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Discussion Starter · #1 ·
So i know that advancing the cam will produce more torque and retarding it will give more high end, but what happens if I get a high end cam and advance it or if I get a low end cam and retard it? Someone said i can get a cam regrind from delta for 50 bucks, I'm trying to figure out how to get more top end out of this torque beast. It wont go past 3500 in fifth floored anymore :lol: And am I right that the 260 is the high end cam and the 270 the torquey cam?
 

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I think the 270 is high end and 260 the torque cam. Maybe one of the guys with a 89 will chime in.
 

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The 260 and 270 is referring to duration. And more equals more top end power.

Advancing and retarding a cam is a less that desirable way to move the power around. Yes it works but if the cam is made right for the engine you will have a fair amount of torque off idle and will more or less be steadily rise throughout the RPM range. Often companies will suggest a cam and say it is good for an engine in the 350 to 400 CI range but that is hardly the case. It takes much more thought than that. but there are simple ways to spec out a cam and be virtually dead on every time.

If you are doing a regrind then you are limited to some extent but sometimes the stock cam is fairly descent and a regrind will hop it up nicely.

If you could post your engine specs including compression, valve sizes, displacement and your intended use and also the specs of your current cam I could help suggest a usable grind.
 

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Discussion Starter · #4 ·
I have a 2.6 with the 2.3 head and valves standard 4.30 gears. I dont have the specific numbers with me now, but I could get them if thats what you need. I use my truck as a wheeler, but I'm also looking for more top end to go down the road a bit better. It has plenty of torque, but not tons, it is after all a 4 banger. I don't know much about using the cam to increase performance so I am looking to learn a bit here. Would putting in the top end cam decrease my torque or leave it mostly alone and add on to the top end? I imagine the torque would be dreceased at least a bit, or even better pushed up a tiny smidge. I do realize messing with cam timing will reduce the power in crease to a certain rpm range, but I thought it might be a way to get a bit more out of it.
 

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A cam made for "top end" will not reduce the amount of torque you get. In fact it may increase it a bit because you can get higher valve lift. However it may not happen until 4000 RPM or more which would not be desirable at all for a street or off road vehicle. What you really need is a cam where peak torque comes on at or under 3000 RPM. This way the engine will idle, not stall when leaving from a stop light and return good mileage. Do not concern yourself with maximum horsepower, this is not a race vehicle. Reliability and drivability are far more important

I don't want to look up your engine specs so you will have to provide them to me.
 

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Discussion Starter · #6 ·
I know its not a race truck, I'm just looking to get a little more out of it. It seems really sluggish for such a big 4 cyl. I think some of my sensors are starting to wear out a bit. I plan on putting a weber 38 on this thing by the end of summer to simplify it a bit (my computer doesn't like the woods much or stop lights). If possible I would like to get my hands on a calmini cam, the power kicked in about 3000rpm and also increased torque but I know they don't make em any more. I hear they stopped making headers too :( Ill get the numbers soon
 

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If you like going in the woods/offroad then I wouldn't change fuel injection for anything. I suggest you keep it and fix any minor problems your EFI may be experiencing. You'll save money over buying a new carb and have better drivability, fuel economy and power.
 

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The 2.3L head has smaller valves (& runners IIRC) then the 2.6L head, so you'll starve for air long before you run lean. You can move the CAM a tooth or two, but it will be very noticeable. Be ready to undo that one, incase you don't like the side effects. Are you running premium in that ~9.5:1 motor? If not you should be, thst will keep you from blowing a piston & give better umph.

+1 for making sure your current setup is in tip-top shape before trying to tune/tweak anything.

~psguardian
 

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Discussion Starter · #9 ·
Yeah thats why I'm carbing it. The FI on my truck is too moody, and I'd rather deal with a carb than a huge bundle of wires and fancy computer gizmos. Im waiting to do this cam stuff, I'm just figuring out what would maybe be best for when it runs ABSOLUTELY perfect. I'm going for simplicity and reliability. The isuzu FI setup is really simple and can be reliable, but carbs are more simplerer and i understand them more, and my truck isn't very reliable right now. I didn't know that the head would push my ratio up that much though! I'll try a tank of premium and see what happens, I've been running 87 since the switch. I only learned about the impulse FI 2.3 heads after i got my carbed head :evil:
 

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Another head option is from a 93 or newer 4ze1. Large runners & valves, heart shaped combustion chambers (small like the 4zd1 chambers). The idle modifiers are a pain on the fi system, bur you can delete them without going carb. (the two valves that increase idle speed; for cold start & overheat can be bypassed but it makes for a cold blooded fi system that won't idle up in hot weather in traffic). Or you could go carb, just watch out for the smog police, they don't allow older engine design in newer bodies (i.e. 2.3L carb top end in a 2.6L vehicle).

~psguardian
 

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A lot of people say they understand a carb. But do they really? Do they understand the principal behind jetting, emulsion tubes, boosters, acceleration enrichment, idle and transition circuits? Doubtful. But they know that is they adjust a screw or two on the front they can get it to run better.

Well the same goes for EFI. Change a broken sensor or two and your golden. The beauty about EFI is that it works perfectly if the sensors on the engine give it the correct info. You never have to adjust, and you never have to rebuild it or clean it.

I highly suggest you give your current fuel injection another chance. I would solve any minor issues you might have and enjoy much better drivability, fuel economy and power. Also consider that something else may be troubling the motor and its not the EFI that is at fault. If this is the case a carb will show the same symptoms or be worse since it has no way of compensating.

Also consider the short and long term cost savings. A carb swap, assuming a new carb and replacement manifold, will run in the thousand dollar range. Replacing a couple sensor or components on your current motor may run under $100. Plus your going to see a long term savings in the cost of fuel.
 
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