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

I have some AQ145A parts here that I just picked up, and the cover that goes over the air filter says .25mm-.45mm cold for the valves, or .010"-.018", and that's with an H cam that begins ramping off of the base circle at more than 360°.
 
OVERDRIVE said:
I have some AQ145A parts here that I just picked up, and the cover that goes over the air filter says .25mm-.45mm cold for the valves, or .010"-.018", and that's with an H cam that begins ramping off of the base circle at more than 360°.
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For gits and shiggles I looked up the clearances for an aircooled vw race, performance cams, Baja cams, etc… 0.006” in and out. If using lash caps and chromoly pushrods they recommend zero lash when cold (this is surprisingly common with flat tappet push rods and some direct acting rockers) and when warm you get the proper clearance. It’s also easy to set as you don’t need feeler gauges.
 
culberro said:
For gits and shiggles I looked up the clearances for an aircooled vw race, performance cams, Baja cams, etc… 0.006” in and out. If using lash caps and chromoly pushrods they recommend zero lash when cold (this is surprisingly common with flat tappet push rods and some direct acting rockers) and when warm you get the proper clearance. It’s also easy to set as you don’t need feeler gauges.
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VW engines expand a lot though, which is why the tiny 8mm head studs only get something like 21ft/lbs. The cylinders will expand more than the push rods. .006" is the spec most people follow, but there's some original documentation that shows .004" recommended. It's a different engine but still good to consider.
 
How about mechanical cams in a small Chevy? You're talking 0.030" at the valve, so 0.020" at the cam/lifter interface? This is some old school grinding though, nothing modern is like this. I kinda thought that maybe Volvo was thinking "Well, if they never adjust the valves, and they start to sink a little, there's margin for error with a big lash to start with". I don't know.
 
If I had a nickel for every time I saw someone write, "A VX3 is a VX cam advanced 3°", I'd have enough to buy a geniune Volvo VX3. So I did!

I had suspicions that the VX3 was not actually advanced. This is evident by the fact that Volvo retarded most of their cams a few degrees, especially emissions cams, and I don't know why the VX3 or VX would be an exception.

I mocked up this VX3 in a cylinder head with a snug .015" of lash on both sides. I measured lift off of the valves underneath. This method was reliable to within a degree or two. I spoke with Cam (no pun intended) before doing this, and he said that he and his dad degree the cams in-car, I found that the timing belt added enough room for error that I chose to rather do it off of the cam gear. I copied the style of spreadsheet from the master Google Sheet with all of the specs. It will have to be up to shoestring to accept this cam card as canon.

Volvo lists intake and closing events for the VX cam, and when you decode them, it gives a 109.5° lobe separation angle, 111° intake lobe centerline, and 108° exhaust lobe centerline. The IPD "VX" that IPD sells is a 111° LSA, 115° ILCA, 107° ELCA. While the lobes themselves seem correct, where they are is strange. The IPD "VX" is nowhere near "advanced", its retarded 2.5° from what Volvo says the VX is, the exact opposite of the internet myth but we knew that already.

The genuine VX3 is pretty close to the IPD "VX", with a large 115° intake centerline, but with a wider 111.5° exhaust centerline, giving it a 113.25° LSA, pretty much ground -2° (-1.75°) like the A,B,K etc.

My consensus is that the VX3 is a VX with a 3° wider LSA, ground on the same -2° baked in retard. This is based off the the listed opening and closing events and I'm not too sure how much weight I want to put in those, but it adds up. It will be nice to try this cam advanced 8° or so, I bet the wide LSA and advance can get the exhaust open sooner, and thus with more energy still in the chamber to help overcome the inherent crutch of a reverse split cam.

TLDR the VX3 is not an advanced VX, nor is it like the one that IPD sells, it is a poopy emissions cam.

Geniune VX3 cam card
 
I could feel in my bones I'd been summoned.

How did you find TDC? I have a couple different ways you could do it with the head off the engine but I'd like to see your methodology here. Ultimately, it doesn't matter because you can put the intake centerline wherever you want it, but it'd be nice to know for those who would just jam this in there and let 'er rip.

I do enjoy dispelling internet lore. Great job in finding that the "3" in VX3 may in fact have some relevance, but not in the way that's been understood.

