Engine operation troubleshoot

[Steve D.]

63 convertible, small block

I hear a popping sound through the carburetor when accelerating or at rest when bumping the throttle . Initial timing is set at 9 deg.

Background: No popping noise experienced until after I yo-yo'd the intake manifold to fix an oil leak. I had marked the distributor orientation and thought I had dropped it back in the same spot. The engine started right up. I drove it a while and it seemed to be running a little hot. At one point when I was stopped, the engine suddenly died. It started easily, but then I started hearing the sound when accelerating. I went home and shut it down. Next day it started right up, but I still had the popping noise when bumping the throttle (no noise at idle). I noticed that the distributor hold down was not tightened, so I snugged it down. I let it idle to warm up before checking the timing. After idling about 5 minutes, it suddenly died. Would not restart. Let it cool a bit and it started right up. Checked the timing and found it to be 16 deg. Set it to 9 deg., but popping noise still persists. The engine is NOT spitting gas and backfiring through the carburetor. Comments?

Steve

[Edward J.]

Re: Engine operation troubleshoot

Steve, it may be possiable that the two center intake manifold bolts on each side may be to long and are contacting the push rod or rods, there are a few different length bolts on the intake. if a longer bolt is contacting the push rod it will cause the valves not to open and close properly. the best way to check this is to is pull the valve covers of and look at the push rods on the 2&4 and 3&5 cylinders. start up engine and check the movement on the push rods.

[Loren L.]

Re: Engine operation troubleshoot

Coil. Can someone tell me why this ystem insists on extra meaningless characters? Is it owned by a Congressman?

[Edward J.]

Re: Engine operation troubleshoot

Loren , Sorry my typing skills are not the best.

[Steve D.]

Re: Engine operation troubleshoot

I neglected to mention that I replaced the coil before I started the engine the next day. A friend had suggested that as a possible problem, so I changed it as part of the process.

[Loren L.]

Re: Engine operation troubleshoot

Loren , Sorry my typing skills are not the best.

I don't understand - my comment was Why Mr. Waggoner's sytem just wouldn't accept a one word response - coil. Had nothing to do with your response at all.

[Edward J.]

Re: Engine operation troubleshoot

Loren, oh, I thought it was my typing era.s if you read my post.was not good .

[Dick W.]

Re: Engine operation troubleshoot

I don't understand - my comment was Why Mr. Waggoner's sytem just wouldn't accept a one word response - coil. Had nothing to do with your response at all.

None of the Vbulletin based forums will take a one word response. VH will not take a one word response

[Wayne P.]

Re: Engine operation troubleshoot

I am sure you will find one exhaust valve not opening .Could be rocker arm off of cam lobe worn excess. I have diagnosed more than a few with this problem . let us know what you find.Here is what happens .The intake opens and air and fuel come in on intake stroke then up on compression,ignition occurs,down goes the piston, then up on exhaust, but the exhaust valve doesn't open,leaving pressure in the cylinder,and now the intake valve opens and you get your pop in the intake which you hear at the carb.I saw this a lot in chev motors early 70's. their were some cam problems.You can find which cylinder by disabling spark to one cylinder at a time ,then excellerate,or just pul both valve covers and inspect.I also had this problem on an engine that had one exhaust port restricted,but thats unlikley.Let us know
Goodluck Wayne

[Mike H.]

Re: Engine operation troubleshoot

Did you remove the plug wires from the dist. cap and get a couple out of order upon reinstalling?
CORDially Mike

[Edward J.]

Re: Engine operation troubleshoot

Steve, how did you make out with the problem? Just wondering.

[Steve D.]

Re: Engine operation troubleshoot

Edward

You nailed it. When I pulled the driver side rocker cover, the first thing I noticed was #5 exhaust rocker sitting askew. I loosened the rocker and pulled the rod. It was slightly bent and had thread marks on it on the inside of the bend.
What are the chances that the lifter (solid) was damaged in the process?

Steve

[Steve D.]

Re: Engine operation troubleshoot

Corbett

You were right. See my reply to Edward above.

Steve

[Wayne P.]

Re: Engine operation troubleshoot

Is unlikely any damage was done to lifter other than it could jump out of lifter hole, but you can tell when you install push rod.

wayne 26443

[Steve D.]

Re: Engine operation troubleshoot

Wayne

The lifter is still in place. Thanks.

Steve