Head adaptor question? - Well not really a technique, but . . .

[bruce]

I know this question has been asked on the forum before somewhere but I can't find it so I'll ask again . . . what is the "standard" depth of the bore in the head adapter. I know it's a percent of the stroke but can't recall?

[106-1194218389]

Bruce,
I thought it just had to be at "least" a certain percent of stroke. I have made all adaptors 6" long as far as cylinder length. I feel you would want it at least the length of the stroke, but on some engines that seems pretty short to work with. You would also have to consider that in an engine it hits the bottom of the "well" when it gets to the piston top.

[106-1194218389]

[color=#000000]Bruce,
I found this on the Super Flow web site:

[MMack]

I don't know if I saw it here or somewhere else, but I use 1.5X as a minimum and not more than 2X. I don't know much, but I thought I learned that here.

Mike

[MMack]

1.5X and 2X the stroke, left out that little detail.

Mike

[bruce]

I was thinking it was a percent of the bore instead of the stroke.

[racehead-1]

If I have a 5.5 inches hole on top of my bench, does the tube of the head stand have to be the same diameter. If it is only possible to get a tube of 6 inches is that ok to use on top of the 5.5 inches hole ?....

Well different opinions of the lenght of the stroke, which is the more acurate? I am thinking in building a head stand out of acrylic.
This information would be very helpful .

[86rocco1]

No, use a tube that matches as closely as reasonably possible the bore of the engine whose head you're testing. That way you're able to replicate any shrouding or other effects the cylinder wall may have on air flow.

[DWC]

My superflow head adapters bore length is 131mm half of that length is an inside diameter of 4" and the other half is 4.250".
To my way of thinking it would be best if the length of the bore adapter had a relationship with its diameter that way different bore diameters would be relative.
Darrin.