Need help with some mopar info on a 383

[jasper]

I have been working on a 73 challenger for a friend. Installing a painless wireing kit and a affordable fuel injection kit new dash and gage set. He had a guy rebuild is motor for him and that's where the fun started. I got the car running after installing the kit. now this is my problem the more the car ran the worse the motor got back firing threw the intake started missing just went to ****. I started pulling plugs and looking at compression the best out of all 8 cyc was 90 worst was 65 psi on a cold motor hot motor 70 to 30 on this ? REMAN ? I started doing some test with the compression tester I doing a leakdown test first and you can hear the air passing the rings luckily not pass the valves. so I know the rings are shot or on wrong. this is where I need help! I loosened the rockers or the rail what ever you want to call it. And retested the compression on that side and it went from 80 to 120 so I know some thing is holding the valves open too it has solid push rods with hydraulic lifter CAN YOU DO THAT? next the lifters are stock with a aftermarket cam CAN YOU DO THAT? WITH STOCK SPRINGS? I pulled a head to have a look it is 30 over 383 but notice the pistons are flat top but they do not come to the top of the block at the end of the stroke IS THAT WRIGHT FOR A 383? What in am trying to find out is if any has any ides what this clown did the motor is a 69 383 are they a way some parts got mismatched from different years on these motors and I have two motors out of some old motorhomes that are 440"s WILL THE PARTS SWAP OFF OF 383 TO A 440 INTAKE AND DIS SO I CAN INSTALL THE FUEL INJECTION KIT ON THAT MOTOR ? PLEASE ALL THE INFO I CAN GET WILL HELP

 

[mopar 3 B]

Parts that will not interchange without machine work or adaptors. Intake manifold, crank shaft, connecting rods, push rods, main bearing caps and distributor. If compression increased by closing valves one would not think piston rings would be the problem. Has the oil been checked for fuel contamination? Sounds almost like to much fuel washing cylinders down and fouling spark plugs. Yes push rods are solid. Oiling of upper valve train is threw rocker shafts. Rocker if stock are not adjustable. Stock piston will normaly set below deck height. What was oil pressure when engine quite? Where spark plugs fuel fouled? What was controlling timing?

 

[rscurtis]

Is there a possibility that someone installed a solid-lifter cam with the hydraulic lifters?

 

[Average Joe]

Have you looked at the Timing chain to see if the valve timing is correct. It could be so many different things. Depending on lift and duration if the cam is close to stock spec stock rockers will work to a certain point then they need to be adjustable.

- - - Updated - - -

Also when you got the motor running did you break the camshaft in?

 

[bm02tj]

Is it possible that the valves were ground and they did not cut to length so when the lifters pumped up it was holding the valve open
remove rocker shaft and lay a straight edge across the valves

 

[jasper]

the distributor has a pic up in and the ecm controls the timing oil pressure is 60 all day

- - - Updated - - -

know I did not how do you brake it the cam how do you do it? and I have not pulled the timing cover

- - - Updated - - -

I have wonder that my self are they different?

 

[Average Joe]

Hey Jasper, engines with flat tappet hydraulic camshafts require a camshaft break in when you first start the engine. To do the break in you want to start the engine,get timing close then run it at 2000 to 2200 RPM for twenty minutes. This will heat the metal on the camshaft lobes and lifters and harden it. After twenty minutes let the engine cool and tune.

 

[mopar 3 B]

Personally would have broke this in before installing a new efi system and then installed efi. Does the efi have enough base perimeter built in or can you program it in? If you have access to the engine builder he should be able to eliminate a lot of guess work as to valve train conserns and if any milling has been done to block or heads and yes if right push rod are obtained they can be shortened to obtain proper valve gap.

 

[193rdsow]

If it wasn't built by a professional, I would recommend pulling the motor and tearing it down. In the end, you will probably save time and $$.