No compression on '79 318 cylinder 7

[Greybush]

Sorry if this has been done before. I searched for an answer and all I got was compression ratios and how to raise them. YouTube was no help either

It's a 79 318 with no compression on the no. 7 cylinder. All others are at 120. The new oil is pitch black after 20 miles and the intake valve on 7 isn't moving. The pushrod seems too short. I'm a good mechanic on newer stuff but not familiar with these older engines. I'm using my Harley knowledge on it. I'm thinking the lifter is bad? I found a video on changing the lifters on a 360 magnum. Is that close to doing them on a 318?

Thanks for your help.

 

[RustyRatRod]

Sounds like a wiped cam lobe and destroyed lifter.

 

[Hellrats]

I found a video on changing the lifters on a 360 magnum. Is that close to doing them on a 318?

Yep, but the magnum has roller lifters and your 1979 LA 318 will be a flat tappet cam. Rusty I'm sure is correct, the cam is wiped out. But I'd pull the lifter first and take a look. Maybe you'll get lucky. I know I wouldn't.

 

[jos51700]

Does the pushrod move? Is the rocker arm tight or floppin'?

 

[George Jets]

☆☆☆☆☆

 

[RustyRatRod]

Comprehension ain't some of yall's strong suits. Jes sayin. Let's see if this helps.

"...intake valve on 7 isn't moving. The pushrod seems too short."

Reading is fundamental.

 

[toolmanmike]

Or it spent too much time at elevendy-500 rpm and bent a pushrod.

 

[RustyRatRod]

Or it spent too much time at elevendy-500 rpm and bent a pushrod.

Also a possibility!

 

[toolmanmike]

Also a possibility!

 

[Greybush]

Wow! Thanks for responding so quick. So check the pushrod then check the lifter. Is it normal for one cam lobe to be so far off? All other cylinders are at 120psi.

Not second guessing you guys, just trying to figure out this old engine. with the black engine oil I was expecting a stuck open valve or broken spring. Leaking to the valve cover area and polluting the oil. Also, since the valve was closed the whole time, why couldn't it build compression?

Thanks again and sorry if I sound like a dick.

 

[Greybush]

Hey jos51700, yep pushrod moves but doesn't move the rocker arm at the apex. Yep rocker flops. Pushrod not coming up far enough to engage it.

 

[toolmanmike]

Hey jos51700, yep pushrod moves but doesn't move the rocker arm at the apex. Yep rocker flops. Pushrod not coming up far enough to engage it.

Flat cam lobe, bad lifter or bent pushrod.

 

[RustyRatRod]

Wow! Thanks for responding so quick. So check the pushrod then check the lifter. Is it normal for one cam lobe to be so far off? All other cylinders are at 120psi.

Not second guessing you guys, just trying to figure out this old engine. with the black engine oil I was expecting a stuck open valve or broken spring. Leaking to the valve cover area and polluting the oil. Also, since the valve was closed the whole time, why couldn't it build compression?

Thanks again and sorry if I sound like a dick.

It's normal if something is tore up.

 

[Greybush]

Thanks again guys. Not good news, but I was ready to pull the head this morning and thought I better ask you. So I'm grateful for the info. I'll take some pics tomorrow

 

[Greybush]

Yep, 2 bent rods. Was supposed to have been rebuilt but he got snootered. He's just gonna go with a crate engine. Will the old parts bolt up to them? Lokking at the ATK 3601at jegs. PN 059-3601. Only 2800 and can ship next week. Any other suggestions are appreciated.

 

[Greybush]

Oh yeah, Found a valve guide rattling around the bottom when I pulled the intake.

 

[RustyRatRod]

Yep, 2 bent rods. Was supposed to have been rebuilt but he got snootered. He's just gonna go with a crate engine. Will the old parts bolt up to them? Lokking at the ATK 3601at jegs. PN 059-3601. Only 2800 and can ship next week. Any other suggestions are appreciated.

View attachment 1716539546

That may be good news! If the pushrods are all that's bent, replace those two and run a compression test before you put it back together. It may have just been over revved. You wouldn't have found a valve guide in the intake valley. Maybe a lifter? Put it back and replace those pushrods.

 

[Greybush]

That's what I was thinking but he's so upset with the situation he just wants a new engine. The last mechanic tore the dash apart and sold the original 360. Drugs. The 318 was supposed to have been rebuilt but it wasn't and he's never been happy with it.

 

[jos51700]

Stab a couple pushrods in it. If anything, it'll sell easier that way, but hopefully if it runs he'll get over his emotional thinking.

I've never seen pushrods bent like that, but that's what I was suspecting

 

[jos51700]

And get rid of that orange rtv. Gag.

 

[toolmanmike]

Yep, 2 bent rods. Was supposed to have been rebuilt but he got snootered. He's just gonna go with a crate engine. Will the old parts bolt up to them? Lokking at the ATK 3601at jegs. PN 059-3601. Only 2800 and can ship next week. Any other suggestions are appreciated.

View attachment 1716539546

See post #7 and #12.

 

[furrystump]

Oh yeah, Found a valve guide rattling around the bottom when I pulled the intake.

A valve guide or seal? Guide you got bigger fish to fry than bent pushrods. Seal, no real biggie, but will need to find which is missing a seal and replace it. Valve probably got stuck and something had to give. For the pushrod to not reach the rocker ever, would have been 1/2 through the lifter.

 

[MOPAROFFICIAL]

Sorry if this has been done before. I searched for an answer and all I got was compression ratios and how to raise them. YouTube was no help either

It's a 79 318 with no compression on the no. 7 cylinder. All others are at 120. The new oil is pitch black after 20 miles and the intake valve on 7 isn't moving. The pushrod seems too short. I'm a good mechanic on newer stuff but not familiar with these older engines. I'm using my Harley knowledge on it. I'm thinking the lifter is bad? I found a video on changing the lifters on a 360 magnum. Is that close to doing them on a 318?

Thanks for your help.

Stuck valves. Smack it with a hammer and see what happens...then get a couple new pushrods

 

[Greybush]

Sorry it's been a couple days. Been trying to figure out the magnum motors. Not for us. Can't get any answers answered and it's crazy hard to find brackets and such to switch it to a 360.

Yep toolman, you da man. Called it from the start!

Hah, still ran pretty good before I took it apart, if you believe that. Well, it ran good, bad, good, bad. Maybe sticking valve?

Yep Rusty, that sounds like a plan. If it's just a couple of lifters and rods. Test compression. sell it, with the history disclosed.

 

[Greybush]

Oh yeah, saw the big hole when we fished it out but it has a small oil type hole on the bottom.