Well after replacing my steering gear on my 91 F-250 460 I noticed that my timing gear cover is leaking coolant around the block to timing cover gasket. So In the near future I will be doing a timing chain replacement and reseal the timing chain cover.

I did a search on this and found that there are some chain sets which are 8 degrees retarded while others are straight up. Now this is a little confusing because how the heck can a chain retard the timing 8 degrees? Or is it the placement of the crank and cam gears that retard the timing 8 degrees which would make more sense?

So basically what is the best timing set to get? And should I replace the timing cover?

 

Go with the straight up timing. The difference is the gears that come with the set. Stock Ford retarded the timing 8 degrees. But by going to a straight up TDC you will gain power.
Craig

 

John, curious where your leak is? i have an 89 w/ 460 and I am getting a little seepage in the area of the block/timing chain cover right beneath the thermostat. I wonder if this a common problem? The strange thing with mine is it does not leak all the time. Some time I will have a little anti freeze at the seam and other times I will have just a very slight weepage of oil.

 

jadmt,

There are weep holes on either side and a little channel surrounding each water passage through the timing cover,..on the block side.
PITA to get to, but simple to fix.

If it's on top of the timing case you are probably seeing coolant from the heater hose tucked in at the top of the pump, if it's oil it is likely coming from the base of the distributor.

 

Thanks, it is possible the coolant is coming from the heater hose (original heater hoses on an 89), The oil is definetly coming from the seam between the block and the timing cover directly beneath the T stat. The area at the base of the distributor is bone dry. If I watch the engine heat up I can see the oil start to weep up thru the seam, altho not really enought to puddle just enough to appear moist along the seam between the block and timing cover.

 

It's the crank gear(key way) that's different,you will see the diff when you look at the gears side by side.It's basically moving the crank to TDC

 

advancing a cam gives higher low end torque retarding the cam gives better high end hoarsepower

 

Well after further research I am a little confused. Some say the timing is straight up on the EFI Motors while others point out that the timing is 8 degrees retarded. So on my 91 F-250 460 what do I have for sure?

Also if and when these timing chains break. do they cause damage to the cam via pistons hitting the valves? Or are they non interference meaning that the engine will not self destruct.

 

i gave basic info on cam timing.old time hot rodders set them a little front and back

 

John,
You are correct, FI engines run "straight up" timing.
Weather or not the cam is ground retarded, I don't know.

There should be no need to replace the timing case unless the aluminum is very corroded around the water passages or you break it because the bolts are seized in. (I use Locktite PST where bolts go into the water jacket.)
You may find that the backplate on the water pump is horrendous though.

The heads were redesigned for fuel injection so I'm not one to say.
But since the compression was raised along with moving the ports I would imagine things would not be pretty if the chain actually snapped.
Usually the chains stretch to the point where it's running so bad they get replaced first.

 

HI, the timing chain rarely breaks, usualy stretching or jumping teeth causing bad or not running at all. cam retarding is done to alter emissions, usually when replacing with earlier t/chain set it can improve overall operation, as far as i know in standard form these motor's are NON/interference

 

In the course of replacing the water pump on my '93 F350 the Timing cover was destroyed. So I figured I'd replace the Timing chain also, the one I got was from Crane cams and offers a few different positions if you want your cam advanced, straight up, or retarded...

 

Cool Pic. Well I sure do appreciate all the info this is bit##**. Any how I decided to check my base timing, just to see what it would be at since it hasn't been touched to my knowledge since it was manufactured in Canada. So I proceed to loosen my distributor hold down nut and all is good. Then I find that my distributor is stuck to the block. Ok so I notice that ford put a nifty place for a 1"1/8 open end wrench at the top base of the TFI Distributor. So I put some moderate strength on it, a little more and she still won't budge. Not wanting to break the distributor I decided to leave well enough be alone. I then disconnected my Spout Connector near the left front fender and checked my timing. I found that I am about at 8 to 9 degrees BTDC. So I figured for a 130,000 mile engine this was satisfactory.

So what should I use to get the distributor base loose from the block? I figure the aluminum reacted to the cast to form a corrosion layer which I guess welded my distributor base to the block.

Also wouldn't bringing my base timing back to spec be similar, if not the same as replacing the Timing set? I now am taking the Bus to Cuesta College and only drive the truck on fridays when I go to the bank to deposit my check, therefore I do not plan on putting too many miles on the truck.

 

I used PB Blaster, and *time*.
Soak the base of the distributor, let it sit, give it a few whacks with a brass drift (or similar) down at the base, see if it will budge.
If not, more PB, try tomorrow, or that night.
Took my a couple of days this way to get mine free going at it morning and night like that.

Even then it was too worn to use but at least I had a 'good' core to trade in on a rebuilt dizzy.

No it's not "the same as replacing the timing set".
The chain has no tensioner. When it stretches both cam and ignition timing get sloppy.
I know the computer is taking care of advance on your truck but pull the spout, hook up your timing light, then start and rev the engine.
Watch the timing marks.
Can you see them jump around when you apply and release the throttle? This is from the loose chain flailing around in the timing case.

As I alluded to above, check the distributor shaft for sloppy bushings once you get it out.
IMO, any visual movement side to side is cause for replacement.

Also: Check the balancer for wear at the front mainseal. If there's a groove, you should sleeve it now. Don't forget to oil the new seal on re-assembly.

I hope this helps.

 

I have also heard that if you were to install a stock 1970 429scj timing set that this will greatly increase the the performance of this poor smogged engine. I am not entirely sure how the computer reacts to it but seeing as how I own an '88 250 to pull a 34' travel trailer and carry my car on it I guess i'll be trying everything. Geo.