VIIISecondRide

Hi! I am new here and have been doing a lot of reading, now I have a problem. My 1984 had a tick/knock in the front of the engine. My husband and I debated on if it could be a timing chain making the noise- I won . The very next time we drove it, it just shut down. Crank but no start. It had the dreaded factory timing set, the big plastic gear chipped off, and it let the chain "skip" teeth, rounding off what was left of the metal under the fine plastic.
I installed a new timing set, put no 1 TDC, checked the ignition wires, tried to start it and it popped through the intake. My husband said it was probably a tooth off (he's really old school- everything by ear) so to humor him I moved a tooth each way- still popping through the intake. Thinking I MIGHT be 180 off, I tried re timing it 180 opposite. Still popping through the intake.
My question is, when the big gear let the chain slip, could the pistons have smacked some valves being the gears were no longer lined up, but the chain was still driving them? Sort of interference engine style but not as violent?
Just seeking some insight before I tear it down.
Thanks in advance and thanks for letting me read some good stuff

ex-x-fire

Do a compression test first.

ghoastrider1

no, there will be no valve interference. popping thru the intake is timing set to early, a wore out cam, stuck valve, dist wires wrong..ect. Best tool for you at this point is a timing light. That will answer some questions and tell you what it isn't. Hopefully, it will tell you what it is as well.

VIIISecondRide

It was running perfect with the tapping noise before the gear failure. I can't get it to run enough to get the timing light on it!
I also put on a new harmonic balancer (or whatever it is really is called ) a few days before the failure hoping that was the noise.
So if I get no 1 at TDC with the timing mark on the balancer at 0 degrees, then stab the distributor with the rotor pointing at the no1 plug wire, I should be able to get it to run enough to check the timing, correct? I will stab it one more time and see what I got.
I will also try the compression test as soon as I can find a tester. Will that tell me if a valve or lifter is stuck?
Thanks for the reply!

ghoastrider1

without a timing light, the easest way to find compression @ #1 is to remove sparkplug, put finger over ( NOT IN) sparkplug hole, then crank. You will hear,feel when piston comes up ready to fire. Your harmonic balancer should then be pointing toward somewhere between 0 and 8 degress or so. line that up by hand using whatever to rotate balancer until timed. I have to wonder if your marks are in the correct place on the balancer and or the timing gear. I have seen/helped before when the person lined up the wrong mark on the timing gear.Also, you should be able to use a light on a cranking engine. If all else fails, I am sure someone on this forum would come help you and hubby get I running again..but you gotta tell what part of the country your in.

VIIISecondRide

I didn't know I could use the light on the cranking engine. I will try it. If I lined the marks on the timing set up but was off 180 on the no1 piston, would I then stab the distributor 180 off or would I have to re-do it? I put the timing set in a few months ago and we got busy, so I am second guessing myself!
Thanks

ghoastrider1

you cant get the timing gear 180 off. The cam , cam gear, turns twice as fast as the crank balancer .. the balancer and crank gear only goes on one way as does the cam gear .From what I can infer from your post, you folks have been around a wrench or two, so I am pretty sure cam gear isn't 180 out. That would mean crank gear was right and timing dot was at top insteadf of bottom to meet/line up, with the crank gear dot.

VIIISecondRide

What I was thinking was if I had no1 on the exhaust stroke instead of the compression stroke, would that put the cam 180 off? I am sure we had the right stroke, but it might be better to pull the timing chain cover again just for my own curiosity!

ghoastrider1

it would be 180 off, yes. BUT, then the dots wouldn't have lined up. If anything is180 off, its your dist..most likely. you sure your firing order is correct?

VIIISecondRide

I have checked the firing order every time I stab it- even wrote the plug numbers with silver sharpie on the boots to make it easier!https://www.corvetteforum.com/forums...ilies/ack2.gif After several attempts I started to become Mrs. Obvious!
I will recheck it again if not tonight then tomorrow. I will let you know how it turns out

VIIISecondRide

Okay, I checked for vacuum lines, I established TDC with no 1, I stabbed the distributor, I installed the plug wires, double and triple checking the firing order. I checked the timing while the engine was cranking, with the brown wire unhooked. It was like 16 degrees BTDC. I nudged the dist. counter clock wise twice, no change in timing either time, I nudged it back clockwise a little more than I had advanced it, the mark disappeared. I do not know if it was too far advanced or retarded, I couldn't find it. Then it was time to go make dinner.
Here is a Youtube video of how it sounds when we try to start it.

cadmaniac

I have bought balancers that were not marked in the correct spot. I would take a coat hanger down the number one cylinder, and get the #1 piston at tdc on the compression stroke (using my finger over the cylinder hole). Then check the location of the balancer mark. If necessary get some timing tape and mark the balancer in the correct location and then check the position of the distributor in relation to the balancer. Then install the distributor in relation to tdc and the firing of the #1 cylinder if it in not correct.

This assumes that you installed the timing chain in the dot to dot (crank up, cam dot down) position. That, by the way is firing on the number 6 cylinder when the timing chain is installed. Once you rotate the engine 1 revolution the marks at compression stroke #1 cylinder are dot top of engine (cam) to cylinder to dot top of engine crank gear.

Good luck.

VIIISecondRide

So are you saying when I installed the timing set dot to dot with no 1 TDC it was wrong? So when the marks are dot to dot the rotor should be pointing to no 6 ? So moving the distributor 180 should fix it?
I will be pulling the valve covers today and trying to find a compression tester.
Thanks

corvettenorway

pull out nr 1 plug turn the engine by hand and find tds !! and mark it on the balancer !!

VIIISecondRide

It was in the correct spot and I marked it with my little silver sharpie

corvettenorway

http://www.ebay.com/itm/Used-84-89-C4-Corvette-Electronic-Spark-Control-Module-CR-/390777288422?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3ACorvette&hash=item5afc2436e6&vxp=mtr and compression test ???????

VIIISecondRide

I am trying to borrow a tester- or find a good used one. I will check with Autozone tomorrow.

ghoastrider1

while your checking and rechecking...please check the pin holding the dist cam gear to the shaft and make sure its still together. I once went thru what your going thru and it was a sheared dist cam gear pin. Found it when I tried to turn the rotor by hand and it did..alot.

VIIISecondRide

cadmaniac

If you installed the distributor at #1 cylinder with the crank dot up and the cam gear dot down, your distributor is 180 degrees out.

You must rotate the engine 1 crank turn to get the distributor to fire cylinder number 1 or install at number 6 cylinder. Now that you have cranked the engine I would turn the engine by the crank bolt until you feel compression on the number one cylinder. Then watch the balancer as it comes up to Top Dead center. Once there, pull the cap and check to see if the rotor is pointing at the number one cylinder. If not, re-install the distributor in the correct location.

Checking compression and mechanical problems is excellent advice if that doesnt work.