I need an opinion on these compressions numbers...

[Hoosierman]

Still trying to sort out a no start condition but I keep thinking back to the valve lash adjustment that I performed when I had everything off because of the leaking valve covers. So I did a dry compression test on all six cylinders and here is what I got:

1- 110psi
2- 140psi
3- 145psi
4- 150psi
5- 150psi
6- 140psi

I even retested #1 with an ounce of oil in the cylinder and it read 120psi thereafter. I know the 110psi is a significant drop (more than 15%) from 140. Significant enough to make a difference?

 

[alwaysFlOoReD]

That shouldn't prevent a start.

 

[Hoosierman]

Didn't think so.

About the low PSI number, should I look to adjust the valve lash anyway?

 

[Blmpkn]

Didn't think so.

About the low PSI number, should I look to adjust the valve lash anyway?

It certainly wouldn't hurt. Fingers crossed that's all it is for you

 

[Snoranger]

If you’re looking for a no start problem… you didn’t find it there. I’d leave that alone until you find and fix the no start problem.
Fix one issue before you dig into it a create another.

 

[85_Ranger4x4]

My 2.8 had enough blowby it would push out the dipstick and spray the exhaust manifold with oil... and it still started great.

I agree, your problems are elsewhere.

 

[bobbywalter]

you knocked something loose or maybe.....have slingblade check for gas.

 

[Uncle Gump]

Did it run before you fooled with it?

Spark... fuel... compression

Compression isn't it.

 

[Hoosierman]

It ran, but it ran very poorly.

 

[bobbywalter]

cap rotor fuel pump carb

 

[Uncle Gump]

I would think you're aware.... but many 2.8L people swap to Duraspark and replace the feedback carb.

There is a bunch of info in the Tech Library and 2.8L forum for how to get there.

 

[Hoosierman]

I've been through all of the tech articles, I've searched this forum and others numerous times, scoured posts and written notes. I have an original 2150 non feedback carb already on it. Spark is blue and strong. Fuel is getting in, occasionally it backfires through the carb. I recently removed the carb to inspect everything (it was rebuilt before I got it, everything looks fine).

I just don't know. That's why I thought I would give compression a test, but it seems like other than cylinder 1, I am a-okay. As for timing, I have been through that rabbit hole more than a dozen times now. I finally found my timing light (lost in a move) and intend to check that next. I guess I'll double check the gaps on the spark plugs while they're out just to be sure, I mean this whole thing could be a result of stacking errors.

Should I try an HEI coil instead? I forget the numbers as I've got other things I've been doing, but I remember checking voltages and ohms and the canister coil's numbers seemed okay.

Thanks for checking my numbers everyone! At least there seems to be a consensus that the compression isn't the cause.

 

[Jazzer]

Backfiring through carb is usually timing.

 

[Hoosierman]

Yeah but you'd think after setting it more than a dozen times, you'd get somewhere. So I paused on the timing and looked at the carb and compression just in case something else was amiss there. But I recently found the timing light so I think what I'll do is find the wire that is closest to TDC and set that as cylinder #1 and reorder the wires from there, just to get started.

 

[Jazzer]

You’ll get it. We’re all pulling for you.