Duster Help #3

[wagnerjw]

Wondering if anyone has a cast 318 4-barrel intake or a resolution for a problem I'm having. I've asked on here before with help to my Duster not having any power after switching the 2-barrel over to a 4-barrel with an aluminum intake, .484 purple cam, and some other stuff. I went to shop that builds race engine and asked a guy if he could help me with my timing and he told me that my biggest problem is a Edelbrock or any other aluminum intake will not work on my late model 318 because the ports won't match up. So he said I either have to find a cast 318 4-barrel intake or put on a set of magnum heads from the 90's 318-360 engines. Will the newer heads work ok? What other options do I have. I received a cam from someone on here and I think I'm going to be putting that in this winter. If the person that sent that remembers the specs could you message me. Thanks for any help.

[JVMopar]

Why not just port match your heads? But yes the aftermarket intakes are almost always made for large port heads. I do believe there is a small port aluminum intake though, but I don't remember which one it is.

[chirorod]

Even though the ports don't match, they still would work. You won't get as much power that way, but you won't be completely doggy. I think there is some other problem.

[440roadrunner]

A port mismatch is not causing this problem

You WILL lose some absolute top-end power because of a port mismatch problem, but I've see lots of combos that ran pretty well with mis-matched manifolds. "Back in the day" there was a lot of that. You'd buy a used manifold, and figured it was "better'n what ya had." Ya, it was mismatched, but it still RAN, and often pretty good.

Also PLEASE STOP STARTING NEW POSTS

It is getting more and more difficult to follow what you have tried.

One of your other threads you mentioned 2.x rear end. That and a low stall TQ will ruin your day, but even at that, you should be able to "nurse" the car up to 3K RPM in first, and it should take off


One thing I think would be help ful at this point is to carefully list the engine/ car build AND WHAT YOU HAVE DONE

What heads again? ported/ shaved?

What cam? You sure the valve gear is OK, the springs? Checked compression?

Did you degree the cam when you put it in? What exactly are the specs, lift, duration? How about valve adjustment? You do a compression check/ leakdown check?

What do you have for exhaust oil/ valve cover blowby?

Distributor? timing curve? You sure? where is timing? you sure? Did you check your timing marks with a piston stop?

Intake? exactly? Not just the "name" but the exact number?

Carb? What model/ part number? Has it been rejetted? Did you check for full throttle open?

Engine temp? You sure? accurate temp gauge?

Fuel pressure / type of fuel?

Exhaust? Manifolds/ headers? ANY possibility of a restriction somewhere? Heat butterfly? Poor muffler design? debri inside?

[dodger1]

IIRC, Edelbrock made a small-port Performer for 318s, but I agree with the previous comments. You have other problems if it's a doggy engine. Also, I'd be tempted to find a set of big-port (360) heads and have them machined to suit the 318's smaller bore, rather than swapping manifolds.

[DartGT66]

The 318 cast iron intake will not solve the problem. All the 318 LA four barrel engines used 360 heads and intake = big ports on both. Good for a whopping 10 hp over the 2 barrell and small port/valve heads!

[440roadrunner]

I think this is either a "basic issue"

cam timing, distributor advance curve, carb jetting, or.....

the compression ration has been drastically lowered by those heads.

I would CERTAINLY save the last comment for "last."

You need to get SERIOUS about checking the timing and the timing MARKS. Get a piston stop and make sure the marks are correct

Tear down the cam drive if necessary, and "degree" the cam. You may have a "smogger" retarded cam drive set

Go through the distributor and make sure WHAT you have for advance curve, and that it is WORKING, and what the timing IS and what it BECOMES

What do the plugs look like? Running burned white, running black, ???

What TEMPERATURE is the engine running at?

[wagnerjw]

I originally had 340 heads and took them off. I now have the 74 original heads, headers, Edelbrock performer intake, Holley 650 Dbl Pumper, 2800 Stall and the Mopar Performance .484 Purple Cam. I've tried timing it-took it over to a Mopar guys house, he says it's right where it needs to be. What those numbers are I don't know. Temp is @ 190 degrees. We pulled all the plugs checked them, most where black, compression checked each cylinder head and they were all ok. I respect the engine builder because he's had Lunati, Edelbrock and several others contact him for cam specs and recommendations so he know his stuff. He said that there is no way the aluminum intake will work with my heads. He doesn't recommend porting the heads I have on there because it isn't worth the time and money. That's why he said find an older 318 barrel intake or switch out the heads. The engine guy stated that there is going to be a swirling effect because of two different port sizes which will create too much pressure resulting in the carb thinking it needs to pump more fuel which is why the plugs are all burnt up and you smell like you've been riding dirt bike all day after you've drove the car. He also stated that maybe the carb isn't set up right but I'm no carb expert and he won't look at for me. He only builds race engines, he doesn't work on them. I'm just trying get the car running as good as it sounds. I know all my engine parts and how they work I just don't know the tip and tricks to get it tuned correctly. Chevy and Ford guys are 0 help so that's why I'm trying on here. Maybe I'll just have to put it back to stock.

