I have a problem with bumpy timing @ idle. I check the dist and is fine , so today I pulled the timing cover

pics ->

L1


L2


R1


R2





around 80k miles....replace? :>

 

That looks pretty loose and sloppy. It also looks like the oil was changed every ten or so thousand miles or a heating issue. But I would for sure change the chain out while the cover is off. Also change the front crank seal. Make sure to install the cam gear aligned with the crank. Dot to Dot. Then the timing should be okay. I just rebuilt my motor last summer and only replaced the timing chain as the steel gears were still in good shape.

 

Hi

I'll change only the chain, sprockets looks fine

do you mean that light blue on the block face behind the cam sprocket? I don't know what is this...
I do oil change always after 3000km and car never overheated (of course I don't know what previous owner done hehe)

 

Replace both the chain and the sprockets as a set.

Make sure your distributor hold down bolt is tight.

 

Looks like normal wear. I am sure your idle problem is something else.

 

HI

Do you have any hints what else should i check?

thx

 

Not really. I know mine jumps around every now and then with a new chain. Most motors I have torn down for a cam swap or just a rebuild have showed he same wear for a chain. It'll get a tad streached after a few thousand miles.

 

How "bumpy?" Floats around a couple of degrees? If so, that's your timing chain. It's fairly well worn, but I've seen worse (like the stock chain that came out of my 200K mile 305 TBI motor- loose and floppy!!)

Here's a nice replacement for the crappy stock link belt timing chain for factory roller cam motors:

http://www.sdpc2000.com/catalog/3520...-Chain-Kit.htm

If you're talking about a much bumpier timing problem than a few degrees of float then you might want to look at the gear on the bottom of the distributor- if it's bad the teeth will wear down almost razor thin, the timing will jump around quite a bit and eventually it will fail outright.

Beyond that you're talking about a zillion different electrical/ECM problems that it could be.

 

I do that ->

start the engine and let him reach the operating temp. With ESC connector unplugged I connect timing light to #1 spark wire. Engine idling and lamp flashes at timing marker....but this is not stable flash for example @8 BTDC..flash jumps to random degrees all over the marker and sometimes light throws flash out of marker :/

idle is good quality, performance ok, no overheating and other issues. only this jumping timing kills me

hmm today I took out the cap, catch the rotor and trying turning it...rotor goes up and down. Sounds like worn dist gear? maybe camshaft dist gear ?

thanks for help

 

Might be your timing light causing problems, not an actual timing problem. If your spark timing occasionally jumped up, say, 10* and then back down real quick you would hear it in the way the motor runs.

Try another timing light, and try positioning the pickup at different points on the wire (and not near other wires) and see if the readings get more stable. Also, some timing lights don't work too well with MSD boxes. For instance, my timing light sometimes shows a quick advance of about 20* when running an MSD box. Sometimes it catches the END of the muti-strike spark burst instead of the BEGINNING of it and this causes a jump in the timing reading even though the timing is actually perfect and unchanged.

 

I tried 2 timing lights. one with inductive pick-up and another one mounted directly to the spark end. same effects
I don't have any boxex, just stock 350 ignition