TA-Perf (Schneider?) Cams are of any quality?

Hi, I posted another thread earlier here. I'm rebuilding my 1967 430 for the second time. In the initial build, the TA 212 cam went flat within a few hundred miles. That cam was made by Schneider Cams. Now for this rebuild, I decided to go with a smaller cam, TA 112. I can't say if it was made by Schneider or not. Also, I decided to upgrade to a double-roller timing set from TA, made by SA Gear. Now I'm degreeing in the 112 cam. With the dots aligned, I get either 12 degrees retarded or 3 degrees advanced from the specified 108 degree intake centerline specifified, that is, 120 or 105 degrees (one tooth either way = 15 degrees). There's a slight clerance in the two bolt holes in the cam gear, so taking up all the slack I ended up at 106 degrees, that is two degrees more than specified. I measured both the intake opening point @.050" and intake centerline, and I measured intake centerline by the before+after/2 method. Both give me 2 degrees advanced from spec. Intake opening should be 3 degs ATDC @ .050" and 108 centerline, and I get 1 degs ATDC @ .050" and 106 degrees centerline. Close enough, I think.

Then I go check intake #6, and get 6 degs ATDC @ .050" and 111 degrees centerline! I double check this and then check #1 again, and verify my previous measurements were correct. WTF! There's a 5-degree difference in the timing of #1 and #6 cam lobes! I don't think I'll take my chances with this cam. Have you ever got similar variation? Do you know if the Lunati cams, available at Summit, are better?

 

And before someone asks about it, yes I took the readings always rotating the engine in the same direction, the way it runs.

 

You probably covered it, but did you make sure that the timing chain always stayed tight on the tension side and didn't roll over the top of the lobe and then pop? It's difficult to grind individual lobes out of time with each other, but not impossible. At this point you have to choose to either bail on this cam and try another one, or run the numbers on each lobe to find out what the grind is actually like.

 

Tom, what do you mean by "didn't roll over the top of the lobe and then pop?"

 

Chain slack can allow the cam to pop forward after the lobe peak passes the lifter baseand thus alter the lobe centerline calculation. The actual error will vary depending on number of valve springs or pushrods in use, spring pressure, and chain slack.
When I run a cam, I like to have all the pushrods in to balance lobe kick as much as possible and I hold the cam back when turning the crank if there is any chain slack at all. I also run the numbers at least twice to check for consistency.

 

I see. I have a bare block with only #1 piston in. I'm resisting the cam movement with one hand, while rotating with another.

 

The cam probably didn't go flat because of anything the cam maker lacked.
'If' it is indeed off from lobe to lobe, I would take that up with whoever you purchased it from and have them rectify it.
I would trust a Schneider over a Comp or Lunati.
Most of these companies use the same cores, and Schneider grinds in house.
Companies like TA aren't going to mess with low quality cores and grinders.
One wouldn't think they choose them for price reasons alone, sacrificing quality to make $15 more bucks a piece.

Side note...if you are showing signs of detonation contributing to related failures in your other thread why would you go smaller on the cam specs? That seems counterintuitive to the project.

 

On your intake center line method, it sounds like you took the measurements at 50 before max lift and 50 after correct?

The good thing about this method is if you get numbers like this, try going at 100 or even 200 before. Some ramps of cam lobes are not the same shape on each side. Meaning you could be getting from one measurement to other faster and it will look like the centerline is in a different spot.

I prefer to run the open and closing numbers on a few holes for both the intake and exhaust valve and take kind of an average. This allows me to only have to rotate through once for the intake and exhaust and with a couple of dial indicators at the same time I can quickly check several valves at the same time.

This will also let you spot if only 1 is out.

But I have almost never had a cam measure spot in on the openings and centerline. I'm sure some of this is the angles looking at the wheel can cause a slightly different reading. The diameter of the wheel will effect how easier it is to read.......larger wheels have more space between the numbers.

 

New data. Okay, so the specs call for 108° Intake Centerline and Intake Opening point @ .050” 3° ATDC. Setting the #1 intake lobe to this spec, I find my #6 lobe to open 7.5° ATDC with centerline at 112.5°. Then I check all the other lobes, and find #1, 3#, 5# and 7# spec all the same, 3° ATDC opening and 108° centerline, while 2#, 4# and 8# measure 7° ATDC and 112° centerline. So basically there’s a four degree difference between banks, while the #6 is off 0.5° from other lobes of the same bank, which could be within the accuracy of my measurements. What am I looking at here? Could there be a factory production tolerance in the orientation of lifter bores that could explain this? Should I just split the difference between banks to 106° for left bank and 110° for right bank? I’m actually able to do that with my adjustable timing set.

