Question about bearings for a bug engine

VOLX Commited Dubber

67 posts · joined Sep 2004 · 12 Oct 2004, 9:27 pm

#245199

I have a query and hope than someone can help with my question. My name is Karin BTW and I'm wife of VOLX (Linus).I'm having an engine rebuild at the moment and have been waiting for bearings for months now (10 mths actually)as the mechanic tells me they are not available in Australia. I finally asked exactly what size are we looking for and he said 1.25mm over size from original 1600 crank. I have since been told today that if crank has been machined over 1mm then the radius has nothing left to grind and the crank will actually crack. Does anyone know if this is the case? The engine is an 1840 and used to be very nice until the generator stand broke and broke the fan and the blades came through the fan housing and stuffed the engine. This mechanic is charging us top dollars to fix this and now I'm beginning to worry if this means the crank will soon stuff up, If anyone can offer some advice this would be great before this guy goes any further with this engine.
Thanks
Karin

Che Castro ankle straps

1,945 posts · joined Aug 2002 · 12 Oct 2004, 11:50 pm

#245270

The crank and crankcase can only really be cut about 4 times. each cut is 0.25mm. even at the 3rd cut its at the end of the road. Dump the crank altogether as I have never heard of 5th cut bearings, it would be cheaper to just get another one that is uncut or on 1st cut.

or even better get another mechanic!

Jon

lugnuts Custom Title Time!

1,070 posts · joined Aug 2002 · 13 Oct 2004, 4:24 am

#245363

What ^said 😉

VOLX Commited Dubber

67 posts · joined Sep 2004 · 13 Oct 2004, 9:18 am

#245423

Well I rang the mechanic this morning and apparently the crank is a performance crank he said it's a "counter weighted crank" and can be ground up to 1.5mm. Does this sound right or is he having me on?

Che Castro ankle straps

1,945 posts · joined Aug 2002 · 13 Oct 2004, 10:40 am

#245452

I think he is having you on. Ideally you dont want it ground at all. 1.5mm would be sixth cut. no one goes beyond 4th cut because its silly. 4th cut is really the end of the road and you would only use a 4th cut in an ultra low budget stock engine - that's at a stretch. it would be cheaper to just buy another crank!

Jon

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 · 13 Oct 2004, 11:30 am

#245480

A new counter weighted crank is what $500 max??

That said i know several places that a new welded CW crank is 20/20.

they need to grind them after welding and maost are at least first grind down.

5th grind seems over the top to me.

Personally i wouldnt go there.
Guess it depends on the $$$ :duh

Futue te ipsum!!!

low55 Seriously Crusin Dubber

173 posts · joined Aug 2003 · 13 Oct 2004, 8:21 pm

#245738

hmmm sounds a bit sus to me do your self a faver and go see bill and alan
at mr bug on elliot road dandenong thay have brand new c/w shafts ready to go these are brand new forgings balanced 8 doweld the works and they now what there talking about and there cheap and heres some food for thort if you cut 1.25 of your grank you should get it nitrided again because you have cut all the hardning off it
it want last it will be a total wast of money when i did my shaft they guys said thay would not cut any more than 1 mm or 40 tho so i found a std crank and thay went 20 thou
hope you work out what to do
travis

i thirt of some thing funny and stupid to write here then i forgot it

lugnuts Custom Title Time!

1,070 posts · joined Aug 2002 · 14 Oct 2004, 2:26 am

#245874

VOLX wrote:Well I rang the mechanic this morning and apparently the crank is a performance crank he said it's a "counter weighted crank" and can be ground up to 1.5mm. Does this sound right or is he having me on?

Its just a standard crank with welded on counter weights to enable higher revs (over 5000) upto 7000 or so either way your crank is past its useby :duh

VOLX Commited Dubber

67 posts · joined Sep 2004 · 14 Oct 2004, 9:05 am

#245920

Thanks guys for all the feedback but I'm caught between a rock and a hard place.:cry The mechanic keeps saying it'll be fine and everyone else says no it's not! So short of me having an absoulute fit and removing everything from this guys premises I don't know what to do. So I guess all we can do now is suffer the $$ and get all our stuff out of there and then have to do another rebuild as soon as possible. Thanks for all your help.
Karin

barls Administrator Causer of Chaos and Mayhem

9,473 posts · joined Jun 2004 · 14 Oct 2004, 4:41 pm

#246124

but remember that all rebuilds come with a warranty so if it breaks go back. but as the consumer you have the right to say what parts are to be use in a rebuild.

[Edited on 14-10-2004 by barls]

“We all pay for life with death, so everything in between should be free.” Bill Hicks
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VOLX Commited Dubber

67 posts · joined Sep 2004 · 14 Oct 2004, 5:20 pm

#246143

Well thats what I decided that if anything stuffs up they have to warranty it for 12 mths anyway. I just have to have some hope that he knows what he is doing and he says it'll be fine. Here's hoping anyway.