Compression and Leak Down Test (1 Viewer)

[Timmy65]

I did a compression and leak down test of my buddy Rey's engine. The back story is he had his alternator belts way under-tightened and one of them came off while he was driving down the highway, it wrapped around the fan clutch and stopped it from spinning. By the time he noticed his coolant temp rising and he got pulled over on the side of the highway, he registered a temp of 263. As a result, his radiator sprung a leak. I replaced his radiator but I noticed the idle seemed rough and I asked Rey if the idle was like that before he overheated. His answer was no which got me thinking his engine wasn't ok. A couple weeks went by and he told me he now has a Cylinder 1 Misfire. The following video is me figuring out it is an issue with the cylinder compression and then me trying to figure out where the compression is leaving the cylinder. I hope you find the video helpful.

 

[flintknapper]

Hey Dudes, If you wanted to know how to perform a compression and leak down test of your engine cylinders, this video will show you how to get it done.

Hope you enjoy the video and Happy Wrenching!

p.s. I wonder what the know-it-all peanut gallery is going to say about this one. I almost didn't post this video because of the BS that seems to follow every time I post a video on this forum but maybe I'll be surprised this time

If you'd spend a little time here, grow some thicker skin....you might actually learn something that would help you. Instead of insulting those who clearly know more about these engines and vehicles than you do. There is collective knowledge on this site that FAR exceeds the little bit of experience you have working on these vehicles.

Anyone here could have told you, you could STOP right after the compression test and start pulling the head. There is NO scenario that isn't going to end up there anyway. It is unusual for this engine to have issues with the rings, but can happen. Much more likely a head gasket. Typically at the #1 or #6 cylinder. And as you aware (hopefully) there are number of ways a head gasket can fail.

In any case, please DO post back here and let us know what you found. We in the 'peanut gallery' are anxious to know.

 

[Timmy65]

Yep, I knew better. This was my last post on this part of the forum. Anyone that wants to watch any of our videos for the FZJ80 will just have to come to my channel or find them on some of the Facebook pages I post on.

By the way, I consulted the owner of an engine rebuilding shop who knows this engine inside and out and he's the one who told me about the possibility of the rings getting damaged from the engine hitting a very high temp. But, what does that guy know? He just rebuilds engine for a living.

Adios!

 

[FMC80]

I appreciate your vids as I told you in the last time you posted; I'm sure others do too. But this is on you dude.

Maybe Onur is a dick...I don't know him personally, but you invited this by calling him out in your initial post without any provocation and then have the audacity to act like a victim when @flintknapper calls you out.

Good luck to you. Bu-bye.

 

[Grandlooser]

Damn. This WAS the one forum I visit where I never see unjustified high level butthurt. Days of yore.

 

[flintknapper]

Yep, I knew better. This was my last post on this part of the forum. Anyone that wants to watch any of our videos for the FZJ80 will just have to come to my channel or find them on some of the Facebook pages I post on.

By the way, I consulted the owner of an engine rebuilding shop who knows this engine inside and out and he's the one who told me about the possibility of the rings getting damaged from the engine hitting a very high temp. But, what does that guy know? He just rebuilds engine for a living.

Adios!

^^^^

It IS a 'possibility', I allowed for that. So when you know for SURE what happened, come back and let us know. More often, these engines (many with over 300K miles) still show the factory cross-hatching in the cylinders and piston rings are rarely an issue. But anything is possible with an overheat.

The compression test you did compares favorably with what others see (mine included).

But history shows a more likely reason for the one cylinder being 'down' will be a head gasket leak. Very common to see that on the #1 and/or #6 cylinders. The leak down test (if meant to be a tutorial) was semi-OK, but unnecessary with respect to this engine. There is no scenario that won't lead to pulling the head and visually inspecting everything, so you might as well get started.

I'm saying that for YOUR benefit, not ours. We already know that. We appreciate anyone that will take the time to make videos and present them here. But don't come in here spewing insults about 'BS', 'Know it all's' and 'Peanut Galleries'. It begins to sound a lot like projection. The Pro's can be found right here...my friend. They've been driving and working on these vehicles for a LONG time and don't deserve your disparaging attitude. Learn from them.

