Electric problems after new rockers ???
Thread Starter
TECH Resident
Joined: Aug 2004
Posts: 875
Likes: 2
From: Portland Oregon
Electric problems after new rockers ??? I had shaft rockers and valve cover spacers, after fighting oil leaks I decided to change to Harland Sharp rockers and get rid of the spacers.
New rockers, new pushrods, new spark plugs and wires. Start it up and it runs like crap. Missing on the two back cylinders. The headers are hot except the back cyl on each side I can put my hand on. Pulled the plugs, they look wet with fuel.
Compression check, all are 150. Pulled valve covers, all rockers are good.
Pushrod length is right 1.25 turns on the rocker bolt. I replaced the coil on one of the dead cyls, then held a spark plug next to the head with the wire in. It has spark, but orange and fuzzy. Not a hot blue spark. Has 12volts at the coil. It ran fine before. What could I do to screw it up like this. I had the coils off, valve covers, alternator off, battery was dis-connected. Put it all back together, it just does not want to run, and I cannot find the problem. Everything I check is good. Any ideas appreciated.
New rockers, new pushrods, new spark plugs and wires. Start it up and it runs like crap. Missing on the two back cylinders. The headers are hot except the back cyl on each side I can put my hand on. Pulled the plugs, they look wet with fuel.
Compression check, all are 150. Pulled valve covers, all rockers are good.
Pushrod length is right 1.25 turns on the rocker bolt. I replaced the coil on one of the dead cyls, then held a spark plug next to the head with the wire in. It has spark, but orange and fuzzy. Not a hot blue spark. Has 12volts at the coil. It ran fine before. What could I do to screw it up like this. I had the coils off, valve covers, alternator off, battery was dis-connected. Put it all back together, it just does not want to run, and I cannot find the problem. Everything I check is good. Any ideas appreciated.
If they are wet with fuel then obviously you are not getting spark.
Do this...
1. Try a plug you know to work and see if you get good spark
-does not fix-
2. Change the spark plug wire (with known good plug) and try again
-does not fix-
3. Must be the coil, switch coil with known good one (using known good plug and wire) and try again.
-does not fix-
Out of ideas!
Do this...
1. Try a plug you know to work and see if you get good spark
-does not fix-
2. Change the spark plug wire (with known good plug) and try again
-does not fix-
3. Must be the coil, switch coil with known good one (using known good plug and wire) and try again.
-does not fix-
Out of ideas!
Thread Starter
TECH Resident
Joined: Aug 2004
Posts: 875
Likes: 2
From: Portland Oregon
7th. Thanks for the ideas. I tried it with new plugs and new wires, that was when spark looked weak.
Today I found a few places where the coil harness was rubbing on the coil bracket. I didn't see bare wire, but the insulation was chewed up, so I taped that up, and put the old spark plugs back in. I started it and it is still missing so I just held it at about 2000 for half a minute and it started geting better, then another minute and it started running good. I went for a drive and it ran fine.
Before I started it yesterday, it had been sitting for a week with the battery disconnected. Maybe the fuel pressure was low, or it has to relearn something in the computer. Or by changing the rockers, the lifters may need a minute to adjust to a small change in pushrod length? I can't explain it. I am going to try the new spark plugs tomorrow. This car has always been a mystery, it can never be easy.
Today I found a few places where the coil harness was rubbing on the coil bracket. I didn't see bare wire, but the insulation was chewed up, so I taped that up, and put the old spark plugs back in. I started it and it is still missing so I just held it at about 2000 for half a minute and it started geting better, then another minute and it started running good. I went for a drive and it ran fine.
Before I started it yesterday, it had been sitting for a week with the battery disconnected. Maybe the fuel pressure was low, or it has to relearn something in the computer. Or by changing the rockers, the lifters may need a minute to adjust to a small change in pushrod length? I can't explain it. I am going to try the new spark plugs tomorrow. This car has always been a mystery, it can never be easy.
Thread Starter
TECH Resident
Joined: Aug 2004
Posts: 875
Likes: 2
From: Portland Oregon
I took off the valve covers today because I am hearing a knock inside there. There are a couple of bumps inside the cover, under where the bosses are on the outside, sure enough, the rockers were hitting. I carefully filed that down. Put the new NGK plugs in, with the new MSD wires and went for a drive. Wow, it runs great. I stll don't know why it ran so bad when I first started it the other day, unless the coil wire harness was contacting the bracket, or low fuel pressure. Don't know. It rocks today...
Ready for the track or dyno..
Ready for the track or dyno..
