Straight 6 timing
Thread Starter
|
New User
Joined: May 2017
Posts: 19
Likes: 0
From: Calgary AB
Straight 6 timing
Hi all, long time lurker on this site and now I need some wisdom.
I got a 77 300-6. Its been on propane for the last 20 years and I have just switched it back to gas. Fired up and ran great from the start but it keeps detonating.
I found TDC and everything lined up with the #1 cylinder, rotor and teeth on the passenger side. Using my timing light i set it at 8 BTC and it ran good but still detonating. I have from there ran up and down from 14 to 0 and it wont stop detonating.
I have a buddy thats a 300-6 wiz and one hell of a mechanic and we played with it for awhile and he couldnt get it to stop either.
With it being on propane for the last while I didnt think there would be alot of carbon build up. I was wondering if someone might have jumped a cog on the distributor when timing it on propane or something.
I can only find 2 marks on the pulley and there both triangular notches. Should there be a line on there to?
Am I maybe doing something wrong or missing something?
Any input is greatly appreciated.
I got a 77 300-6. Its been on propane for the last 20 years and I have just switched it back to gas. Fired up and ran great from the start but it keeps detonating.
I found TDC and everything lined up with the #1 cylinder, rotor and teeth on the passenger side. Using my timing light i set it at 8 BTC and it ran good but still detonating. I have from there ran up and down from 14 to 0 and it wont stop detonating.
I have a buddy thats a 300-6 wiz and one hell of a mechanic and we played with it for awhile and he couldnt get it to stop either.
With it being on propane for the last while I didnt think there would be alot of carbon build up. I was wondering if someone might have jumped a cog on the distributor when timing it on propane or something.
I can only find 2 marks on the pulley and there both triangular notches. Should there be a line on there to?
Am I maybe doing something wrong or missing something?
Any input is greatly appreciated.
Senior User
Joined: Mar 2017
Posts: 395
Likes: 1
From: Everton MO
my 300 6 had retarted timing and was causing major loss of power to the point that i could barely get it over a 3 inch step up to the garage. my timing was correct but the dist. advance was connected to a manifold vacume source and the carb was adjusted correctly but still that loss of power. i connected the dist. advance to the ported vacume port and readjusted the carb but the retarted initial timing was causing it to die and bog bad. when i raised the idle it causes run on and dieseling. i had to put spacer in the distributor advance bar in order to achieve the correct initial timing and have it connected to the correct place on the carb. your problem is most likely your initial timing. your dist advance could have a hole in the diaphram and could be causing timing change upon acceleration. does it detonate when accelerated or just when idling? the last thing i can think of would be the propane causing the carbon build up and when the engine heated up it caused that carbon to combust a little bit at the wrong time or when the piston is coming back up causing your detonation.
Fleet Mechanic
Joined: Sep 2014
Posts: 1,627
Likes: 79
From: NE Texas
When you verified TDC on the rotor and the timing marks, did you check whether the #1 wire was at the same place as the rotor? Did you verify that the plug wires are at the right holes and in the right order?Could be maybe a coupla plug wires crossed, or on the distributor 180 out.
Think a notch on the edge of the pulley is all you get. A little white-out fill makes it easier to see with the timing light.
Only other thing that occurs to me is try timing it with a vacuum gauge instead of a timing light and see whether that helps.
Think a notch on the edge of the pulley is all you get. A little white-out fill makes it easier to see with the timing light.
Only other thing that occurs to me is try timing it with a vacuum gauge instead of a timing light and see whether that helps.
Thread Starter
|
New User
Joined: May 2017
Posts: 19
Likes: 0
From: Calgary AB
Yes I did verify rotor and wire position. Everything seems to line up. Could a bad dist. Advance or vacuum be causing this?
It ran great on propane and has only been on gas for a week. The carbs brand new reman.
It ran great on propane and has only been on gas for a week. The carbs brand new reman.
