slipped timing chain?? [Archive] - Chevelle Tech

: slipped timing chain??


archburycontrol
Jun 13th, 06, 9:53 PM
How can you determine if a timing chain has slipped, without removing timing chain cover. This is a new 350 rebuild 3000 miles ago so I know chain is new and was properly installed then.
Struggling to get motor started after installing new stock HEI.

Did everything by the book, Constant 12V to coil, 10 degrees BTDC on compression stroke, rotor firing at #1 cylinder. lots of gas and strong spark.

any help would be appreciated. Just trying to rule out the chain slip before I focus on other possibilities.

thanks!!

66 Buick Special
Jun 13th, 06, 10:18 PM
Please excuse me if this sounds ignorant (because I often am!:rolleyes: ) Could you just pull the #1 plug rotate the piston up to top of the compression stroke and then pop the cap and see where the rotor is pointed?
If it's at the #1 plug wire terminal then the timing chain would still be ok, right?

Or, I might be missing something obvious because that seems too easy to work! :p

Johnny O
Jun 13th, 06, 10:20 PM
I dont know what the experts will say, but I have been around engines for a long time, and I have yet to see a timing chain jump or slip. I dont believe it happens. Especially in your case, it's practically new. Did the engine run good before the dist. change? What else did you do. If you have spark and gas, it has to be a matter of timing. Just to check your theory, pull the left valve cover, bring it up to TDC on #1 compression stroke, and see that both valves are closed. Im willing to bet that if you re-do the distributor, check your wires (firing order) and all the basic stuff, it will fire up. Does it do anything at all? Pop a little or try to start? Did you mess with the valves at all, and are they adjusted properly?

ssal396
Jun 13th, 06, 10:46 PM
I dont know what the experts will say, but I have been around engines for a long time, and I have yet to see a timing chain jump or slip. I dont believe it happens.

I have seen one, it was in my 69 Le Mans back in the 80's.. Although it was one of those old factory nylon timing gears & the teeth had all actually came off of the gear, all that was left were little nubs.. One day I went to jump on it and it just burped and died..

Then to make it even better, a couple of months after I struggled to replace the timing chain with the motor in the car, I found all those teeth IN THE FRIGGEN OIL PICK UP!! Yep, one day my oil pressure dropped to 0 at idle :eek: .. So then I got to have the fun of swapping out the oil pump with the motor in the car.. Oh, those were the days :clonk:

.........Now, to get back to topic, I agree with the prevous posts.. It's more then likley the timing.. If this engine has yet to start since installing the timing chain, you might have installed it a tooth out or off of the compression stroke..

Just trying to throw out suggestions..

Scott

69bu
Jun 13th, 06, 10:49 PM
Did you mess with the valves at all, and are they adjusted properly?

If you adust the valves too tightly then both valves will be open and you won't be able to build any compression. Ask me how I know!! Has anyone else adjusted hydraulic-cammed valves on the engine stand only to have them keep the valves open once you get the lifters pumped up.....

CNC BLOCKS N/E
Jun 14th, 06, 7:52 AM
Been doing this 32 years and have not seen a chain slip yet and was the cam degreed in or was the dots just lined up?????????

glennslanaker
Jun 14th, 06, 11:04 AM
did you get the ROTATION of the distributor correct? you can hook the wires up in the right order but if you are going the wrong way around the cap.... i have a 442 that i changed out the distributor on, and it didn't run. well, i had assumed it rotated just lilke a chevy, WRONG, it's goes the opposite direction.

BUDS1970
Jun 14th, 06, 1:22 PM
Like someone in a previous post said pull the cap and the spark plug from #1 cylinder and make sure of all that.If you are going to HEI from points remember the #1 position on the cap isn't exactly the same for both.You probably have to turn the slotted drive around a little to get on #1.

d1_bradley
Jun 14th, 06, 2:12 PM
Just pull the valve cover and crank it over to TDC and watch the valves on #1. This way you will be SURE to be setting the distributor to fire #1 and not #6.