1979 D100 Custom Bed Project

[Joebull]

Hey guys, I have a 79 D100 w/a 318, I just did the compression test to see if I needed to rebuild or if a head job would suffice. The issue I'm having is all cylinders are only putting out 35psi. I'm confused because I know it should be at about 110psi, but the truck runs smooth, still has power and all of the cylinders are the same. Is this a huge issue or perhaps the previous owner put in low compression pistons in preperation for an engine addition?

Here's a pic of the truck... I fell in love with it for the fenders alone.

 

[Joebull]

Got a new tester and retested all the cylinders again... 2&4 are still putting out 35, all the rest are between 65-75. I'm guessing it's going to have to be a full rebuild.

 

[bear]

Just a thought , but you are doing your test with no fuel going to your cylinders right ?

 

[Joebull]

No, I still have gas going to the cylinders. I just unhooked the dist, jammed open the throttle and tested the cylinders. Am I supposed to stop the flow of gas to the engine? And if so, what's the point of jamming open the throttle?

 

[bear]

I've gotten mix readings sometimes when I did'nt . If there's fuel getting into some of your cylinders then your rings arn't going to be sealed and you will get a lower reading .

 

[Bob Cain]

More pictures PLEASE

 

[Joebull]

Thanks for the tip! I'm currently organizing a yard sale to make room in the garage. Should have the room to start pulling the motor next week. I'm just going to go ahead and rebuild it.
Bob, I'll get my old lady to snap some pics once the tear down starts.

Also, while waiting on the space to open up, I went ahead and pulled the wiper motor, arms and associated wiring. Also yanked out the seat belt warning light and the box that buzzes when you turn the key. Anything not really useful is going to find its way into my trash can.

 

[Bob Cain]

Thanks for the tip! I'm currently organizing a yard sale to make room in the garage. Should have the room to start pulling the motor next week. I'm just going to go ahead and rebuild it.
Bob, I'll get my old lady to snap some pics once the tear down starts.

Also, while waiting on the space to open up, I went ahead and pulled the wiper motor, arms and associated wiring. Also yanked out the seat belt warning light and the box that buzzes when you turn the key. Anything not really useful is going to find its way into my trash can.

Still waiting for more pictures Joebull : }