I'm new here to this forum, so hopefully someone can help. I had a reputable shop in my area do a cam swap for me yesterday. My motor specs are as follows:

1974 Dart
1971 383 Magnum (9.0-1)
ported 452 heads with steel shim gaskets
Performer RPM intake
AED 750 DP
Cam WAS a Comp XE 268 hydraulic
headers
Dana 60 with 4.10. 2400 stall
Mopar electronic ignition with MSD box.

I went with a Mopar .484 hydraulic. It was installed straight up per their recommendation. (I was thinking 4 degress advanced). I know it may be a bit big for my 383, but I figured with the light car, gears, good intake and headers that I would get some more upper RPM power. Now keep in mind my motor ran great prior to yestedray, no ignition issues at all. Well, I picked the car up last night after hours and this is what I found. It fired right up. Idle was not adjusted so it barely idles in gear. Upon slow accleration, the carb spits and car almost stalls. This happens at every take off. Then the car feels like it is running on 5-6 cylinders. NO POWER at all. Frequent popping from header pipes (sounds like a backfire, but not as loud.) My tranny which normally shifts around 2800-3000 RPM at cruise now needs to go to over 4000 RPM to shift!!! I finally limp it home and look under the hood. They removed the timing tape from my balancer and did not replace it! And the same oil filter was on the motor that was there before I took it in!! So I'm assuming they never even changed the oil, who knows? I was so tired last night that all I was able to do was verify that the firing order was correct. They claimed that they had to replace some of my "burnt" plug wires and that they were having ignition problems, but I never had any ignition problems until it was at that shop. So suffice it to say, I am very angry. I had a great running car that now runs like crap (my Corrola could blow my Darts doors off). The only thing it does remotely decent is idle, as soon as you drive it sucks. It literally feels like if you removed 2 plug wires from the motor and tried to drive it. I don't even know where to start now. (I will be dealing with that shop on Monday) but don't want to take my car back there. I don't trust them. I would appreciate any and all recommendations Thanks

Double check the firing order 1 8 4 3 6 5 7 2. Make sure the timing isn't advanced or retarded too much (distributor). Look for any vacuum hoses off. They may have got your cam a tooth off, did they degree it?

it ran good with the comp XE then the shop swapped cams now it runs as described? I'm assuming they reused the timing chain/gears which'd eliminate that potential (mismarked gears). I'd turn the dampener timing marks to 15BTDC #1 compression then line up the magnet with the tooth that places the rotor under the #1 plug wire on the cap & retry it. They may have inadvertently retarded the cam but I'd talk to them before I opened it up that far. I would check the plugs/wires/reluctor gap. Holler how it turns out with them. EDIT they may have caused a vacuum leak at the valley pan

I did verify the firing order last night. I didn't see any vacuum hoses off, but I'll look harder when I get home tonight. They did not degree the cam. Installed it dot to dot. I wanted them to degree it and install it a 4 degrees advanced, but they said that because my heads were milled 0.060" that there could be PTV clearance issues, so they recommended straight up.

Lots wrong here, 1st the old cam is a much better cam especailly for a 9:1 motor. Even when you get it going I doubt you'll see much if any improvement. 2nd take it back to the shop and demand it run right. Seems they probably don't know anything about older cars...at least mopars. The trans issues is because they dorked up the linkage, you will have to re-adjust it. Other than that YOU are going to have to start from scratch and TUNE it. You might need to also pull the carb and drop down the PV as the 484 will not pull great vaccum... if you need to know "how to tune" we can go more into details. Sorry for all of this. I think the best advise I can give is do it yourself. Not too many shops know how to work on older "hot rods"

NO WAY no how a 9:1 383 is going to have a clearance problem w/ a 484 cam. They just didn't want to degree it.

Just something easy to check, and they were in there...pull the dist cap and make sure the rotor contact isn't twisted and is indexing right...

RapidRobert,

Yes, they did reuse the timing chain and gears. So you are saying turn the engine over until timing tab is at 15 degrees BTDC on the compression stroke, then line up the rotor of the dizzy under the number one plug terminal right? And yes, the car ran very good with the 268. Other than the cam change, nothing else was done. There cannot be too many things that can be causing this right?

Mr Yuck,

I agree about them not wanting to degree it too. I know I should take the car back there, but now I don't trust them and I think I would just rather learn to tune it myself with all of your help of course. I like to learn (this is my first MOPAR, former chevy guy) and I know I will give more attention to my ride then than any shop ever will. And honestly, I'm not sure if the car would make it there with how it is running now anyways.

pull #1 bump the engine untill your finger blows back.. Then back the engine to TDC. Now check #1 on the rotor. Some distrib caps have 2 number 1's and some are in the wrong place. Now check the order. Then crank your idle up to 2200. With NO vac advance set your timing at 36* then bring the idle down to 1000. Set for best vaccuum. Go for a drive. If they re-used the old gears and are off a tooth or more it isn't going to run right and you'll have to plull the front of the motor apart...of course I'd make THEM do that. to check if you have a vac leak around the intake, start it and spray brake clean around the edges.

by the sound of the shop they may have not broke the cam in might have flat lobes

probably needs the timing advanced you will likely have to recurve the distributor.

next dot to dot could be anywhere on the cam timing?? degree is the only way to know. Yes those cams like a little extra advance at 108 to 110 it will be a dog calls for 106 probably best at 102 to 104.