Senior User
Joined: Mar 2017
Posts: 395
Likes: 1
From: Everton MO
okay so mine did the same thing and my idle adjustment was too high but my 300 was idling at a good speed but the idle was high with a low mixture, make sure you are getting 0 vac advance at idle and that the dist advance line is connected to the ported or timed vacuum port and that that port gives no vacuum at idle. look down the carb and feel for clearance between the throttle blades and the carb flange. there should be little to no space between them.connect a vacuum gauge to the manifold, if it pressurizes on shut down then you know your timing gets way off. are you running a 4bbl 2bbl or 1bbl?
Fleet Mechanic
Joined: Sep 2014
Posts: 1,627
Likes: 79
From: NE Texas
When you say detonation, sounds like you mean post-run dieseling? If so, the normal cause is excessively high idle.
Trending Topics
Senior User
Joined: Mar 2017
Posts: 395
Likes: 1
From: Everton MO
right but my over advance at idle was causing the run on to cause my timing to advance to the point that my carb and manifold pressurized and it detonated.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Thread Starter
|
New User
Joined: May 2017
Posts: 19
Likes: 0
From: Calgary AB
I got a carter 1bbl carb. This is all great info, has me looking at it from a different angle now. After work today ill give it a go and let you know what i find out.
Thanks for the help guys.
Thanks for the help guys.
Thread Starter
|
New User
Joined: May 2017
Posts: 19
Likes: 0
From: Calgary AB
Yes it continues to run a bit after i turn off the key. Sometimes backwards, sometimes forwards.
Lead Driver
Joined: Mar 2008
Posts: 7,193
Likes: 385
From: Near Los Angeles
Uh! First off, I think you should be over at the Inline 6 section of this forum. I'd also ck the sharpies at Fordsix dot com, where the best mechanics hang.
I would, as the other guys mentioned, go through the normal stuff: time with a v. gauge, ck your wires and remember the order by this: 15 is too young, 36 is too old, 24 is just right. Put a v.pump on your dizzy diaphram and make sure the advance mechanism is working--with the cap off. Check the + wire to the coil and make sure it turns on and off with the key.
My first thought was, as you mentioned, that it had jumped a tooth. They are gear to gear, and sometimes you find a phenolic gear that lines to loose teeth with high mileage, but you said it only happens when you shut down, so that makes me suspect a carb issue. throttle plate plate not closing, ...
I would, as the other guys mentioned, go through the normal stuff: time with a v. gauge, ck your wires and remember the order by this: 15 is too young, 36 is too old, 24 is just right. Put a v.pump on your dizzy diaphram and make sure the advance mechanism is working--with the cap off. Check the + wire to the coil and make sure it turns on and off with the key.
My first thought was, as you mentioned, that it had jumped a tooth. They are gear to gear, and sometimes you find a phenolic gear that lines to loose teeth with high mileage, but you said it only happens when you shut down, so that makes me suspect a carb issue. throttle plate plate not closing, ...
Thread Starter
|
New User
Joined: May 2017
Posts: 19
Likes: 0
From: Calgary AB
I'll keep that section in mind for next time F-250 restorer.
Just wanted to give an update. I did an efi manifold swap which fixed a big vacuum leak, tuned and timed over and over and still dieseled.
A friend was talking to his dad who suggested a higher octane so i topped it off with premium and a little shot of octane boost and my problem was solved. Thanks for all the input.
Just wanted to give an update. I did an efi manifold swap which fixed a big vacuum leak, tuned and timed over and over and still dieseled.
A friend was talking to his dad who suggested a higher octane so i topped it off with premium and a little shot of octane boost and my problem was solved. Thanks for all the input.
Thread
Thread Starter
Forum
Replies
Last Post
nates-new-old-f150
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
3
Apr 2, 2008 02:20 PM
hellbilly1932
Y-Block V8 (239, 272, 292, 312, 317, 341, 368)
13
Jul 1, 2007 12:35 AM
VintageBlueOval
1987 - 1996 F150 & Larger F-Series Trucks
8
May 5, 2004 10:47 PM
Ratsmoker
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
2
May 26, 2002 03:00 PM