IIRC off the top of my head, 380-400 across the board.

 

Well, it snowed a few inches yesterday Rich. Mid 30's today. Not bad yet, but I'm thinking we'll just let Glenn do it in his spare time next spring when he comes up. That way he can get a little "working on truck time" in during the summer/spring instead of just in the fall/winter.

I'm not much for working out in the cold anymore either. I spend as much spare time in my shop as I can this time of year.

 

Those are excellent numbers Todd.

"working on truck time", LOL

 

That's very good numbers glenn.that piece of mind information will go a long way to make youfeel better.

 

That is the one and only reason I did it Aaron, you nailed it. My nephew kept saying that I don't have a problem because it doesn't miss, I just wanted to see for myself!! Worth the effort!!

 

LOL! Seems like every time I do a test something for "piece of mind", I find a problem!

 

Good numbers Glenn!

 

glad your test worked out Glenn - I hope mine does as well - i'm going to attempt to do the compression test with the engine on the stand. I guess i'll see how that goes/if its possible.

a question with compression vs. mileage on an engine though - it seems there are 3 main ways compression can go bad on an engine:
1. simple, plain old, unstoppable wear - the kind that would cause our engines to all need a rebuild somewhere around 500,000 miles.
2. something accelerating wear, like a bad air filter (which would cause steady wear on all cylinders at an elevated rate)
3. the engine swallowing something large (like an air filter) that could cause instantaneous bad compression on one or more cylinders.

it seems that mid-life compression tests that we're all doing/planning on doing are really checking for problems number 2 and 3 above. the 'they should all be within a certain range' requirement checking for number 3 and the 'they should all be above X psi' requirement checking for number 2. so, you pass both of those test, great! but...

now correct me if i'm wrong here, but relative to number 1: since piston rings are a kind of spring design that are always pressing outward against the cylinder wall, theoretically, I could check my engine compression one day, find that everything is good, then the next day (or week, or year), the rings will reach the end of their life (i.e. wear down enough that they cease to seal the piston to the cylinder properly), and i'll need to rebuild her.

clearly there is no way to check ring-life without removing the heads and connecting rods, but am I correct with my logic?

i'm not really sure where i'm going with this - just a thought I had earlier today...

 

Actually I usually do to, that's why I'm celebrating! LOL

Thanks Pete, I wish I had what Todd had at 380-400 but I'll take what I got.

Theoretically, I think you have to much time on your hands, LOL I'm no engineer so I just run good oil with a oil bypass system and hope for the best. I do know that I've run the crap out of these motors up mountain grades and I should have left chunks of block and pistons all over the road!!

 

There are plenty of other potential compression killers:
* Fuel/combustion problem leading to a burnt/cracked valve
* Other valve train issues (bent valve, cam issue, etc)
* Blown head gasket involving a combustion chamber, venting compression to either a coolant jacket, an oil passage, an adjacent cylinder or the outside world
* and of course, the dreaded cavitation

 

ha - you're exactly right! actually i'm home from work watching my son while my wife and daughter are away next these next few days, so I do have a lot of time on my hands now!

and yes, that seems to be the general concensus - treat em right and these engines will last a LOONG time!

very true - and very good point(s). if the compression test passes, great! if not, its just step one in the diagnosis/repair process.

thanks fore setting me straight, guys!

 

I don't think I was setting you straight, just giving you some shi! LOL

My wife asked me why my truck wouldn't start. I said I wasn't trying to start it, I was doing a compression test. Like a 3 yr. old, WHY? I said its like you and I getting a blood test, it 'helps' in telling us what's going on.

 

Pretty much the same numbers as my 390k mile engine. lol Except mine has two that are at 320psi.

Definitely nothing wrong with those numbers. A fuzz lower than I was hoping to see with your mileage, but that'll run for quite a bit longer yet and run good. I was hoping to see yours up around 380-400 across the board. You may get closer to those numbers on a warmer engine though as the pistons and rings expand into the cylinder a touch. Good results buddy! Now we can work on making the setup work even better.

 

well, I couldn't say "thanks for giving me some *****!" ha!

 

Thanks Travis and its good to see you around. I hope your new job isn't driving you crazy, LOL. I was also hoping to see a 'fuzz' better but that's OK. Maybe one of these winters I'll rebuild it.

Why couldn't you say that?? haha I keep forgetting to play with the decibels meter now that I have it downloaded.