|
#1
|
||||
|
||||
Minor problems with cam break in?
I broke in my cam in my 440 last night and had a few minor problems that I would like to get everyone's opinion on. These are all issues that I have looked for and reviewed in other topics, just not together.
The timing mark was jumping all around, making it really difficult to get the timing correct. I used a dial back style light that I have never had any trouble with. I was shooting for about 35 degrees advanced. This is a recently tested MSD6AL box with a distributer with no vacuum advance, and 1 Mr Gasket Recurve Spring (should all come in by 1800 or so). Any ideas what would cause the timing mark to move around like this? The headers were all equally glowing orange, most likely since the timing was retarded from the timing issues from above. This is the result of retarded timing, correct? The carb on this motor came directly off of my 318, which had a lot of tuning to run correctly on the 318. It should be close enough for the 440 for now. Can this possibly be the result of a rich or lean condition? The car started fine and got through the break-in period with only minor issues (forgot to plug in fan). When completed, it idled farily well, but when I gave it gas it backfired slightly through the carb. I checked for vacuum leaks and I found none. What do all of these things mean? I imagine that they all could be related to the timing issue, or a combination of several issues. Any ideas where I should start? Dartman |
#2
|
|||
|
|||
Sounds like a typical lean condition. Richen it up and everything will probably come together, even the erratic timing marks, red headers, ect. What color are your plugs?
|
#3
|
||||
|
||||
hello, a very lean condition, also, MSD states; do not use a dial back timing light with their MSD boxes. they have a delay in them. causes erratic timing.
just food for thought. |
#4
|
||||
|
||||
Plugs looked pretty good. They actually looked nearly new, with only a faint light brown discoloration.
When we are talking lean, are we talking about the idle circuit or the main circuit? The 2500 RPM or so should be well past the idle circuit, so I was just wondering. The blades in my primarys have a small 1/16th drill hole in them left over from the tuning I did on the 318. If it is main jetting, what would you suggest for a starting point? Could I similate a richer mixture by using the choke to see if that helps me set the timing? Is a lean condition also responsible for the carb backfiring or is that timing? Thanks! Dartman |
#5
|
||||
|
||||
When the headers glow red it is because it is rich and it is burning in the headers still, so it is creating more heat.
I have noticed when I time that if i put the clamp around the wire and pull it away form other wires it will stop bouncing all over, I think it is getting feed back off of another wire when it bouces like that. try that once. |
#6
|
||||
|
||||
I just caught perfmachst comments.
Can use a dial back set to zero in conjuction with a timing tape? Or can I simply take a harmonic balancers outside diameter and calculate where 35 degrees lands on the harmonic balancer? Or is it actually half of the diameter? Is 35 degrees fairly normal total timing for a big block? Would I be better off trying to set the initial at 6-8 degrees, and then letting the total fall into place? Thanks again... Dartman |
#7
|
||||
|
||||
set for 35-38 and let the timing fall back to wherever, it is adjustable by changing the slot length in the distributor by grinding or welding up. Yeah, try and use a different in line timing light or at least set it to zero, that may help. You can see 7 or so hits on an MSD at idle with a snap-on timing light! just time to the first one...carb out of whack, not likely too far out. you should be able to time a 440 using a 600 as the CFM's are not being exceeded. They used 500 CFM carbs on 400+ Buicks and they ran great to about 4500.
|
#8
|
|||
|
|||
Lean will usually cause the spitting back thru the carb as will a weak shot from the accelerator pump. Sometimes the choke trick works well for pinning it down. 35 deg is 2-3/16" from the TDC mark.
|
#9
|
|||
|
|||
Make sure you dont have a intake valve too tight.
|
#10
|
||||
|
||||
I still was fighting the backfiring problems last night when I think I figured out at least part of the problem.
I checked the firing order and looked for loose plug wires onelast time, and then decided to start pulling the plugs to see if one was fouled or vastly different from the others. I pulled the first two and they looked pretty rich. I previously pulled #1 and found that I previously called "faint light brown discoloration" but I believe it was a little rich then too. I grabbed my screwdriver and checked the air/fuel adjusters and found that they were almost completely screwed out! I reset them to the standard baseline of 1 and half turns, and the car started, ran, and revved with no noticible backfiring or problems. The whole time I assumed this carberator was "as run" from my 318, and should be ready to go. I failed to realize that throughout this project I have had my "tuning buddy" helping me in garage... my 7 year old son. He typically won't get into too much trouble if I let him have a screwdriver and crescent wrench, I just didn't realize my carb was on the bench within his reach before it went on. I guess this is a good type of problem to have... I still am fighting the timing mark jumping around however. I have tried 3 timing lights and the problem still remains. I have marked my balancer at 35 degrees and have timing it there for now. Any ideas on this one? Dartman |
#11
|
|||
|
|||
Dartman, when my timing jumps around with the light, its usually the plug misfiring, look at the light and see if it has a steady flash, bring the rpm up and see how it reacts, you most likely fouled some plugs, take it for a spin if you can, clear them out.
|
#12
|
|||
|
|||
make sure the pickup and wire of the timing light is not touching any of the other plug wires but #1. or it will create a false signal from one of the other plug wires - at least mine did. After isolating the pickup wire all worked fine with a dial back light.
Your red headers are a result of not enough initial timing to allow burning in the combustion chamber so it kinda burns in the header tubes. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
HELPPPPPPPPPPP break problems again | 1fastski | Vintage MOPAR chat | 6 | 11-29-2004 07:47 PM |
'61 morris minor | Donald Scott | Performance Talk | 5 | 05-05-2003 05:41 AM |
Minor improvements - which ones first? | JeepMan_Iowa | Ram Truck Chat | 5 | 01-18-2001 02:38 PM |
very cheap minor mod | gouge97 | Ram Truck Chat | 0 | 08-14-2000 03:10 AM |
a few minor glitches | CRISCO2 | PT Cruiser Chat | 2 | 07-13-2000 05:24 AM |