New member need help.

I have a 77-78 kenne bell 231 v6 3.8. Its an even firing engine and Im trying to find a diagram of the even firing order. If anyone could help that would be really nice. (Reason I need it). When I start the engine it runs. But there is alot of spitting and popping comming from the Carb and also from the tail pipe. I really feel like the timing is wrong. Any suggestions would be appreciated.
 
I really appreciate but the diagram for this engine has an even firing crank in it. So I need the specs for even firing order.
 
By the way I was told when timing this engine that the mark needs to be on 16 degrees. Should I time it the normal way at TDC with the crank at 0 degrees?
 
Here is the write-up from the '78 Buick Shop Manual describing how the even-fire V6 operates. The even-fire was introduced in mid-year '77. So this is the first shop manual to show it.

The firing order is the same as the earlier odd-fire. The difference is in the split crankpins used on the even-fire. Each cylinder reaches TDC in turn for every 120 deg of crankshaft rotation.
 

Attachments

  • IMG_1762.JPG
    IMG_1762.JPG
    811.5 KB · Views: 11
  • IMG_1763.JPG
    IMG_1763.JPG
    824.1 KB · Views: 15
  • IMG_1764.JPG
    IMG_1764.JPG
    716.1 KB · Views: 13
Here is a copy of the emissions label for a typical '78 V6. I would guess this is not available for your rebuilt motor. It shows timing instructions and notes the 15 deg mark should be used. The idle RPM is different for manual vs auto transmission.

Also included are the shop manual pages from the ignition and emission sections. These indicate setting the timing is pretty much done by the standard procedure.

A classic cause of sputtering and backfiring is mismatch of the distributor gear to the camshaft gear. This could occur when the distributor has been removed and reinstalled a few teeth off.
 

Attachments

  • IMG_1761.JPG
    IMG_1761.JPG
    846.9 KB · Views: 8
  • IMG_1756.JPG
    IMG_1756.JPG
    853.2 KB · Views: 8
  • IMG_1757.JPG
    IMG_1757.JPG
    636.9 KB · Views: 8
  • IMG_1758.JPG
    IMG_1758.JPG
    851 KB · Views: 6
  • IMG_1759.JPG
    IMG_1759.JPG
    895.3 KB · Views: 6
  • IMG_1760.JPG
    IMG_1760.JPG
    483.9 KB · Views: 6
Last edited:
I just want to say thank you so much for all this info. Im gonna post a pic later today of what Im working on. But as of right now I am about to pull this timing cover and make sure the retard who touched this engine before me put everything TDC. I was told before I put my hands on this engine the guy who was working on it before was on drugs and always doped up. An ever since he touched it it hasnt ran right. But I will get back to you later today or in the near future and keep you updated. Thank again TODD.
 
Just wondering one more question do you have the info on the timing cover for this particular engine. Just wondering if it has a torque sequence and if so what is the Ft Pouds?
 
Here's the torque chart and the section about removal/replacement of the timing chain cover. Also a section on checking TDC vs camshaft and crankshaft sprockets.

Looks like 30 ft-lbs is needed. There appears to be no bolt-tightening sequence given. I guess I would start at the dowel pins working out while alternating side to side. Maybe torque it gradually, going around 2 or three times to hit 30.
 

Attachments

  • IMG_1800.JPG
    IMG_1800.JPG
    636.9 KB · Views: 10
  • IMG_1801.JPG
    IMG_1801.JPG
    726.6 KB · Views: 13
  • IMG_1802.JPG
    IMG_1802.JPG
    684.6 KB · Views: 10
  • IMG_1803.JPG
    IMG_1803.JPG
    603.6 KB · Views: 8
So I put everything back on an put everything at TDC an fire it up it starts up but keeps backfiring from the exhaust. I wonder if it’s because it has an aftermarket distributor on it. It’s a Mallory with a vacuum advance on it.
 
Haven't come up with any new ideas yet just a few more questions:

Did performance improve after latest disassembly/reassembly?

Did it ever run right with the combination of parts in place now?

Does behavior improve at all by rotating the distributor one way or the other?
 
I will have to check that. But from what I could tell is that the distributor is good. But that engine is still sitting in the car. I have another one just like it that I have on a motor stand an I’m gonna fire it up tomorrow an if it runs good put It I. The car so I have something dependable in it so I can drive it. But the engine thats in the vehicle now.... I’m gonna pull it out an send it to a performance shop. I’m over messing with it.
 
Haven't come up with any new ideas yet just a few more questions:

Did performance improve after latest disassembly/reassembly?

Did it ever run right with the combination of parts in place now?

Does behavior improve at all by rotating the distributor one way or the other?
Yes it sounded a lot better. No the backfire/popping noise got worse or took longer for it to happen. I noticed it got better or didn’t pop so much when I used carburetor cleaner an sprayed it in the carb while running.
 
Okay first off I want to thank everyone for the help an all the great info. But after about a month of messing with this thing I decided to rebuild the same exact engine. ( Because i have 2 of the same v6‘s) So I swap everything g from the Engine I side the car now to the one outside the car. Because I was gonna send off the engine in the car to an engine shop an have the rework everything an send it back with a warranty. Anyone long story short the problem all along was the rotor button in the distributor. The dumb ass before me randomly grab one off the shelf an put it in. The rotor button on the distributor was for a v8. I installed a rotor button for a v6 put everything at TDC. An it Fired off an ran great... no backfiring, not spitting, no nothing. I’m super happy right now.
 
Back
Top