Camshaft timing?
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Joined: Jul 2001
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Camshaft timing?
Hi all,
I built up a 460 last year for my boat, it has the following;
-96' block bored .030
-Rebuilt heads off of my old engine
-Edelbrock performer Cam (idle-5500)
-Edelbrock performer intake (idle-5500)
-Edelbrock 600cfm marine carb
-Mallory unilite distributor
-High output coil
The problem I am having is I cant get the engine above 4200RPM, the engine that I blew would run up to 5000 no problem, and I really need to get to 4700 for the boat to plane right. I had a 670cfm Holley Pro-jection unit on it for about the last 8 months, I thought it was the problem so I tried my old 600cfm holley, and the new 600cfm Edelbrock, none seem to help it still hits 4200rpm.
I was reading the Edelbrock cam documentation and it says not to use a standard Timing kit as they could be machined retarded for fuel injection, could this cause the problem I am having? I would like to try all options before I tear into the engine again to change a timing chain. Do you guys have any other ideas I can check out?
Thanks!
John
I built up a 460 last year for my boat, it has the following;
-96' block bored .030
-Rebuilt heads off of my old engine
-Edelbrock performer Cam (idle-5500)
-Edelbrock performer intake (idle-5500)
-Edelbrock 600cfm marine carb
-Mallory unilite distributor
-High output coil
The problem I am having is I cant get the engine above 4200RPM, the engine that I blew would run up to 5000 no problem, and I really need to get to 4700 for the boat to plane right. I had a 670cfm Holley Pro-jection unit on it for about the last 8 months, I thought it was the problem so I tried my old 600cfm holley, and the new 600cfm Edelbrock, none seem to help it still hits 4200rpm.
I was reading the Edelbrock cam documentation and it says not to use a standard Timing kit as they could be machined retarded for fuel injection, could this cause the problem I am having? I would like to try all options before I tear into the engine again to change a timing chain. Do you guys have any other ideas I can check out?
Thanks!
John
Freshman User
Joined: Feb 2002
Posts: 40
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Camshaft timing?
If anything, i would think that retarded cam timing would help you spin to higher rpms, not hold you back. 600 cfm sounds a bit small to be feeding a non-stock big block...i dont know if that would cause the problem youre having though. any time ive ever been limited to rpms like that, its always been an ignition problem. are all the plugs and wires good? how about your ignition timing? just some thoughts.
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New User
Joined: Jul 2001
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Camshaft timing?
I was able to obtain 5000+ with a 600cfm before, but maybe with the changes we have made to the enigine.. The timing is good starts at about 10* and advanced up to about 34* at 3500RPM, we where able to get to about 4600RPM by advancing timing on the fly, but then the engine starts reeeaaaall slow or maybe not at all.
I just thought of something, but not sure if it matters? When I baught the engine it was a short block setup for fuel injection, we had my heads rebuilt and put them in there, but I never messed with the pistons, is there a difference in stroke or pistons from a fuel injected and non fuel injected engine?
all I can say for sure is... I am getting frustrated......
could a wrong voltage to the mallory unilite or maybe a defective unilite module cause this?
Blah I dont know what to do next, think I'll go fishing, oh wait I cant THIS IS IN MY FISHING BOAT!
thanks again all!
John
www.sturgn.com
I just thought of something, but not sure if it matters? When I baught the engine it was a short block setup for fuel injection, we had my heads rebuilt and put them in there, but I never messed with the pistons, is there a difference in stroke or pistons from a fuel injected and non fuel injected engine?
all I can say for sure is... I am getting frustrated......
could a wrong voltage to the mallory unilite or maybe a defective unilite module cause this?
Blah I dont know what to do next, think I'll go fishing, oh wait I cant THIS IS IN MY FISHING BOAT!
thanks again all!
John
www.sturgn.com
Freshman User
Joined: Feb 2002
Posts: 40
Likes: 0
Camshaft timing?
the short block should be the same. ya after my first reply i figured it definitely wasnt the carb since you had tried other ones also. im still thinking its ignition related. when you advanced it on the fly did it start running any smoother? maybe its just not getting enough advance...although 34 degrees sounds like plenty. have you checked for spark in each cylinder? also, what kind of plug gap are you running? sometimes running too much gap with not enough juice will cause the plugs to blow out at higher rpms... i would check all the little things like that before replacing major components.
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