baracis

This was also posted in the Engine Overhaul section, I wasn't sure which section was best for this question.

My brother in law is having issues with his 350. After taking the intake manifold off, cleaning it out (ports, etc) removing the lifters, putting them back on, replacing the manifold, and putting the carb back on we just can't get this thing right.

The intake manifold was gasket matched and polished, the lifters were re-installed but could possibly be too tight, no gasket leaks anywere, but the damn thing won't start up and keeps back firing. The distributor was removed, TDC was found, plug wires ran appropriately, but still fire out of the carb.

My leave ran out and I had to report back to Florida. He's stuck in Indiana with a car that he can't fix. Nothing bottom end was touched on the car (pistons, crank, etc). What do you guys think it could be?

cooter26

What do you mean the lifters were re-installled but could be to tight? Did you set the valve lash? You cant just tighten them on like a ford. Do a search for setting valve lash on a hydraulic cam.

cooter26

V6 and V8 Engines

See Figure 1

1. Remove the rocker covers and gaskets.
2. Crank the engine until the mark on the damper aligns with the TDC or 0 mark on the timing tab and the engine is in No. 1 firing position. This can be determined by placing your finger on the No. 1 cylinder valves as the marks align. If the valves do not move, it is in No. 1 firing position. If the valves move, it is in No. 6 firing position (No. 4 on the V6) and the crankshaft should be rotated 1 more revolution to the No. 1 firing position. To adjust a valve, back off the adjusting nut until lash (play) is felt at the pushrod. Tighten the nut just until all lash is removed. This can be determined by rotating the pushrod with your fingers. When all lash is removed, the pushrod will stop rotating. When all play is removed, tighten the nut 1 full turn (360°).

Fig. Fig. 1: Adjusting the valve-gasoline engines

1. With the engine in No. 1 firing position, the following valves can be adjusted:

V6 Engines




Exhaust-1, 5, 6,

Intake-1, 2, 3,


V8 Engines




Exhaust-1,3,4,8

Intake-1,2,5,7

1. Crank the engine 1 full revolution until the marks are again in alignment. This is No. 6 firing position (No. 4 on the V6). The following valves can now be adjusted:

V6 Engines




Exhaust-2, 3, 4

Intake-4, 5, 6


V8 Engines




Exhaust-2,5,6,7

Intake-3,4,6,8

1. Reinstall the rocker arm covers using new gaskets.
2. Install the distributor cap and wire assembly.

baracis

He adjusted the rockers correctly, but it's still backfiring. He's redone the timing over and over and over so I would be surprised if thats the issue. Initially the rockers were WAY to tight and bent the pushrods. Could that have mushroom the lifter or anything?

Could it be possible that it's a carb issue? We're lost...any help would be great.

stlhedr29

check ur timing again, u could be be 180 degrees out on timing

Screacher

I went round and round with one of my first rebuilds, similar symptoms as yours...kicked me around the block for a week...my brother in law came over and rotated my dist 180...sometimes a fresh set of eyes finds the problem

2wd-K5

^^^^^ happened more than once to me

sgf123

I had similar problem when swapping distributer. A friend came over and picked up the distributer and rotated the roter counter clockwise 4 times set back down and truck started. something about pickup being set. indent on shaft gear should line up with mark on shaft I guess.