Stick around and contribute what you have to offer. Don't expect any special treatment though. We are far from a tough crowd here. Quite the opposite I would say.

 

[ppc]

Sounds like he just wants to post YouTube videos to generate revenue.

 

[manofthewoods]

^^^^

It IS a 'possibility', I allowed for that. So when you know for SURE what happened, come back and let us know. More often, these engines (many with over 300K miles) still show the factory cross-hatching in the cylinders and piston rings are rarely an issue. But anything is possible with an overheat.

The compression test you did compares favorably with what others see (mine included).

View attachment 2783034

But

 

[manofthewoods]

This community has been nothing but awesome for my work on re-doing my vehicle (bushings, Birfs, brakes and complete engine teardown, etc.). The knowledge here IS deep and wide. A little fun here or there shouldn't hurt anybody. I know I certainly deserve a few dope slaps for my ignorance (usually only I notice - luckily ).

When I'm done, I'll have to "pay it forward" somehow...
I do know the list of who to thank on here is getting way way too long

oh well. Buh bye

 

[FMC80]

Deleted video and original post. Hahahahaha unbelievable.

 

[flintknapper]

Deleted video and original post. Hahahahaha unbelievable.

Butt-hurt....I suppose, pretty lame.

 

[FMC80]

Butt-hurt....I suppose, pretty lame.

Yeah man, it’s pathetic. What gets me is him being butt-hurt after he incited the s*** talking. That’s a millennial move

 

[DivByZero]

Okay. Ummm...

 

[Timmy65]

If you'd spend a little time here, grow some thicker skin....you might actually learn something that would help you. Instead of insulting those who clearly know more about these engines and vehicles than you do. There is collective knowledge on this site that FAR exceeds the little bit of experience you have working on these vehicles.

Anyone here could have told you, you could STOP right after the compression test and start pulling the head. There is NO scenario that isn't going to end up there anyway. It is unusual for this engine to have issues with the rings, but can happen. Much more likely a head gasket. Typically at the #1 or #6 cylinder. And as you aware (hopefully) there are number of ways a head gasket can fail.

View attachment 2782850

In any case, please DO post back here and let us know what you found. We in the 'peanut gallery' are anxious to know.

^^^^

It IS a 'possibility', I allowed for that. So when you know for SURE what happened, come back and let us know. More often, these engines (many with over 300K miles) still show the factory cross-hatching in the cylinders and piston rings are rarely an issue. But anything is possible with an overheat.

The compression test you did compares favorably with what others see (mine included).

View attachment 2783034

But history shows a more likely reason for the one cylinder being 'down' will be a head gasket leak. Very common to see that on the #1 and/or #6 cylinders. The leak down test (if meant to be a tutorial) was semi-OK, but unnecessary with respect to this engine. There is no scenario that won't lead to pulling the head and visually inspecting everything, so you might as well get started.

I'm saying that for YOUR benefit, not ours. We already know that. We appreciate anyone that will take the time to make videos and present them here. But don't come in here spewing insults about 'BS', 'Know it all's' and 'Peanut Galleries'. It begins to sound a lot like projection. The Pro's can be found right here...my friend. They've been driving and working on these vehicles for a LONG time and don't deserve your disparaging attitude. Learn from them.

Stick around and contribute what you have to offer. Don't expect any special treatment though. We are far from a tough crowd here. Quite the opposite I would say.

Ok, I'll admit it, my original post had attitude written all over it but it's not like this came from out of nowhere. I admit I still have a ton to learn about these rigs and I'm not trying to come off as some sort of expert. I do plenty of research before shooting a video which usually includes reading through the factory service manual, looking for write-ups on the subject and looking for existing videos on the subject. When I feel I have a decent grasp of it, I go for it.

What I've found about this forum is there's a bit of attitude from the old guard, like, "Who is the Timmy the Toolman guy? He doesn't know anything and I'm going to make sure he knows it." There is such a thing as tact. I don't mind being corrected and I have no problem admitting when I make mistakes. I share my mistakes in the videos I make and I don't try to hide them. What I don't like is I post a video on this forum and for some guys it's all vinegar and no sugar in response to it. I don't need people kissing my butt but or giving me false praise but some level of acknowledgement of my effort to help people would be nice before you go on to telling me all the things you believe I'm wrong about.

