Guys,

 

If any of you were at silverstone you will have seen my engine go spectacularly up in smoke during the final track session which was a real pisser as it was going real well.

 

Anyway i have now got a replacement engine and gearbox with 33,000miles on them :D and have decided to start my quest for 500bhp+ and a manwell conversion. :hyper:

 

I am in the process of sourcing the Z1 motorsport GT600 (T28 based) turbo kit and plan to do Z1 uprated throttle bodies, fuel rail injectors and chip the ECU accordingly.

 

I already have stillen side mount intercoolers.

 

My question is has anyone gone this route and if so what lessons learned can you share. Does anyone recommend a different turbo set up?

 

I want to do the flywheel and clutch at the same time so what combo will be best for this kind of output.

 

Also is 500bhp a realistic target on stock internals or can i reliably get more?

If so what is the limit? It won't be a daily driver but it will get used.

 

So many questions i know but i had to do this rather than scrap her.

 

Chris

I wouldn't trust stock pistons on a 15 year old engine even though it has low mileage for anything over 400bhp. If you want that sort of power your gonna need an engine rebuild with stronger internals IMHO.

I will do that if necessary as i can get titanium rods and std size forged pistons at the same time as the turbo kit but i must say i have had conflicting advice:-

 

Some folks say do a rebuild as its 15 year old etc. others say "done loads of these and below 600bhp the standard internals are great even with an old engine." :confused:

 

I do not want to have to pay later on but it will probably double the bill if i have to do stronger internals.

 

Will go with the weight of opinion on this one as it comes in so team,

 

To re-build or not re-build that is the question.........

If your going to do a build its worth doing it properly go for the uprated internals, their the most important part of the engine, then you will have peace of mind, dont be penny wise and pound foolish! :D

hmm penny wise and pound foolish......

 

I spent over £4,000 on my last powertrain and it still went bang!

 

Would you re-bore? or just replace the stock pistons with forged items.

 

Chris C

no need to replace con rods as there good for over 500hp its the pistons that need to be sorted so go forged ie arias/je/weisco

any piston brand clearly better than another?

Also in the re-build doing the crankshaft main bearings is a right pain as its not until you know what colour code your stock bearings are that you can order your replacements. So my current thinking is leave the bottom end as is but do:- titanium rods (i can get them whilst stateside for amazingly low price) with wiesco pistons, metal head gasket and ARP bolts.

 

Chris

any piston brand clearly better than another?

Also in the re-build doing the crankshaft main bearings is a right pain as its not until you know what colour code your stock bearings are that you can order your replacements. So my current thinking is leave the bottom end as is but do:- titanium rods (i can get them whilst stateside for amazingly low price) with wiesco pistons, metal head gasket and ARP bolts.

 

Chris

arias :hyper: circlip design is spot on, quality is good expect to pay around £600 a set though obviously includes rings/clips etc.

 

weisco on a budget, although im not keen on circlips fiddly to fit, and a few clips have failed, im not starting a debate as some have them fitted with no problems, i wouldnt use them personally but for the money and all that :smw:

 

you get what you pay for and with an engine important components need good engineering work, best products in the world can go wrong if matching products are over/under spec'd

 

south cerney engineering are very good, not cheap but who is!

any piston brand clearly better than another?

Also in the re-build doing the crankshaft main bearings is a right pain as its not until you know what colour code your stock bearings are that you can order your replacements. So my current thinking is leave the bottom end as is but do:- titanium rods (i can get them whilst stateside for amazingly low price) with wiesco pistons, metal head gasket and ARP bolts.

 

Chris

bearings

 

although japanese manufacturers over design bearing grades! for instance grade 2 against a grade 3 is so minimal even a micrometer wont register, so some people go for one grade available from good engine shops. you can get oversize + -

 

 

You wont see the colours of the bearings after 15+years. you take the numbers from the crank and con rod caps

 

so for example

from cylinder 1-6

crank 1 1 2 0 1 0

rod 0 0 1 1 0 0

= 1 1 3 1 1 0

 

add to give correct grade

 

big&main

crank&block

 

again add numbers from front to rear on block&crank

block 1 1 1 0

crank 0 1 1 0

= 1 2 2 0

 

 

HTH greg

any piston brand clearly better than another?

