Possible bad rings? (1 Viewer)

[airon23]

I've been doing some reading and learning over the last few months and the little that I've driven the FJ40, I'm thinking the rings on the pistons in my 2F probably are bad and need to be changed. Lots of smoke on deceleration, and when running but not at idle. I'm no engine builder although if you seen my FJ40 refresh thread I've taken the motor down and resealed it and then it miraculously somehow ran when I put it all back together

I know what you're thinking why didn't you just do the rings then, and that's a good question. Fact is I was still learning and I guess hoping I didn't need to and probably got in too big of a rush. Live and learn I guess.

So now I'm at the point of what do I do? My ignorance led me to drive it a little here and there since that time last year. Have I done damage to the motor? It still runs and drives as I've taken it around the neighborhood at low speeds. Maybe it didn't really show itself over that time, but what do I do about it now? Do I just bite the bullet and do all the same work over again to tear apart the motor to get to the pistons? Do I let a trained mechanic "expert" do the work for me? Can I drive it as is for some time?

A video at idle for context.

 

[pjohnson]

Are you sure it's oil? What does your exhaust smell like?
Take a thin white t-shirt or cloth and cover the tailpipe, rev the engine a bit and see what hits the cloth.
Do a wet and dry compression test.
Did you change valve seals when you re-sealed it?

 

[airon23]

I'm not sure it's oil.
I'm not sure how to describe the smell well enough, but I can check again.
I can try the white shirt thing and update.
What's the difference between wet/dry compression test?

I did change the valve seals at the time, because there was some white smoke previously as well.

 

[Skreddy]

Hot and cold compression tests can tell you different things because the metal is cold and contracted vw hot and expanded. I agree, try to catch some exhaust juices for a better look and do a compression test. When you pull the plugs, look at them as well. Oil burning (if enough oil is getting in there) will leave deposits on the plugs and piston tops.

 

[mrboatman]

You can also Indus compressed air and see if the air is leaking by the rings and coming out. Like the exhaust or carb or oil galley

 

[pithicus]

If it is the rings, A 2f is a relatively easy engine to re-ring. As long as the bores are ok, no scoring or out of round. If you have the time, DIY will save you heaps , and it should go for another 200k miles.

 

[cruiserkev]

When my rings were going bad the most obvious signs were fouled spark plugs and blue smoke from burning oil. Do you have either issue?

 

[pb4ugo]

I'm not sure it's oil.
I'm not sure how to describe the smell well enough, but I can check again.
I can try the white shirt thing and update.
What's the difference between wet/dry compression test?

I did change the valve seals at the time, because there was some white smoke previously as well.

Dry and wet compression check. Get the engine up to operating temp. Remove all the spark plugs and rig the carb to be wide open. Now install the compression gauge in #1 spark plug hole. Crank the engine over and allow the cylder to hit 4 or 5 times and record the number you get. Do this to all cylders. To be an accurate test each cylder needs to hit the same # of times on each cylder. If you let it hit 4 times then do 4 times on all cylders. Now do the same test except squirt oil into the cylder b4 it's tested. Do this for each cylder, try to squit the same amount oil into each cylndr b4 its tested. If the Compression jumps significantly then the ring are bad. The oil is filling/sealing the gap between the cyldr wall and the rings. If there's a minimal change then the issue is in the head, possibly valves, valve seals or valve guides. Post your results here, inquiring minds want to know.

 

[JDNs78FJ40]

I've been doing some reading and learning over the last few months and the little that I've driven the FJ40, I'm thinking the rings on the pistons in my 2F probably are bad and need to be changed. Lots of smoke on deceleration, and when running but not at idle. I'm no engine builder although if you seen my FJ40 refresh thread I've taken the motor down and resealed it and then it miraculously somehow ran when I put it all back together

I know what you're thinking why didn't you just do the rings then, and that's a good question. Fact is I was still learning and I guess hoping I didn't need to and probably got in too big of a rush. Live and learn I guess.

So now I'm at the point of what do I do? My ignorance led me to drive it a little here and there since that time last year. Have I done damage to the motor? It still runs and drives as I've taken it around the neighborhood at low speeds. Maybe it didn't really show itself over that time, but what do I do about it now? Do I just bite the bullet and do all the same work over again to tear apart the motor to get to the pistons? Do I let a trained mechanic "expert" do the work for me? Can I drive it as is for some time?

A video at idle for context.

