How to determine if my 3.0 rings are shot

[mikedks]

OK, am new to Toyota's, bought my 95 3.0 as a project, 150K miles, little to no compression in #6 cyl, and only about 60 lbs in #2, poured oil in cylinders, nothing in #6 but a 30 lb boost in #2. I'm thinking I got some serious issues. It ran OK, dead miss, but OK, no smoke, no bearing noises, no water in oil, etc...

Now machine shop guy who is going to do the heads(maybe block?)also has a 3.0, tells me its probably the heads, burned valves, head gasket, usual suspects. Long story short, have gotten all the mess out of the way and am about to pull the heads. How does a back yard mechanic tell if any of the cylinders have bad rings?, what am I looking for? about only thing I know to look for is cross-hatch pattern on cylinder walls, or scoring on the walls.

Any mechanics can help?

thanks

 

[Bad_Vision]

a compression test will tell you if the rings are bad.

If your going to have the heads redone you might as well do the rest of the engine you could re ring it by the time you get the heads back from the shop.

 

[mikedks]

a compression test will tell you if the rings are bad.

If your going to have the heads redone you might as well do the rest of the engine you could re ring it by the time you get the heads back from the shop.

Sorry if I wasn't clear in my post, I have already completed the compression test, and have poured oil into the cylinders that presented problems. That would be in place of a leakdown test.

BTW, huge difference between rebuilding the top end and completely rebuilding the motor, at least a grand more. Don't really feel like throwing big $$ at this motor.

 

[run4yota]

look online, i've seen rebuild kits brand new that include EVERYTHING minus the rods, crank, camshaft, and new valves for under 300.00.. i have one ready to go for when my motor takes a pooper. it comes with new pistons, rings, all gaskets, water and oil pump.. all timing equip and bearings.. it's really a cheap price for a decent rebuild kit, and you can order it in different clearances/over-bores depending on how much wear you have, if you cant find any PM me and i'll get you a link.

i agree if your having the heads done.. might as well throw in some new bearings and rings, you should be good to go for a while then. i'm about to do it to mine as well.

 

[Ricky B]

Being a bit older than a lot of you guys here, I'm a firm believer in new crate motors. Yeah I know it's a few bucks more, but if your time/salary vs. their time/salary is a wash or so, it's sometimes better to just do what you do best, and let them do what they do best. Then spend your free hours cleaning up the engine bay, checking out the other components and repairing/replacing all the weird stuff that you can't normally get to when the engine is in the truck. Honestly, y'all might be surprised at how much less expensive and easier this really is to do in the long run. Cuz I've done this same thing with our '87 Bronco, a '69 Duetto, a '63 Econoline pick-up and a '91 MR2 turbo, and I wouldn't do it any differently.........

 

[mikedks]

look online, i've seen rebuild kits brand new that include EVERYTHING minus the rods, crank, camshaft, and new valves for under 300.00.. i have one ready to go for when my motor takes a pooper. it comes with new pistons, rings, all gaskets, water and oil pump.. all timing equip and bearings.. it's really a cheap price for a decent rebuild kit, and you can order it in different clearances/over-bores depending on how much wear you have, if you cant find any PM me and i'll get you a link.

i agree if your having the heads done.. might as well throw in some new bearings and rings, you should be good to go for a while then. i'm about to do it to mine as well.

I have seen the rebuild kits, and yes they are cheap. However, ya still gotta get the block machined, and that ain't cheap. Like I was saying, this is a cheap project,not a big $$ project, if I really wanted to, I would ditch this engine and put in a 3.4 or a Chevy V-8 but that's not going to happen. Bottom line is why rebuild the bottom end if there is nothing wrong with it.

Which brings me back to the original question, how can I tell if the rings are shot when I am physically looking down the cylinder at the top of the piston.

 

[90 t4r]

if it has no compresion the rings are shot most likely only real way to tell if rings r shot looking at them is if they are ate up and broke

 

[Bad_Vision]

there is no sense doing the top half to last another 100,000 if the bottom end gives out in 20,000 miles.

