Timing Gear Change Out (258)

[Rollbar]

1986 CJ7 (1982-258CID). I have her '86 engine I will be rebuilding next yr after I get the 360 on the road.


Well, Peach drove home the other day and the CJ was running rough.

Since I haven't done much to the CJ (been running great), I rebuilt the carb (bbd), changed out the cap, rotor, coil pick up, coil, module. Ran good for a 1/2 day. Checked the timing and it was about 15* (from 9*). I advanced the timing to where it would just stumble and then backed off a little, checked timing and it's about 25*.

So, that leads me to changing out the timing gears.

It has been a long time since I have done this and the book is vague at most.

I'm going to do it next weekend and I have a few questions.

1. Which front valve is the intake, first or second (to the front of the Jeep, can't remember).

2. When I get this on TDC I will check the timing marks to see how far off, but, when I get it set on TDC, do I remove the old gear set and install the new set (pin make to pin mark/asterisk mark on gear) seeing that it SHOULD be on ZERO/TDC.

3. After it being on TDC I should set the damper on ZERO (hopefully it will line up), on the re-install so I then can set the timing right.

4. I plan on leaving in the distributor and just rotating the crank before removal. This should line everything up on the re-install so the dizzy would be set correctly, correct. Or would it be off due to the cam?

Sorry for so many questions/statements but it has been a while and I need some pointers.

Thanks again,
Jim

 

[IOPort51]

2nd valve is intake.

 

[ken98k]

I just did this. The easiest way to find tdc is; pull the spark plugs, put your finger over/into #1 spark plug hole and get a helper to turn the motor over. When you feel the compression building up, stop and finish turning slowly until the timing marks on the balancer indicate tdc.

 

[Rescue Diver]

The valves line up with the intake and exhaust runners, so since the furthest forward runner is exaust, so is the first valve.

Like Ken said, pull the number 1 plug to find TDC. Only I would turn the engine over slowly by hand with a screw driver down the spark plug hole touching the crown of the piston. That way you can actually feel when it's at true TDC.

By your question about which valve is intake, I take it you're already planning to find TDC after the intake valve closes. At least since you don't have to remove the distributor on an inline 6 to replace the timing chain, you don't have to worry about installing it 180 degrees off. I've done that more than once on small block chevys when I'd already installed the valve covers and lost track of whether it was on the intake or exhaust TDC.

Ya gotta love that loud pop through the carb with the ignition timing off that far!

 

[Casuall454]

I use a 3/8" doll road.... just roll the motor over and you can find TDC with out any damage to the spark plug threads. After it simple to R & R your timing chain set.

The only problem I ever had was the bottom of the timing chain cover dripping oil. This was over come with a "dot" of RTV Permatex Ultra Blue on both sides.

Best of luck on your swap and getting the jeep back on the road mate.

 

[Rescue Diver]

One other thing you should do while you have it apart is when replacing the harmonic balancer front seal in the timing cover, buy a microsleeve and press it on the hamonic balancer sealing surface. Any engine with enough miles on it to need a timing chain will also have a groove worn in the balancer where it meets the seal. The sleeve is available at just about any parts store, and should only cost a few dollars. They come with a little tube of sealer that keeps oil from getting between the balancer and the sleeve. It's cheep insurance against having to pull your radiator and balancer again because of a front seal leak.

 

[IOPort51]

please explain "doll road".??

I use a 3/8" doll road.... just roll the motor over and you can find TDC with out any damage to the spark plug threads. After it simple to R & R your timing chain set.

The only problem I ever had was the bottom of the timing chain cover dripping oil. This was over come with a "dot" of RTV Permatex Ultra Blue on both sides.

Best of luck on your swap and getting the jeep back on the road mate.

 

[Rescue Diver]

please explain "doll road".??

I think he meant dowl rod?

 

[Rollbar]

Good thoughts and thanks.

One thing that has repeatedly happened. Every time I change some thing out the jeep ran better doe a day, now I advanced the timing and it ran better for a day.

Before I go pulling the front end apart (of which I will do a write up) I was thinking of setting the timing to 9* like it was and then finding TDC. Then to make sure it is the chain I was going to look at the dizzy to see if it is pointing to #1 Cyl. If it is then maybe all of this is a the fuel pick up in the tank or the sock in the tank clogged.

What say ye!

 

[LongHorn]

I use a 3/8" doll road.... just roll the motor over and you can find TDC with out any damage to the spark plug threads. After it simple to R & R your timing chain set.

The only problem I ever had was the bottom of the timing chain cover dripping oil. This was over come with a "dot" of RTV Permatex Ultra Blue on both sides.

Best of luck on your swap and getting the jeep back on the road mate.

please explain "doll road".??

I think he meant dowl rod?

I think he meant Dowel rod, since were doing spelling lessons. Sometimes y'all just crack me up.:laugh:

 

[IOPort51]

@ Horn: I have an excuse, I was raised by wolves.

I say dive right in and do the most inefficient and expensive things you can possibly think of. It's the way we do things around here!!:laugh:

For real I say more diagnostics won't hurt a bit. I always like to know for sure what is broken before I fix it, Fixing things that are not broke is embarrassing and expensive, to say the least.

 

[LongHorn]

@ Horn: I have an excuse, I was raised by wolves.

I say dive right in and do the most inefficient and expensive things you can possibly think of. It's the way we do things around here!!:laugh:

For real I say more diagnostics won't hurt a bit. I always like to know for sure what is broken before I fix it, Fixing things that are not broke is embarrassing and expensive, to say the least.

A-men to that Brother IO.

 

[Rollbar]

Ok spent the past two days cleaning the garage so I can tare into the CJ.

Pulled #1 plug, found TDC, marked base of cap, rotated to (had help looking etc) "0". Rotor is just past the #1 mark like it skipped two teeth. Rocked the balancer about a 1/2" each way and the rotor did not move. I'm convinced the chain is loose and it is my problem. I did start it and advanced the timing but it runs rough at all degrees of advancement.

I'll try to do a write up and post it. Next weekend will be the event, if you see a big cloud to the West, it's just me


:ty: all & I'll post back.

Jim

 

[Rollbar]

One other thing you should do while you have it apart is when replacing the harmonic balancer front seal in the timing cover, buy a microsleeve and press it on the hamonic balancer sealing surface.
They come with a little tube of sealer that keeps oil from getting between the balancer and the sleeve.

Thanks, I did get the gasket kit from NAPA and it is included. Pick everything up tomorrow and start the next day.

 

[Rollbar]

Ok timing set ok, a little loose but on the marks/in time but while I was there I changed it out anyway w/a new t-stat/h20 pump and valve cover gasket.

Next, drop the tank to see if it is clogged/the pick-up. Maybe this will solve the running rough problem.

Tired.


P.S. The jeep had umbrellas on the valve already.