DJ_Jon

iTrader: (7)

the bottom end is knocking on my car & I have been advised that the crank can't be re-ground, only replaced by a new one. Is this the case?

my car is a UK MY99 Turbo

next question, 2.5 bottom ends seem cheap, what about 2 litre short motors, what do they come in at?

TIA

p12mem

i was told that, but had mine ground and used acl racing bearings and an uprated oil pump, done about 10k now and still ok, touch wood

silent running

Well I think you might have been following my recent big end troubles on various threads - the consensus that I've had from a lot of people is don't do a regrind because you'll take the surface hardening off.

The other thing I've found is that contrary to what you would think, 2.0 short blocks are certainly no cheaper than a 2.5, in fact they're a lot more expensive unless second hand.

N602 WRX

The manual states the grind limit is 0.25mm....

Suppose that refers to a car running standard power though??.

But dont the rods ride on a oil film anyway so in effect dont actually touch the crank?

Maybe peaple say they cant be ground because there an awkward shape to grind and cant guarantee a perfect finish, thus putting the bearings at risk ??

Only speculation...

Maybe someone knows for sure???

smokingkills

iTrader: (3)

Thats weird, I had a chat with a guy in a works car park this evening with the same MY, same colour & same problem. Find someone with a 2.5 to test drive & you won't look back, a worth while upgrade anyway

DJ_Jon

iTrader: (7)

Its strange who you meet in carparks near work

I really want to drive yours, but I know if I do then I'll want a 2.5 conversion & the slope is slippery enough already!

debbiesonic

iTrader: (7)

Most in the know will advise against a regrind, it can be done, it's just not recommended. Mainly due as stated above to the surface hardening, it's marginal to say the least.

New_scooby_04

iTrader: (4)

Don't do it! Get the job done properly, pay once!!!!

Talk to David at APi for advice.

Ns04

DJ_Jon

iTrader: (7)

Agreed, after the money I've just paid out on my car to have it mapped to 320 bhp I'd like to get it sorted. the real pisser is I haven't even had the chance to test out the new power as it was knocking as soon as I drove it away from the garage after bob mapped it.

maybe I should break it as I've spent close to 2.5k on it recently & another potential 2k on a rebuild is more than I paid for the car 14 months ago

New_scooby_04

iTrader: (4)

Are you sure it is bottom end knock mate?

If so,

Nuts! That's bad luck! Speak to David at APi for your options and a no BS no obligation quote mate

Tell him NS04 says hi!

DJ_Jon

iTrader: (7)

yep, its definitely the big ends

p12mem

yeah your right the shells do not touch the crank, as they would pick up and start to knock, mines had 3 bottom ends from the dealers and they've all gone bang, so thought i'd try the and save instead of throw the old one away as in my eyes and the engineers it could be ground, and at the mo, it's running pretty good, time will only tell

N602 WRX

Yeah but, if subaru state that the regrind limit is 0.25mm you can bet they took into account the thickness of the hardening process they used which im guessing was induction as its the cheapest.

So if they say 0.25mm is the limit then you must not be going through the treated portion otherwise they wouldnt state it. Afterall they made the cranks, so they must know the depth or treatment..

I think the major thing to take into account would be to check for cracks and getting the oil clearence bang on.

Obviously fitting a new crank is easier but as long as yours was free of cracks and within tollerance i doubt it would be essential..

I know if it were me i would be checking the condition of mine first before splashing out on a new one.

New_scooby_04

iTrader: (4)

How much is a new crank?

How much would another re-build be if a re-ground one did go?

Is it worth the risk?

I do know that one of the most experienced Subaru engine builders in the country says don't do it, so on that basis alone, I wouldn't!

Ns04

DJ_Jon

iTrader: (7)

I've decided to strip the motor myself and see whats what. if the crank is within tolerances then I'll lobb in some new shells and and an oil pump etc. if the crank is buggered then I'll get a new one, like NS04 says its not worth he grief & ££ of doing it twice

N602 WRX

I agree with what your saying.. Too me it wouldnt really matter £ wise as i do all my own work, i like working on them as much as driving them.
Ideally yes i would fit a new one, but that could be said about any part if the funds are there to do so.

The thing im getting at is alot of peaple on here go off "heresay" and theres alot of scare mungering without peaple knowing the facts... That subaru themselves say 0.25mm is the headroom you have regarding re-grind and at the end of the day, they made it and they know the depth of hardness it was made to.

Obviously if you were planning on much more hp then yes undoubtedly a new crank would be top of the list along with uprated shells and so on...

But if i were just trying to get my car away again i would be checking what i have first and if the crank was in the middle ground of the tolerances and required a light grind then so be it.

New_scooby_04

iTrader: (4)

Here is what David at APi and Paul at Zen have said on the issue and they've rebuilt more Impreza engines than most of us have had hot breakfasts!

https://www.scoobynet.com/general-te...y-scoob-3.html

Page 3 post 72 onwards!

Ns04

Ghetto Dude3

i think a new crank is around 300 quid ?

might be wrong, its been 2 years (i think) since mine was replaced

harvey

iTrader: (48)

The cost saving between a new crank with bearings and a reground crank with bearings is not great so the incentive to go with a reground crank is not high. That said, a crank regrind specialist told me they would pay for a new crank and put money towards the rebuild if the crank they proposed to do for me failled in the first 12 months regardless of mileage.
That was over two years ago and probably 25-30,000 miles at up to 400bhp.
I think it depends substantially on the experience and ability of the regrinder and the extend of the problem with the original crank.

New_scooby_04

iTrader: (4)

About £350 IIRC. But, as David said, its the first thing to go in and the last thing to come out, so labour costs are also a significant factor if it fails and requires a second build.

Ns04

DJ_Jon

iTrader: (7)

Right, after a long chat with David at API I'm going to get them to sort my car. Got to say I was very impressed with David's knowledge and down to earth approach. the best bit of the conversation was the price quoted, more than I wanted to spend, but now I know my car is going to be sorted properly.

I feel a full write up (NS04 styleee coming on..) once I get it sorted.

Thanks to all who have given advice.

New_scooby_04

iTrader: (4)

Your in good hands, what did he pursuade you to get done?

Any news on the costs issues you raised via PM and when the failure happened, probable cause etc, Jon PM if you prefer.

Ns04

DJ_Jon

iTrader: (7)

Probably just a standard rebuild, my spec is good for 320hp, any more than that & the gearbox will leave the stage..

I'll PM you NS04....

stoneface

iTrader: (6)

Good route to go down keep us posted

DJ_Jon

iTrader: (7)

car is all booked in with API for next week, looking forward to picking it up!