TFI Distributor Problem
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Postmaster
Joined: Aug 2001
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From: Delaware
TFI Distributor Problem
My 434 has an aftermarket TFI distributor. It has run good since it was installed.
Recently I had some crossfiring and had to replace the cap and rotor. I also reset the timing with the Spout removed to 10 degrees BTDC. The crossfiring stopped, but now it pings at light throttle. It never did that before. Also, while setting the timing, I noticed the timing mark jumping.
I just removed the cap again, and found that I can wiggle the rotor back and forth. It has more than a few degrees play.
Should an installed TFI distributor have play in the rotor? There are no springs below tha breaker plate like a normal distributor.
Recently I had some crossfiring and had to replace the cap and rotor. I also reset the timing with the Spout removed to 10 degrees BTDC. The crossfiring stopped, but now it pings at light throttle. It never did that before. Also, while setting the timing, I noticed the timing mark jumping.
I just removed the cap again, and found that I can wiggle the rotor back and forth. It has more than a few degrees play.
Should an installed TFI distributor have play in the rotor? There are no springs below tha breaker plate like a normal distributor.
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From: chicago burbs
did you ever check the dizzy for gear installed height? my Mallory Unilite beefed the gear and took out the gear on the cam too, may've been my fault because i had swapped the gear prior to finding it worn... i never checked the overall length or made sure there was free play clearance between the gear & block ledge. not that the gear should float above the ledge, but it can't be held in place against it either, it needs to be able to lift from resting on the ledge
http://www.fordracingparts.com/downl...tM-12390-A.pdf
http://www.msdignition.com/instructi...stributor+gear
MSD's have been reported to be 'out of spec' from the box, and at one time they gave a spec that didn't jive with what Ford stated. looks like MSD is giving a shorter than Ford measurement?
non-magnetic? aluminum, bronze?
what kind of gear do you have on it, are the outside edges of the teeth sharp or do they look as mfg'd?
http://www.fordracingparts.com/downl...tM-12390-A.pdf
http://www.msdignition.com/instructi...stributor+gear
MSD's have been reported to be 'out of spec' from the box, and at one time they gave a spec that didn't jive with what Ford stated. looks like MSD is giving a shorter than Ford measurement?
non-magnetic? aluminum, bronze?
what kind of gear do you have on it, are the outside edges of the teeth sharp or do they look as mfg'd?
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Postmaster
Joined: Aug 2001
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From: Delaware
The distributor gear is steel. The shavings appear to be aluminum, and may be from the distributor housing. The hold down clamp was hung up on the bolt, and the housing was not as secure as it should have been. The distributor gear looks good, and looking down the hole at the cam gear, it looks OK, but I am not sure.
The teeth on both gears look squared off on the ends, and not sharpened.
I'm going to check the play in the timing chain tomorrow. It could be a timing chain problem.
The teeth on both gears look squared off on the ends, and not sharpened.
I'm going to check the play in the timing chain tomorrow. It could be a timing chain problem.
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From: chicago burbs
if you do go into the front cover, that's about the best/easiest way to check your dizzy gear free play clearance... snug the hold down clamp like you'd drive it and see what it really is
now i see you stated that the shavings were AROUND the dizzy hole, i always jump to the dizzy gear clearance having been bitten... but it's still important
now i see you stated that the shavings were AROUND the dizzy hole, i always jump to the dizzy gear clearance having been bitten... but it's still important
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Postmaster
Joined: Aug 2001
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From: Delaware
I'm not going to take the timing cover off yet. I'll check the timing chain by rotating the crank back & forth and watching the rotor. I have timing tape on the damper, so I should be able to get a good reading of the number of degrees of play.
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Postmaster
Joined: Aug 2001
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From: Delaware
There is a chance that this is an electrical problem. Testing the crank-to-rotor play should help determine if it's mechanical, or if I should look elsewhere.
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Lead Driver
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I'd cut the oil filter open and see whats in there seeing as you found the shavings in the block.
