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Old 11-27-2017, 09:48 PM   #1
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shoestring's Avatar
Join Date: Jun 2009
Location: Swampscott, 01907
Default We measured Redblock cam valve events; here's what we got.

So for years and years now, there's been no reference as to any kind of real, hard data concerning the redblock cams as far as, well, anything. The duration figures we have, what lift value is it? How does one manufacturer compare to another? If you do get some kind of info, it's often at some mystery measurement. As someone who values data versus speculation, it's been a challenge.

Anyways, we took matters into our own hands and measured up 5 of the 6 cams we have access to and put it all in a Google sheet which I'll share here. Here's what we did:

Installed each cam in my '91 245 as per the service manual and shimmed #1 intake and exhaust to 0.015" clearance. Note: this engine has had .040" trimmed from the head, but I have previously measured what this does to cam timing, and as rumored it absolutely retards timing 4 degrees. ALL TIMING MEASUREMENTS HAVE BEEN CORRECTED TO AS THOUGH THE ENGINE WAS ABSOLUTELY STOCK. I have a stock head gasket in this car so it does not come into play.

We measured lift using a dial indicator on the shim bucket. The first data point is at 0.001" lift, what we called "first movement", you could call seat-to-seat, though that would be just before any movement at all (too hard to be very accurate). We then recorded at 0.005", which, if you add in the 0.015" lash, would equal 0.020", or 0.5mm, a common Euro data point for some manufacturers. Next was 0.025", which is 0.040" or 1mm when you add the lash figure, another Euro data point. The last of this style of measurement was 0.035", 0.050 after adding in the lash, and everyone should be familiar with this. We then measured every 0.050", starting at 0.100", figuring that would be more relevant to cylinder head flow data points if you have them. We recorded intake and exhaust centerlines and the lift values we got (again, as installed, not gross lift), then went down the back side of the lobes recording the same points so you could calculate duration figures at whatever lift point you are working with. Finally, we recorded intake lift at TDC, which the Europeans also seem to like.

A couple notes here. First, these cams are all used, so there may be some variance from original, brand-new camshafts, though the IPD cam has few miles on it. Second, I've done this type of thing a lot of times over the years, so I'm confident in the numbers we generated. If something didn't look or sound right, we went back around (ALWAYS clockwise!) to check it again. Even if we were comfortable with what we got, we went back and randomly checked a couple points on each cam to make sure everything was repeating correctly. If the data's no good, what difference does it make how long it took, or how pure our intentions? Assume a MAXIMUM of 1 degree error, which should have no impact on comparisons for our purposes. Additionally, I occasionally find errors in my CALCULATION, that is, where I added the valve events to get the total duration figure. If you find some, hit me up so I can fix it. I do want to assure the crowd that the measured valve event timing is absolutely correct. When in doubt, use those numbers.

Anyway, for now we've done the factory Volvo A, D, H (oh yes I did), and K, as well as the IPD "VX". I have a B and a T which I'll get to, but it takes almost 2 hours to set it up and about 45 min per cam, so it's pretty much an all day affair.

Hope you get into this, we enjoyed doing it so that we could share it. When you click the link, give it a minute to load. There are tabs at the bottom for each cam that take a second to come up.


Last edited by shoestring; 06-10-2019 at 09:24 AM..
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