Well, I finally got my tranny back in and and now my engine has a vibration of some sort. Oh joy! The first thing I decided to check was the ignition system and there seems to be a very faint glow coming from the coil.

Here is the question: Should the coil emit any light while the car is running at 2K+/- RPM? I am guessing not but I dunno.

All the wires (Crane Firewire 8mm, remember when those were on closeout??) are pretty new and are in the right places. The timing is at 10* w/o EST and very steady. I did not check the plugs but they are not very old, I should replace them soon anyway tho.

Any thoughts??

Thanks
Dale

 

Hey Dale,
For about $30-40, you cannot go wrong wiht a HiPo coil upgrade.
It does help.
PS, We'll be chatting next week, alot of things finally in place. Hurrah!

 

Check your tranny flywheel bolts because they maybe bad, get new ones from GM. I had this problem on another car, felt like the car had bad bearings but when I replace the flywheel bolts, it fixed the problem, I think the old ones where coming lose.

 

Well, the new coil is in and it made no difference. I probably solved a problem down the road so it was worth it anyway.

Ryan, I don't think that the bolts are a problem. I just put a new clutch in about 20 miles ago and I made sure the flywheel bolts were plenty tight. It also had the same problem before the last tranny install.

My next idea is to check the cylinder compression and see what shows up. I'll have to wait until next weekend to work on it.

If anyone else has some ideas I'm open to suggestions.

Karl - Glad to hear things are coming together!

Thanks All

Dale

 

How would you describe the vibration? Do you think it could be something as simple as the tranny mount? Checking the compression sounds like a good idea though.

 

Yea, I guess I should clarify the problem a bit.

This vibration occurs whenever the engine is reved above 1500RPM or so. The vibes are independent of vehicle speed ie. they show up when the car is parked in the garage or driving down the road. They do not change if the clutch pedal is depressed or not.

The car had a bad extension housing bushing that caused a vibe while driving but that seems to have disappeared after I rebuilt the tranny the last time.

This is the second pressure plate / clutch combo on the car. Both exhibit the same problem.

My car was an auto at one time and I thought that maybe my flywheel might be off-balance for my engine (internal vs. external balance) but this vibe did not show up until about 5K miles after the swap. In fact, the car ran absolutely perfect for the first 5K then all downhill from there.

The car is testing me

Dale

 

Well if you had an out of balance fly wheel that was a little out of balance it won't show up right away until it wears out the rear main engine bearing. If I where you I would rebuild that whole area, including clutch pressure plat, throw out bearing, and fly wheel, and center fly wheel bearing where the spline rids with all with new major brand parts and bolts. You had a BAD COIL but thats not your problem now. YOU SHOULD relocate your coil because it's a common problem on the V6 cars of coil failer due to it being right next the hot exhaust. I made a braket and put mine on the fender. I can't see how you could use an automatic fly wheel. Your problem is in the drive train some place.

 

I don't think the placement of the coil is a problem... even V8's have their coil hung in that spot. You could always buy a $25 Blaster 2 from Summit Racing. I can tell you how to convert the 4-wire GM harness into a 2-wire coil output. Then you could put the new coil somewhere else, and leave the old coil as "backup".

I wonder if the mark on the balancer has moved, and even though you think it's timed at 10 degrees advance, it's not. Bring the #1 cyl up to TDC and see if the balancer mark meets the 0 mark of the timing tab. Or if you've got an exhaust leak anywhere? Is the inside of the distributor cap relatively clean? (My terminals were so gunked up once, my car would barely move at low RPM's.) Check the terminals on the plug wires for corrosion, too. Maybe one worked it's way loose, and it's still getting spark, but thru air, not a direct "clipped on" connection. And if that's true, make sure the wire's terminal isn't full of deposits by now.

 

Since the vibration occurs at a certain RPM regardless of what speed you're at, I going to bet that the transmission/motor mount needs replacing.

 

Hey all!

As far as the bearings going because of the flywheel balance, I'm not sure about that. I would think that after 115K miles of wear before the swap, if there was a balance problem, it would have shown up right away after the donor flywheel was installed. I'll be the first to admit I am wrong but I need convincing on that one.

I agree with TomP on the coil placement. If it lasted 16 years / 120K miles I don't think I want to mess with it. I'm going to keep the old one as a spare since it still works OK.

I haven't pulled the cap off yet but it and the rotor are under 2K miles old. Checking that will be on my list for this weekend. The wires were all making good contact, I pulled 'em all off to check corrosion etc and add a dab of dielectric grease to all connections. Unfortunatly one of the wires broke but I had a spare laying around to use until I can fix it. I need to go thru and check the plugs for any ominous signs.

I didn't think about the balancer being messed up and showing the wrong timing. I'll have to check that, too.

Also, I forgot to mention that the motor mounts and tranny mounts are new-ish(also < 2K miles old). Motor mounts are from GM and the tranny mount is ES Poly.

My dad is leaning toward some type of valvetrain problem (broken spring, burnt valve, etc.) but I would think the car would be much worse if that was the case. My grandfather is betting on a vacuum leak or two. I'm going to borrow his vacuum guage this weekend and check things out.

Thanks all! Any other suggestions?

Dale

 

Dale,
On my 85 Firebird, I hooked a vacuum gauge very close to a metal cylinder on the firewall, by the wiper motor.
Perfect vacuum signal.
Good Gremlin you've got there.