Lol well at least this will be thread of the year!

If Bob stepped in and made some of these issues right then it would be thread of the year. Then I'd tip my hat to off to him for being a stand up guy. If not he's just gonna be like all the others in the marine industry...

Yes and he is passing me as the most hated man in Oso I think haha

Maybe not but sounds good!

There would have to be alot of refunds being issued. Costs prob well into the six figures !

If you guys would have heard him blow a gasket when Dan was pushing his buttons way back when, I can only imagine now because we all know he's reading this

He's probably gonna start threatening to sue everyone again.

Pretty sure we can threaten back with a class action suit... We would win!

All I said was lets have a drink every time someone says call Bob. He blew a gasket. Hence Butt Hurt Bobby, guy has no sense of humor. Yet it`s ok to hide known issues for years. How does he sleep at night?

Btw, where`s that Zone 5 guy? Over at Boatfreaks still in love with BHB?. Boatfreaks looooove them some magic Bobby cams.:bananalove:

In anyones still in need if a custom cam, for a 502ci, 540ci, 548ci, 9:1 , 10:1 , 650hp , 700hp, 5600rpm, or 6000rpm, my recommendation is

241/246 112 LSA.

Or, if you have a lighter boat, a 241.9999999/246.99999999 .

Its a great cam, just works in everything!!!

Lol Joe

mike tkach said:
09-15-2016 07:52 PM(Quote)
and their are still some people that think you can spin a hyd roller cam to 6000+rpm with 140 on the seat&under450 on the nose,then they blame the cam or the lifter when things get beat to failure.
MIKE TKACH (Quote)
Been there w a camaro. You can do a 6-700 lift solid lifter cam and run 6500 in a basically stock motor. But hydraulic floats around 4500. I know you know this

My ears started burning because one of my old threads were dredged up. ;) Yes, I did have an clearance issue with how the step of my MK cam was machined. I ended up installing a shim to get the proper clearance. Probably not the ideal solution, but that is what I went with. Interestingly enough, when I put that thread up saying that maybe there was a bad lot of cams from CM, I suddenly got a PM from Bob because he was concerned about me posting stuff about his cams and he was getting calls from concerned customers. He was all over the damage control on that one.

I bought my MK cam from another OSO member who is running an identical cam in his 502. As far as I know, he is not having any issues with his. I had a number of interesting things come up with my adventure. The piece of paper that served as my cam card specified an LS firing order, and that is how I set the motor up. Routed the plug wires according to this firing order, and when I ran it on the stand, it wanted to backfire a lot. I figured I maybe had some valve adjustment or timing issues. Was short on time, so took it to the shop to dyno it. When we had it on the dyno and started it for the first time, he took a temp gun to the primaries and determined that two cylinders were not firing. Found out that this cam did in fact have a STANDARD firing order, not LS as indicated in the documentation I had. I did not disclose this to Bob immediately - instead I called him with the cam number and had him verify the firing order. Honestly, I can't recall if he insisted if it was the LS firing order - it has been 3 years, and I knew for a fact at this time that the cam card was wrong. I did degree the cam and verified the lift and the valve timing events, so it wasn't like it was the wrong card for the cam. It was hand written on the document that it had the firing order swap.

I also had some weird issues with reversion on what should have been a very mild cam - If I recall correctly, it was about 226*/230* on a 114* LSA. Everyone agreed that reversion should not have been an issue with Lightning headers and such a mild cam. Buddy of mine is running an HP500 Carb cam in his 502 with the same headers and no reversion issues. I have probably only put 30 hours on the boat since the engine was built, and have developed a strange chirping sound in the exhaust. Needless to say, the top end is probably coming off the engine this winter, and I will be taking a very close look at the cam in it.

Honestly, at this point I am just about done with high performance boating. With my lifestyle the way it is, I seldom get out on the boat anymore, and I sure as hell don't want to be worrying about it breaking down when I do take it out. Getting very tempted to just drop stock power back in it over the winter, and then either part out the 489 or set it up to drop in one of my cars. I would rather keep the hatch down and go slow boating rather than staying up at night worrying about throwing more time and money at it - I have very little of either these days!

Good luck with your build, Tim.

The unfortunate thing is that this is what happens....We get an issue like this and it ruins boating for a few people and they get out of it.

That was part of the reason behind my idea for a proven recipe idea. so that people can easily build something dependable and enjoy boating instead of constantly fixing stuff, trying to get stuff to work right and throwing good money after bad.

