What does "polished cups" mean?

 

I had the advantage of doing this with the engine in a crate I made myself. This crate allowed me to put a cheater bar on the crank to prevent it from spinning from the air pressing down on the cylinders. One thing I learned years ago - engines rotate until a valve opens when you inject air in the cylinders.

This is my way of asking if you locked the crank at TDC on the power stroke, and assuring you that you wouldn't be the first to overlook this.

 

Before Iubed up the injector o-rings and re-installed I cleaned the inside of the injector cups thoroughly with a soft bristle brush wrapped with a large gun cleaning pad with some carburetor cleaner on it. I said polished as they where just installed in 2017 and they cleaned up like new. I also bore scoped them to look for any potential issues and they all looked good. And torqued injectors to 120 inch pounds.

Blue

 

I turned crank and checked with a small stiff wire until piston came all the way up and I could see where both valve were closed. Then I backed off the rocker arms bolts until there was no pressure on the valves. I shined I light through injector cup and could see top of the piston. I left the BFR on the crank bolt at the 12 o'clock position during the test and watched to make sure it did not rotate while under pressure. BFR meaning Big Freaken Ratchet. I had no movement of the crank on either of the cylinders I tested.

Question I have is can you get good information from a cylinder leak down test on a cold diesel engine? And might add this one is not a new engine but has 200k miles. I seem to recall reading something about small engines with small bores it's possible but on larger /big engines with big bores, especially diesels, it doesn't work as well or is not accurate due to the larger surface contact area and the way the piston and the ring tolerances are designed in diesel engine versus gasoline engine.

Thus, In hind site I should have pulled the valve covers and done this cylinder leak down test before doing anything else? Or based on first two test results cylinders #1 and #2 have major piston, cylinder wall, or piston ring issues? But good compression readings?

I was seeking information on the OTC leak down test results Tugly did and if you can do this test on a cold engine and get good information from it on this post. I think I will start a new post and go back to the begining on how I got to this point. It is long and very painful and basically sucks! I haven't got over over it yet. And may never. But just due to timing, Santa, or should I say Mrs. Clause did relieve most of the pain with a new 6.7 for X-mas. But I still love my 7.3 and want to keep it. But I if can't fix it cheap, i.e not a total rebuild or new motor, Mrs. Clause said it has to go!

Blue

 

I did this so long ago now... in a galaxy far far away.

I remember it wasn't a matter of pressure, but a matter of differential - and I think it had more to do with flow. There is a fixed flow from the supply to the cylinder, and that is allegedly supposed to account for tolerances within the cylinder.

Translated: "Here's the air that supposed to escape and a bump"

The pressure drop between the supply and the gauge connected to the cylinder is supposed to be read in %, which I can't remember what the spec or results were... so off to the search feature I go... nuthin'.

I remember the engine I had was in spec, with one cylinder just barely in spec. I want to say it was something like 10% or 12%, but I'm sure the experts will correct me.

 

FWIW, leakdown on fresh rebuild from Swamps was between 0% to 3%.

 

Thanks. I think I recall around 10% as well and consistency between cylinder's when troubleshooting. But what I'm not sure about is can this test be done reliably on a cold engine with miles on it. The videos and instruction guides for the various leak down testers I researched were for gas motors. And they talk about warming engine up and removing spark plug. Not easy to warm a diesel then get to where you can pull the valve cover to get to the glow plugs and keep the engine warm. Well I guess you can run them at idle without to big a mess with the valve cover off from some videos I've seen. But I was thinking this model 7.3 would not crank or run right without CAC pipes installed.

Anyway, I'm past the point of cranking it now. I'm going out to leak check the rest of the cylinders anyway. Just disappointing after the first two that it is showing both no good and I do not know if it is actually a good true diagnostic doing it this way.

It was running strong as it always has when I parked it. And it passed all the Auto Enginuty tests I could throw at it and all systems and test passed. So, I'm leaning towards doing this leak test at this point is of no value as the block/cylinders and piston and rings are not mating up and sealing as tight as they would be if the engine was at operating temperature.

The short is, from the current issues I have had lately the symptoms appear to point to a compromised/damaged head gasket thus why I'm at the point of pulling the heads. Just didn't think about and it wasn't mentioned to me to consider doing a cylinder leak down test until I got to the point of pulling the heads. Now in hind sight, I would have done this before I did the cylinder compression check.

Blue

 

I did my leak-down test on a removed engine, so cold works - but the results will show more leakage than when warm.

With those compression numbers, I wouldn't pop the head - particularly since head gaskets rarely fail on the 7.3L.

What symptoms are you experiencing that convinces you to rip ' er apart, despite passing many diagnostic tests?

