After reading this thread:

https://ls1tech.com/forums/showthrea...ighlight=grind

I decided that getting my actual cam specs would be important as to figure out proper set-up and compression. Boy am I glad I did. The cam I ordered directly from comp is similar to Patrick G's cam except with a different LSA and ICL. While his is more focused on torque, mine was shifted more towards the horsepower side as a Z06 vette's light weight isn't as torque dependent compared to an F-body.

So anyway, when I ordered the cam, I told the Comp rep that I wanted a Cam Pro Plus report. Well they had no such thing. What they had was an ADCOLE report which is done on some extremely expensive piece of machinery Called an Adcole Model 911 that is supposed to be extremely precise in it's cam doctoring. The upcharge for an Adcole report was $50 and I went ahead and had it done. There are some very interesting findings as this report does ALL the lobes. I'm going to list the important stuff from the report and comment afterwards.

Cam I ordered: LSK lobed 223/227 .636/.639 114+2

Adcole report:

=====================================
=====================================

Cyl.....LSA......Advance

1 --- 114.02 --- 3.86
2 --- 114.16 --- 4.31
3 --- 114.07 --- 3.97
4 --- 113.96 --- 3.90
5 --- 114.28 --- 4.09
6 --- 114.23 --- 3.98
7 --- 113.77 --- 4.59 <----Think about this one folks
8 --- 113.77 --- 4.46

===================================

Intake Lobes:

cyl ------ .020 --- .050 --- .200 ---- lift

Design-- 249.3 -- 222.8 -- 148.9 -- .3750

1 ------- 250.5 -- 223.8 -- 149.4 -- .3752
2 ------- 250.6 -- 223.9 -- 149.4 -- .3745
3 ------- 250.5 -- 223.7 -- 149.2 -- .3742
4 ------- 251.4 -- 224.4 -- 149.6 -- .3751
5 ------- 251.5 -- 224.4 -- 149.4 -- .3747
6 ------- 251.5 -- 224.4 -- 149.4 -- .3746
7 ------- 251.0 -- 224.1 -- 149.5 -- .3747
8 ------- 251.0 -- 224.1 -- 149.5 -- .3750

=======================================

Exhaust Lobes:

cyl ------ .020 --- .050 --- .200 ---- lift

Design-- 253.3 -- 226.8 -- 152.6 -- .3770

1 ------- 254.2 -- 227.6 -- 152.9 -- .3758
2 ------- 254.0 -- 227.5 -- 152.9 -- .3759
3 ------- 254.6 -- 227.7 -- 152.8 -- .3757
4 ------- 254.7 -- 227.8 -- 152.9 -- .3760
5 ------- 254.3 -- 227.7 -- 152.9 -- .3758
6 ------- 254.1 -- 227.5 -- 152.8 -- .3755
7 ------- 254.4 -- 227.7 -- 152.9 -- .3761
8 ------- 254.3 -- 227.5 -- 152.6 -- .3758

==========================================
==========================================


Ok, so I left out such stuff as Base Circle radius, Base circle runout, lobe taper, and journal dimensions.

As some may have noticed, they ground me a 114+4 instead of the 114+2 I ordered. I didn't expect perfection but being 2 degrees off is just plain wrong. So now i'm forced to have to degree the cam to get my 112 ICL. This is something i didn't want to do. I would have been happy if they could have gotten it between 114+2 and 113+1.

Also take notice of the number 7 cylinder LSA and Advance that I flagged, and even clylinder 8 for that matter. The ICL of those two cylinders is even less and the correspondiing IVC event occurs sooner. This will elevate the DCR in those two cylinders with 7 being the worse. With all the speculation as to why number 7 tends to be the one that comes apart, maybe this is a clue as to why.
It might be possible that comp is machining all their LS cams this way??? It's obvious that I need to base my head milling with this bumpstick on cylinder number 7's DCR.