I don't see why this shouldn't be accepted with the rest of them, pending TDC clarification. As Cam and I explained from the start, our dial indicator is only accurate to 0.001", and at low lifts that could be a lot of cam timing. We've also made several corrections and confirmations throughout the years, so we acknowledged going in that this would never be meant as Moses delivering the 10 Commandments of Redblock Cam Timing. If thou hast LH2.4 Thou shalt run the V cam and none other!!! (Lightning bolts and Charleton Heston and such).

I appreciate you keeping the format. I'll look it over more seriously this weekend and probably add it to the master sheet.

I see a use in this where I would advance the snot out of it and use it in a small exhaust turbine housing application with a bunch of boost. I like the low overlap figures for that type of setup.

Good work, gang. We should have this all figured out by the time there's none left!
 
shoestring said:
How did you find TDC?
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B21 valve cover on a B21 cylinder head, it has the notch. Cam gear was bolted on, I had a timing wheel on the cam gear too indexed to the TDC notch on the gear. Regardless of if this is 100% TDC, it was repeatable enough to calculate the LSA.
shoestring said:
I do enjoy dispelling internet lore. Great job in finding that the "3" in VX3 may in fact have some relevance, but not in the way that's been understood.
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Thanks, I really don't know what the 3 could mean.
shoestring said:
I don't see why this shouldn't be accepted with the rest of them, pending TDC clarification.
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I will be installing this cam in my car with a very minimal head resurface and stock gasket, so I can double check some measurements to confirm TDC
shoestring said:
I'll look it over more seriously this weekend and probably add it to the master sheet.
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I will say my computer died while doing this and I forgot to get the .050" overlap measurements. My cam is still mocked up, I can get those later. Also I calculated out the centerline angle for all of the duration figures and it's within a degree, sometimes a degree and a half all the way up so I feel pretty good about how reliable this data is.
shoestring said:
I see a use in this where I would advance the snot out of it and use it in a small exhaust turbine housing application with a bunch of boost. I like the low overlap figures for that type of setup.
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In Europe you see people +T B230FB's often. The 531 exhaust flows much better at low lift than the 530. If you strictly look at opening and closing events and disregard the immense amount of retard, it's kinda like if you had a V on a 109.5" LSA, except the exhaust valve closes 6-8° sooner. Advancing the snot out of it would also open the exhaust earlier and probably help evacuate the cylinder with the minimal duration. If that was the case I'd want a 38mm exhaust valve.
 
mertz said:
Have you guys had a chance to measure that Classic Swede "T25" cam I sent a year ago?
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Just added! Thanks so much @mertz for sending this and sorry it ate itself in your car.

Measured this and the K cam at zero lash - you'll see the sheets are a lot more detailed, stopping at each thousandth in the "valve lash" range before continuing as normal.

K cam was timed as per the B23 factory rebuild manual, then the Classic Swede cam was installed with the gear timed the same way. Did this on the racecar so there would have been a lot of cam timing question marks otherwise. The car has some 3 mm (a little less but close to that, dad claims he has the correct number somewhere) off the head, a .036" Cometic and an STS adjustable gear.

Worth noting that the gear needed 6.5 CAM degrees advance to restore correct timing, or 13 crank degrees.
 
I want to clarify the difference in how we measured the cams today vs how we did it in the past. Previously, we set the lash to 0.015" and then took our measurements from there. As I was recording the data from the RBP FRC a few weeks ago, it occurred to me how much of a difference even half a thousandth could make, say if I didn't get BANG ON 0.015" lash, which is probably the case for most of them. @culberro had mentioned that he would have liked to see multiple lash points displayed so that you could get a good idea how much you could vary the seat-to-seat timing with different lash settings. He may have even mentioned just setting the cam to zero lash and then take all your measurements from there, if not, it was my own thought then. Anyway by chucking a honking big shim in there (5.00mm) we set the cam to zero lash and eliminated another variable.

Next, we had to figure out what the baseline setting should be for this head with so much taken off, with the adjustable cam gear, MLS head gasket, etc. The only factory cam we have is a K, so we used the info in the Greenbook that says that at 22.6 degrees BTDC, the intake valve should be open 0.5mm. You'll have to be happy with 0.5mm at 22.5 degrees because that's the best we can do. We had to advance the cam 13 degrees to get it to that measurement. That's 13 CRANK degrees, 6.5 cam degrees. This head has a critical dimension of 143.3mm, 2.8mm shorter than advertised 146.1 out the box. That, combined with the 0.036" head gasket, means that it's a total of 0.121" shorter, and took 13 degrees to correct. Now, I don't know how accurate that 146.1mm standard head height number is for all heads, and I don't know where a stock cam gear lands you. My memory says that many years ago I checked this and a stock cam gear is 1 degree advanced, which kind of makes sense in that if you mill the max factory allowance of 0.020" off of it, it'll retard a couple degrees but keep it in the ballpark of zero.

