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Re: [Spridgets] was oil pickup...bottom end questions

To: a_d_webster@yahoo.com.au, spridgets@autox.team.net
Subject: Re: [Spridgets] was oil pickup...bottom end questions
From: Daniel1312@aol.com
Date: Thu, 21 Jun 2007 12:37:41 EDT
You haven't said what rpm you plan to run the motor too or how often.  
Probably up to 6.5K on a stock bottom end, up to 7.5K on a strapped and 
anything 
over 7.5K a 4 bolt?

I'm not sure if there is a debate about line boring even when strapped.

I'd rather have a 4 bolt main on stock main cap bolts and a couple of good 
bolts on the 2 extras than ARP studs on an ordinary cap.

If you have an A+ crank than you either have the journals machined down for 
Spridget rods or have big journal 1275 rods or big journal A+ rods.

If you have a Marina in-line 1275 or Ital +A block either will be clearly 
different from the Spridget block.

Daniel1312

In a message dated 21/06/07 07:36:07 GMT Daylight Time, 
a_d_webster@yahoo.com.au writes:

> 
> I know Vizard et. al. say to strap it or fit a 4-bolt main...
>  4 bolt main...line boring and the necessary deep pockets...say no more.
>  As far as the strap goes... I just don't like the idea of milling away the 
> guts of the main cap... I'm no engineer.. and no doubt some of you are... so 
> feel free to correct me.
>   
>  Unless you're building a mental engine, wouldn't a set of ARP main studs be 
> adequate, and considering no machining is required..similar $$ outlay as a 
> strap?
>  feel free to shoot me down or reassure me..I'm about to assemble an engine, 
> so I might as well get the bottom end up to the task now. 
>  Inline 1275's are scarce and expensive here...I don't want to break mine.
>   
>  while on that topic... Is there any way to identify what year/series a 
> crank is from by the numbers cast in it?
>  I have an interesting situation which i have mentioned before where there 
> is about .030 of crank end float when standard thrusts are fitted... Colin 
> Dodds mentioned that this arises when an A+ crank finds its way into an A- 
> block... or was it the other way around...?
>  i have thinned down a set of .030 oversize thrusts to fit... but now I'm 
> worried about the crank being in the right place end-wise.
>  I figure BMC tolerances would let me proceed as long as there is no 
> pinching between big ends and the crank cheeks.. anyone care to shed light on 
>this?
>   
>  Andy
>  Brisbane
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