The only other thing is, for $50, they could have given the actual duration @ .006 lift. This number does effect the DCR calculation in pianoProdigy's DCR spreadsheet. Maybe I can call them and see if it can be pulled off their records. From what I've seen on others Cam Pro Plus reports, the actual duration and Cam card durations are usally a few degrees off with the actual numbers being typically larger.

So other than Comps poor control of setting the ICL and advance, everything else looks fine. It would be nice to see others get an Adcole report and see how other LS cams compare.

Hammer

 

**** that, send it back and get what you wanted. By degreeing it more you will move overlap area away from TDC. You will be gaining more bottom end and losing more top end.

 

You should flow test the heads as well with a flow bench as good as what the OEMS use to calibrate MAF's.why not since you are literally worrying about tenths of degrees which BTW no cam grinder i know of can achieve better results.Not for $400 ( if you wanna spend $2000+ I can point you that direction). Its just the nature of the beast FTRC. I have zero Idea why you think comp ground your cam wrong. I'd bet someone at comp put the order in the system incorrectly for which you should send it back. everybody has a bad day once in a while. However just publicaly bashing a company for building a camshaft to within the published tolerances and a mistake was made processing your order is rediculous. Call Compcams tech help tell them what happened I would be willing to bet they can grind up another camshaft likity split and you drop that one in the mail. Jezz just make a phone call.

 

I can degree it retarded back two degrees and make it what it is supposed to be. Definately not something I want to do though.

Hammer

 

So you don't see an issue with the amount of advance ground in and how they have really over done 7 and 8? Why do you care that I revealed this? Do you think I am the first one to post cam doctoring results?

I'll tell you what, you pay for my cam doctoring in the future and I'll let you decide if the results should be posted.

Hammer

 

did it occur to you that maybe comp does that becuase spintron testing shows that cams twist a shitloads upto sevral degrees when running and they grind that in to help offset the shaft twisting.

but maybe in the future you should opt out on the cam doctoring and do what the rest of the pros do. stab the cam in the motor line up the dots check the card to make sure its ordered correctly and enjoy. Oh and check PTV to make sure it won't puke all over itself.

 

Hammer,
Like Sean Collins recommended, I'd suggest that you call Comp and see what they will work out for you. I'll bet that you'd be pleasantly surprised!

Steve

 

I had my cam also go through the cam doctor. My results were similiar to yours. The intake lobes were advertised at 218 degrees but in fact were around 220.7 degrees. In my mind that was good. The lift on my number 7 exhaust lobe was low compared to the others but close enough in my mind.

I think what you are seeing is quite typical. Also why you need to degree your cam in for optimum results. Years ago no one really new the difference when they bought a cam. But with new technology filtering down to the average guy he can see the nuances of the lobes and they aren't quite the way we thought they were.

When I did my motor build up I found out you have to check everything. The CC's on my heads were not as advertised. They were supposed to be 64cc chambers but were around 69cc. I bought them used off a friend so I just had them milled.

My pistons were supposed to have 3.4cc reliefs. In fact they were 2.8cc. Another error in my favor this time. Hope this is of some help.

 

I understand that a long stick with a twisting motion only on one side will be stressed and the front wanting to turn faster then the rear, but if its known why not use a metal that is tortionaly stronger then offsetting the profiles? This would keep constant timing throughout the RPM band and not just the areas where the cam has the most stress on it. Im in no way disagreeing with u as iv thought about things like this myself (just in larger V motors such as 10 and 12 where the cam is even longer)

 

Let's entertain your spintron notion for a second. assuming that is the case here, I would expect the lobes nearest the driven end to be close to on spec and progressively advance as you move towards the non-driven end. Considering that number 2 is the 3rd highest advance on the cam and it's up towards the front, I highly doubt that is the case here.

Hammer

 

I do plan on calling them.

Hammer

 

Lets entertian your a backyard wrench mulling over bullshit for no reason and that grinding an asymetrical shape even with the best CNC controlled equipment in the wolrd isn't easy. You your self point out that only the rear lobe were advanced further. As for your duration comming up a bit longer LASH RAMP !

