crankshaft??
10 February 2009, 12:38 PM
#1
Scooby Regular
Thread Starter
Join Date: Jul 2008
Location: west midlands
Posts: 364
Likes: 0
Received 0 Likes
on
0 Posts
crankshaft??
my bottemend has gone knockin badly ive just bought a used crankshaft but ive just had it regrounded with new shells in it i was just gonna put it but the other day some1 told me not to i dnt know what to do
10 February 2009, 12:54 PM
#5
911 C4 pilot
iTrader: (7)
Join Date: Jan 2007
Location: In an Air Cooled Porsche
Posts: 3,578
Likes: 0
Received 0 Likes
on
0 Posts
Lifted from an email David @ APi sent me:
Originally Posted by David at APi
Can we re-grind the crankshaft ? In our experience re-grinding a Subaru Turbo crank is a poor idea. Once the surface hardening has been removed in the re-grinding process, the crank is ' soft' and will fail again quite quickly. It can of course, be re-hardened, but this is a specialist process and will involve extra cost in re-polishing and straightening the crank after the hardening treatment. Cost saving by then, is minimal. Even so, the gallery plugs that need to be removed when cleaning a crank, are unable to be removed easily on a Subaru crank and the risk of not being able to clean out metal swarf created by grinding is too great
Trending Topics
10 February 2009, 01:03 PM
#9
911 C4 pilot
iTrader: (7)
Join Date: Jan 2007
Location: In an Air Cooled Porsche
Posts: 3,578
Likes: 0
Received 0 Likes
on
0 Posts
The term is "re-ground", not "regrounded" - if you want to go and fit a re-ground crank into your car, then that is your choice. You asked for reasons why, I gave them.
You could try ringing a few of the usual suspects on here, Api, Enginetuner, Zen, Andy Forrest etc to get their opinion.
I suspect if you rebuild with this crank then you will be doing the same job a few miles down the road.
Your choice buddy
You could try ringing a few of the usual suspects on here, Api, Enginetuner, Zen, Andy Forrest etc to get their opinion.
I suspect if you rebuild with this crank then you will be doing the same job a few miles down the road.
Your choice buddy
10 February 2009, 01:07 PM
#10
The term is "re-ground", not "regrounded" - if you want to go and fit a re-ground crank into your car, then that is your choice. You asked for reasons why, I gave them.
You could try ringing a few of the usual suspects on here, Api, Enginetuner, Zen, Andy Forrest etc to get their opinion.
I suspect if you rebuild with this crank then you will be doing the same job a few miles down the road.
Your choice buddy
You could try ringing a few of the usual suspects on here, Api, Enginetuner, Zen, Andy Forrest etc to get their opinion.
I suspect if you rebuild with this crank then you will be doing the same job a few miles down the road.
Your choice buddy
To the OP, you asked for people's opinions and you've got them.
Perhaps you should of asked them before you spent your money?
There have been loads of threads on here where people have used reground cranks and the engines have gone **** up again fairly quickly.
Feel free to use your reground crank and prove prove us and all the experts wrong.
It's your car and your cash at the end of the day!!
10 February 2009, 01:19 PM
#11
Scooby Regular
iTrader: (2)
Join Date: Nov 2008
Location: holywell
Posts: 453
Likes: 0
Received 0 Likes
on
0 Posts
Ive been building Impreza engines for 9 years, road, race and rally cars, used a re-ground crank once in the early days, lasted about 800 miles, ive never used one since. I also now of 3 other people that have tried and all failed within a short time.