[chirorod]

First, carbs don't pump gas, except when the throttle moves, the accelerator pump works. Otherwise, a carb just allows gas to pulled into the the intake by the bernoulli effect. The plugs are black. There is your story. Something is wrong. Black plugs can mean too much fuel, bad ignition, or oil burning. Oil burning could be from bad rings, worn bores, bad pistons, or worn valve guides or seals. Too much fuel could be from fuel pump pressure too high, such as from an electric pump that requires a regulator, or from a bad float or needle and seat or someone having drilled out jets. Bad ignition could be anywhere in the ignition. Could be bad points and/or condenser, if you have those, bad rotor, cap, wires, plugs, coil, etc. You say compression checks out, but you don't know for sure, I think. But I would check compression again. All you need is for compression to be low to not have any power. If compression is really ok, do a tune up. The basics are first compression test, then tune.

[440roadrunner]

Black plugs could also be a false clue. If he's been "idlling around" they might be rich at idle. You need to make a "power run", shut it off "clean" and THEN take plug readings

I CAN NOT BELIEVE the intake is causing this problem

[coupe32]

That 484 purple shaft cam may be hurting you on low end power. Check the cam specs for that cam.

[dodger1]

My 2002 Mopar catalog shows 3 versions of the so-called "484" cam. All have 241 duration at .050" and .484" lift on both in. & ex. Part numbers are P4529958, 4120231, and 5007695; centerlines are 106, 108, or 114 respectively with a power range of 2600-6000 RPM.
Too much cam for this engine imho.

[wagnerjw]

Originally Posted by 440roadrunner

Black plugs could also be a false clue. If he's been "idlling around" they might be rich at idle. You need to make a "power run", shut it off "clean" and THEN take plug readings

I CAN NOT BELIEVE the intake is causing this problem

I can't believe it either. I keep going to different people to get advice because I'm finding out after what you guys tell me on here that everyone is telling me the wrong thing. I don't know what to do anymore. You want to buy a Duster!!!

[wagnerjw]

The cam Belvedere2 sent me is a Comp 268?? I tried googling it and was overwhelmed by specs and they are all different. good for my setup or not??

[wagnerjw]

Originally Posted by dodger1

My 2002 Mopar catalog shows 3 versions of the so-called "484" cam. All have 241 duration at .050" and .484" lift on both in. & ex. Part numbers are P4529958, 4120231, and 5007695; centerlines are 106, 108, or 114 respectively with a power range of 2600-6000 RPM.
Too much cam for this engine imho.

How would a Comp 268 cam work in your opinion. A guy on here mailed me one a couple of months ago. I'm thinking about putting it in.

[wagnerjw]

Anyone know how to make my old Carter 650 AFB work right? It's rebuilt with about 50 miles on it. I'm told they won't work right with low vaccuum circumstances like I"m having. The engine builder guy was saying something about shortening springs, cutting this and that. He lost me after about 2 seconds. I asked him if I could bring him the carb and he said he wouldn't work on it. He suggested putting that carb back on and getting rid of the Holley. Just thought I'd ask.

[wagnerjw]

Thanks again everyone for your help. I'm trying not to come off as stupid and I can see I'm aggravating some of you. I'm trying to get this running right on a budget and I get 10 different answers from everyone I talk to. One person says the cam is fine, the next says it's too big, One person says the carb is to big, stall isn't big enough, timing is off, heads are bad, cam is off a tooth. I'm on a limited budget and I have to rely on others who have tools and knowledge that I don't. thanks again for advice, keep it coming if you have anymore.

[cageman]

not enough compression, to big a cam and to big a carb. Thats why the factory engineered two barrel whoops its butt. You also probably have to tall a gear, and the add ons you have have made the low end torque non existent.
I have a 273, it runs pretty good, but I have compression, and a decent cam. I am running a 600 carb on it, and it is still too big. I have been looking for a 390 four barrel holley, but Im to cheap and the ones in my price range are usually junk, lol
I also have a 318 with the same combos as you want, 484, 80's cop car heads and cast iron 4 b intake in my power wagon. It has a dp 600 holley and it runs pretty good, once it gets rolling, I blame the turd being the 4.10's and 35 inch tires, so its either give it more gear, or put a cummins in it. lol again. It worked in another turck, why not my power wagon. Took out the 318 and put a cummins in and never looked back. Why does the cummins work good, it has torque, lots of it. tall gear, torque and it goes.
Your combo is tall gear, low stall, and to much cam, carb and lack of compression, all of which lowered the torque.

[chirorod]

I think you are going to have to educate yourself. You have to know what your are doing. You are in too deep for the amount you know. Get a book on how engines work and how to do the basics. Get or borrow a compression gauge. Learn how to use it. Then pull all the plugs and check the compression.
If compression is low in one or more cylinders, you will have found one problem. That would have to fixed before anything else.
If compression is good and even, learn how to do a tune-up and do it. If it runs ok then, great. If not, check cam installation. Maybe cam timing not set right. Maybe valve springs are wrong. Maybe pushrods are wrong, so valves don't close.

