MikeDobbs
Petty Officer 1st Class
- Joined
- May 8, 2015
- Messages
- 205
Hey everyone,
I've been working on this engine for weeks, and thought I was almost completely done. For the last couple of weeks the engine has been starting and running great (every time), except for a tapping noise which I've been chasing, and some detonation getting up on plane. I will give a brief description of the history in case it helps you to understand what may be happening.
A few days ago I checked the timing and found it was WAY advanced (by about 12-14 degrees), so I adjusted that to close to factory specs (I needed a second pair of hands). Engine started and ran fine after this adjustment.
Friday, I replaced the lifters in the hopes of getting rid of the ricking noise. The engine started up and ran fine after that job, but the ticking was still there. I posted a video of the engine running on the forum, and Bondo suggested it sounded like rod knock or piston slap, and I should pull each spark plug wire one at a time to see if the noise decreased.
So this morning, I went out to do that. I ran the engine for a while to get it up to operating temp, and while that was going on I readjusted the timing to exactly the factory specs. The engine was running fine the entire time. Then, I shut her down to loosen the wires at the distributor, after which she started right back up again. Pulled the wires from the distributor one at a time, and didn't notice any appreciable difference in the ticking sound (supposed to be good news I think). When I pulled the wires I did notice a fair amount of arcing between the coil wire and the Purple engine harness wire that feeds the coil power when the key is on. There are several "scars" or "pock-marks" on the insulation of the wire from where the arcing took place.
So, after the wire pulling test I shut the engine down; intending to do one final re-adjustment of the valves just to be on the safe side. I pulled the cables from the top of my valve cover, and tried to start the engine. Cranking, but no start (this engine has started immediately every time for the last several weeks, so this was very strange). I was eventually able to get it started by giving a substantial amount of throttle, and it immediately ran VERY rough; AND was smoking like crazy out the exhaust. I tried giving throttle to get it to settle down, but it would not run smoothly and continued to smoke no matter what I did. I shut it down and restarted several times with no change (i.e. smoking and running rough). I tried pulling the spark wires again, and this time it seemed that #4 was not firing at all. The engine ran exactly the same with or without the wire attached. So, I checked for spark on the #4 wire- spark was good. I pulled the plug and replaced with a brand new one- no difference.
Fearing the worst, I ran a compression check and all four cylinders were solid - 140-148 psi on all four (#4 was actually the highest).
So now I'm really at a loss. I'm thinking it must have something to do with the arcing that took place during the cylinder checks- but am not sure how to proceed. I would be extremely grateful for any suggestions you may be able to offer.
Thanks!
I've been working on this engine for weeks, and thought I was almost completely done. For the last couple of weeks the engine has been starting and running great (every time), except for a tapping noise which I've been chasing, and some detonation getting up on plane. I will give a brief description of the history in case it helps you to understand what may be happening.
A few days ago I checked the timing and found it was WAY advanced (by about 12-14 degrees), so I adjusted that to close to factory specs (I needed a second pair of hands). Engine started and ran fine after this adjustment.
Friday, I replaced the lifters in the hopes of getting rid of the ricking noise. The engine started up and ran fine after that job, but the ticking was still there. I posted a video of the engine running on the forum, and Bondo suggested it sounded like rod knock or piston slap, and I should pull each spark plug wire one at a time to see if the noise decreased.
So this morning, I went out to do that. I ran the engine for a while to get it up to operating temp, and while that was going on I readjusted the timing to exactly the factory specs. The engine was running fine the entire time. Then, I shut her down to loosen the wires at the distributor, after which she started right back up again. Pulled the wires from the distributor one at a time, and didn't notice any appreciable difference in the ticking sound (supposed to be good news I think). When I pulled the wires I did notice a fair amount of arcing between the coil wire and the Purple engine harness wire that feeds the coil power when the key is on. There are several "scars" or "pock-marks" on the insulation of the wire from where the arcing took place.
So, after the wire pulling test I shut the engine down; intending to do one final re-adjustment of the valves just to be on the safe side. I pulled the cables from the top of my valve cover, and tried to start the engine. Cranking, but no start (this engine has started immediately every time for the last several weeks, so this was very strange). I was eventually able to get it started by giving a substantial amount of throttle, and it immediately ran VERY rough; AND was smoking like crazy out the exhaust. I tried giving throttle to get it to settle down, but it would not run smoothly and continued to smoke no matter what I did. I shut it down and restarted several times with no change (i.e. smoking and running rough). I tried pulling the spark wires again, and this time it seemed that #4 was not firing at all. The engine ran exactly the same with or without the wire attached. So, I checked for spark on the #4 wire- spark was good. I pulled the plug and replaced with a brand new one- no difference.
Fearing the worst, I ran a compression check and all four cylinders were solid - 140-148 psi on all four (#4 was actually the highest).
So now I'm really at a loss. I'm thinking it must have something to do with the arcing that took place during the cylinder checks- but am not sure how to proceed. I would be extremely grateful for any suggestions you may be able to offer.
Thanks!
