Mature engine timing
Thread Starter
|
Posting Guru
Joined: Apr 2005
Posts: 2,018
Likes: 0
From: Longview, TX
Mature engine timing
At $60-70 per fillup I am in tweaking mode...going to buy a timing light and am wondering if 9 degrees BTC might be better than 10. I had a 302 in a very high milage 1986 van. A mechanic put a socket on the crankshaft and showed me lots of slack in the timing chain and said we would have to drive time it because the cam was so far behind the crank in timing. I don't remember if it was fuel injected (I've have had many Ford products). Anyway, we advanced the timing until knocking at full throttle under heavy load then backed off a little. Now the current question, when I put a socket on my 351w crank I can rock it 3/8 to 1/2 inch measured on the pully. Ford shop foreman said that is not enough to be concerned about on my 172K 351w. I am wondering if we still need to try to time to the crank in high mileage engines or compensate for a little timing chain wear by trying to time to the cam? I realize that setting the timing is really just telling the PCM the crankshaft position. Also, any timing light suggestions for use every couple of years?
Thread Starter
|
Posting Guru
Joined: Apr 2005
Posts: 2,018
Likes: 0
From: Longview, TX
Ouch! The truth hurts sometimes. Think I will delay chain replacement until I have time after the first of the year. I will need a timing light then so might as well get one now and check timing. Do you think I need the $80 one with the advance feature, $60 one or $14 cheapie?
Hotshot
Joined: Jul 2002
Posts: 14,285
Likes: 12
From: Bend,OR
get what you can afford. the timing should stay at 10*btdc with spout connector removed or even bumped up to 12*btdc with spout connector removed this will help with gas mileage as well. also a good tune up, fuel filter change, proper tire pressure also help. you may also have a clogged cat converter which will hinder performance and mpg as well.
Thread Starter
|
Posting Guru
Joined: Apr 2005
Posts: 2,018
Likes: 0
From: Longview, TX
Kem, so I do not need the "advance" feature on the timing light just a $50-60 one? Timing at 10+ to maybe 12 would lead the cam to allow for chain wear. Do you know how to check for a clogged cat? All the exhaust is original as far as I can tell and I have not heard any hissing from tail pipre. New copper plugs and fuel filter, no plug wire arcs on humid nights. It runs great, just want to do all I can to tweak it and remain stock. Don't know if oxygen sensor has been changed but gets clear 111 codes.
Elder User
Joined: Jul 2004
Posts: 757
Likes: 0
From: Fredericton NB, Canada
Originally Posted by b4hntn
Ouch! The truth hurts sometimes. Think I will delay chain replacement until I have time after the first of the year.
Thread Starter
|
Posting Guru
Joined: Apr 2005
Posts: 2,018
Likes: 0
From: Longview, TX
Please don't take it the wrong way. I GREATLY appreciate your help. I did not realize I had an immediate problem. My feeble memory was trying to was going back 15 years and see the mechanic move the breaker bar about five inches on a 302 and I drove that sluggish van for a couple maybe 50k more with no uh-oh. This Bronco 351 is driven less than 6k per year and mostly during the fall hunting season. I have a company vehicle for a DD so I was not in a rush but don't want a great engine damaged either. Going back to the Ford shop foreman's observation..."the chains still have a plastic coating on them. Not changing the oil oxidizes the plastic faster." I have maintenance records of original owner showing regular 3k oil changes. Thanks for the heads up. I'll crawl under and check the chain slack again. I just eyeballed it before but will mark and measure this time.
Trending Topics
New User
Joined: Mar 2006
Posts: 9
Likes: 0
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Thread Starter
|
Posting Guru
Joined: Apr 2005
Posts: 2,018
Likes: 0
From: Longview, TX
I finally got the time to measure the chain slack. The crank moves exactly 1/2" inch before moving the cam. I think that means the cam timing may be 8.5 degrees behind the crank and the dizzy gears wear would make the spark even slower. Could this be correct? The pully diameter is 6 3/4' and the movement is 1/2". .....6.75 X 3.14 = 21.20 .... .5/21.20= .0236....
.0236 X 360 degrees = 8.49 degrees. Thoughts????
.0236 X 360 degrees = 8.49 degrees. Thoughts????
Thread Starter
|
Posting Guru
Joined: Apr 2005
Posts: 2,018
Likes: 0
From: Longview, TX
Timing chain set selection
I want to replace OEM 172,000 timing chain and gears and would appreciate your expert suggestions. The crank rocks 8 degrees or 1/2 inch. The selection of replacement timing chain/gears at the parts store web sites is overwhelming. I want to keep it all stock and drive it forever. The previous owner gave me the oil change receipts showing changes every 3K since new and the miles were almost all highway so do I need the chain that is for closer gears? Oil pressue on mechanical guage is good. Silent or roller? Single or double? Iron? Ford lasted 172k so might it be best? What brand is best? What brand to avoid? As you can tell, I want to do it right the first itme. Anything else? What special tools will I need?
Postmaster
Joined: Jun 2001
Posts: 2,809
Likes: 3
From: Loveland, CO.
Has anyone tried advancing the timing by 1 or even 2 degrees? Sometimes this will squeeze out a very noticeable amount of extra seat of the pants power, which should also increase gas mileage as long as you stay out of the throttle. In my experience, retarding the timing causes the gas mileage to be worse because the truck will be down on power. I don't mind buying super unleaded to prevent detonation due to the advanced timing. I have not checked for play in my timing chain but it was replaced a couple of years ago when the cover had to be removed to get a broken water pump stud out.
I've always "power timed" my vehicles, in other words I have somebody floor the truck in drive and hold the brake very tightly while I set the timing to be advanced as far as possible without pinging. This results in optimal timing and sometimes a quite noticeable increase in power. But I have always kept the Bronc timed per factory settings.
I've always "power timed" my vehicles, in other words I have somebody floor the truck in drive and hold the brake very tightly while I set the timing to be advanced as far as possible without pinging. This results in optimal timing and sometimes a quite noticeable increase in power. But I have always kept the Bronc timed per factory settings.
Last edited by JBronco; May 13, 2006 at 09:42 PM.