A 650-700 hp 540 isn't exactly a stretch in 2016... Shiism be easier then this lol

Hello, To everyone here !!! 'I've been logged out, just got my username and password straight...

I'm already up to speed on the issues and today is the first day looking at this..I have data, pictures, and back to back testing...

Hi Mark. Welcome back

Hey mark... Welcome to the party...

:hitfan:

Just saw this on yellow bullet

This is a copy and past..

They both flow close to the same after porting but the darts took more grinding to get there. So far I can't say one is better than the other except the darts from head to head the valve job was off .022 in height difference on exhaust and the intake difference is .005. The Brodix was within .003. The dart has a harder aluminum but it has more porosity in the casting. It looks like pepper on the top of the port.

My 540 with one of Bob's cams only made 567HP. 600 would have been a nice upgrade

I could probably do better than that with a set of GM heads and leave 2 spark plug wires off.

I had same issue

Interesting read! I have one of bobo's cams with 20hrs on it and 5 bad lobes, or was it 4.. The only reason I only have one cam of his, is because I sent the next one, that I did not order, back to him. He has hated me ever since for making him eat $350. That was in 2008. The block I ruined with that cam sits in the corner waiting for a rebuild. Too much metal in the skirts and scars on the walls to just reassemble. My loss was a motor worth 100 times more than his loss!
Some day I would like to put a big crank in it and slide it under a old Chevy cab over.. Maybe..
Hopefully others will not drink the bobo Kool aid and learn from other people's stories.

Dick

Just to be fair though, it was with some Edelbrock marine heads and a Mag MPI manifold that had the runners cut down, ported and extrude honed with a bigger throttle body. Not the best combo for making power, but 567 hp is still a little light I think

So far we have learned

Some of these cores quality suck?

Some of these cams are beating parts up?

Most of these "custom" cams, aren't very custom at all. I mean, a 9:1 540 with GM iron heads, gets the same cam pretty much as a 540 with AFR 325s and 10:1 , or a 555ci , or within a few degrees of a 502ci combo

The timing sets provided, don't fit well without modifications

Some cams didn't have the proper firing order as ordered, or as cam card stated

Some cams have been removed, replaced with an off the shelf cam, and made more power , with less lift , and no longer having issues

Some have had quality control issues with his AFR heads

Wow what were them build specs?

Is there anyone out there that bought a set of MK cams and ended up with stout running motors that made good power??

Maybe this will abruptly end the thread. Lol. Power and hours of use is more like it.

Anyone have any issues with the Scorpion rocker arms?

i don,t understand,are you saying hyd roller cams float the valves at 4500 rpm?

As I mentioned in my earlier post, I bought my MK cam from another OSO member, BBCLiberator. He was running an identical cam in a 509 with stock GM rectangle port heads, Eddy Air Gap manifold, Holley 800 (or 850?) carb, Stainless Marine manifolds, IIRC. Maybe he will see this thread and chime in on how his build is holding up. Back when I bought the cam from him he was very happy with his build.

I am wondering if the MK cams that have milder lifts are going to have the same issues with valvetrain harmonics and keeping the wheel on the lobe as we are apparently seeing with some of the more aggressive designs. Mine was relatively mild lift, only about .596 and .612. Now of course that had accordingly shorter durations on the lobes - 226* and 230* on a 114 LSA. Like I said, I have been hearing an odd chirping sound that appears to be coming from the exhaust, but I have not had the time to get out there to really diagnose the damned thing. Plan is to pull the heads and take them to a machine shop to take a look at guide clearances, since I never did that when I put it together. Tim's problems have me spooked enough to do this, along with the odd sound it has developed. Hoping to head any disasters off before they happen.

In all honestly, I am frustrated beyond belief to be spinning wrenches on a boat I hardly have the time to take out anymore. Truly tempted to drop a motor out of someone's Suburban in it. :party-smiley-004:

yes.............I answered the question, don't make me out to being a cheerleader :cheer:

Budman, what rocker arms are you using? just curious.

Has anyone had any contact with Bob lately? I shot him an email the other day about my springs and haven't heard anything back.

Scorpion marine endurance.

Was that a Cam Motion 8620 core?

You have 540s too dont you? I forget . How many hours ? Any issues since built?

yes 540's around 50 hours with no issues, they have gone to a new owner so I wont have any more info to share.

mk cam,scorpion rockers.low power 454 with afr 265's. and stainless marine exhaust.not sure of hours yet will find out.thinking of looking into it just to see.no problems so far.Im one of the 385 to 500hp builds tim was talking about earlier