[LBL]

I got it back together and fired it up and it ran okay for a about 30 seconds and then started with the crankcase pressure thing again. So much that it won't allow the engine to rev up . Now I'm wondering if it might be possible for a lifter to be bad and possibly I have an exhaust valve that isn't openning causing the backpressure in the cranckcase ?

[cobalt327]

Originally Posted by LBL

I got it back together and fired it up and it ran okay for a about 30 seconds and then started with the crankcase pressure thing again. So much that it won't allow the engine to rev up . Now I'm wondering if it might be possible for a lifter to be bad and possibly I have an exhaust valve that isn't openning causing the backpressure in the cranckcase ?

Remind me- has a leakdown or compression test ever been done on this engine? It sounds to me like the ring seal is shot.

An exhaust valve not opening would (besides pumping pressure past the rings into the crankcase) tend to push the contents of the exhaust cycle back into the intake tract causing bad performance and popping through the carb- not ALL the contents of the exhaust cycle will be pushed into the crankcase, even if the ring seal is very poor.

[LBL]

I just finished pulling the plugs and checking the compression again and although it's not perfect, it's much better now and I believe that it will get better once the new rings are completely broke in. I still have 150 on the passenger side and the drivers side which was 145, 100, 145, 105 is now 145, 130, 145, 135 so rehoning those two cylinders made a real improvement. I pulled the valve covers and turned it over and the valves are all moving as they should so I think the valve train is fine. I did notice that the plugs were awfully black when I had them out, I know that would indicate too much fuel but not sure whether this would be causing any problems..

[cobalt327]

Originally Posted by LBL

I just finished pulling the plugs and checking the compression again and although it's not perfect, it's much better now and I believe that it will get better once the new rings are completely broke in. I still have 150 on the passenger side and the drivers side which was 145, 100, 145, 105 is now 145, 130, 145, 135 so rehoning those two cylinders made a real improvement. I pulled the valve covers and turned it over and the valves are all moving as they should so I think the valve train is fine. I did notice that the plugs were awfully black when I had them out, I know that would indicate too much fuel but not sure whether this would be causing any problems..

There's too much fuel, as in a too-rich air/fuel mixture that will soot up the plugs, then there is too much fuel where the carb is flooding because of the float level is too high or there's a problem w/the float or needle and seat assembly. If THAT is the case (carb is flooding), you have to correct it immediately or risk wearing out the cylinders and rings by washing the oil off the cylinders.

There's ~15% difference low to high. Better than it was but still high. That said, the engine should still rev up given those readings. I'm starting to think the cam is out of phase- as in the timing set is off. Was the cam degreed in?

How are you verifying there is pressure in the crankcase? You need to get a number on this by attaching a pressure gauge to the dip stick tube and see what it is.

[LBL]

the instructions when I installed the cam and lined up the dots on the timing set when I installed them, and they only go on the crank and the cam one way so I think that is correct. As well, it will run great for 5 or 10 seconds when I first start it cold. If it was getting too much fuel, would it load up and not rev up properly. I feel that the crankcase pressure issue is gone now that the 2 bad cylinders are breaking in and getting a better seal.

[LBL]

I'm now thinking it may be a fuel problem, I pulled the carb apart and found the float levelas to be okay but when I started looking at it. i noticed that one of the metering rods was bent to the point where it wasn't even near the jet so I figured that was my problem. Staightned it out and put it back in and it appears to be working so I fired up the engine and it ran great....for about 5 seconds , then it loaded up again and backfired, something it has never done before. I think I'm getting too much fuel but I'm not sure why. It will idle all day long but bogs and won't rev when I step on the gas..

[123pugsy]

Originally Posted by LBL

I'm now thinking it may be a fuel problem, I pulled the carb apart and found the float levelas to be okay but when I started looking at it. i noticed that one of the metering rods was bent to the point where it wasn't even near the jet so I figured that was my problem. Staightned it out and put it back in and it appears to be working so I fired up the engine and it ran great....for about 5 seconds , then it loaded up again and backfired, something it has never done before. I think I'm getting too much fuel but I'm not sure why. It will idle all day long but bogs and won't rev when I step on the gas..

Any chance of a restricted exhaust?

[cobalt327]

Originally Posted by LBL

I'm now thinking it may be a fuel problem, I pulled the carb apart and found the float levelas to be okay but when I started looking at it. i noticed that one of the metering rods was bent to the point where it wasn't even near the jet so I figured that was my problem. Staightned it out and put it back in and it appears to be working so I fired up the engine and it ran great....for about 5 seconds , then it loaded up again and backfired, something it has never done before. I think I'm getting too much fuel but I'm not sure why. It will idle all day long but bogs and won't rev when I step on the gas..

Just curious- what carb?

[LBL]

The carb is an 650 Edelbrock Thunder. I am wondering if I need to change the jets and metering rods. I was going to buy a new carb but can't really afford to at this point.

[cobalt327]

Originally Posted by LBL

The carb is an 650 Edelbrock Thunder. I am wondering if I need to change the jets and metering rods. I was going to buy a new carb but can't really afford to at this point.

If it was me, I'd set up the timing curve first then tune the carb.

The Edelbrock Owner’s Manual covering Performer and Thunder series carbs is here. With the info from it and from Edelbrock Performer Series Carburetor- Complete Guide to Set-Up, Tuning, and Performance Jetting, you can go about adjusting it for better performance.

[LBL]

and bought a new carb. I bought another Edelbrock but this one is a 1406 which is a 600 with the auto choke. I put it on and expected to have solved all my problems but it is the very same, idles well but loads up under throttle. I checked the fuel pressure and the gauge says 9.5 psi if it's correct. That's pretty high but I don't know what else to do. The fuel pump is a brand new Mr. Gasket 7705 and it says it should not go over 8 psi. Someone else suggested the torque convertor but I can't see anything there causing a problem when I'm sitting in park.......grrrrrrr!!!

[cobalt327]

Originally Posted by LBL

and bought a new carb. I bought another Edelbrock but this one is a 1406 which is a 600 with the auto choke. I put it on and expected to have solved all my problems but it is the very same, idles well but loads up under throttle. I checked the fuel pressure and the gauge says 9.5 psi if it's correct. That's pretty high but I don't know what else to do. The fuel pump is a brand new Mr. Gasket 7705 and it says it should not go over 8 psi. Someone else suggested the torque convertor but I can't see anything there causing a problem when I'm sitting in park.......grrrrrrr!!!

Verify the fuel pressure w/another gauge- if it's 9.5 psi, that is too high.

[LBL]

I replaced the gauge and it's running around 6 psi. Just to be sure, I replaced the fuel pump but the results are the same. I'm kinda wondering if somehow the transmission is holding it back but for now, I have bigger problems. I wanted to make sure that the transmission was in park so I disconnected the linkage at the tranny and put it in park, I think it has been in neutral up until now. Anyways, I was revving the engine when the son of a ***** dropped into gear, squealed the tires and drove through my garage door, well not right through it but it pushed it out 2 feet. Now I have an insurance claim on top of the cost of the carb ( which doesn't look like it was the culprit) I'm beginning to hate this car ! You can see the damage to the door in my avatar. At least the car didn't get damaged.

[67Mustang Al.]

Glad you were not standing between it and the door. You can buy new doors.
Al.

[LBL]

I am standing in front of the car working the throttle at the carb, for some reason I got in it this time so I am lucky in that regard. I am hoping I can install the new door in lieu of paying my deductible . Car still isn't running right, is it possible that the torque convertor is holding the rpms back somehow??