm guessing in my case its a casting problem. Nice build though, clean looking car. Are you going to flow the heads? or was the port polish job just to clean them up?

[nick81xd]

I talked to a few people who have played with RB's and its apparently to help bleed the cooling system faster and more reliable. If thats true or not is anyones guess.

The head was just a clean up. didnt remove that much material from the inlet that would warrent a flow bench. Exhaust side is after combustion so not critical, all ends up in same spot in turbo housing.

Edited October 27, 2012 by nick81xd

[ssxRicho]

Watching, looks great.

[mickr33couple]

Updates

[nick81xd]

The rods have been honed out to suit the pins so this weekend will be weighing pistons and rods and matching them together and if all goes to plan dropping the bottom end together.

Waiting on a few things to come before we can put it back into the car. ARP flywheel bolts, oil filter tower amongst few other things.

Should go back together fairly quickly from here now that most of the parts/jobs are ticked off the list.