cj's mopar
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Is there a better cam for me?
- Thread starter cj's mopar
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Contact 68 hemi GTS here. He has run a six pac in the high 10 second range.
Doug
Doug
cdr
Well-Known Member
As said by others, 1ST thing to do would be to deg the cam, Those multi setting timming gears can be off, mine was, ALWAYS deg a cam, even if it is a stock rebuild.
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That would be compression height, not deck height
So you have a 470" engine with a hydraulic roller cam that doesn't run like a scalded dog? It should from all the components you have there.
I am not a fan of Hughes cams, but far less impressed with that cam lift.
From what I see the cam lift is far to low. I would want at least .540" lift and I wouldn't change to a 1.6 rocker. We run 5.42 in the 1/8 with 1.5 ratio rockers.
BBM's have a wonderful size cam lobe.
There is no point causing excess pressure on the valve train using larger ratio rockers for any lift less than .700" lift. Mine is .688" with a 1.5 ratio.
First thing I would ask, Was a degree wheel used on the build? If not that's probably your issue. You can't EVER assume a timing set is correct, or that a cam is ground correct.
I've seen engine that have had timing off 8 or 10 degrees, and while they run, they are not producing crisp power.
From what I've read there is absolutely no reason that engine shouldn't run great.
Tom
gtxrt
Well-Known Member
It is easier on the valve train to run 1.6 ratio than to have a high lift low duration camshaft with 1.5 ratio.
gtxrt
Well-Known Member
are you saying a short duration cam with a high lift is not hard on the valve train and cam wear. most of the time you need more valve spring pressure.
Last edited:
Geoff 2
Well-Known Member
No, what I am saying is that it is an apples-to-oranges comparison. You could have a very aggressive lobe using a 1.5 rocker that is harder on the valvetrain than a milder lobe used with a 1.6 rocker.
Here is an example, two Isky lobes. Solid flat tappet. Both have the same 050 duration of 250*.
Lobe #S-84 has 0.298" lobe lift and 144* duration @ 0.200" lift
Lobe # S-633 has 0.350" lobe lift & 162* duration @ 0.200" lift
If 1.6 rockers were used with the S-84. it will not he as hard on the valvetrain as the S-633 used with 1.5 rockers. Less valve lift, & lower acceleration rate of the valve train.
Here is an example, two Isky lobes. Solid flat tappet. Both have the same 050 duration of 250*.
Lobe #S-84 has 0.298" lobe lift and 144* duration @ 0.200" lift
Lobe # S-633 has 0.350" lobe lift & 162* duration @ 0.200" lift
If 1.6 rockers were used with the S-84. it will not he as hard on the valvetrain as the S-633 used with 1.5 rockers. Less valve lift, & lower acceleration rate of the valve train.
cj's mopar
Well-Known Member
Thanks for the input here .That would be compression height, not deck height
So you have a 470" engine with a hydraulic roller cam that doesn't run like a scalded dog? It should from all the components you have there.
I am not a fan of Hughes cams, but far less impressed with that cam lift.
From what I see the cam lift is far to low. I would want at least .540" lift and I wouldn't change to a 1.6 rocker. We run 5.42 in the 1/8 with 1.5 ratio rockers.
BBM's have a wonderful size cam lobe.
There is no point causing excess pressure on the valve train using larger ratio rockers for any lift less than .700" lift. Mine is .688" with a 1.5 ratio.
First thing I would ask, Was a degree wheel used on the build? If not that's probably your issue. You can't EVER assume a timing set is correct, or that a cam is ground correct.
I've seen engine that have had timing off 8 or 10 degrees, and while they run, they are not producing crisp power.
From what I've read there is absolutely no reason that engine shouldn't run great.
Tom
This is exactly why I asked the question.
I feel the cam was a bit small when Hughes recommended it .
He said he likes it because it wasn't a long rod motor , so I took the expert advise.
My current plans are to be sure I am not running out of fuel on the big end.
If not then I will definitely degree the cam.
That will be my winter project .
I have almost zero time at the moment
Helping with elderly care.
But I really think a bigger cam is going to be the best thing.
cdr
Well-Known Member
When you do deg the cam, it would be a good time to make sure the timing marks on the balancer are correct.
BSB67
Well-Known Member
I’m not sure what you are saying here. But to put it simply, your engine is way underperforming and it’s not due to the size of the cam.
cj's mopar
Well-Known Member
I am just saying I don't think the lift on the cam I have is taking the full advantge.of the stroker motor's potential.
Some people would be very pleased the way my car runs to each their own .
I feel trouble to build the stroker at this point was wasted time and money.
A 440 could have gotten the same performance or better.
Some people would be very pleased the way my car runs to each their own .
I feel trouble to build the stroker at this point was wasted time and money.
A 440 could have gotten the same performance or better.
The cylinder head flow will dictate what cam lift is optimal. And yes a 440 ( 446 @ .030, 452 @ .060) would perform the same, they're essentially the same . Rod length and deck height do not make dramatic changes to output.
cj's mopar
Well-Known Member
Can the cam be degreed with the hyd roller lifters and current springs?
Do I need light weight valve check springs?
Do I need light weight valve check springs?
62 Dart Convertible
Well-Known Member
Cam can be degreed with valvetrain in place. Dial indicator must measure travel of lifter body - not the plunger or rocker arm (with a hydraulic lifter anyway).
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