Adjusting Idle and Timing 1985 Ramcharger
#1
03-29-2010, 01:18 PM
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Adjusting Idle and Timing 1985 Ramcharger
Hey guys,
I am helping my brother with his 1985 Ramcharger. He doesnt know sqwat about cars so I am trying to help him get it fixed up. The Truck has a 360, I just put a new cam in it due to a worn cam lobe. Got the truck fired up last night and it runs pretty good. My problem is the only way to get it to idle decent is if I have the timing way advanced. If I even bring it back down to TDC it starts to stumble and die. I know a little advanced is okay but I cant even see the timing mark it is so far off. Also he is running a Rochester Q-jet for his carb. Why that carb is on this truck I have no idea but it has worked for the past 10 years so what the heck might as well keep running with it. Any ideas on what to check? Is it possible to plug off all the vacume lines and try to set timing to eliminate any poss vacume leak? Or is there some kind of ECM control on an 85? Thanks in advance for all of your help. Look forward to getting this beast back on the road.
I am helping my brother with his 1985 Ramcharger. He doesnt know sqwat about cars so I am trying to help him get it fixed up. The Truck has a 360, I just put a new cam in it due to a worn cam lobe. Got the truck fired up last night and it runs pretty good. My problem is the only way to get it to idle decent is if I have the timing way advanced. If I even bring it back down to TDC it starts to stumble and die. I know a little advanced is okay but I cant even see the timing mark it is so far off. Also he is running a Rochester Q-jet for his carb. Why that carb is on this truck I have no idea but it has worked for the past 10 years so what the heck might as well keep running with it. Any ideas on what to check? Is it possible to plug off all the vacume lines and try to set timing to eliminate any poss vacume leak? Or is there some kind of ECM control on an 85? Thanks in advance for all of your help. Look forward to getting this beast back on the road.
#2
03-30-2010, 11:22 AM
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Update,
I was able to get the timing set last night at about 10 BTDC. and more advanced than that and it wants to die. Idles pretty good right there, but when you it the gas it is very under powered, and I thought when you rev up the engine the timing is supposed to advance. Every time I did that the mark would retard rather than advance. Is this normal?
I was able to get the timing set last night at about 10 BTDC. and more advanced than that and it wants to die. Idles pretty good right there, but when you it the gas it is very under powered, and I thought when you rev up the engine the timing is supposed to advance. Every time I did that the mark would retard rather than advance. Is this normal?
#3
04-02-2010, 02:21 AM
A couple of thoughts.. 1. Assuming this is an old Quadrajet, I don't believe that carb was ever intended for use on a Dodge 360. In fact unless highly modified, I don't believe a stock QJ has enough CFM capacity for that engine. QJ's had a history of damaged or plugged idle passages. Your friend may be better off with a universal carb such as a Holley or Demon carb.
2. One usually doesn't adjust idle with timing. Having to advance the timing to keep the engine running only punctuates that it may be operating with low vacuum or in a lean condition at idle. The best way to set the timing is to start out at 0TDC, adjust the idle at the carb to around 800 RPM, adjust the timing to the correct factory spec at idle, then readjust your idle speed at the carb back to 800 RPM. Idle is adjusted by changing the idle mixture jet(s) in combination with the idle throttle stop. If you have access to a chassis dyno, you can really dial things in by finding the best advance setting with mixture setting for lowest emission and most power to the rear wheels. The vehicle creates the most power and lowest emissions when the timing and mixture settings are adjusted properly.
Trying to course adjust the vehicle idle speed by timing alone, especially while operating in a lean condition, will create drivability issues and potential engine damage.
2. One usually doesn't adjust idle with timing. Having to advance the timing to keep the engine running only punctuates that it may be operating with low vacuum or in a lean condition at idle. The best way to set the timing is to start out at 0TDC, adjust the idle at the carb to around 800 RPM, adjust the timing to the correct factory spec at idle, then readjust your idle speed at the carb back to 800 RPM. Idle is adjusted by changing the idle mixture jet(s) in combination with the idle throttle stop. If you have access to a chassis dyno, you can really dial things in by finding the best advance setting with mixture setting for lowest emission and most power to the rear wheels. The vehicle creates the most power and lowest emissions when the timing and mixture settings are adjusted properly.
Trying to course adjust the vehicle idle speed by timing alone, especially while operating in a lean condition, will create drivability issues and potential engine damage.
#4
04-05-2010, 02:03 PM
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Well you are deff right I am sure the Qjet is not stock. It has been on the truck for years, and I have always called the thing a gutless wonder so that may be a reason for that. This weekend I capped of all the vacume lines except for the secondary, and the Electronic advance (i think thats what it is). After that it did run a lot better and had much better throttle response with the current timing. I did find the EGR has a leak when I sprayed it with Carb Cleaner. Thank you for your response I was begining to get a little dis heartend that no one would be able to at least shoot some ideas my way. I have a 650CFM holly sitting around that I could throw on for a trial, Would that be too much CFM you think? Also I am never able to advance the timing past about 10BTDC at 0TDC it will not run. I can retard it further and it seems to run better but I can not see the marks on the flywheel to see where it is, would this also indicate a lean condition? Thanks for your help, I would love just to get this thing figured out.
#5
04-06-2010, 07:34 AM
Assuming the carb was in good shape and adjusted properly, I agree that a Holley 650 would be a much better choice for that truck over a Quadrajet.
Before potentially over-advancing the timing, I would get the fuel situation resolved. Once that is done, make sure you're reading the timing marks correctly and even mark the scale where you want to be with a thin silver paint line while the engine is off. As I recall, the factory engine timing should only be somewhere in the neighborhood of 6-8 degrees BTDC. Unless of course there is a performance cam installed, and the timing could be differrent.
Once you get the engine idling, watch the timing mark (via timing light of course), and see if the mark moves up and down on it's own without moving the distributor. If so, then the timing chain may have slipped a tooth or have stretched to the point where your timing won't stay put. You could have worn distributor bearings too.
Before potentially over-advancing the timing, I would get the fuel situation resolved. Once that is done, make sure you're reading the timing marks correctly and even mark the scale where you want to be with a thin silver paint line while the engine is off. As I recall, the factory engine timing should only be somewhere in the neighborhood of 6-8 degrees BTDC. Unless of course there is a performance cam installed, and the timing could be differrent.
Once you get the engine idling, watch the timing mark (via timing light of course), and see if the mark moves up and down on it's own without moving the distributor. If so, then the timing chain may have slipped a tooth or have stretched to the point where your timing won't stay put. You could have worn distributor bearings too.