What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Engine lost compression

45acpJr

45acpJr

1/2 ton status
Joined
Jan 7, 2003
Posts
633
Reaction score
5
Location
Tucson, Az
Took a quick drive today and everything felt/sounded normal til I got on the skinny pedal. Heard a ticking sound and watched my oil guage drop to zero. Got out checked the oil and it's not even registering on the dip stick. Not sure where the oil went, I park on cardboard to watch for leaks and the exhaust has not been smoking. I have a few different scenarios and questions to get everyones opinion.

First question is, is it worth fixing this tired engine? I know it could be a variety of different problems/fixes. I don't know a lot about engines so I'm feeling stupid right now.

Second question I have a buddy who has a buddy selling a 350 ci vortec engine mated to a 700r4. It was pulled out of his late fathers 72 c10. But it has sat covered up in a garage for the past two years. It supposedly ran strong when it came out. He wants 1200 for all of it. What problems could I be looking at from an engine sitting for two years? Is it a good deal? Whats involved in swapping from a th350 to a 700r4? And will it mate to a 205? Any help or info is much appreciated:thumb::popcorn:
 
Well, first put some oil in it and see what happens. Hopefully the ticking sound was the lifters collapsing from lack of oil.

As for fixing it, its hard to say until you present us with the other ideas and information.
If its running strong, just using some oil, then you may just bump up the oil viscosity and get a lot more use out of it.
But, it depends on what you want to do with it.

If you just need something to go to the store and haul some occasional stuff in the bed, then it might give you years of service as is.

If you want to haul heavy trailers or go mud bogging, then you are probably going to need some work.
But, first thing is to figure out where the oil went.
May sound stupid, but is the drain plug still in? I have seen them fall out.

And if you changed the filter recently, any chance the old seal stuck to the block?
 
Sorry forgot to add that part. Put 3.5 qts in it and it runs like ****. Feels like I'm starting in 3rd gear. Ill tear in to it more this weekend.
 
45acpJr said:
Took a quick drive today and everything felt/sounded normal til I got on the skinny pedal. Heard a ticking sound and watched my oil guage drop to zero. Got out checked the oil and it's not even registering on the dip stick. Not sure where the oil went, I park on cardboard to watch for leaks and the exhaust has not been smoking. I have a few different scenarios and questions to get everyones opinion.

First question is, is it worth fixing this tired engine? I know it could be a variety of different problems/fixes. I don't know a lot about engines so I'm feeling stupid right now.

Second question I have a buddy who has a buddy selling a 350 ci vortec engine mated to a 700r4. It was pulled out of his late fathers 72 c10. But it has sat covered up in a garage for the past two years. It supposedly ran strong when it came out. He wants 1200 for all of it. What problems could I be looking at from an engine sitting for two years? Is it a good deal? Whats involved in swapping from a th350 to a 700r4? And will it mate to a 205? Any help or info is much appreciated:thumb::popcorn:
Click to expand...

First engines eat oil even without smoke from the exhaust, so it may have just been that low if you haven't checked it in a while. Getting on the skinny pedal and increasing the R's will easily suck up the remaining oil and starve the pump causing your tick.

Next possible is that the pick-up for the oil pump fell off...which is less likely with the low oil level.

Assuming you hurt the motor, I'd consider buying your buddies motor only. Smaller can of worms to deal with. After sitting two years I wouldn't pay more than $350 for it unless you get to hear it run, see oil pressure, and compression numbers for yourself. If that isn't possible treat as a buildable core and don't pay more than that value for it. Your tranny is not wrecked, so why change it if you don't have to?

Have you run it since you topped the oil up? How low was it? How long did you run it critically low?
 
Also, is it still making the ticking noise? All the lifters may not have pumped back up, which would cause all kinds of power problems.
 
Yes it was critically low 1 qt or less, I did fill it back up and it sounds fine but it has no power at all. Coming iff a stop it feels like its in 3rd
 
Any chance that loose distributor is your power problem? Maybe get that dialed in and see if some power comes back.
 