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Postmaster
Joined: Aug 2001
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From: Delaware
The shavings were on the top of the block, around the distributor hole. I will remove and cut open the oil filter.
I put my Mallory Unilite in the motor and turned the crank by hand, in both directions. I did it several times and the play was about 10 crankshaft degrees. I don't know how much is normal.
I set #1 cylinder to TDC, then reinstalled the TFI distributor. There are two sets of timing marks. The 10 degree mark on the correct set was partially obliterated by silicone. I removed the silicone and remarked the 10 degree with white paint.
I started the motor and moved the distributor until the 10 degree mark was at the pointer. It didn't seem to jump around like before. I reinstalled the spout, and it idled right down.
I haven't driven the truck yet, but it sounds much better.
I think that I had the timing set wrong, and due to the oblitered marks thought it was jumping. I'll give it the seat-of-the-pants test next.
Does 10 crankshaft degrees play in the crank-to-rotor motion sound normal?
I put my Mallory Unilite in the motor and turned the crank by hand, in both directions. I did it several times and the play was about 10 crankshaft degrees. I don't know how much is normal.
I set #1 cylinder to TDC, then reinstalled the TFI distributor. There are two sets of timing marks. The 10 degree mark on the correct set was partially obliterated by silicone. I removed the silicone and remarked the 10 degree with white paint.
I started the motor and moved the distributor until the 10 degree mark was at the pointer. It didn't seem to jump around like before. I reinstalled the spout, and it idled right down.
I haven't driven the truck yet, but it sounds much better.
I think that I had the timing set wrong, and due to the oblitered marks thought it was jumping. I'll give it the seat-of-the-pants test next.
Does 10 crankshaft degrees play in the crank-to-rotor motion sound normal?
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From: chicago burbs
10* doesn't sound real bad, but not real good either. where does that leave your cam with that deflection factor? might wanna do a quick degree check
i pulled the front cover off one of mine after about 500 miles on a cheap timing set and was very surprised to find that it was pretty much toast. i didn't do the rocking rotor test on it because i was already in there and could see the slack on the loose side of the chain. after seeing that i knew why they only race 500 miles
i pulled the front cover off one of mine after about 500 miles on a cheap timing set and was very surprised to find that it was pretty much toast. i didn't do the rocking rotor test on it because i was already in there and could see the slack on the loose side of the chain. after seeing that i knew why they only race 500 miles
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Postmaster
Joined: Aug 2001
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From: Delaware
This is a Rollmaster timing set. It was installed by Tim Meyer when the motor was built. I don't have a lot of miles on this motor, but it does have a lot of valve spring pressure.
I emailed Tim to find his opinion about 10 degrees crank-to-rotor play.
I emailed Tim to find his opinion about 10 degrees crank-to-rotor play.
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From: chicago burbs
how much of that 10* is just the dizzy vs cam gear? in your first post you say that the rotor moves more than a few degrees by itself, the actual chain slack is that much less...
and now you don't see the variation that you were seeing, so maybe it's all good
also don't forget that crank / distributor is 2:1, so if you're seeing 10* at the crank the gear slop could be most / all of it
i'm still interested in doing a 'post stretch' cam degree comparison someday
and now you don't see the variation that you were seeing, so maybe it's all good
also don't forget that crank / distributor is 2:1, so if you're seeing 10* at the crank the gear slop could be most / all of it
i'm still interested in doing a 'post stretch' cam degree comparison someday
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Postmaster
Joined: Aug 2001
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From: Delaware
I just got a messge from another forum that says if you use a MSD Multispark ignition, do not use a dial back timing light. It can trigger on the multiple spark and make it look like the timing is jumping.
My ignition is a Holley Annihilator Multispark. I don't have a dial back timing light, but it might be possible that my light is false triggering from the multispark.
My ignition is a Holley Annihilator Multispark. I don't have a dial back timing light, but it might be possible that my light is false triggering from the multispark.