Also in the re-build doing the crankshaft main bearings is a right pain as its not until you know what colour code your stock bearings are that you can order your replacements. So my current thinking is leave the bottom end as is but do:- titanium rods (i can get them whilst stateside for amazingly low price) with wiesco pistons, metal head gasket and ARP bolts.

 

Chris

 

finally if grade of bearing is unknown

 

just order all sizes 0-4 rod bushings/big and main then you can go wrong :D

 

might need a few packs though

im in waffaling mode ignore me! :rofl:

Arnt zed rods forged items anyway .Im sure standard pistons will take 500 bhp aslong as the mapping is spot on [no dett],maybe an APEXI power fc from a RB engine modified wirring to fit the z32 ecu plug ive been told it can be done.

Yes Z32 rods are forged and the Jun guys told me the stock crank is the one they used at Le Mans so leave it well alone.

 

That leaves the pistons as the weak link that seems to be the balance of opinion here but what do others think?

 

Chris

Arnt zed rods forged items anyway .Im sure standard pistons will take 500 bhp aslong as the mapping is spot on [no dett],maybe an APEXI power fc from a RB engine modified wirring to fit the z32 ecu plug ive been told it can be done.

no stock pistons arent forged and are rated to 400hp rule of thumb, again if fueling is perfect they might be alright for more, but not worth the risk, especially on a tired 15year old engine, you may aswell put something in there for peace of mind

Greg is right on the money.stock pistons and higher boost spells disaster and certain ring land failure.if your going for 500hp your certainly gonna be running some high boost and way past the reliability boundaries of stock items.

So..........

 

It seems my plan will be to run is to run the Z1 600r T28 based turbos, Stillens titanium rods and JE / Arias pistons. (or do cosworth do Z32 pistons?)

I will fit a metal head gasket and go with the 555 injectors and appropriate re-map. ARP bolts on the re-build.

 

I already have big ass intercoolers, exhaust and intake etc.

 

Crank and mains left as-is or replace?

 

Chris C

Cosworth make the pistons for JUN.

Cosworth make the pistons for JUN.

 

Yeah but they are a bespoke JUN design and not the same as the cosworth own brand ones.

 

My sources tell me cosworth are on par with Wiesco.....

Set of wiesco's £400'ish - job done.

It's WISECO and they're £440 delivered from Smithy

http://www.smithys-place.co.uk/engperf.php

Doh, you would think I should know how to spell it by now LOL

Will cosworth uk not make them to JUN spec in the UK.Is it not worth speaking to cosworth techincal dept in the uk.

Will cosworth uk not make them to JUN spec in the UK.Is it not worth speaking to cosworth techincal dept in the uk.

 

yeah have done that conversation with Cosworth.

 

Facts are Jun own the Intellectual Property (IP) for their piston design. They developed their piston spec from basic cosworth forgings in the early 90's. They arrived at a high power road design during the development of their bonneville record breaking 300zx (eventually producing over 1,000hp and 263mph top speed). Note unlike many so-called tuning shops Jun actually have extensive workshop facilities for development purposes but not the capacity to mass produce items. So they did a deal with Cosworth.

 

When I spoke to cosworth they said they don't 'officially' offer VG30DETT pistons and have no plans to. It seems that the IP deal they did with JUN was for multiple years as part of a non-compete type deal. They also said that Tomei's pistons are sourced by them in a similar deal. Interestingly Cosworth ARE finally now entering the Japanese performance market as the ford gravy train draws to a halt but only for newer models. One assumes they did these kind of deals with the japanese tuners when they were something happening 'over there' and both had their own market to themselves. The result is that Cosworth now make a 350Z kit and market it direct from the cosworth site. So.........

If you want Cosworth / JUN pistons for your 300zx the only way to get them is they get made in northhampton to a drawing and knowledge that came from japan over 16 years ago, they then get shipped to japan and put in a JUN box with JUN fitting instructions, shipped back to the UK, via a dealer that gets a mark-up too.

With all those hand-offs, shipping and everyone making a margin or collecting TAX it is easy to see now why wiseco are £440 and JUN are £1,300

So what is a man to do?

Luckily I can play the game in reverse......

Given the dollar is over 2:1 to the £ and I go to the US every month I will probably work it the other way and get a set of wisecos sent to my pittsburgh office for less than they would cost me in the UK.

I sense a big increase in my baggage over the next few trips!

Crazy world eh?

Good idea as they'll cost you about £300 in the States