 

[Saved]

OK, am new to Toyota's, bought my 95 3.0 as a project, 150K miles, little to no compression in #6 cyl, and only about 60 lbs in #2, poured oil in cylinders, nothing in #6 but a 30 lb boost in #2. I'm thinking I got some serious issues. It ran OK, dead miss, but OK, no smoke, no bearing noises, no water in oil, etc...

Now machine shop guy who is going to do the heads(maybe block?)also has a 3.0, tells me its probably the heads, burned valves, head gasket, usual suspects. Long story short, have gotten all the mess out of the way and am about to pull the heads. How does a back yard mechanic tell if any of the cylinders have bad rings?, what am I looking for? about only thing I know to look for is cross-hatch pattern on cylinder walls, or scoring on the walls.

Any mechanics can help?

thanks

Unless at the factory they installed the rings on those cylinders pistons wrong (upside down) then it should not be the rings. There should never be that much of a difference between cylinder compression due to normal wear. My guess is that you had bad valves and or, blown head gasket getting blow by.That being said I would still do a ring job. You can mike the bores yourself before you remove the pistons to see if they will require a re-bore. Hopefully they will not because that would require new pistons.
I have done ring jobs and never remove the block. In fact i have done bearing jobs, rod and mains, and never totally remove the crank although the main bearing closest to the transmission is usually not possible to replace on the top side. So you have many possibilities, but I would replace the rings and if the bores are not worn out of tolerance you will not have to pull the block. Just mike the bores to see if they are in tolerance
Also one more thing. You do need to at least unbolt those two piston rods and push out the pistons and see if the rings are broken.

 

[mikedks]

Unless at the factory they installed the rings on those cylinders pistons wrong (upside down) then it should not be the rings. There should never be that much of a difference between cylinder compression due to normal wear. My guess is that you had bad valves and or, blown head gasket getting blow by.That being said I would still do a ring job. You can mike the bores yourself before you remove the pistons to see if they will require a re-bore. Hopefully they will not because that would require new pistons.
I have done ring jobs and never remove the block. In fact i have done bearing jobs, rod and mains, and never totally remove the crank although the main bearing closest to the transmission is usually not possible to replace on the top side. So you have many possibilities, but I would replace the rings and if the bores are not worn out of tolerance you will not have to pull the block. Just mike the bores to see if they are in tolerance
Also one more thing. You do need to at least unbolt those two piston rods and push out the pistons and see if the rings are broken.

Thanks, very helpful information.
Now I suppose I could pull the block and re-ring if the bores are good, but what about the bearings?, did you mic those as well or just drop in the new
ones and hope it still spec'ed out?
I'd be really interested to know

 

[Saved]

Thanks, very helpful information.
Now I suppose I could pull the block and re-ring if the bores are good, but what about the bearings?, did you mic those as well or just drop in the new
ones and hope it still spec'ed out?
I'd be really interested to know

This all depends on the budget. If the old bearings still look like they have Babbitt on them and are not starting to wear through to the base metal, on a low budget just put them back. You can expect to get at least another 100,000 out of them and probably more.
If you have a little extra in the budget to work with then mike the crank to see if it is not worn and it really should not be, also one never knows if someone else put a regrind in it. If the crank is not undersize then just replace the old bearing with standard new ones if it is a regrind then replace it with bearings of the correct size.
Also all this depends on how hard you are going to push the vehicle after you repair it. If you are an avid off road person then everything will wear faster so that should be part of your consideration as to if you replace with new parts or go with the old ones.

 

[mikedks]

This all depends on the budget. If the old bearings still look like they have Babbitt on them and are not starting to wear through to the base metal, on a low budget just put them back. You can expect to get at least another 100,000 out of them and probably more.
If you have a little extra in the budget to work with then mike the crank to see if it is not worn and it really should not be, also one never knows if someone else put a regrind in it. If the crank is not undersize then just replace the old bearing with standard new ones if it is a regrind then replace it with bearings of the correct size.
Also all this depends on how hard you are going to push the vehicle after you repair it. If you are an avid off road person then everything will wear faster so that should be part of your consideration as to if you replace with new parts or go with the old ones.

