45 WR: Cams & Flow

Here are a few interesting tidbits about the 45 WR motor which I have been working on, that seemed worth sharing. Recently I put the cylinders on the flow bench; not because I intended to port them, but just to have a record of their flow. The results were surprising, at least to me.

The cylinders were brought to me with the customer's understanding that they were 1948 WR. At first I assumed that to be correct, but upon a lot of online research, I managed to convince myself that they were actually 1940 WLDR Specials. But finally, thanks to Eric, one of regulars on the FlatheadPower Bulletin Board, and his Beauty of Speed web site, I have returned to my original (less informed, but correct) assumption. The cylinders are '48 WR. Clearly a case of confusion brought on by information overload.

In any case, here is a side by side flow bench comparison of a WR cylinder and a stock WL cylinder. I tried to keep the tests as much "apples to apples" as possible, but here comes the disclaimer. After 62 years and very likely a hard life, an exact comparison between how the parts compared when new is well nigh impossible. But that doesn't mean the results should be discounted, just that they should not be taken as absolutes.

Intake Flow @
.100 - WL 48cfm / WR 52cfm
.200 - WL 84cfm / WR 90cfm
.300 - WL 99cfm / WR 105cfm
.350 - WL 103cfm / WR 108cfm
.400 - WL 104cfm / WR 108cfm

Exhaust Flow @
.100 - 42cfm / WR 52cfm
.200 - 82cfm / WR 77cfm
.300 - 104cfm / WR 89cfm
.350 - 111cfm / WR 92cfm
.400 - 116cfm / WR 94cfm

I don't know about you, but that sure wasn't what I was expecting. The WR has a larger valve and a much larger port opening. I tested both with a clay radius inlet guide directly on the plumber fitting so that manifolds would not be a factor. I tested the WR with a K model intake valve which is 1.810" diameter, verses the WL's 1.625. Now I have seen conflicting specs as to the WR intake valve size. One source lists 1.750, another 1.810, and the worn out valves that were in the cylinders when they came to me were 1.710. Perhaps the chamber wall shrouding of the 1.810 valve is affecting the results. The chamber wall definitely shrouds the exhaust valve more on the WR than the WL, which I believe helps explain the poor flow on that side of the equation. Also, both of the valves run out of space between valve and the roof of the chamber at the higher lifts, limiting flow. I expected much more from the WR.

And if that is not depressing enough for the WR aficionado, consider that a WL with a bigger intake valve and good porting will flow 124 cfm on the intake and 133 on the exhaust at .400" lift and one might begin to wonder what in the world is going on. But of course there are many other factors involved in performance, and I will only attempt to address one more of them here today.

Bottom line (in my opinion), is that the superior performance of the WR motors did not rely on the valves and ports as much as one might think. Degreeing the WR cams, on the other hand was quite revealing also, but in a much more positive direction. The cams are the WR flat tappet variety, which I had reground by Leineweber to stock WR specs. Here is what I found:

Intake Opens:
seat - 57 BTDC
.020" lift - 38 BTDC
.050" lift - 26.5 BTDC
.053" lift - 25.5 BTDC

Intake Closes:
seat - 70 ABDC
.020" lift 47 ABDC
.050" lift 36 ABDC
.053" lift 35 ABDC

Exhaust Opens:
seat - 83 BBDC
.020" - 62.5 BBDC
.050" - 51.5 BBDC
.053" - 50 BBDC

Exhaust Closes:
seat - 46 ATDC
.020" - 21 ATDC
.050" - 11 ATDC
.053" - 10 ATDC

This gives a duration (measured at .053) of 240 degrees, intake and exhaust. By way of comparison, a set of stock WL cams which I had reground by Jim to his .360 lift and +10 degrees duration, check out to only 208 degrees at the same .053 checking point. But as informative as that spec is, the real eye opener is only revealed with a plot of the cam lobes. The "hot" reground WL cams held the valves within .010 of full lift for 25 degrees, both intake and exhaust. The stock WR cams held the valves in that same range for 50 degrees! Clearly, it would take a lot of flow increase from the WL cylinder to make up for the amount of air that the WR valve is able to pass with so much more time to accomplish it.

Oh, and if you haven't already figured this out, it takes a gearhead mentality bordering on the insane to spend so much time analyzing a 60 year old racing motor. What is really scary, is that I am not alone; there are others out there.