Cam shaft suggestions

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vines

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I have a1987 5.2 carbureted factory roller tappet engine , the computer has been eliminated.( the engine is now in a 1984 D150 short bed pickup) Now using mopar ECM ignition. Need camshaft suggestions due to no bottom end power and timing issues . Want to keep with the roller cam , due to Major cost in going back to a flat tappet cam … any suggestions ?
 
Factory roller cam will give you about as good as low end as any cam will. Check this list ....
  • Timing chain - install a new, good, double roller like a edelbrock, and I'd go 2* advanced.
  • Check compression, a few cylinders low on compression is a killer in performance and gas mileage. Just a few leaky valves is all it takes
  • Set the initial and total timing. Very important as well.
If all three of these are lacking just a little, they add up to a lot.
 
I see alot of reground roller cams on ebay. Several different grinds to choose from at a good price. I don't have any suggestions though.
 
aaronk785 said:
I see alot of reground roller cams on ebay. Several different grinds to choose from at a good price. I don't have any suggestions though.
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Be careful of those roller cams- most are Magnum cores, which will do two things in the OP's case:
1.) They are short-nosed cams that will lose you the ability to run a mechanical fuel pump, unless you use the Hughes cam adapter.
2.) The cam specs will be off when used in a roller LA, since the Magnum uses a 1.6:1 rocker ratio and the LA uses 1.5:1 .
 
i'd sort out why you don't have any bottom end and timing issues before jumping to the conclusion that the camshaft is the answer to those issues.

318WR brought up a very salient point, or the "death by 1000 cuts" as i like to call it. compression is a little low, timing is a little off, carb tune is wonky and you get a turd that doesn't have enough power to pull a sick ***** off a piss pot.

get your basics in order: compression test, cylinder balance test, leak down, distributor timing and curve, carb dialed in, all vacuum leaks eliminated. make it run a good as possible before tearing into it. throwing a cam and timing chain at a motor with a soft cylinder isn't gonna make it any better.

as far as a cam goes, i'd contact oregon and talk with them and have the cam reground to their suggestion for the application.
 
Do all the aforementioned first. Then if you decide on a cam regrind:
Oregon Grind #1006
203/208 @ .050
260/264 @ .006
.410/.425 lift
110 LSA but have the LSA set on the tightest your core will allow, which will probably be a 109 if you have a 111 LSA core.
Ken recommends this grind more often than not for towing applications.
 
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I'll just echo what's been said by the previous posters...very sound advise.

Low end power can be very suggestive and with your ''stockish combo'' it's never gonna be a tire blazer imo even though it's not a real heavy truck, thou 318WR may disagree :). I suspect the cranking compression will be fairly low...125/135 ish psi, so once that's known you'll be able to justify if a cam upgrade will be a good cost per dollar endeavor.

That said, get as much timing in it as it will take on the fuel you run and find out what rear gear you have and how tall your tires are. That may have more to do with the performance then any cam swap could bring. The Magnum teen 6' bed i had wouldn't have been anything to right home about except for the low gear 5spd, 3.55's & smallish 29'' tires.
 
I agree with all the above. Just know that if you go with a "larger" than stock camshaft, you're moving the power peak UP in the RPM range, so that will have a negative effect on the bottom end torque you want to keep.
 
Just to compare;
I put my absolutely stock long-block, 1973 Low compression, winter motor into my son's 84 D150/regular wb, and and it smoked the 275/60-15s. In fact, to keep the tires from getting violent, I had to fabricate a long pinion snubber.
The teener had 4bbl and a single exhaust system with the truck logs, that's all, and on a good day pumped 138ish psi.
I installed 3.55s, a 2800 stall and an A998 with the 2.74 low gear, and we run at 900ft elevation.
Eventually, we put 3.23s in it, to bring the hiway rpm down..
___________________________________________
My guess is yur gonna need a new convertor and some gears.
 
RustyRatRod said:
I agree with all the above. Just know that if you go with a "larger" than stock camshaft, you're moving the power peak UP in the RPM range, so that will have a negative effect on the bottom end torque you want to keep.
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I think question/trick become especially in a small cid, low cr, stock stalled/geared.
How much can the peak tq/hp can be moved up by cam before it's an issue ?
Some say zero and others a fair amount, part of the problem is that it mainly comes down to personal preferences.
 
vines said:
I have a1987 5.2 carbureted factory roller tappet engine , the computer has been eliminated.( the engine is now in a 1984 D150 short bed pickup) Now using mopar ECM ignition. Need camshaft suggestions due to no bottom end power and timing issues . Want to keep with the roller cam , due to Major cost in going back to a flat tappet cam … any suggestions ?
Click to expand...
How many miles are on the engine?
 
the computer camshaft is my problem! According to Chrysler , the computer advances ign 55+ degrees off idle . Have been told I need a totally re engineered cam the dist only gives approx 28 degrees total advance
 
vines said:
3:55 factory positrac
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Sure grip, okay yeah it sounds like it needs more torque if you don't like how it is....I don't think those engines made much for power but since it's not computer controlled I'd go with what Garrett Ellison said, that should work.
Also try a little more advance on your timing
 
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vines said:
the computer camshaft is my problem! According to Chrysler , the computer advances ign 55+ degrees off idle . Have been told I need a totally re engineered cam the dist only gives approx 28 degrees total advance
Click to expand...
I don't know where you're getting that load of bull.
The cam doesn't care if the ignition and advance is supplied by a computer or an ECU with a mechanical/vacuum advance distributor.
Your cam specs are:
432/432 lift
31* overlap
113 centerline ( a little much, but not a deal breaker)
115 installed.
I run this exact cam in my Dakota (2.9x ish gears) with a Holley 600 4 bbl. and Chrysler electronic ignition, and I've got enough bottom end to peel your lips back even pulling a trailer... You've got something else going on.
Make sure your advances are both working- vacuum and mechanical (your vacuum advance IS hooked up to a ported vacuum source and not manifold, right?). Make sure you've got at least 15* initial dialed in, give it more if your engine likes it. You should be looking at close to 40* total...
You didn't say what you're running for a carb- hopefully you're not trying to still run the computerized "feedback" 2 bbl.- if so, that could be the majority of your problem. It requires input from the computer (now gone) to function correctly. If you have a different carb, go through the usual diagnostics to make sure it's performing as it should.
Bottom line is that bottom end should not be an issue with this cam.
 
273 said:
I think question/trick become especially in a small cid, low cr, stock stalled/geared.
How much can the peak tq/hp can be moved up by cam before it's an issue ?
Some say zero and others a fair amount, part of the problem is that it mainly comes down to personal preferences.
Click to expand...
It's a good question and one I was worried about having to choose a cam whose duration is 250 @ .050 for a high compression slant 6. But the results surprised me as there's no real loss of torque down low. I'm sure the 3.23 gear and manual transmission help, but still, it's way snappier than I figured it'd be. So there are exceptions.
 
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the dist only gives approx 28 degrees total advance
That's pretty easy to fix. They only need about 34 total any way. Plug the vacuum advance into ported vacuum for around 50°.
 
RustyRatRod said:
It's a good question and one I was worried about having to choose a cam whose duration is 250 @ .050 for a high compression slant 6. But the results surprised me as there's no real loss of torque down low. I'm sure the 3.23 gear and manual transmission help, but still, it's way snappier than I figured it'd be. So there are exceptions.
Click to expand...
No wonder the 264 @ .050 is like a street car cam in my 471
If your intake closing point is sooner or closer to some of the smaller cams, yeah it will kick some *** down low
 
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