It appears that mine are the right color cores.
.
http://i43.photobucket.com/albums/e3.../MK%20Cams.jpg

I have a cam here that has track marks on the lobe. It is an 8620 core. Now, this cam was mocked up in the block. Spun by hand with checker springs on two valves. I never noticed it until yesterday when I pulled it out of the box and looked at it. This cam wasn't spun (by hand) more than a dozen times when I was setting up the shaft rocker stands. How could this brand new cam have track marks on it? This is in a $4,000 block that was CNC machined to perfection with a $2,000 set of Jesel lifters and checker springs that I installed on the valves with my fingers= 0 spring pressure 0 rpm. What is gonna happen when I go and throw a big boy valve spring on and spin this thing 7,000 rpm?

On the inside or outside at SP?

The color on the cam cores is the copper plating. They plate the whole core. grind it, then harden. then regrind. Copper keeps the whole cam from hardening and breaking .

There is always going to be some marking , The cam is usually softer than the lifter wheel ( Jesel through hardens their wheels so the ID can be used as a bearing race for the needles) Now Jesel wheels are highly polished so on a less the optimum finish on the cam , it could be smoothing the finish on the cam. Like and english wheel on a body panel or a steel rolling mill. Be interesting to see the RA numbers on the lobe grinding. We always had our stuff REM finished.

after reading this post I am not feeling too good with my MK cams. I just got a heads and cams package specked from MK 2 months ago and numbers are not than much off of Tim's. thought I was doing the right thing going to MK spent to me was a lot of money building my 540's. my motors are almost finished and I may end up with a couple of 540 stones for the money I spent. that sucks. my grind # is XA242-390/247-385/112+4 core# 315629 actual on cam card reads 242.2 .664 247.1 .656 325 AFR heads

whats XA mean,,extra acceleration,,yikes and that 5° split sucks in a marine motor.I'd change that cam asap.

I like this cam for a sub 6000rpm 540. Very strong midrange and carry's the torque through the upper rpm so you can swing a decent sized wheel. Depending on exhaust peak hp should be between 5600 - 5800 with those heads.

http://www.lunatipower.com/Product.aspx?id=3153&gid=261

Perhaps another thread in the spring. Yours specs are very similar to ones out there running around all over and haven't necessarily had problems. I'd be questioning the hardening process and if he's still with CM etc. see if it's 8620 core. Also ask Bob if your gonna get more than 60 hours out of them?

You`d think after all these issues he`d go back to just copying stock grinds and changing them slightly.
Mistakes happen, trying new things isn`t a bad thing but realize the mistake, admit your mistakes, own it, make it right, learn from it, don`t repeat it, move on. That`s just good business.

Where are all these similar ones that are running around all over without issues?

Can you explain why? I've read up on and expermitted with different splits over the years on stock heads vs aftermarket good flowing heads but am curious as to what you input is. And perhaps jsand117 can have some input when he contacts Bob this week. The numbers very similar to his make decent power but long jevity is a huge concern here.
Tks
John

..specd for a 500efi with dart 325 heads. 237/239 ..

Most havent had much more than dyno time.

Did you take the marine ready heads apart and check or open guides? They are custom made for him by just sliding in exhaust valves... I'd inwere you I would not run them if you didn't...

Or went from 365's to mild 550 hp engines and we're stoked....

Many have stressed with a wet exhaust of any sort, a 5 degree split is nowhere near enough, that's why...

Send Bob the pic of mine at 65 hours let's hear how it's my fault again... That's what he would say...

Whats interesting to me, is how similar, all these custom cams are from MK.

BCK has a 548ci. Tim has a 540ci. Both have intake durations around 241 if i recall and 9.5-10:1 range?.

This last pic, guy has a 502ci 9:1 deal, he gets a 237* intake lobe.

MER had a 502ci 525 merc, inital cam was like 238 or 239 intake lobe.

Some other 540-548 builds getting the 241 ish intake lobe.

I mean, what RPM are these engines supposed to be spinning? A 548ci turning 6k peak, is gonna need a significant different intake lobe, than a 502ci turning 6k rpm, and a hell of a lot different than a 502ci turning 5500.

While head flow plays a part, its not like going from a head that flows 400cfm at 600 lift, is going to require a grossly smaller intake lobe, than one that flows 350 at 600 lift. We are talking a couple two three degree change in duration to compensate for a better flowing head. Main factor is CID x RPM. You have to at least be in the ballpark .

I get another text from an oso guy just now.

His 540, gets a 239/246 cam. He is running GM IRON HEADS. So, whether you have 325 afrs, or 305 afrs, or GM iron heads, you pretty much get the same exhaust duration, and within a deg or two of intake duration.

Sounds awesome. I need custom cams for my tailored application.

Damn! Wtf

Be interesting to build a database, on these "custom" cams.

Im sure everyone had to listen to speeches about area under the curve, exhaust port efficiency, rod angles, how tall decks suck becuase of the angles, and all the other reasons they need a custom tailored cam. And what they actually get, is a common cam everyone else is getting within a hair or two.

I would like to know what you guys think of my 496s from MK. Lobe seperation 113.1 duration 237.1 / 243.5 lift 663 / 654 305 AFR heads.

Just my opinion but seems low duration for the lift, how many hours? Any signs of issues?

I was talking to MK last year about a new cam as my ZZ502 unit is less than ideal, but the ordering process felt unnecessarily complicated so I just said forget it, and then the off the shelf cam thread popped up confirming that all of that extra trouble and expense wasn't worth it for me. It seems like I may of saved myself even a lot more trouble by leaving things alone.

Unreal. All needing this that and the other thing and hours on the phone many have spent to actually think what they were doing was time well spent to have cam tailored to their specific needs. Ah... OK. Not cool. I agree. If I had to guess valve timing events are all with a degree or two of opening and closing also. Wtf

Bet he's been busy on the phone the last few days doin some splainin.:party-smiley-004:

No issues yet, not many hrs. maybe 10.

Still deciding if he's gonna get email with my pics, I would bet my life he's seen this thread, and still no response so it's most likely wasting my time...

Not any action since 2015... About the time things went public [ATTACH=CONFIG]559952[/ATTACH]

Should start a new thread called rmbuilder or Bob grinds and have all post their cam cards.

Probably blame the oil system.

Yea really... Well that's not an issue lol you lifters have axle ouling, also had lifters opened up to give more oiling to rockers, have 80 psi under way and 12 qt pans... Mom ouling issues here at all

Cam design is pretty easy at Marine Kinetics.


http://33outlaw.zenfolio.com/img/s9/...70702380-4.jpg

^^^^^^^^^^^^
That's some funny $hit right there! :poopoo:

Lolololol!

Maybe, i can have guys email me their combos and cam specs, and i can make an easy to read list. Easier to compare that way, plus, bob cant yell at them for putting it on the interweb

Chit, i might have to open a dedicated email for this project.

Here is the card from my old engine I had Bob spec out.

439 CU
10.4:1 CR
Stealth Dual Plane
AFR 265 Ovals
Pro Systems 950

Never dyno'd the engine but based on the speeds I got it was a solid 530+ hp engine. Ran it for two seasons and then sold the engine. Either way here is the cam he designed for that engine.

[ATTACH=CONFIG]559953[/ATTACH]

Omg hahahahhahaha