i recently did a head gasket install on my 89 4.9L, and when i got it back to running condition, the performance was very sluggish. so, i kept advancing the timing more and more and it feels better everytime. currently, im at about 16 deg BTDC. timing is specified to be at 10 deg BTDC. is what im doing ok?

 

2 questions:

1) Are you SURE you got the distributor back in in the right orientation?

2) What are you using for timing marks? The cast and numbered marks at the top of the timing cover are NOT the timing marks.

 

1) i am sure that the distributor is back in the right spot.

2) haha, they arent??? where are the timing marks?

 

im not for sure where but i just rebuilt a 84 5.7 liter desiel and the timing marks were on the gears the connect the cam shaft to the crank, ussually the timing mark on the gear that in on the crank is pointing toward the #1 piston at TDC

 

Not sure on an 89, but I think they're at about 9 o'clock on the passenger side of the timing cover similar to the later models. The visible notch in the pulley is not the timing indicator either. There are 2 VERY faint lines on the damper marked 0 and 10. Get out the paint-stick.

 

what are the marks cast into the timing cover for then?? the only mark on the damper is that notch, there is no faint anything.

 

The cast marks are a vestige from the older carbed engine. They never updated the casting. The only way you can see the lines on the damper are by crawling underneath and using a work light on the damper.

 

alright...i took some sandpaper to the damper and found a faint line in it. that must be what you are talking about. i also found the timing marks on the other side. the thing is, i cant make out what the marks say. they have a ****load of rust on them. can anyone help me out? thanks.

 

I have a 1990 f150 XLT Lariat with the 4.9L 6cyl.
The V notch is 10 Deg BTDC,
the "eye" (little circle cut out of raised part of damper) is 10 deg after TDC;
0 deg is half way between the two, right where the notches start.
I think the marks are labelled for even degrees 0, 2, 4, 6, 8, 10, etc.
At least the label numbers I can make out are all even, increasing counterclockwise (downward).

 

Also make sure you pull the spout connector when setting timing to disable the computer advance.

 

is that eye on the on timing mark plate, or is it on the actual damper? also...will timing that is too advanced (2-3 deg) give you poor gas mileage? what are the other effects of it?

 

Here is a fuzzy picture of the thing.




As you know the (base) timing should be at 10 deg BTDC right at the middle of the V mark, with the timing spout removed of course.
The computer will pretty much control the timing in normal operation (with the spout inserted) ,
sometimes advancing the timing by 30 Deg or more!.

Do you mean what happens if you advance the base timing by 2-3 deg at say 12-13 deg BTDC?
Some people have reported some modest "power" and MPG gain by advancing the base timing by a few degrees.
The gain is due primarily to more complete/slow/efficient combustion of the fuel, often in combination with
performance Chips on applicable engines.
But that often leads to more pinging at acceleration/under load, unless higher octane fuel is used.

 

enough said in that one sentence right there...

 

Hey there.. seen you were all talking timing and i figured i might just jump in. I just re welded the air tube back onto my catalytic converter, and found i had to adjust the timing again. You said there is a faint line on the dampener? I thought it was the notch.. lol that explains a lot. I painted a line from the notch and never seen it, ended up changing the timing by ear, and if you ask me its still a little advanced. I dont think the timing has ever been perfect in my 89 4.9, but i'd love to get it there. I think when i find this faint line your talkin about i'm going to scratch it with my grinder, make my own line. Now from what i've been reading, if i want to advance my timing a little, i would generally need to start upping my octane to prevent early detonation? I have to do this with my SHO after the chip upgrade (timing / spark advance included ) or it misses and pings for days. but when i dont advance it enough, the idle is rough. ? any ideas? Thanks