I'm not new to forums, far from it. I contribute to quite a few. Hate to say it dudes, if the shoe fits, wear it. There is more than just a tinge of attitude from some of the people on this forum. It seems like people feel the need to flex their knowledge muscles and put people like me with less knowledge in their place. As a YouTuber and forum contributor, I could easily slam people when they ask what I believe to be a stupid question or total newbie question but I refrain from doing so. I answer their question to best of my ability without attitude.

I appreciate you sharing the knowledge about all the different possibilities of how a head gasket fails. I didn't understand this fully. For the most part, everything you can find about leak down tests is if you hear air escaping into the crankcase, it's piston rings. If you see bubbles in the coolant, it's a bad head gasket. Now you got me thinking that it could very well be a bad head gasket and the failure is between cylinder and the oil gallery.

I don't know for sure what's next for Rey's engine. I'm willing to give the head gasket replacement a try but I think he's leaning on just replacing the engine. The temp he registered was 263. The engine rebuilder I consulted said that's not good. I'm just wondering from your experience, would you no doubt go for the head gasket replacement or would you also be leaning towards a new engine as well?

Thanks.

 

[sin nombre]

Just curious, does anyone still pour a little motor oil down a spark plug hole to eliminate bad rings when testing compression?

 

[DivByZero]

Just thought I'd chime in to comment on the whole mess before. Look, most people here are not mechanics or engineers by trade, and nobody knows everything, no matter how much experience they have. One of the things I've appreciated about MUD over years of lurking, and more recently actually posting, is that there are a lot of people here with diverse experience and opinions, and people seem to generally feel comfortable enough to share them freely without worrying about some kind of "pecking order". Of course some people can come across as short or gruff at times, we all do, but it's been my experience here that it's safe to assume that someone is trying to be helpful. Even if someone's contribution is to disagree or contradict something I say, it's not personal, it's just people trying to make sure that, in their opinion, the most accurate and helpful information is being provided, because thousands of people can and do read the stuff we write a decade later. It's about making sure we don't ruin their day by sharing something that's wrong or harmful and not correcting it. And there's usually more than one way to go about doing something. Giving a range of options and opinions and letting other people use their own judgement to pick and choose what they want to go with is healthy and proper I think.

Your video looks very detailed, and it must have taken a long time to record and edit. It is absolutely going to be helpful for people out there. Anytime I need to diagnose, fix, repair, or build just about anything I haven't done before (and I'm not just taking about cars), one of my first stops is usually a youtube video nowadays, as for a physical, practical task nothing's better for learning than watching it being done by someone else before your eyes. That said, one of the problems with a youtube video is it's non-interactive, and it's generally one person's opinion. On a forum like this, you can assume anything you try and do, dozens or hundreds of other people here have done it before you, and many of them will have opinions. That's a good thing for people who are looking for help or trying to research a topic. Please continue to make videos and share them here, just assume people are also going to try and add to what you've shared, by sharing in things they've learned from their own experience. All of this just helps to make things easier for the next person who comes along. And if we all miss something, that person can bump the thread, ask a follow-up question, and expand the bucket of information a little more for the person who comes after them. The pattern of that happening over the last 20 years or so here is what has made this forum such a useful resource for everyone today.

 

[flintknapper]

Ok, I'll admit it, my original post had attitude written all over it but it's not like this came from out of nowhere. I admit I still have a ton to learn about these rigs and I'm not trying to come off as some sort of expert. I do plenty of research before shooting a video which usually includes reading through the factory service manual, looking for write-ups on the subject and looking for existing videos on the subject. When I feel I have a decent grasp of it, I go for it.

What I've found about this forum is there's a bit of attitude from the old guard, like, "Who is the Timmy the Toolman guy? He doesn't know anything and I'm going to make sure he knows it." There is such a thing as tact. I don't mind being corrected and I have no problem admitting when I make mistakes. I share my mistakes in the videos I make and I don't try to hide them. What I don't like is I post a video on this forum and for some guys it's all vinegar and no sugar in response to it. I don't need people kissing my butt but or giving me false praise but some level of acknowledgement of my effort to help people would be nice before you go on to telling me all the things you believe I'm wrong about.

