Spacer for shear plate?

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Spacer for shear plate?

Post by andyf » Sat Aug 20, 2011 5:37 pm

Does anyone make tapered spacers so a shear plate can be bolted on a cast intake? I've looked around a few times but haven't ever found anything other than the spacer that Reher Morrison sells. Wilson sells several types of shear plates but they don't provide anyway to bolt them to a cast intake.

I made my own tapered spacer so I could do some dyno testing but it was a fair amount of work. Just wondering if anyone knew of an off the shelf solution?
Tapered.jpg
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Re: Spacer for shear plate?

Post by andyf » Sat Aug 20, 2011 5:39 pm

Here is what it looks like with the Wilson shear plate attached.
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Re: Spacer for shear plate?

Post by OriginalHO » Sat Aug 20, 2011 7:25 pm

I don't mean to hijack your thread, but that tapered spacer and "shear plate" looks a lot like the H-O Racing "Rocket Box" from 1977. Here's a link to its design disclosure thread on Performance Years:

http://forums.performanceyears.com/foru ... Rocket+box

Do you have a link to further explanation of its design and implementation?
Craig Hendrickson, the "H" in H-O Racing Specialties.
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Re: Spacer for shear plate?

Post by andyf » Sun Aug 21, 2011 1:04 am

Hi Craig,

I don't have a link for you but if you search for "shear plate" you'll find some stuff at Braswell and Reher Morrison. The shear plates I've seen use a small tapered section (usually 5 or 7 degrees) and then a thin shear lip with a pressure recovery groove. I'm not sure how or why they work (or even if they do) but they are typically found on higher rpm engines. They seem to show up mostly on sheet metal intakes rather than cast intakes.

Here is a picture of the bottom side of the Reher Morrison shear plate. The Wilson shear plates are a little more involved. The Braswell shear plates are very involved.
shear.jpg
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Re: Spacer for shear plate?

Post by andyf » Mon Aug 22, 2011 1:33 am

Craig,

Here is a view of the Wilson shear plate mounted on a Dominator carb. This view shows the tapered bore extensions as well as the pressure recovery grooves. The problem is that all of this stuff takes up room so these shear plates will not fit into a normal cast intake. As far as I can tell, nobody builds tapered spacers to adapt a shear plate to a cast intake. Either it is becauase nobody has thought of it, or because it doesn't work. Wilson makes shear plates and they make spacers but they don't make a shear plate spacer for some reason. Anybody know why???
shear.jpg
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Re: Spacer for shear plate?

Post by jmarkaudio » Fri Sep 02, 2011 2:51 pm

This will be a little easier to see.

Image

Image

Image
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Re: Spacer for shear plate?

Post by andyf » Mon Sep 19, 2011 9:40 pm

Thanks, I didn't have those pictures hosted anywhere when I posted the links.

I did some dyno testing of the various spacers recently and didn't come to any conclusions. I was told by some people that a shear plate wouldn't work with a cast intake but it seemed to work okay. Others told me that it would pick up some power but it didn't really do that either. Basically I didn't see any difference between a shear plate and a flat plate.

I've been around long enough to know not to read too much into a series of dyno tests. I'll have to think about the results a bit more and figure out a different testing strategy. I'm sure there is some power potential in this area but I haven't figured out where it is hiding yet.
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