Tuesday, January 25, 2011

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.

8 comments:

Anonymous said...

Lee,
There are also some of us out there who hold this type of fanaticism in awe ! This post makes wonder how serious the small bore on our El Bonneville Knuckle motor will detract from our dual carb flow numbers. BTW did you get the chance to look for the numbers that you recorded for the Knuckle Dragger and other Knuckleheads that you have done ?

St.Lee said...

John, I am sorry. I forgot. I will email you with some figures

Mark said...

Lee, Do you think it would be worth the effort to add the larger valves to the WL cylinders and having some cams ground to the WR specs. or maybe trying the WLDR cams?

St.Lee said...

Hi Mark, I really don't have any specs on the WLDR cams, so I can't give an opinion on them. I would assume they would be a nice upgrade from stock WL cams though. The secret to the WR flat tappet cam lies in the flat tappet which allows the valve to "dwell" at full lift for so long. You could not get similar specs with a reground cam using roller tappets. Enfield Racing has a bunch of different cam lobes that he is manufacturing, but I don't have the excel program to view it. A bigger intake valve would definitely worthwhile.

Garand69 said...

Lee,

Thanks for the nice comparison post. I agree those numbers at first look crazy when you figure that the WR had nearly 60% more HP than the WL. While I agree that the Cam was a major player in the equation, I also believe the heads work as "planned" as well. I don't believe much thought to big HP numbers was applied to the WL's original design. But when the Company gurus started trying to get the most out of it, they may have realized that they were way heavy on EXH compared to INT flow numbers. Doing a quick crunch on Intake/Exhaust flow ratio, the WR has it right at 85-87% of the INT flow versus 87-112% on the WL.

One of the reasons I think the factory was paying attention here is that the INT. Valve Lift/Dia ratios are the same on the factory cams/valves, which leads me to believe that somebody had decided what that number should be for a Flathead (at the time).

The other thing I find very interesting is that the EXH port should scavenge better than the WL due to higher port velocity. I am basing this on the excellent low lift numbers @ 100", which in theory would create a stronger pulse on initial cylinder blow-down, then the smaller flow number at the higher lifts may maintain EXH port velocity.

The valve shrouding on a flathead is not as detrimental compared to a wedge or hemi head, because the flow is more off the side of the valve rather than around and past the valve. So going with the larger valve, despite some shrouding, offers much better low-lift numbers, and for the 45, I would think that would be a good thing.

Would do you think, am I nuts, or possibly on track?

Thanks for a great blog.

Dan H

St.Lee said...

Hi Dan,your ideas certainly have merit, and in fact are good food for thought. One thing to keep in mind concerning the percentages/low lift flow/etc, is that they had no flow bench to work with, so, to the best of my knowledge their methods had to be intuitive coupled with "cut and try."

The exhaust ports show signs of being "worked" but not to the extent of the intakes, which may lend credence to your theory. On the other hand, the flow discrepancy between WL and WR exhaust could just be due to the limitations of this particular casting, and/or the valve depth from multiple valve jobs. Only way to know would be to test multiple WRs (and WLs) on a flow bench - something not likely to happen unless I get an influx of work on them.

You are right that the majority of the flow on a Flathead is on the bore side, and that a larger valve will especially help low lift flow. However, that is just the low hanging fruit, and while that is the first place to pick, for maximum performance I think one needs to maximize the flow on the back side and over the top of the valve. This of course needs to be balanced with loss of C.R. and maybe finding a place to make up that compression.

If only someone would pay me shop rate to spend all the time needed to research all this stuff, I could get it all sorted out.

Unfortunately anyone willing to spend that much would likely find someone brighter than me to do the work. :)

Bill Parnell said...

I'm looking for a way to contact the old swiss owners of flathead power I'm Zach Ellis my dad was benwa who raced big twin flat head at Bonneville ecta producing 7 land speed records he has since passed on I'm playing catch up as I plan on following his lead please contact me at 417 2346147. Mail@ 5667 hwy 13 Brighton mo 65617

St. Lee said...

Hi Bill, the founder of Flathead Power is back in business in Sweden under the name Flathead Poverty (showing he has kept a sense of humor through his trials and tribulations). His web site is:
http://www.flatheadpoverty.com/
Good luck with your project!