10 February 2009, 01:24 PM
#13
Scooby Regular
Thread Starter
Join Date: Jul 2008
Location: west midlands
Posts: 364
Likes: 0
Received 0 Likes
on
0 Posts
i wana say thank you to all of u for your advise im only asking as ive bought to bottom ends and they have been scrap as iv ebin ripped off
10 February 2009, 01:56 PM
#16
Scooby Regular
Thread Starter
Join Date: Jul 2008
Location: west midlands
Posts: 364
Likes: 0
Received 0 Likes
on
0 Posts
crank help
the only reson the crank is good the person i bought it off said 1 of his headgasket has went on his engine so he decided to put a redtop lump in it and stripped the engine to recover some money
10 February 2009, 02:21 PM
#17
Scooby Regular
Join Date: Jan 2009
Location: dumfries and galloway
Posts: 307
Likes: 0
Received 0 Likes
on
0 Posts
sorry to hijack this thread i dont have any rod knock but can you tell me for instance if it just started knocking would you still need to change the crank or could you get away with just replacing the bearings if crank was still within specification and i know on some cars if its on the piston end itself can you do the job without taking engine out ie from underneath just so i know in the future thanks.
Last edited by legacytt; 10 February 2009 at 02:24 PM.
10 February 2009, 02:58 PM
#18
Scooby Regular
iTrader: (2)
Join Date: Nov 2008
Location: holywell
Posts: 453
Likes: 0
Received 0 Likes
on
0 Posts
Ive had one crank that was ok after big end failure, very unusual that the bearing doesn't spin and result in metal to metal. If the used crank measures up ok and is straight, then there is no reason not to use it. make sure it's the correct thrust position though!
10 February 2009, 06:23 PM
#19
as said above using a reground crank is false economy and will see you spending more in the long run, the £250 you have already spent would have seen you well on the way to a new crank and bearings.
10 February 2009, 07:13 PM
#21
Scooby Regular
Join Date: Nov 2001
Posts: 243
Likes: 0
Received 0 Likes
on
0 Posts
sorry to hijack this thread i dont have any rod knock but can you tell me for instance if it just started knocking would you still need to change the crank or could you get away with just replacing the bearings if crank was still within specification and i know on some cars if its on the piston end itself can you do the job without taking engine out ie from underneath just so i know in the future thanks.
Last edited by scooby(puppy power); 10 February 2009 at 07:15 PM.
10 February 2009, 09:31 PM
#25
For absolute, total peace of mind, discuss with APIDavid. He'll be able to sell you the correct brand new crank and apppropriate sized shells, etc.
Then try and sell on any of the other bits (although it'll be something of moral dilemma, won't it?)
.
Then try and sell on any of the other bits (although it'll be something of moral dilemma, won't it?)
.
10 February 2009, 10:48 PM
#29
How would you know it's good? Forget it - just get a brand new crank. The relative price of it... comapred to another rebuild... simply isn't worth the ball ache! 
You're mindset is all wrong, if you're trying to save a few quid on a new engine build IMHO.
Please, for thr sake of your sanity/pocket, re-read this:-
Originally Posted by David at APi
Can we re-grind the crankshaft ? In our experience re-grinding a Subaru Turbo crank is a poor idea. Once the surface hardening has been removed in the re-grinding process, the crank is ' soft' and will fail again quite quickly. It can of course, be re-hardened, but this is a specialist process and will involve extra cost in re-polishing and straightening the crank after the hardening treatment. Cost saving by then, is minimal. Even so, the gallery plugs that need to be removed when cleaning a crank, are unable to be removed easily on a Subaru crank and the risk of not being able to clean out metal swarf created by grinding is too great
Do it right... Do it ONCE!
You're mindset is all wrong, if you're trying to save a few quid on a new engine build IMHO.
Please, for thr sake of your sanity/pocket, re-read this:-
Originally Posted by David at APi
Can we re-grind the crankshaft ? In our experience re-grinding a Subaru Turbo crank is a poor idea. Once the surface hardening has been removed in the re-grinding process, the crank is ' soft' and will fail again quite quickly. It can of course, be re-hardened, but this is a specialist process and will involve extra cost in re-polishing and straightening the crank after the hardening treatment. Cost saving by then, is minimal. Even so, the gallery plugs that need to be removed when cleaning a crank, are unable to be removed easily on a Subaru crank and the risk of not being able to clean out metal swarf created by grinding is too great
Do it right... Do it ONCE!
Last edited by joz8968; 10 February 2009 at 10:55 PM.