I measured the centerline by taking the readings at a certain lift before and after the max lift. Even if the lobe design was asymmetrical, it should give the same reading for each lobe. And the opening point shows the same difference. I took the measurements without cam lube, using the same lifter.

I live in Finland so sending the cam back to TA for inspection is not feasible.

 

At this point I would call and talk to Tim or Mike at Ta and let them advise you as to what they think. Be interesting to hear

 

Yes, that's possible.

Who said anything about doing this?
I would CALL whoever you purchased the cam from, and TA.
They will advise you on your measuring methods and what to do IF something's wrong with the cam.

 

If you split the difference between the 2, you'll have one bank retarded and the other bank advanced! Perhaps this will work out to be the best of both worlds? The bank that is advanced will give you more low end torque and the bank that is retarded will give you more upper RPM HP? Maybe this is how they designed it to be to do what I wrote?(they didn't figure anyone would check more than one set of lobes!?)

OR its gonna run like a turd with the cam grind all over the place? Either way I wish you would try the cam out and let us know how it runs being SO OFF!! Perhaps you'll start a new trend, 4 cylinders for low end torque and the other 4 for high RPM HP!? But maybe they should be spread it out between the 2 banks so it runs smoother?

 

This is the point where you call TA and they will tell you to send the Cam to Schneider even though TA sold you the camshaft. this is one reason why guys are buying Buick cams from Bullet and Scott Brown instead.

 

I learned over 25 years ago to check cam lobe lift and runout using V-Blocks. Recently after enlarging the Right oil feed galley on a 455, I noticed the lifter feed hole of the exhaust lifter bore of #8 looked visibly smaller than the rest. I loaded lifters into the Right bank and ran a straight edge front to back along the lifter bodies. Sure enough there was a measurable gap at the #8 exhaust lifter (positioning that lifter bore to the outside of the block). Looks like GM didn't position the lifter bores exactly in line which may equate to different cam timing variables (at the vary least it would affect the consistency of the pushrods geometry to each other by the time they reached the shaft mounted rocker arms). This may be what you are experiencing. I haven't checked to see if the lifter bores are inline according to their angles to the cam yet. Maybe JW can verify how often or not this occurs on our blocks.

Larry

 

Reply by Jerry Cantrell of Schneider Cams:
There is a difference in the tappet bores. That’s why most pro racing teams have their tappet bores trued . I would split the difference and run it.

I think I'm going to follow his advice and split the centerlines 106/110

 

At this point it's all you can do unless you wanted to have a cam custom ground to make the difference.......basicly 2 patterns but then you could have each ground to be 108. The issue with this if you ever wanted to advance it you would have to have another custom ground. But if someone was having a custom ground if their motor happened to be the same way that would be the time to address it.


Honestly the +/- 2 degrees mostly likely could only been seen on a dyno. I have run my 308s any where from 112 to 104 centerline and it changed nothing as far as the car ran......it was just a lot of work and gaskets.

 

You could slide another cam in your block to verify, if you were curious.

 

Jyrki,
My son and I were installing a cam in his engine a few years ago and ran into this same problem. I learned a few things that day. The cam was a .550"-231"-113' LS straight pattern hyd roller cam. I degreed in #1 cylinder, it cam in as 230' int, 234' exh on 111' LS. We did it many times it varied a little 229-235 or so, still 111' Lobe Sep. I was getting a little upset, because it was to be a straight pattern cam. Same lobe on both intake and exhaust. We degreed #6 cylinder, it cam in at 231' on 113' LS both intake and exhaust. Now I was even more upset that there using the same masters but they can not get the lobes all the same. Michael had known that I had purchased a Cam Pro cam checker. He asked if I would like him to set it up and check this cam, sure lets do that. Well, to my surprise when we checked the cam lobes on #1 cylinder they also came out at 231' on 113' LS just like #6 cyl. Thats what the cam card said it should be. We put the cam back in the block and degreed #1 again. 230'-234'-111' LS. That's when I realized the Buick blocks also have problems with lifter bore placement. We have struggled with this scenario many times over the years in many Buick engines, I always felt the Buick blocks were better than the others machining wise but I was wrong. Without the means to check the cam independently you have no idea whats really wrong. The block is NOT a good means to verify a cam. Even though the cam checked out correctly at 231'-113'LS the #1 cylinder at least will see it as 230'-234'-111'LS. One bank was pretty good the other bank was off on this block as well, like yours. Engine ran great, but without truing the lifter bores there was not much that could be done. Our cam was ground by Schneider. Most all current cams are ground by Crower for TA Perf today, Schneider was having trouble keeping up, got tired of back orders. Hope this experience helps you and others.

 

You would see a similar variance with the next cam using the block and the light bulb would glow.

 

Well I sure learned something from this thread