I have recently had my original 67 400 GTO engine professionally rebuilt and, upgraded with forged pistons, and rods, balanced, Full roller rocker arms and the Milling SP7 cam(068) and lifters. Ram Air cast iron manifolds. Original Qjet intake and 1970 GTO Qjet carb. Original Turbo 400 rebuilt. Today I had it out on a short run. It was up to full
Temp and showing 40-50 PSI oil pressure. As I was going down a slight hill about 40 mph and decided to see if it would downshift into 2nd. It did and started pulling real hard! It got to about 4300 RPM and back fired! I let completely off of it. I was real close to my house and drove it into my garage. When I put it in Park it was idling at 1200 RPM. I shut it off and let it set a little while. It didn't want to restart. It turned over real slow, kind of dragging.
I have been trying different things.
1. Could it have jumped timing when it backfired?
2. The plugs have 300 miles on them. The plug wires are brand new. It has been converted to electronic with an
pertronix module, and their coil.
3. I had to replace the timing cover due to corrosion of the nozzles and had to use a 65 case that has the pointer for the timing mark and the stock 67 balancer so I have to use a Advance type timing light to set timing. I assume that when the pointer is lined up with the mark on the balancer that is TDC Does that sound correct?
4. I have played with the timing and had it running a couple of times. Sounded ok run smooth, but when I cut it off it is turning over slow when trying to restart. It has a High Torque starter and the battery was put in new and only has 300 miles on it, but is 3 years old
Any help would be appreciated. My engine builder is real busy and I will have to wait on him a while.
Thank in advance!
Richard
67
Temp and showing 40-50 PSI oil pressure. As I was going down a slight hill about 40 mph and decided to see if it would downshift into 2nd. It did and started pulling real hard! It got to about 4300 RPM and back fired! I let completely off of it. I was real close to my house and drove it into my garage. When I put it in Park it was idling at 1200 RPM. I shut it off and let it set a little while. It didn't want to restart. It turned over real slow, kind of dragging.
I have been trying different things.
1. Could it have jumped timing when it backfired?
2. The plugs have 300 miles on them. The plug wires are brand new. It has been converted to electronic with an
pertronix module, and their coil.
3. I had to replace the timing cover due to corrosion of the nozzles and had to use a 65 case that has the pointer for the timing mark and the stock 67 balancer so I have to use a Advance type timing light to set timing. I assume that when the pointer is lined up with the mark on the balancer that is TDC Does that sound correct?
4. I have played with the timing and had it running a couple of times. Sounded ok run smooth, but when I cut it off it is turning over slow when trying to restart. It has a High Torque starter and the battery was put in new and only has 300 miles on it, but is 3 years old
Any help would be appreciated. My engine builder is real busy and I will have to wait on him a while.
Thank in advance!
Richard
67