Where to buy Curvy con rod shells?
 

Hey guys as the title says,

I need a big end bearing for my front con rod, had a look on wemoto and general googling, do u have to get these from ur Suzuki dealer usually or were is best ??

Cheers guys

Chris

Re: Where to buy Curvy con rod shells?
 

Paging Squirrel Hunter!!!!

There is a place in Bristol (I think) that can supply crank bearings

Bing: This may help http://forums.sv650.org/showthread.php?t=152509

Re: Where to buy Curvy con rod shells?
 

I haven't asked in a long time, but last time I did they didn't sell them as the rods & crank come matched together and could only be bought as an assembly, at the time a secondhand engine was less money.

You could of course get yours re-whitemetalled and machined, but you'd probably have to do some digging to find someone still doing that sort of thing.

Cheers Mark

Re: Where to buy Curvy con rod shells?
 

You ringed?

Piston Broke Engineering, Bristol (0117) 9412300 is where the engine to SH2 got new big ends. And its where SH2's engine is at the moment, which reminds me...

Re: Where to buy Curvy con rod shells?
 

you owe £50 again!

Re: Where to buy Curvy con rod shells?
 

suzuki seem to do 4 different big end shells,green black yellow and brown,but if the crank is worn then it is scrap,but you'l need 4 shells so as to keep them all the same tolerance

Re: Where to buy Curvy con rod shells?
 

Ok guys cheers for the help! Il carry on stripping the engine to see what the damage is to the crank!

Re: Where to buy Curvy con rod shells?
 

If big ends have spun crank will be scrap, in every one I have seen. First damage is galling between shell and crank as they get microscopic welds together, then bearing spins when it has been scraped flat. I think this is first knocking you hear. That knocking is crank steel battering against conrod steel, at this point it will be scored and knackered.

Re: Where to buy Curvy con rod shells?
 

This.

There are no standard parts available, so as stated earlier in the thread someone will need to be engaged to make parts or adapt them from another engine. Also, as Chris rightly says, if the bearing has failed the surface of the crank upon which the bearing runs will almost certainly be damaged. Dependant on the amount of damage it may be possible to reface the crank journal and have bearings to suit made or adapted.

However the economics of the situation should be carefully examined before any decision is made, by the time the crank assembly is repaired and the gaskets and seals needed to rebuild the engine have been bought, it may well cost more than replacing the engine, which is also significantly less work.

Re: Where to buy Curvy con rod shells?
 

But cutting the big end journals undersize resulted in a snapped crank. How much got ground off?

Re: Where to buy Curvy con rod shells?
 

I've no idea.

All I can go by is what I've been told by a very experienced engineer. As stated in the other thread there was no clear cut explanation of the failure. As far as I know I'm the only one to get an SV crank reground after oil starvation but I'm not the only one who has had a crank reground after oil starvation. I doubt very much the service would have been offered if he didn't think that it was possible. I offer no advise on if this should be done, I'm not the right type of engineer, I can only relay my experience.

Re: Where to buy Curvy con rod shells?
 

Have you not got snapped crank you can measure?

Re: Where to buy Curvy con rod shells?
 

I seriously doubt so much came off the journal as to weaken the crank, I can't imagine more than 20 thou or so was taken off.

Re: Where to buy Curvy con rod shells?
 

Aye but it's rare to snap one there normally.

Re: Where to buy Curvy con rod shells?
 

You have to be very careful at the fillets (radius out at the end of the pin). Quite often these days cranks are fillet rolled to increase the fatigue strength (same effect as shot peening), if you machine through the depth affected by the rolling it will probably break. The basic material doesn't have sufficient fatigue strength. Similarly the actual fillet radius and surface finish of the fillet are important and not always easily reproduced, any grinding marks left in the fillet will cause stress concentration.

Re: Where to buy Curvy con rod shells?
 

Hmmm... Interesting.

Re: Where to buy Curvy con rod shells?
 

I think his snapped in middle of big end journal

Re: Where to buy Curvy con rod shells?
 

Here is SH's crank

http://forums.sv650.org/showpost.php...&postcount=174

Re: Where to buy Curvy con rod shells?
 

Makes what embee suggests very plausible.

That looks like fatigue cracking followed by brittle failure to me too.

Re: Where to buy Curvy con rod shells?
 

It does rather.

Re: Where to buy Curvy con rod shells?
 

Yep, looks like classic fatigue failure starting at the inboard side of the fillet (i.e. nearest the crank centreline), that's where the higher tensile stresses tend to occur under firing pressure, the crank tries to straighten out, and tends to be compounded by balance weight effect. You see the classic "beach marks" as the crack grows.............then snap.

As for the fillet rolling thing, it can be very clever when they use "Asymmetric rolling" so it rolls hard on the inboard side and less so on the outer side, put it where it's needed and not where it isn't, more cost effective and easier on tooling. It's not something I know a lot about in detail, just familiar with it.

Re: Where to buy Curvy con rod shells?
 

cant see why you cant get suzuki shell bearings in the uk as they are on there parts lists and come up as available, in the usa on the alpha web site anyway,i know they only do 4 sizes to make up for different rod and crank manufacturing tolerances,and crank regrinding is a waste of time and will rarely works and no under size shells are available

Re: Where to buy Curvy con rod shells?
 

What does my post say? Have we been here before? Is there an echo in here?

Yes, you can get replacements, of course you can - but as no undersize shells are available the question at hand is answered by my post, no?

Not sure what you're saying here - perhaps I'm missing something.

Re: Where to buy Curvy con rod shells?
 

i know where talking about knackered cranks here but i thought people were saying if you changed a crank or rods from a different engine or different cases on a good crank and you needed shells to match the different manufacturing tollerances that they couldn't get suzuki shells to match this, when different tollerence/size shells appear on the parts list for this purpose