No I took care of that problem when I got back home, I'm pretty sure it's a compression problem. We'll find out tomorrow, I'm kinda torn I hope it's a cheap fix but I kinda like the idea of having to put a new engine in
 
Wasted Wages may be right--the timing chain could well have jumped if it was loose,especially if it had the crappy stock nylon coated aluminum cam gear--running it low on oil may have been just what it needed to get the chain hot enough to slip over what was left of the gear teeth,after all the nylon crap came off..(and is likely in the oil pump screen and pan now!)..

You can check to see if the valve timing is still "right" without doing too much work...put the #1 piston at TDC compression stroke and ensure both valves are closed fully,there are specs in old motors manuals that tells you when the intake valve should start to open...its poosible the cam lobes were wiped out too,from running it too low on oil...that'll kill a lot of power,yet still run quietly,to a degree--the lifters will pump up more to take up the slack,and the valves wont open far enough..
 
diesel4me said:
Wasted Wages may be right--the timing chain could well have jumped if it was loose,especially if it had the crappy stock nylon coated aluminum cam gear--running it low on oil may have been just what it needed to get the chain hot enough to slip over what was left of the gear teeth,after all the nylon crap came off..(and is likely in the oil pump screen and pan now!)..

You can check to see if the valve timing is still "right" without doing too much work...put the #1 piston at TDC compression stroke and ensure both valves are closed fully,there are specs in old motors manuals that tells you when the intake valve should start to open...its poosible the cam lobes were wiped out too,from running it too low on oil...that'll kill a lot of power,yet still run quietly,to a degree--the lifters will pump up more to take up the slack,and the valves wont open far enough..
Click to expand...

I vote cam flat lobes from running low on oil
 
Well I don't have a good enough area to do this myself nor do I have the experience. So it's at a shop my family as used for years. I should have an answer later today
 
im also going with wiped out cam, but depending on how long it was run low on oil im going to say at least one lifter wiped too.
 
Since you're saying it has lost compression, have you hooked up a compression tester to confirm? Definitely a good idea to rule out the bottom end as a factor.

A leakdown test would be even more useful, and could pinpoint head and valve problems. From the sound of it the engine isn't breathing, which points to the cam/valvetrain.
 
Nothing is confirmed yet, since this problem is a little beyond my current ability/knowledge I brought it to a shop that I trust
 
And the winner is.......imiceman44 with flat cam. Also it turns out that it was burning oil but apparently stopped smoking before it came out the tailpipes which is why I didn't see it. Lesson learned, even if you hardly drive your truck check your fluids:doah:
 
45acpJr said:
And the winner is.......imiceman44 with flat cam. Also it turns out that it was burning oil but apparently stopped smoking before it came out the tailpipes which is why I didn't see it. Lesson learned, even if you hardly drive your truck check your fluids:doah:
Click to expand...

Robert aka diesel4me mentioned it first among other things, I thought for sure that is it.
 
Good eye, I missed it. I sure wish I had a garage, this is gonna cost me a pretty penny
 
Thanks for giving credit to me Iceman...it was an afterthought ,that I remembered while typing about the timing chain possibly having slipped..if the valves are not opening much,your not gonna get much power out of that cylinder!..

The compression might still be "normal",but the fact some valves are not opening enough to let air in or out will reduce the power greatly..

Though I have changed a few cams with flat lobes ,and replaced the timing chain and gears and had no further issues in several chevy V8's,I would say in your case,if it were run that low on oil long enough to wipe out several cam lobes,that the rest of the engine suffered some too,like the main and rod bearings,oil pump,etc..

All that metal had to go somewhere,and it has to pass thru the oil pump & bearings on the way to the oil filter ..it might need the cam replaced,the bearings,oil pump,and possibly the crank may have been scarred up ,that means a reground crank kit would be needed..
You might as well do a total rebuild,because the rings and pistons might be scuffed up too..
At this point a good running salvage yard engine would be the cheapest way out,its not that hard to yank your old engine out and drop in a good one,compared to bending over under the hood for days installing a cam,intake,and lying under it trying to roll in new bearing inserts,,that rarely pans out well too..you could have the good engine in it in one day if your good no sweat,a weekend if your not probably..a shop will charge a lot less to put an engine in than put a cam and timing chain in one usually..
 
You must log in or register to reply here.

Latest Posts

Top Bottom