We measured Redblock cam valve events; here's what we got.

[Fred Gwynne]

The hushers will not affect the max lift figure. They will make shimming for clearance a little more difficult, I usually discard them. I did run a new set for a while with no perceptible difference in sound.

Yes, the "max lift" figure you would get should be extremely similar to the value I have listed. Please be reminded that the figure I have listed is "as installed". Valve events are measured off the lifter bucket, not on the cam.

Thanks very much.

 

[Lord Tentacle]

Yes, I'm sure about 0.040" giving 4 degress retard. Years ago when I cut my first head I had read that this was the case and measured to confirm. If you go more, it may not be a linear value, but at least at this point it's accurate.

Outside diameter of the cam pulley is just over 4.46" so I'll use the smaller value of 4.46 which makes this worse...

4.46 times Pi is 14.01 which is the outside circumference of the pulley
So each * of wheel is 14.01/360 or .039"
When you bring the head down it shortens the distance from the head to the intermediate shaft by a distance
there is a slight change of angle as well which reduces the actual amount of loss of timing because the angle is increasing

End result is your math is wrong
As above... Laws of math and physics say .040" == 1* at most

 

[shoestring]

Outside diameter of the cam pulley is just over 4.46" so I'll use the smaller value of 4.46 which makes this worse...

4.46 times Pi is 14.01 which is the outside circumference of the pulley
So each * of wheel is 14.01/360 or .039"
When you bring the head down it shortens the distance from the head to the intermediate shaft by a distance
there is a slight change of angle as well which reduces the actual amount of loss of timing because the angle is increasing

End result is your math is wrong
As above... Laws of math and physics say .040" == 1* at most

I sincerely appreciate being challenged, it makes me go back and check my work.

This was a measurement I took that looked to confirm the rumored 1? retard per 0.010" of head milling, which I found to be as accurate as I could using my $25 Summit degree wheel. It was not, on my part, a calculation. Two things you may be missing is that decking the head shortens the belt on both the leading and trailing halves, so you need to double the value you cut the head. Additionally, the relative measurement is with regard to CRANK position, not cam position, and the circumference of the crank gear should be half that of the cam gear. If you work that math, the 4? is about correct.

 

[leinex]

D Cam Experiance

Hi Guys

I've tested the D cam from a marine penta engine in my turbo setup with different turbos ( mainly Holset HX40 / HX35 / China Clone HX40).
I can say this cam i a beast in the middle and higher RPM range a bit sluggish in on the low RPM's - preffered for manual trans i think.
maybe 4-5 degree retard was benefitial - otherwise stock engine with 531 head with cleaned ports.
So when you can catch a D cam - go for it!!!

Cheers
leinex

 

[klr142]

Very cool thread, thank you for your time! I haven't looked at anything yet, other than to read through the posts.

On the topic of retarded cam timing with shaved heads, all I can say is that on my motor(when shaved .040" and with a .040" MLS gasket), my car ran like I expected it to with the cam timing straight up(any cam I tried, K, H, RSI Stage 1 NA and ENEM K13). I typically run cams 2-6? advanced to bring the powerband down for better around town use. If I have the cam gear set at 6? advanced, it totally kills the power above 5500-6000rpm. This suggests in my real world experience that the cam timing isn't as far off as one would think based off of what people say(.010"/1?). Or if it is, I like running camshafts retarded(but before the head work, I ran cams advanced a couple degrees with similar success as well, so..........).

Also, when suggesting that there is a cam timing issue with even more shaved heads, such as .080" off and using a belt that's a tooth shorter, why should I advance the camshaft a tooth to compensate and make the timing marks NOT line up. I wouldn't do that, a timing mark is still going to be right(note, the cam timing should be accurate/straight up at .080" off with a stock headgasket).

So, basically, in my experience, in the real world it doesn't make that much of a difference and if you are always shooting for the timing marks to be close to normal, it's fine. You can adjust the cam timing from there to suit your use and desired powerband, but it does NOT have to be set "x amount advanced" if you have "x amount shaved/thinner headgasket" to work "right". FWIW.

 

[shoestring]

Very cool thread, thank you for your time! I haven't looked at anything yet, other than to read through the posts.

On the topic of retarded cam timing with shaved heads, all I can say is that on my motor(when shaved .040" and with a .040" MLS gasket), my car ran like I expected it to with the cam timing straight up(any cam I tried, K, H, RSI Stage 1 NA and ENEM K13). I typically run cams 2-6? advanced to bring the powerband down for better around town use. If I have the cam gear set at 6? advanced, it totally kills the power above 5500-6000rpm. This suggests in my real world experience that the cam timing isn't as far off as one would think based off of what people say(.010"/1?). Or if it is, I like running camshafts retarded(but before the head work, I ran cams advanced a couple degrees with similar success as well, so..........).

Also, when suggesting that there is a cam timing issue with even more shaved heads, such as .080" off and using a belt that's a tooth shorter, why should I advance the camshaft a tooth to compensate and make the timing marks NOT line up. I wouldn't do that, a timing mark is still going to be right.

