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308 Camshaft choice

Started by _Torana308_ , Jan 09 2009 11:54 PM

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10 replies to this topic

#1 _Torana308_

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Posted 09 January 2009 - 11:54 PM

Im looking at changing the cam in my LJ as i have to do valve springs anyway so may as well upgrade the camshaft.

The current camshaft has 218 duration at 50thou, approx .460 lift and seems to run out of puff at about 5000rpm, the problem being that my
car with the 4.11 gearing crosses the line at nearly 6000rpm. This cam is about 8 years old and probably fairly worn out as it has always been in streeters
that get worked hard.

Engine is a 308, 10:1 compression, B cast heads that have been cleaned up etc and done professionally, rollmaster timing set, performer manifold,2 Inch spacer, 650dp holley, 3000rpm converter, 4:11 geared nine inch and 225/50/15 bfg drag radials. The car is rarely street driven any more and only seems to leave the shed to head to the drags, however i would still like to keep it semi streetable.

I will buy roller rockers and springs to suit the new camshaft

I would prefer to stay with a hydraulic camshaft for now so I have looked at a few camshaft websites and come up with a few that I think will work well

1) Crane CCH304A- Rpm range 3000-6500 236 dur @50 thou, .520 lift

2) Crow 5690 - Rpm range 3000-6000 240 dur @50 thou, .524 lift

Has anyone got any preferences or other recommendations, Im leaning towards the Crow but im still in the planning stage here

Edited by Torana308, 09 January 2009 - 11:55 PM.

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#2 _ass308_

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Posted 10 January 2009 - 08:06 AM

my engine and yours arent really the same.but i used your choice number 1 compucam 304.im very happy with the result,and glad i didnt go bigger.
http://s453.photobuc...=Picture209.flv

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#3 Struggler

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Name:Andrew or AJ
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Posted 10 January 2009 - 08:15 AM

I would be a bit more conservative and go with the CCH 286 ( a real favorite of mine !!)

JMHO

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#4 _1QUICK LJ_

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Posted 10 January 2009 - 06:45 PM

i agree with struggler you dont need to go overboard with the cam, i would suggest a h226 crane they make great power to 6200 and are very snappy

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#5 _rocket_

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Posted 10 January 2009 - 07:08 PM

The crane 286h is a great street , bit of dragging cam, had one in mine when it was a streeter, top choice.

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#6 _Torana308_

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Posted 10 January 2009 - 11:39 PM

The only thing that worrys me is that it is revving fairly hard across the line now, so if it goes faster will I end up in the same situation where it is at the moment as in, before i get to the line in top gear it has basically stopped making power. At the moment my best is 105mph and it touches the 6500 rev limiter just past the line.

I know that the combo as it is now is not well matched the 4:11 gears are to low for the current setup, the converter is probably to big as well, also only running a 24 inch tall tyre exagerates the overall gearing with 4:11s

Edited by Torana308, 10 January 2009 - 11:43 PM.

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#7 _rocket_

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Posted 11 January 2009 - 06:24 AM

I have a Reed cam, GTL-278 in mine atm, it works really well for what Im doing.

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#8 fuzzypumper

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Posted 11 January 2009 - 12:04 PM

It seems Crane and Crow have different ways of measuring rev range because Crane rates the CCH404A
as having 500rpm more than the the Crow 5690 but is actually slightly less duration and lift. :huh:

You have chosen to look at cams which are probably 2 options higher than what you have now.
They start at 3000rpm which is where your stall converter starts. If your happy with your current camshafts
start range at 2000rpm & 3000rpm stall combination, then you may need to consider a higher stall with these cams.

What have you calculated that you need? another 500, 1000 or 1500rpm to get the terminal speed you need?
There are cams with 2500-5500rpm power ranges which will easily power to 6000rpm or higher with the right combo
and may Ok with your current stall.

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#9 _Torana308_

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Posted 13 January 2009 - 12:07 AM

The current engine/cam/converter combo as how it was put together a long time ago for a mates Commodore streeter. I left it mild in the cam department when i wanted to street it alot but never realised how poorly matched it was until I started comparing cam specs to what I already had. I would like to be able to run a low 11sec pass however to hit 120mph i need to rev to 6900rpm with a 24in tyre and 4:11 gearing( and prob won't as i dont want to tub the car either meaning traction will be an issue) All this is according to the power speed calculator

Maybe I am better off following Strugglers advice and changing my diff gearing to 3.9:1 and leaving the 3000rpm converter in place then seeing if it needs more stall speed or not. The car already pushes through the brakes anyway at about 2200rpm of stall

Im trying to gauge how much i need to change of my current combo to get some numbers out if it. I know running 13.0s at 105mph that something is severly lacking here

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#10 fuzzypumper

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Posted 13 January 2009 - 12:35 AM

Im also thinking along the lines of STRUGLER, go abit more conservative than the Cam options you stated, maybe choose a 2500 to (5500-6000)
range cam & with the weight of an LJ, drop to 3.9 Diff not more.
Im no expert really but it very interesting to see what happens.

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#11 _[BOTTLEDUP]_

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Posted 14 January 2009 - 12:55 PM

With a 3000 stall I'd run the H226 Crane. You need to replace springs anyways, use a CR98602-16, 99915-16 retainers and 99095-1 collets. The Performer will start to struggle around 5800-6000 even with a 2" spacer. For more top end power I'd suggest the Peter Michael's Strip Master or a Torque Power single plane manifold.