BritishV8 Forum

How wide are they from register face to register face?

129,5 mm

= 5.0984" @ 70 deg F

thanks much.  so i need to check for a gap of 5" or less.

The main bearing is the same size as the Buick 300 uses, I was hoping they'd be a source for heavier duty main caps that would have much more significant registering to the block than the stock Buick caps provide.

Doesn't make any difference though, the webbing all of the cap areas except for the rear main is all wider than 5 1/8".  Two of the middle webs ( 2 and 4 ) don't even approach the cap.

I suppose it's possible you could use a 4.6L rear cap by itself on a Buick 300 if you really wanted too.

Todd, What block do you have ?

300, 340 and several 350's.

I don't have the tall deck blocks pulled apart right now but i suspect the webbing is going to be similar.  And the whole question of 4.6L main cap application is a waste of time for the tall decks anyways.  The 340/350 use a 3.00" main bearing journal compared to the 300 / 4.6L 2.50".

You'd be better off just having a new set of caps machined from scratch.

How about the Buick Supercharged V6 cap?  That's it on the top, 4.6 Rover on the bottom.

http://forum.britishv8.org/file.php?6,file=4519

http://forum.britishv8.org/file.php?6,file=4518

There's also an aftermarket cap for the Turbo Buick V6:

http://forum.britishv8.org/file.php?6,file=4521


Greg

Still not providing the 'total cap height register' I was looking for, even in the v6 install.   Your 'installed' pic only shows registering on the  1/4" or so of the cap closest to the crank.


And, as I said, it would only work on #1,3 and 5 anyway.  #2 and 4 would require caps that extend almost the width of the skirt to one side of the crank in order to accomplish a register.

The point I was looking for is a simple way to tie the entire bottom end of the block together in a sort of pseudo-girdle.  Like your 4.6L cross bolts.  Block webbing architecture looks to be a serious stumbling block though.  Even if I can get full cap registration, the webbing appears to be too narrow between the skirt and cap to tolerate drill / tapping from the side.


OT:
Greg, are you the American who was playing with the P76?  If so, did you ever get an 'official' deck height on that?

I know the Rover power tuning book shows a deck height shorter than a 300 ( online by google books ) but I saw it posted that the P76 actually has a wider intake.

I think I get what you're trying to do.  Something close to the LS1 style cap?  And yes, the P76 deck is taller than the 300 but shorter than the 340\\350. No offical deck height though.  Des Hamill's book says the 300 is .5" taller than the Rover and the P76 is .690" taller.

Greg

Des Hamill's book says the 300 is .5" taller than the Rover and the P76 is .690" taller.  



*scratches head*

I wonder if that's a correction in a newer edition?  Because google preview shows on two different pages ( 16 and 23 ) that the 4.4L deck height is 9.5" / 241.3mm.  Everything I've seen says the deck on a 300ci is 9.543" which would force the 300 intake to be wider than the P76 unless the P76 head casting was narrowed on the intake side.

http://books.google.com/books?id=gmSavy1RPxEC&printsec=frontcover#v=onepage&q&f=false


I would buy Hammill's book ... but the asking price on Amazon and Ebay is over $200.  Some are nearly $500.


Also, the numbers I've seen show the 300ci deck to be MORE than 1/2" taller than the 215ci.  What I've got is
215 = 8.96" or 227.6mm
300 = 9.543" is a .583" delta
340 = 10.150"
350 = 10.180"

Todd, some girdle work was done on V8Buick. I made a spacer plate (1/4") which tied into the main studs and the frame rails using the pan bolts but did not tie across the caps. It was not intended to function as a girdle, I just needs pan clearance for the rods and tieing into the studs was just a way to help with cap walk. Anyway I sent the template to Sean so he could lay out a girdle. There were two schools of thought. Some of the guys wanted to cut the caps and use a flat plate. I felt that would compromise the caps and it would be better to relieve the cross straps and provide them with jackscrews to pre-tension the bridge of the cap. In any case custom fit shim washers are needed between the plate and the stud bosses. About a 1/4" relief would be needed across the bridge, meaning a 1" girdle plate. Since then I don't think it's gone anywhere.

Jim

The rule of thumb that I am aware of on deck height is about 9/16" between BOPR and 300 and about the same between 300 and 340, give or take, for an actual of about 1-3/16" betwen BOPR and 340. If the 4.4 is within .030" of the 300 that much is not hard to accommodate with the right gaskets and/or sealant.

Jim

Buick 300 intake is a bit smaller than the P76 intake.  You'd need .25" spacers to make one work on a P76 block.

Greg

Greg
My interest in the P76 is more curiosity than anything.  I'm a data packrat.  I have a fricking huge spreadsheet on Buick / GM / Rover data.  Right now I've got 9.63" for a 4.4L deck height, but I can't vouch for the accuracy of that.

If I was going to be interested in parts interchange the specific interchange would be 4v P76 intake onto a 300ci block.  ~1/4" sounds like a too much to be trying to machine off though.



Something close to the LS1 style cap?
http://image.hotrod.com/f/9255262+w750+st0/hrdp_0606_04_z+supercharged_LS1_Gen_III+mains.jpg

Yeah, that looks like what you'd have to do in a 300ci block for journals #2 and 4.  Well, at least that demonstrates proof of concept of the wide main cap is valid.  LS1 cranks use a smaller journal size though, so I don't think you'd want to try and adapt them.

Also, the #5 journal / rear main already does have full registration in the 300 block.  So there's not really any point in trying to source one from somewhere else.  #1 / front main and 3 / thrust bearing could probably have full registration with a 5 1/4" wide cap.  I'd want to re-measure that to verify though.

Todd, and clan, based on the hp at ? rpm, you're trying to harness, my initial suggestion would be studs, and a "halo" type steel girdle. 1045 steel plate is a good choice for availability and "yield strength", using your stock caps. Once you have a drawing, any H2O jet or many "laser" shops, can cut these out cheaply. It is likely you'll need to have these blanchard ground-flat, for complete accuracy. If this girdle includes the pan rails, you will need studs there also. 1/4"-3/8" thick should be adequate. Stock pan gaskets will not work. Cheers, roverman.