We kept the original K cam card and added today's as a new one, that way you can draw a comparison. In general, it's close enough. I may redo the Jones Cam that's in the car now, and it occurs to me to see how the additional clearance may affect the specs at higher lift points also, although if I had to guess I'd say it wouldn't be much.

The T25 we just installed in the engine like most people would do, keeping in mind that the cam gear was set to factory baseline. It gives a crazy intake centerline of 121 degrees, which I can't imagine anyone would run. I mean, it would run, but it would probably have some weird operational characteristics or powerband. I don't know. In general, from a specification standpoint, we don't hate it. We talked about it a little bit and decided that if you asked whoever spec'd it what their thought process was, they could probably explain it to you. You may not agree with them, but that's a different discussion. The Jones cam I have was ground 11 degrees retarded, the RBP was about that or maybe a couple more, and it looks to me like this T25 may also be ground 11 retarded: a 110 intake centerline sounds a lot more like what you might expect. I'm not sure what's up with this, but I can't emphasize strongly enough that if you're going to run a non-Volvo camshaft, you have to degree it in. Otherwise, you're just shooting into a dark room.

You can compare lift points from one card to the next: when we were measuring today, if we wanted a lift at 0.200" figure, we took the reading at 0.215" so that the 0.015" valve clearance is built in.

Finally, you can find the ones we did with zero lash labeled as such, along with being underscored in green.

Apologies to @mertz for taking so damn long to do this, it was probably pretty frustrating to ship this to us from overseas and then wait for a year plus to get the result. It took us about 4 and a half hours to collect this data on two cams, and I didn't even finish putting it back together so that it runs, I had other stuff to do. We are annoyingly thorough about all this stuff that we do, which is probably why I have so few hobbies.

Check them out, let us know what you think. Ask questions, make suggestions!

Thanks

Dan
 
I'd like to thank @shoestring and @redblockpowered for their time and efforts in measuring the T25 I sent across. I appreciate it isn't a 2 minute job to measure these cams and that this measuring is a real service to the community.

Very interesting to see that it's basically a VX3 camshaft that as I understand, isn't really that geared towards being a performance cam?

I ran the T25 cam on a factory cam gear but it's been so long since I drove it I can't really make definitive statements on drivability/powerband other than I recall it being ok down low, a bit of a dip somewhere in the mid RPM and pulled fairly well at higher RPM. Overall, I'd say having the V cam again in the car for the past year, it's a much better all rounder and consistently pulls harder across the RPM range. Is that fair to say or am I recalling poorly on the T25?

@classicswede do you have any input on the cams design? is this a custom grind to your spec or one from Ali Baba that's a copy of the Volvo VX3?

https://www.alibaba.com/product-detail/In-Stock-Adracing-Billet-Camshaft-for_62019867109.html?__detailProductImg=https://s.alicdn.com/@sc04/kf/HTB1MYSIMFzqK1RjSZFoq6zfcXXas.jpg_200x200.jpg
 
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Mertz, what you're describing is what you can expect from a camshaft with a wider Lobe Separation Angle (well mannered off idle, a little soft in the midrange, and revs out strong up top). On a stock head a V cam would perform a bit better than a VX3. I've had my eye on the Alibaba VX, and since it says 110°, and it looks like the IPD VX, I'd say that that's what it is. The T25 is ground on the same 113° LSA as the Volvo VX3 I measured.
 
The billet cam looks like one of the later IPD cams (that also have a... suboptimal reputation). Can't help but wonder if they came from the same source. It's like a V intake lobe with an A exhaust lobe.

Do you remember how long you ran it for?
 
redblockpowered said:
The billet cam looks like one of the later IPD cams (that also have a... suboptimal reputation). Can't help but wonder if they came from the same source. It's like a V intake lobe with an A exhaust lobe.

Do you remember how long you ran it for?
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I think I ran it for around a year? 12k miles? I'd have to check my paperwork.
 
I had until recently a BSRT5+ cam I intended to run in a build that I've since abandoned. This was the spec sheet provided with the cam. Does anyone have any insight into it? I find it strange the official spec is to have it used with an adjustable gear so I wonder if this is actually a cam from another manufacturer that's been adapted to the below use?




BSRT5+.PNG
 
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