I'm not new to forums, far from it. I contribute to quite a few. Hate to say it dudes, if the shoe fits, wear it. There is more than just a tinge of attitude from some of the people on this forum. It seems like people feel the need to flex their knowledge muscles and put people like me with less knowledge in their place. As a YouTuber and forum contributor, I could easily slam people when they ask what I believe to be a stupid question or total newbie question but I refrain from doing so. I answer their question to best of my ability without attitude.

I appreciate you sharing the knowledge about all the different possibilities of how a head gasket fails. I didn't understand this fully. For the most part, everything you can find about leak down tests is if you hear air escaping into the crankcase, it's piston rings. If you see bubbles in the coolant, it's a bad head gasket. Now you got me thinking that it could very well be a bad head gasket and the failure is between cylinder and the oil gallery.

I don't know for sure what's next for Rey's engine. I'm willing to give the head gasket replacement a try but I think he's leaning on just replacing the engine. The temp he registered was 263. The engine rebuilder I consulted said that's not good. I'm just wondering from your experience, would you no doubt go for the head gasket replacement or would you also be leaning towards a new engine as well?

Thanks.

^^^^^

Tim, I am glad you revisited this. You've had a chance to air some grievances and I/we have had our 'say' about it. So let's just move forward and start anew.

Piston ring failure or extreme wear IS one avenue for pressurized air (during testing) to show up in the crankcase. But a blown head-gasket (to oil galley) is another.

So we turn to the 'liklihood' of each and consider the history and design of the engine. A significantly overheated 1FZ-FE is famous for a blown head gasket (particularly if the original) and much lesser known for piston ring failure. Common practice here is to simply remove the head and carefully inspect the head gasket (failure points will be obvious) and observe the condition of the cylinders. Cracked/Warped heads are not unknown as well.

The amount of pressure loss demonstrated in your video suggests a severe leak. The 1FZ-FE piston has 3 sets of rings, has oil nozzles that squirt oil on the underside of the pistons, a significant oil cooler and IF maintained in any fashion at all will generally not exhibit cylinder wear or ring damage.

BUT....overheating is whole 'nother thing. So....we ask ourselves what are the chances that only ONE cylinder suffered broken rings vs. the head gasket leaking at that location? To lose as much pressure as you did past the rings....all three sets would have had to been severely worn or broken. There is always a small amount of 'blow by', in fact it is by design. The cylinder pressure presses down on each ring set (during the power stroke) and aids in sealing. The ring gaps are staggered only to create a 'maze' for the pressurized gases to negotiate. It attenuates the travel (in time) and thus helps create the ring seal. In a static setting such as your test we might expect more air to get past the rings....but not as much as you saw UNLESS they were severely compromised.

With all of that in mind....I am NOT saying it couldn't be the rings, I am just saying it is less likely than a head gasket.

Also, in the future...if you suspect pressure into the crankcase, just remove the oil fill cap and listen right there.

As for the Engine Rebuilder.....if you take him an engine with the preconceived notion that is has a bad cylinder/rings, what do you think he is going to recommend? A rebuild of course.

In the end....it just comes down to what the owner wants to achieve. IF the owner plans to keep the vehicle, has the money for a rebuild....then sure, go ahead and have it done. But if the owner finds that the issue is actually the head gasket and it is determined that the lower end, cylinders and rings are all OK, then reconditioning the head and new head gasket will put him back on track for a few hundred thousand miles more service.

Thank you for your input I hope you will choose to stick around.

Flint.

 

[Timmy65]

^^^^^

Tim, I am glad you revisited this. You've had a chance to air some grievances and I/we have had our 'say' about it. So let's just move forward and start anew.

Piston ring failure or extreme wear IS one avenue for pressurized air (during testing) to show up in the crankcase. But a blown head-gasket (to oil galley) is another.