Was just looking at my repair manual on rebuilding the lower end, and it looks doable. Never done the bottom end before, but looks relatively easy and if the wear isn't too bad, fairly cheap. Soon as I get the heads off, I'll see how motivated I am and may just pull the short block. Don't think I would ever be so bold as to try to do it while its in the truck. Wish me luck, will let you know what I find this weekend.

 

[RpzInc]

Once the heads are off pour some oil (the lighter the better) on top of the pistons tryand cover as much as you can. mark the oil level with a sharpie and check a day later if a large loss has happend the rings are toast. but if they all have an equil small to no loss you areprobably ok. this is not the best way to test but fairly easy. the best would be a leak down befor you tear down. remember to remove your oil cap and radiator cap when doing a leak down test:naughty:

 

[mikedks]

Finished pulling the heads over the weekend, have attached some photo's for everyone to look at. First thing I noticed is the valley under the intake was half full with oil. Not knowing Toyota's, I thought it may have been a plugged drain hole, then after cleaning out the oil, I realized that there was no drain hole. Seems like an internal leak from the head gasket. Is that right or wrong?

Also, cylinders and pistons looks very good, no ridge in the cylinder, and cross hatch pattern in all cylinders. No evidence of scoring or any abnormalities.

The heads are a different story, cam lobes appear to have a bit of scoring, and the journals are also showing some scoring. The exhaust valves in the #2 and #6 cylinders appear to be deeper in the valve seat then the good cylinders. How can you tell if the valves are burnt?

Anyway, have attached a few photo's, hopefully someone will see something that I am not aware of.

Thanks

 

[mikedks]

Also, filled up the bad cylinders with fresh oil after cleaning, and they have held, no leaking.

 

[RpzInc]

once you have come this far you need to have a shop resurface the heads unless you get all the gasket material off with out any major scratching and the heads fall into specs (which is rare for these motors). if youdohave them resurfaced askhow muchit will be to replace the valve stem seals and check/replace valves as needed. any reasonable shop will do all of it for 350 or less. I would also consider replaceing the heads if the cam journels are shot.

 

[mikedks]

once you have come this far you need to have a shop resurface the heads unless you get all the gasket material off with out any major scratching and the heads fall into specs (which is rare for these motors). if youdohave them resurfaced askhow muchit will be to replace the valve stem seals and check/replace valves as needed. any reasonable shop will do all of it for 350 or less. I would also consider replaceing the heads if the cam journels are shot.

I'm dropping the heads off at the machine shop tomorrow, gave me a rough quote of about $300. We'll see if the cam journals are ok or not.

I'm still curious as to the oil in the valley under the intake, ever see anything like that?

 

[RpzInc]

I'm dropping the heads off at the machine shop tomorrow, gave me a rough quote of about $300. We'll see if the cam journals are ok or not.

I'm still curious as to the oil in the valley under the intake, ever see anything like that?

looking at the pics cylinder #1 looks like it was missing gasket material next to the guid tube... the oil says bad head gasket or cracked head.

 

[mikedks]

looking at the pics cylinder #1 looks like it was missing gasket material next to the guid tube... the oil says bad head gasket or cracked head.

Yeah, like I said, am new to Toyota's and their issues. Though I will say this, while the heads look like crap, the bottom end, to my marginally trained eye, looks solid with little wear. Am still deciding whether to chance it and complete the upper end rebuild and be done with it. Will let you know what I decide.

 

[RpzInc]

If you have any other questions you can ask me or check out my little thread.
I just finished up my top end and i couldnt be happier with the results!
http://www.toyota-4runner.org/classic-t4rs/82087-so-confused.html
once you start putting every thing together i will give you some helpful tips. just let me know when you need help!