[Rich Kinsley]

I saw that you had a 2.something rear-end. That is totally unacceptable for a set-up like you have. A 3:91 is closer to right. Huge tires also cause your gear ratio to change for the worse.
FYI as reference, I have a 318 poly with dual-quads, 3000stall, nasty cam, headers, etc. etc., etc..
I had 2:76 gears stock and used them for awhile till I got the new 3:91's put in. The car was very doggy and the mileage was horrible. It was like night and day to change to the 3:91's. My gas mileage even almost doubled as the converter didn't like the low rpm's around town. I run 255/60R15's on the street but have a set of 215/60R14 drag TA's for even lower gear ratio for the 1/8th mile. That puts my ratio effectively around 4:40.

If you have your tune good, or even not, you will find the gear change to be THE best help for your set-up.

[wagnerjw]

Originally Posted by Rich Kinsley

I saw that you had a 2.something rear-end. That is totally unacceptable for a set-up like you have. A 3:91 is closer to right. Huge tires also cause your gear ratio to change for the worse.
FYI as reference, I have a 318 poly with dual-quads, 3000stall, nasty cam, headers, etc. etc., etc..
I had 2:76 gears stock and used them for awhile till I got the new 3:91's put in. The car was very doggy and the mileage was horrible. It was like night and day to change to the 3:91's. My gas mileage even almost doubled as the converter didn't like the low rpm's around town. I run 255/60R15's on the street but have a set of 215/60R14 drag TA's for even lower gear ratio for the 1/8th mile. That puts my ratio effectively around 4:40.

If you have your tune good, or even not, you will find the gear change to be THE best help for your set-up.

I just got that advice today from someone else. I ordered 3.55's because I was told that if I have a 9 bolt rearend it's a 7.25. so ordered gears for that and once I tore into it I found out it's a 8.25. I'm just waiting on the gears. Hope that cures some of my problems.

[wagnerjw]

Originally Posted by chirorod

I think you are going to have to educate yourself. You have to know what your are doing. You are in too deep for the amount you know. Get a book on how engines work and how to do the basics. Get or borrow a compression gauge. Learn how to use it. Then pull all the plugs and check the compression.
If compression is low in one or more cylinders, you will have found one problem. That would have to fixed before anything else.
If compression is good and even, learn how to do a tune-up and do it. If it runs ok then, great. If not, check cam installation. Maybe cam timing not set right. Maybe valve springs are wrong. Maybe pushrods are wrong, so valves don't close.

I just don't know particular things. I know mechanics who have been in the field for 30yrs who don't know how to "hot rod" engines. Some people have a knack for it others don't. You have to admit there is a lot of crap someone needs to know to make everything work in harmony. Most is learned by trial and error and I don't have the $ to learn the hard way.

We checked compression and every cylinder was the same. I know how to do a tune-up and the plugs have been replaced, wires are new, cap and rotor are new. I took the distributor out and a guy is curving it. I don't know what that is, I know how to time a car but I've never "curved" a distributor before. Next is the gear swap.

[cageman]

On all my stuff, I get rid of the vacuum advance and set the initial timing to around 18 or so. You have to weld up the slots on the mechanical advance to do that. Then I like it to be all in by 2500-3 grand for a total of 36 degrees. cleans up the idle and it gets the advance going faster with lighter springs. Thats what curving a dist is. I dont have a spin machine to tell, so it is trial and error. those things are hard to find.

[dodger1]

Originally Posted by wagnerjw

How would a Comp 268 cam work in your opinion. A guy on here mailed me one a couple of months ago. I'm thinking about putting it in.

At the risk of sounding like I'm preaching, here's my opinion on that cam. I don't have one. Because first, I've never run one, and second, there are several "268" Comp Cams in their catalog. That number refers to what Comp Cams calls the "grind" number. The actual cam specs vary, sort of similar to the "484" purple shaft (Mopar) variables. So you would need to get the exact Comp Cams part number, then go to their website and compare the specs to the "484" Mopar cam. If you know which of the 3 Mopar cams to compare it to.
Same goes for whoever is using a "268" cam. Their experience may be useful to you if the cam specs are known, as well as the rest of the engine specs that the user is running the cam in.
I'm glad you have an 8 1/4" axle - the 7 1/4" one would not last long behind any kind of power. 3.55's will help out.
One of the principles of modifying cars, engines, etc. that took me many years to get through my thick skull is to only make one change at a time. That's basically the only way you're gonna know what the effect of that change is. The axle ratio is a good example of that.
I do have an opinion on the distributor recurve. The term generally applies to modifying the innards in order to change the rate the centrifugal advance curve is applied. If you don't know what the recurve will be, you shouldn't be doing it. As for running no vacuum advance, as cageman does, that's fine if you don't care about cruise m.p.g., which is basically what the vacuum advance mechanism gives you. It is inoperative at low vacuum anyway so will not affect full-throttle advance.
With respect, I agree with chirods advice. Do some homework on the basics before you start throwing $$ in parts at the car.