So, basically, in my experience, in the real world it doesn't make that much of a difference and if you are always shooting for the timing marks to be close to normal, it's fine. You can adjust the cam timing from there to suit your use and desired powerband, but it does NOT have to be set "x amount advanced" if you have "x amount shaved/thinner headgasket" to work "right". FWIW.

Pretty much agree, and we've proven it on the dyno. With increased compression ratio, moving the cam around a little bit with regard to timing affects the power curve little. On a low comp engine, it probably has greater effect. Still not a lot, if I were to guess.

Anybody wanna volunteer me a cam to measure up? I'm ready for one or maybe two. And I haven't forgotten about the B I have, but after that my personal supply is exhausted.

 

[TurboDenny]

Pretty much agree, and we've proven it on the dyno. With increased compression ratio, moving the cam around a little bit with regard to timing affects the power curve little. On a low comp engine, it probably has greater effect. Still not a lot, if I were to guess.

Anybody wanna volunteer me a cam to measure up? I'm ready for one or maybe two. And I haven't forgotten about the B I have, but after that my personal supply is exhausted.

I have a mystery cam if you're interested. Pulled it out of a junked 740 turbo. It's definitely aftermarket, but there are no markings to indicate what it is or where it came from.

 

[klr142]

I have a mystery cam if you're interested. Pulled it out of a junked 740 turbo. It's definitely aftermarket, but there are no markings to indicate what it is or where it came from.

Nothing, what so ever on the back of the cam where everyone in their right mind at least scratches something into it? Pictures?

 

[TurboDenny]

Nothing, what so ever on the back of the cam where everyone in their right mind at least scratches something into it? Pictures?

There is a thread on it with some pictures.

http://forums.turbobricks.com/showthread.php?t=325881

 

[klr142]

Crazy! Send it in for measuring.

 

[shoestring]

I like mystery cam. Send it. I'll pay to ship it back.

 

[shoestring]

Happy 4th of July! Added Volvo B grind and the mystery cam as provided by TurboDenny. Thanks very much for that! Given that the cam has no markings except a blue stripe and is slotted, we're of the opinion that this is an IPD Turbo cam, which I actually kinda like as an N/A cam, given the specs. If anyone has input on it, please feel free. As I said, it's just our best guess.

At this point we're out of cams, except for a T that's in a car right now. If anybody wants to throw a couple at me for the next time I have time (these two took about 5 hours start to finish), that would be great. Don't send me something you're going to need back right away, I just can't get to it that quickly.

Enjoy!

 

[TurboDenny]

Well that's some good news I suppose. That cam was out to the trash until you decided to measure it. Glad I sent it your way!

 

[linuxman51]

Happy 4th of July! Added Volvo B grind and the mystery cam as provided by TurboDenny. Thanks very much for that! Given that the cam has no markings except a blue stripe and is slotted, we're of the opinion that this is an IPD Turbo cam, which I actually kinda like as an N/A cam, given the specs. If anyone has input on it, please feel free. As I said, it's just our best guess.

At this point we're out of cams, except for a T that's in a car right now. If anybody wants to throw a couple at me for the next time I have time (these two took about 5 hours start to finish), that would be great. Don't send me something you're going to need back right away, I just can't get to it that quickly.

Enjoy!

enem C2 sitting on the bench, it's broken (rear thrust collar), but not sure if that matters for just measurements.

 

[shoestring]

enem C2 sitting on the bench, it's broken (rear thrust collar), but not sure if that matters for just measurements.

Nope. As long as it has #1 and #2 cam journals on it, we can use it.

Send to

Dan Samodai
7 Highland Terrace Apt A
Beverly MA 01915

Please make sure to include a return address. I'll pay to send it back.

This goes for anybody.

If you look at these cam profiles, the factory cams all have a ramp speed of 0.050" per 10?, pretty much across the board. I'd like to see what one of these true aftermarket performance cams looks like. I had a KG7 but never measured it, but I can tell you the duration over 0.300" was WAY longer than anything else we'd seen.

 

[linuxman51]

Aight. I got permission from it's owner, I'll get it headed your way soon. It's a lumpy bastard I can tell ya that lol

 

[Chilm]

You are my hero

 

[Stiggy Pop]

Can I get you to do an RSI Stage 3 cam for me in a somewhat expedited fashion? Be willing to pay a few bucks as it's now a service I need.

 

[redblockpowered]

Send to

Dan Samodai
7 Highland Terrace Apt A
Beverly MA 01915

Please make sure to include a return address. I'll pay to send it back.

This goes for anybody.

I'd like to note to any potential camshaft senders that this is no longer the correct address.

 

[shoestring]

I'd like to note to any potential camshaft senders that this is no longer the correct address.

Good point. New address is:

Dan Samodai
12 Elmwood Rd
Swampscott MA 01907

Again, if you want to just send them to me, I'll know what to do with them, and I'll pay to send them back. Please hold until Spring though. Brr.