Bottom end balancing

[campbellju]

I was off to the machine shop this week to get my crank ground, engine re-bored and the whole botom end balanced.

The shop has no problem in doing the boring and grinding at a very good price but said they couldn't do a proper balance of the lot. They went on to say they wouldn't bother wasting my money in getting it balanced unless I particularily wanted an extreme performance engine. Given Nissan tolerances it probably isn't worth bothering?? This comment makes me wonder as the only Nissan bit left in my bottom end is the Crank. The clutch, flywheel, rods and pistons are all aftermarket.

I thought I'd ask everyones advice.

To me, having the bottom end balanced makes sense, reduced frictional losses, less wear more bhp. To do a proper job though, I believe you need to balance everything, not just the crank. Is this right? :?: :?:

How much did it cost to get the bottom end balanced? I have no intention of raising the rev limit as that's even more expense on sorting the top end out and I'd be better off saving my money and fitting a bigger turbo :twisted: Consequently, is it money that could be better spent else where?

How much did it cost to get your bottom end/crank balanced and where did you go?? The only places the machine shop suggested were over 150 miles away. I live in Southport and am wondering about places in the North West.


:?: :?: Can anyone shed any light on this :?: :?:

Thanks,
Jim

 

[ashills]

def get it done yes nissan balance to a reasonable spec but for what it costs to do while its out its a must do job
to have a regrind on teh crank and balance ny bottom end i was quotes 250-350 depending on a few things but im having them put the whole lot together now
but well worth getting it done

 

[skiddusmarkus]

Best to get all the bits balanced together.I'm sure there must be somewhere more local to you.
I always say this,but just have a drive round an industrial estate and look for engineering firms.Where I live there are loads and on one small one I looked round,out of the 8 units there,6 of them were engineering firms.

 

[JU5TY]

Yes defo get it balanced.

My bottom end was Dynamic Balanced for £80 at 'Power 4 Peanuts', which are in Surrey (KT12 3RD). Tel: 01932 246413

I was recommended them by my machiner...

 

[jonesgti_r]

Give Wilson Healey a ring and ask them the owners son races semi pro and he should be able too recomend some one 07104 229217 or ask Ian at hiteq in wigan who they use 01942 721778

 

[campbellju]

Thanks Gents. It did make engineering sense to me.

For the record and anyone else not done it yet, getting the re-bore and crank done for £60 each but was kind of concerned this was specialist. At £250-350 it was in the "I want to but should I spend the money elsewhere" at £80 its in the no-brainer category again.

I'll shop around a bit more and follow up your leads.... or maybe have a weekend in Surrey

Thanks again,
Jim

 

[campbellju]

News Update::::

I managed to find a good machine shop in the end from a local recommendation. I Spoke to john, "god's helper" at the Head Shop Uk ltd 01925 576704. Apparently he's done quite a few Gti-R Engines on the back of a well known tuner.

The work he did was:

Re-bored the block
Polish Crankshaft (He said it didn't need grinding and it might do more harm than good)
Balanced complete bottom end together

Cost £342

This was a good price as the PAR Con Rods were quite mismatched and needed careful grinding to balance them out. They were 9g different in weight which is pretty average in the automotive market. Apparently Porsche allow a 6g limit between Rods but for billeted aftermarket kit I expected better. :roll:

All sorted now though and ready to go back in engine.

Thanks to all for convincing me it was money well spent... I feel a warm feeling already and that not even working yet.

Jim

 

[skiddusmarkus]

What did they think of the PAR rods quality wise(not just mismatch)?

 

[campbellju]

The machine shop didn't really comment on them except for the obvious which he wasn't overly impressed by as if the rods were sold as a set then he thought it should be in the manufacturers quality control to match them up more. He said this is not uncommon though as most petrol heads just get a garage to throw in the new parts without checking/balancing and the manufacturers know this. Porsche would reject the parts, you're average petrol head (me included) wouldn't.

In terms of subjective opinons from myself my friends and my mechanic mate helping me with the build, everyones been impressed with the quality. Lots of ooohs and ahhhs. Compared to the stock ones there's just no comparisson in terms of build quality and apparent strength.

 

[Nad]

The machine shop didn't really comment on them except for the obvious which he wasn't overly impressed by as if the rods were sold as a set then he thought it should be in the manufacturers quality control to match them up more.

Compared to the stock ones there's just no comparisson in terms of build quality and apparent strength.

Is that for or against the PAR's then. I'll take a guess :lol: I have taken mine down for a dynamic balance and the rods went down as well. I will ring him tomoz if he hasnt already done them and get him to note down the differences.

Nad

 

[Anonymous]

I managed to find a good machine shop in the end from a local recommendation. I Spoke to john, "god's helper" at the Head Shop Uk ltd 01925 576704. Apparently he's done quite a few Gti-R Engines on the back of a well known tuner.

quite sure it`s this company that did all my balancing.imho it is the most cost effective mod you can carry out to an engine.just watch how much quicker the turbo will spool up when the bottom end has been balanced.

i know some people will say it`s overkill but,the entire bottom end should be balanced individually then balanced as a complete unit.by that i`m talking about rods,crank,flywheel(pref lightened) and clutch assembly.the results will justify the extra cost and time