James-W

Me and a friend are building a zetec engine, we already have comfirmed the rods/pistons, but are wandering what the rev limit on the standard crank.
We want to know what modifications will be needed, or what aftermarket crank will offer the highest revability.
Is there any reccomendations for modifications to the block to suit a turbo application?
Also, what is the max power limit on a standard crank?

Thankyou in advance for your time.

Regards,
James

biglee

9K on the std item is ok aslong as its been built well.. std crank will do 400lbs/ft and will last but again depending on how well its been put together. and for that figure you will need good rods and pistons. the turbo aplication is really easy to do but.... again you can do it on the cheap with a de-compression plate or properly with a full re-build to a slightly lower compression ratio. there is uber loads of different things you can do to these engines... talk to a good company..

James-W

Thanks for the reply lee
We are using aftermarket pistons and rods, these have already been comfirmed, the rods will take over 10k.
We are definitly going to be doing a proper rebuild, ideally we want big revs (actually we had around 9000 in mind) and were wandering would it be worth the extra money to buy an aftermarket crank, as i am aware these are £1300 upwards, this is alot of outlay for such a small piece on a "cheap" fun car.
My friend has alot of experience in building engines, but is not familiar with high power zetec's so its a bit of a learning curve for us both!
So would the crank be good for around 500bhp?

Thankyou again for your time, it is much appreciated,

James

biglee

im not sure of any ZTT's running 500hp, but i would think there would be good reason to run a different crank at that sort of power... i wil ask a few questions and get back to you as i know a chap running one at 10k with over 350hp... see what he says.. if you want a cheap fun car then i would keep the std crank and do the rest of your mods.... get it on an engine dyno and run it hard....

James-W

Thanks so much for the help, means alot mate.
It will be run hard, no doubt about that
Not exactly a cheap car, all relevant , but £1300+ could buy alot of suspension or brake goodies! that's why im dubious about shelling out all the money on a part what might not be needed, 500bhp isn't a must, suppose around 400bhp and 400 ft/lb would be ample, especially if it revs high.

Thanks again,
James

steve7786

iTrader: (2)

You will need to change the gears within the oil pump as these have been known fail at over 7400rpm. You can get a billet gears form the states.

http://focus.c-f-m.com/index.asp?Pag...OD&ProdID=1184

bassboy

standard crank will take 500hp

bassboy

Johnny Knoxville

I always thought it was less than that

jessie_rs

i thought that too 9k is alot

Luca

iTrader: (2)

Standard crank is good for 500 bhp but this is a top bhp therefore nearing its limitations.

To get 500bhp you mainly need a decent flowing head £££££ and turbo set up, at this kind of power the transmission will need to be highly uprated also. 9k is a high rpm to so will need solid lifter set up.

You say it’s a for a cheap fun car build….

500bhp zetec is by far from being a cheap car.

James-W

All relevant! we know it won't come cheap, we just don't want to spend more money than we need!
Also, head will be shipped of to cnc, or maybe use and st170 head, my friend who is building the engine is on the case of solid lifters.
And probably a gt30 turbo + ext wastegate.
Transmission is sorted too, it's going rwd.

Steve, thanks, will bookmark the page and order one soon.

Thanks,
James

sas

I can confirm that the crank and bottom end can take a 12500 over rev! but the valve train cant!

Was revving my motor regularly to 8500 last year, no issues.

Simon.

cjwood555

Hi mate

I have an ST170 head for sale if you're interested

Ex-Finesse

Add up what you'll need for the top end to take 9k before building the bottom end to take it.

You'll need, double valve springs, 1-piece valves, titanium retainers, oversized solid lifters (requiring additional meachine work to the head) verniers and billet cams.

That lot makes the £1,300 steel crank look cheap

Garage19

Failing that just rev it to 7k and drop a couple of gears

steve7786

iTrader: (2)

I always find that my mtx75 box struggles to go in to gear too when i rev past 7000rpm

James-W

Cool thanks mate.


Hm, might be interested, will have a talk and drop you a pm next week after i see him.

I am willing to spend money on neccessities, if I NEED this doing to the head I will, however if I don't NEED a £1300 crank then i won't buy it, simple as.
It's all relative, If I don't spend £1300+ on a crank I don't need, that's £1300 to spend on having a wrc cradle back end fabricating!
Thanks again for the help people it's much appreciated!

James