Aaron, I think our 2F's have the exact same issues. Lots of what I would call blueish smoke when I take off after sitting at a stop light or stop sign. Smoke on deceleration as well and from what I can tell smoke while driving. I replaced the valve stem seals this past weekend in hopes that would clear things up since that is the easiest thing to take a stab at and It didn't help. I also noticed on a couple of the cylinders when I was had them hooked up to compressed air that they were leaking the air somewhere. The air compressor had to constantly kick on and off to hold 90 PSI. I would like to do what @pb4ugo suggested. I still drive mine pretty much every day. For me it's more embarrassing than anything else at this point.

 

[JDNs78FJ40]

Aaron, I think our 2F's have the exact same issues. Lots of what I would call blueish smoke when I take off after sitting at a stop light or stop sign. Smoke on deceleration as well and from what I can tell smoke while driving. I replaced the valve stem seals this past weekend in hopes that would clear things up since that is the easiest thing to take a stab at and It didn't help. I also noticed on a couple of the cylinders when I was had them hooked up to compressed air that they were leaking the air somewhere. The air compressor had to constantly kick on and off to hold 90 PSI. I would like to do what @pb4ugo suggested. I still drive mine pretty much every day. For me it's more embarrassing than anything else at this point.

I also had oil seeping from #4 spark plug hole and suspect that is a very bad sign. That said, I'm waiting and saving for a HP 2F from mosley but I will drive it as is. It's too much fun!

 

[1911]

You could also perform a leak-down test; sometimes more diagnostic than just a compression test. Can usually tell the difference between ring blow-by and worn/leaky valves, head gasket failure, etc.

 

[airon23]

Thank you all for all the tips and suggestions. I've been a little busy with work so not sure when I can get to try these things but when I do I will post any updates I have.

 

[airon23]

Aaron, I think our 2F's have the exact same issues. Lots of what I would call blueish smoke when I take off after sitting at a stop light or stop sign. Smoke on deceleration as well and from what I can tell smoke while driving. I replaced the valve stem seals this past weekend in hopes that would clear things up since that is the easiest thing to take a stab at and It didn't help. I also noticed on a couple of the cylinders when I was had them hooked up to compressed air that they were leaking the air somewhere. The air compressor had to constantly kick on and off to hold 90 PSI. I would like to do what @pb4ugo suggested. I still drive mine pretty much every day. For me it's more embarrassing than anything else at this point.

When you mentioned the part about still driving it everyday, that's something that maybe is more immediately important to me. If I drive this thing knowing the rings are possibly bad, will I do damage to it? I won't be driving it all day everyday, just am wondering if I don't do the work to change rings right now, can I continue driving it as is with the smoky embarrassing mess but not necessarily hurt the motor?

 

[JDNs78FJ40]

When you mentioned the part about still driving it everyday, that's something that maybe is more immediately important to me. If I drive this thing knowing the rings are possibly bad, will I do damage to it? I won't be driving it all day everyday, just am wondering if I don't do the work to change rings right now, can I continue driving it as is with the smoky embarrassing mess but not necessarily hurt the motor?

I drive mine any chance I get when the outside temps are below 100. Just short trips to the hardware store or gas station for a beer run. I drive it maybe 200 miles per month. I’m not sure if it’s damaging anything as long as I keep the oil filled and my operating temperature never exceeds 190. I don’t know if I am doing damage, someone who is more mechanically inclined then me would have to chime in

 

[fjc-man]

I don’t want to sound like a broken record but keep in mind, there are two compression rings and one oil control ring on the piston. Compression and leakage numbers can be good and can still use excessive amounts of oil if the scraper / oil control rings are stuck in there groove because of carbon deposits.

 

[SteveH]

As long as it doesn't run out of oil, you won't hurt the engine driving it with bad rings. Your PCV system will suck up more crud from the blowby. If your oil pressure (measured with a real gauge) is poor (less than ~10 psi at hot idle), then you should not drive it.

You might try running 15w-40 diesel oil, or 20w-50 gas engine oil (if it's always hot in Reno) and that will cut down on the oil burning.

 

[mrboatman]

As long as it doesn't run out of oil, you won't hurt the engine driving it with bad rings. Your PCV system will suck up more crud from the blowby. If your oil pressure (measured with a real gauge) is poor (less than ~10 psi at hot idle), then you should not drive it.

You might try running 15w-40 diesel oil, or 20w-50 gas engine oil (if it's always hot in Reno) and that will cut down on the oil burning.

I installed a Oil Catch Can in the PCV line just for the purpose of catching any blow-by oil. I just keep the oil level full and drive it. I also use 15-40 diesel oil for the zinc. The main issue with burning oil/smoking is passing smog test but if you are running a classic plate don't worry about it just kept adding oil and enjoy your drive I mean your not putting out a smoke screen.

 

[airon23]

Got it. Thank you all for the help. I'll make sure the oil level stays good and drive it as is for the time being.