I just installed a 509 in a 383 for a friend dot to dot with a new mancini timing set was 114 so 8 degrees retarded form 106 It would have been a super dog and maybe bending exhaust valves too.
I got it to 106.5 so should be fine with a 4 speed and 4.56 gears.

Did you use a fel pro composition gasket? if yopu did it is .017 thicker than the old steel shim so only like milling .044 off or so

What else did the mess with maybe the lickdown linkage adjustment.



Wonder if they plugged the vacuum advance into manifold vacuum to get it to idle many know nothings use this method to make a bigger cam idle at the expense of performance but it helps them idle well as it holds the timing up but when vacuum falls off as the throttle plates open the timing falls back too and the performance really sucks



My honest opinion is the cam is retarded, the timing not advanced enough and maybe a band aid of the vacuum advance on manifold vacuum.

and MR yuck is right on the PV number needing to be changed down.


Also you could probably use a 3000 stall but you should be able to get it running much better than it is with a few tweeks!

The vacuum advance is not hooked up. Ported vacuum port on carb is capped. Even if the cam is a few degrees retarded I can't imagine it would run like this and lose THAT much power. I will check the timing as best as I can when I get home tonight. I won't be able to give total because if you remember from my other posts, the shop removed it and never replaced it. My total was 38 degrees before with around 22 of initial. Just by looking, the dizzy seems to be in about the same place as it was before. I mean other than the cam swap, nothing else was done! I figured they would button it up and obvious it would need some tweeking (new power valve, timing tuning, etc..) but nothing major that I would have to consider taking the motor apart. For some reason I have a feeling that I am going to me taking the front of the motor off and re-doing everything. I swear I will never take my car to another shop again

Given that you got the car back running like crap, I would guess a bunch of things, most of whcih were mentioned here already. First, are you sure they broke in the cam properly? I assume hydraulic flat tappets. Did they use ZDDP additive or breakin oil? You may want to pull valve covers and look into the engine to see if you can verify you don't have wiped lobes already. It may be beneficial to make sure all the push rods are seated too. You didn't mention if you had an oil pressure gage and what it was reading. I have been able to pull lifters out using a small extension magnet (like Harbor Freight sells). You need to pull rocker shaft and push rods. The magenet fits into the push rod pocket and you can pull it out. Take a look at the lobe and bottom of lifter for proper wear. Do one at a time so you don't mix them up. I use the pick tool up to drop the lifter back into the bore and a thin wooden stick (marshmellow sticks in my case) to hold lifter back in bore while pulling magnet off the lifter.

Second, get the No.1 cylinder to TDC, verify timing mark, and pull distributor. The slot in the distributor gear should run along the axis of the cam. It may be off a tooth. You can compensate for that by rotating the distributor, but you will run out of timing adjustment as the vacuum advance can will hit the manifold or water neck before getting good adjustment. So getting it lined up is just good practice. With the slot orientated along the axis of the cam, the distributor rotor should be pretty close to No.1 cylinder on the cap (or 180 deg off, rotate as necassary). Some caps have two No.1s as mentioned. I think you want the one that is toward the cylinder head, not the one pointing towards the carb. If you have a manual (even a Chiltons) you will see what I mean.

OK, with that set, check the firing order on the wires and plugs. Sounds like you got it, but it never hurts to double check. At this point, I usually find an extra set of hands to start the car while I twist the distriubutor a tad to start the car up. I recurved my distributor to get me about 5 deg BTDC (IIRC) at 500 RPM, with full advance of 36 deg at 3000 rpm. I am not sure of initial, but I am sure of my full in. You will have to play with the distributor to get things initially started. Recurving is for another thread once you get this running.

The cam change will probably necessitate some carb changes. I'd think at a minimum idle misture screws and power valve. Once you get the idle and off idle set, go run it to see if you lean out to check main jets. Checking for vacuum leaks before making adjustments is key.

As I am mostly a pessimist, my guess is that your cam is wiped out. If they didn't change the oil (as you indicate by having same filter), I doubt they did anything to add proper protection on start up. And if its running like crap, I would bet they didn't run it in properly. Good luck.

Sorry if this is a repeat, on. A mobile and cant read the whole thread. Anyway, remember that bb fire counter clockwise, they may have the firing order right but have it in the wrong rotation. As stated but some glimpses ive scene start with the basics. Basic timing, baseline the carb, go from there.

This is all under the category of "I second that emotion"....

> Sprocket / chain a tooth off - my #1 hunch.

> Lobe(s) wiped (cut open oil filter and you'll know)

Rick

Could be:

1) Unattached vacuum line(s)
2) Intake leak
3) Distributor installed incorrectly (timing problem)
4) Cam timing off
5) Wiped cam lobe(s)

Do these guys regularly do this type of work?
Is this a professional Auto repair shop?
What is their experiance with classic musle mopars?
Which "484" cam is it?
What was the cost for the labor?

UPDATE!!!

I just got home from work and started the car up and it took forever to warm up. Idled barely at 600 RPM. So I throw a timing light on and check the timing. Would you all believe it was so retarded that the timing notch on the balancer was below the timing tab!!! I'm guessing at least 15 degrees or more AFTER TOP DEAD CENTER!!!! How on earth could a reputable performance shop leave it like that??? I advanced it just to get to 0 degrees and it already seems much more responsive, albeit just revving a little in the garage. I'm letting it cool down now and I'm gonna change the plugs and I have to wait until my wife gets home so she can crank it while I feel for the air coming out of cylinder number one, then I'll go from there. I'm keeping my fingers crossed that this is the problem!!