Differences in 302 engine rebuild kits...?
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Differences in 302 engine rebuild kits...?
Hello all. I need some help identifying the differences in engine rebuild kits for a 302. I have a solid donor 302 engine from an '88 Bronco that I want to rebuild and swap into my '92 F-150. I have seen master kits for '85-'91 and '92-'93, but wondering what the difference between the two are (besides about $250). When I contacted the customer service, they said the '92-'93 is roller cam, but that was the only difference (I specifically asked if cam profile was different). When I asked if the '85-'91 kit would work with my '92 computer, I was told no, which leads me to believe the guy I spoke with wasn't really sure himself.
Sorry for the long-winded post, but can anyone help me clarify what the true difference is, if any? As long as the cam profile is not different there should not be an issue in using the '85-'91 in a '92 (besides maybe changing out pushrods), or am I missing something? Thanks!!!
Sorry for the long-winded post, but can anyone help me clarify what the true difference is, if any? As long as the cam profile is not different there should not be an issue in using the '85-'91 in a '92 (besides maybe changing out pushrods), or am I missing something? Thanks!!!
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I suspect the roller cam is the big difference. You can use both versions in your motor BTW, to use the roller version you'll need to transfer the spider assembly from your current motor and either re-use your roller lifters and pushrods or buy a new set. I strongly suggest you do not get a rebuild kit with a cam however, you're simply throwing away serious performance potential. Instead use a cam that will allow the motor to deliver more of it's potential, you can get this without upsetting the computer.
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Conanski:
You've recommended cams before, I also have a 94 302 roller. So, what cam do you recommend for this, and how much in mileage will we likely suffer (if any) ? Also, how much is the gain ?
You've recommended cams before, I also have a 94 302 roller. So, what cam do you recommend for this, and how much in mileage will we likely suffer (if any) ? Also, how much is the gain ?
More Turbo
Joined: Mar 2003
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From: Detroit suburb
For me, not hot rodding. I ocassionally drive about 225 miles to a property and sometimes do my share of hauling. So, can't afford to lose much for the long distance driving but certainly welcome more HP ....
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Take a look at the graph below. This represents a stock motor, adding a cam, and a cam with headers. The cam broadens the TQ curve and provides some more peak HP, but it doesn't really shine until the exhaust is changed. With longtubes both HP and TQ increase across the board, and this increasd low rpm TQ will actually increase fuel milage when cruising. Interestingly the stock 5.0HO cam produces nearly identical results to this one, just a few less peak HP.
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Re: Differences in 302 engine rebuild kits...?
Conaski, thanks for the info, it confirms what I suspected to be true. And, thanks for the cam info - gives me something to contemplate! You said that the cam can be changed without computer complications? What kind of limits in cam mods before the computer starts to dislike the changes?Also, this is a stupid question and hate to ask, but you referenced changing the "spider" in your first paragraph - what's the spider?
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From: Ottawa, Ontario
The limits on the cam have to do with total duration and lobe overlap, the SD efi system relies on a steady vacuum signal so the cam cannot be too radical, in general LSA of 114 degrees and intake duration below 215deg at 0.050" valve lift. Cams with LSA iof 112 degrees will also work when duration is down close to 200deg@0.050". Total valve lift doesn't really factor into this issue, and more lift will produce more power in most cases, so there's no reason to use a needlessly small cam.
The roller cam motors use what's called a spider assembly in the lifter valley to control the movement of the roller lifters. The rollers are flat so they have to be prevented from rotating in the bores or cam damage will occur. You'll find a dogbone around each pair of lifters and a leg of the spider holds it in place...
The roller cam motors use what's called a spider assembly in the lifter valley to control the movement of the roller lifters. The rollers are flat so they have to be prevented from rotating in the bores or cam damage will occur. You'll find a dogbone around each pair of lifters and a leg of the spider holds it in place...
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From: Detroit suburb
I agree, good post here .... Regarding that exhaust, you suggested the long tube headers and 2.5 inch tubing. Should I leave the converter off, or will I need to put back on ? Also, I am assuming the motor will want the O2 sensor to run right. Say we leave the cam out of this (for now), what will the exhaust modification do to mileage ? Did you make a suggestion for the cam ? I believe the graph was for a 351 - correct ?, mine and the posters are 302s - will that be pretty close for ours ?
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You won't be able to use the stock converter with longtubes, but there's no reason not to use a universal high flow cat, it'll help reduce noise in the cab and won't hurt performance at all. Here's my exhaust system as an example, that's the cat next to the transfer case.
Exhaust on these trucks is a major improvement and easily felt from the drivers seat, expect a couple mpg increase in milage from that alone.
Exhaust on these trucks is a major improvement and easily felt from the drivers seat, expect a couple mpg increase in milage from that alone.
More Turbo
Joined: Mar 2003
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From: Detroit suburb
Conanski:
Thanks for the pics. Nice setup, is that welded stainless ? Also, probably not a good idea to adapt down to the stock converter - smaller diameter tube ? I suspect you have long tubes, can't really see that, but have you researched which brands outperform others ?
Thanks for the pics. Nice setup, is that welded stainless ? Also, probably not a good idea to adapt down to the stock converter - smaller diameter tube ? I suspect you have long tubes, can't really see that, but have you researched which brands outperform others ?
More Turbo
Joined: Mar 2003
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From: Detroit suburb
At the bottom of your setup - you do mention flowtech - perhaps that's the answer. Do you have a muffler further back in the system ? Suggestion on that ? Or is leaving off the way to get that extra mileage ?