So we turn to the 'liklihood' of each and consider the history and design of the engine. A significantly overheated 1FZ-FE is famous for a blown head gasket (particularly if the original) and much lesser known for piston ring failure. Common practice here is to simply remove the head and carefully inspect the head gasket (failure points will be obvious) and observe the condition of the cylinders. Cracked/Warped heads are not unknown as well.

The amount of pressure loss demonstrated in your video suggests a severe leak. The 1FZ-FE piston has 3 sets of rings, has oil nozzles that squirt oil on the underside of the pistons, a significant oil cooler and IF maintained in any fashion at all will generally not exhibit cylinder wear or ring damage.

View attachment 2783228

BUT....overheating is whole 'nother thing. So....we ask ourselves what are the chances that only ONE cylinder suffered broken rings vs. the head gasket leaking at that location? To lose as much pressure as you did past the rings....all three sets would have had to been severely worn or broken. There is always a small amount of 'blow by', in fact it is by design. The cylinder pressure presses down on each ring set (during the power stroke) and aids in sealing. The ring gaps are staggered only to create a 'maze' for the pressurized gases to negotiate. It attenuates the travel (in time) and thus helps create the ring seal. In a static setting such as your test we might expect more air to get past the rings....but not as much as you saw UNLESS they were severely compromised.

With all of that in mind....I am NOT saying it couldn't be the rings, I am just saying it is less likely than a head gasket.

Also, in the future...if you suspect pressure into the crankcase, just remove the oil fill cap and listen right there.

As for the Engine Rebuilder.....if you take him an engine with the preconceived notion that is has a bad cylinder/rings, what do you think he is going to recommend? A rebuild of course.

In the end....it just comes down to what the owner wants to achieve. IF the owner plans to keep the vehicle, has the money for a rebuild....then sure, go ahead and have it done. But if the owner finds that the issue is actually the head gasket and it is determined that the lower end, cylinders and rings are all OK, then reconditioning the head and new head gasket will put him back on track for a few hundred thousand miles more service.

Thank you for your input I hope you will choose to stick around.

Flint.

What you said makes a lot of sense. The engine rebuilder had said when an engine overheats considerably, there's a chance the piston rings will harden and lose some of their elasticity and oil consumption will go up. When I did the leak down test and heard the air screaming into the crankcase, it was my assumption based off my knowledge of where I was hearing the air escaping it had to be piston rings.

I'm going to talk to Rey and try to steer him to trying the head gasket replacement. When I help someone and I'm able to make a new video to share on my channel, I don't charge them for my time so it won't cost Rey too much to explore this route. So, maybe a head gasket replacement on the 1FZ-FE engine will be a future video I make. I've already got some other involved projects ahead of it like a Auto Trans Replacement on a FJ Cruiser and a 3.0 to 3.4 Liter Engine Swap on a 2nd Gen 4runner so it will probably be a minimum of around 2 months before I take this project on. Running a YouTube channel is not how I make my living. I have a regular job and other responsibilities and interests that take up my time as well. But, turning wrenches is a passion of mine and I get immense satisfaction from making videos that can help anyone with an internet connection. So, I spend as much time doing it as I can with still maintaining a relatively healthy balance in my life. People hit me up for help all time but I found I got burnt out trying to help everyone out and something had to give. I now try to limit my help to those who offer a project that I can make a new video to share on my channel because making new videos is how I can do the most good.

Anyway, I've blabbed enough. Thanks for all the help Flint. I appreciate it!

Tim

 

[Timmy65]

Just curious, does anyone still pour a little motor oil down a spark plug hole to eliminate bad rings when testing compression?

When doing the compression test, I was thinking of doing a "Wet Test" which is what you are describing but I didn't do it. I might get Rey back over to do this test to see if the compression numbers go up significantly with the oil contributing to a better seal for the piston rings to the cylinder wall.

 

[SNLC]

I found the comment “he builds engines for a living, what does he know” to be very snarky.

I also build engines for a living, 1FZFE’s, 1HDT’s, 1HDFT’s, 1HDFTE’s and more. I know very little about other vehicles besides Land Cruisers, that’s why we only work on Land Cruisers in my shop.

The snarky comments make me not want to contribute, offer advice or assistance.


Cheers