Cam and valvetrain longevity....??? low duration high lift...
10-03-2016, 09:54 AM
#1051
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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
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
Last edited by mcprodesign; 10-03-2016 at 09:58 AM.
10-03-2016, 10:35 AM
#1052
Looks like you, Mike tkach, budman, amd others had the issue,
. They also had bobs cams. I have not heard of this using a regular gen 6 cam from anyone else.
Budman, in this thread, tried a different gen 6 cam, and found more clearance. Wonder if the issue is because bob used all these 8.1L cam cores on reg bbc gen 6 setups? Was there a slight difference in the machining of the nose between those series of engines? Of he stated how he called bob, and bob didnt think he had an issue. Im pretty sure bob prob had recieved many calls on that topic , and dam well knew about the issue and why there was one.
http://www.offshoreonly.com/forums/g...o-you-set.html
. They also had bobs cams. I have not heard of this using a regular gen 6 cam from anyone else.
Budman, in this thread, tried a different gen 6 cam, and found more clearance. Wonder if the issue is because bob used all these 8.1L cam cores on reg bbc gen 6 setups? Was there a slight difference in the machining of the nose between those series of engines? Of he stated how he called bob, and bob didnt think he had an issue. Im pretty sure bob prob had recieved many calls on that topic , and dam well knew about the issue and why there was one.
http://www.offshoreonly.com/forums/g...o-you-set.html
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.
10-03-2016, 10:45 AM
#1053
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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.
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.
10-03-2016, 11:05 AM
#1054
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A 650-700 hp 540 isn't exactly a stretch in 2016... Shiism be easier then this lol
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.
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.
10-03-2016, 12:38 PM
#1055
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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...
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...
10-03-2016, 03:21 PM
#1059
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.
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.