 

I understand what you are saying. I was already planning to actually measure the CC's of my combustion chambers instead of just guessing based on amount milled. My goal is to have the work done right and was waiting on the Adcole report to see exactly where to set the size of my combustion chamber. From the Cam Doctor reports I seen, the advance usually was slightly less than requested and I figured it might go that way in my case. I was rather surprised when mine was about a full 2 degrees advanced even further.

Hammer

 

Maybe you are missing something...EVERY CAM LOBE IS ADVANCED FURTHER by almost TWO degrees than what I ordered. My point of pointing out the two rear lobe sets is that those two are noticably more than the rest...in their case close to 2 1/2 degrees over the amount of advance I ordered.

Hammer

 

Not an expert here, but do you find it odd they would release a cam that by your evaluation is so out of spec?

Do you think maybe this is within their own in-house tolerance level?

 

Seems like they may have made a mistake on the grind. Also seems like alittle bashing to me without calling them first to confirm if a mistake was made.

The reality is, if you put in this cam or the PERFECTLY ground cam you ordered, you will never see or feel any difference.

How do you know the cam measuring device is'nt fucked up?

 

All i can figure is that they don't do a Adcole unless you request and, of course, pay for it. Maybe the Adcole operator doesn't verify if it meets what was ordered. Maybe they don't care. Maybe it is just as you said. My Intention of posting this report is to show, just like the others who have posted their cam reports, how far off they can be from the cam card.

I'm sure they will fix it if I ask them to. If not, I will just sell it off, I'm sure somebody would be intereted in it because it is an obviously great cam for somebody wanting a torque biased ICL of 110 but also wants the smoother idle and flatter curve that a 114 gives them. Sooner or later, I'll get what i want.

Hammer

 

You make a good point. It just might be. As much as the the rep hyped up the Adcole machine, you would think it could measure the rise of a pimple on a gnat's ***. For that matter, it has been shown time over time that the cams aren't perfectly on spec according to other cam doctors.

Anyway, I wan't looking for nor expecting perfection. In fact, it occured to me that having the real world cam specs for all eight cylinders would allow me to focus my compression calculations on the one cylinder that would produce the highest DCR results and thereby all cylinders would be at or below the max safe level.

Which then leads me to another reason, I posted this report. Since the other reports only show either an average of all or just one lobe...my report, obviously, shows all and it should also be obvious that number 7 is gonna be the max DCR cylinder of the group based on it's cam timing. Maybe it's possible that this is happening more often than we think and could potentially be the reason people are lunching number 7. Isn't this a good enough reason to at least make it worth a thought or civil discussion?

Hammer

 

Can you run an offset key, like available for SBC engines? If so, quick fix, but you'll still want to degree it to make sure you are installed at 112 ICL and not 108!

Usually the no. 7 issue has been fuel related IIRC. Not to say that a higher DCR couldn't effect it, but probably not the primary concern. Notice also that you ordered a 223 duration lobe, and that the duration is listed at 224.1 on 7 and 8. Your extra duration just moved your IVC back where you wanted it.

Unless you have a fully blueprinted engine, you'l likely find that varying chamber volumes and above deck clearances affect the SCR and therefore DCR more significantly than the error. You'd have to measure the deck height of all 8 cylinders and hope they all come out to .006 above deck, or whatever number is being used. If not, the easiest way to get it exact would be to add a comensurate volume to the combustion chamber to compensate for any that are taller.

Patrick also stated in another thread that sometimes you are better off not knowing the exact profile. I do understand you plight though, because in tolerance or not, you did not ask for 4 degrees advance.

 

I have no idea about the key, it is something to consider and look in to.

As far as the ordering a 223. Yeah, technically that is what I ordered but knew it would actually be a 224, so all valve events were calculated as a 224, and in fact, I was plugging in Patrick's measured valve that can be found in the link in my OP.

Hammer