 

I cannot get a cylinder to pass. I have done five in firing order. The last one I did last night which I think was #4 I could not get the gauge up past 50 PSI as was leaking out as fast as going in. Same issue on a previous cylinder and was checking different areas for leaks and noticed PSI started creeping up. And slowly it did and finally got up to 100 psi and had to back down before it got there. On another did the same thing but only went from like 50 to 70 psi. And that was the cylinder that got 420 PSI on the compression check when cold. Thought it was the tester so built a test block with a gauge on it and pressure was dead on with the test gauge.

All can only hear air from inside the block. The last one last night I thought I heard a faint bit of air from the baby butt on the up pipe but couldn't be for sure. That was the first time hearing anything from that location. I think I was just thinking I was hearing things by then.

I'll post the details soon as I can. Will take a bit but don't have time but about once a day. But to give an idea were this started back in July did front steering rebuild took up to 4-wheel drive shop for alignment. As I can't do that or I would. As leaving young kid comes out of shop, maybe 110 lbs, dental issues and dilated eyes, typical crack head from training we get at work. Not saying this kid was. But, who knows. Boy goes on to brag about what a "bad ***" truck I have. I crank the truck and right off it hits a lick that doesn't sound right. I've heard every breath this girl has taken and I know when somethings different. I never run my baby cold or shut her down hot. It was a 100 degree day so I'm thinking that well he must have shut her down hot.

Get home and put her back in the garage and go in and have dinner. Go back out later and grab a flash light and crawl up under to check to make sure everything is still right and Oh ****! I got oil dripping from back of motor and coolant from the radiator dripping under the truck!!

I'm retired USAF and worked on aircraft weapon systems. Everything I own is clean and tight and works right. There was not a single issue with this truck when I took it up there.

That's just the beginning. Since July I have not been able to keep oil or coolant in the engine or in their respective locations. I have done numerous repairs and upgrades only to have the next weakest link let go.

I'll get back and post the sequences of event and repairs up to were I'm now as not even going to test the last three cylinders. What I was hoping to find from this cylinder leak down test is the smoking gun to pull the whole engine or just the heads as planned. But I'm not convinced by these test there's an issue with the bottom end.

The problems I have been having is I'm getting pressures where they shouldn't be and it only shows up when under a load towing over a mountain. Normal driving between repairs had no issues. Ran great like it always has. But eventually had to tow and over a mountain where I go and each time oil or coolant blew or leaked in a another location. Thus, I'm suspecting, and expecting, to find a damaged head gasket that is only showing up when the engine is under a load.

I admit I don't know. I'm suspecting that joker took her on a joy ride instead of a test drive. I've always respected the truck and had no issues. He didn't and didn't let up and lifted the heads and damaged the head gaskets. I'm open for ideas and suggestion. Like I mentioned though If it's just a top end rebuild I think the wife is going to let me repair it and keep it for my daughter who wants it badly! But if its a pull it out and rebuild she is like put it back together and let it go. That's hard to do after going on 18 years in February and all they work I have done.

Blue

 

Blueforester would you update what you found on your truck?
Did you remove the head? Was there a leaking head gasket?

 

I apologize. I should have updated. There have been a many on here who have helped me out by posting their findings.

I think I mentioned I couldn't keep engine running with out some kind of coolant issue. And it always failed when I was towing. And after compression test, dye tests, leak down test, none of them showed conclusive evidence that I could, or anyone I consulted could, with out a doubt say yes there is the problem.

The last thing to go was the turbo seal blew, which was new about two years old. I'm assuming because by then I had got all the other potential areas bullet proof. And again towing with truck full and Gator on my trailer coming back from hunting. And guessing that was the next weakest link. So I pulled the turbo and had a turbo shop check it out and rebuild it. Said absolutely not a thing wrong with it. Was in excellent condition other than obvious sign that oil was getting past seal. Thus as I had suspected and the head turbo guy agreed that the block was getting excessive pressure from somewhere.

I then drained oil and the coolant out of the block and pulled the heads. There was not a sure enough blown out section in the head gasket. But there was a darkened area between two cylinders. The two of which were the ones which I suctioned out the fluids in the cylinder and before I could get bore scope back in to it there would be a small amount of what appeared to be coolant back in the cylinders. And only those two cylinders had discoloration compared to the others which looked pretty dang good for 100k miles. All of them still had the honing swirls.

So, issue is something that cannot be pinpointed to the exact root cause . But based on the repeated issues and symptoms, myself and several other I know suspect that the head gasket, and the head bolts had been comprised. The jack leg who did the front end alignment and came out of shop to personally let me know I had a bad *** truck, took it for a joy ride instead of a test drive. And thus where I respected the truck and the work I had done he did not and it appears that the head bolts have been weakened and or stressed. Thus when I fixed one thing the next time I towed and pulled a load it would get cylinder pressure through that weakened area between the head and the block and thus lead to multiple failures back to back in a row. Starting with the radiator. Then degas bottle, water pump, oil cooler, then turbo seal. All over several months.

Thus got towards end of year, truck was down. Holidays, hunting season was in. And I think my wife was feeling really bad for me by this time. So started discussing getting a new truck. And sure enough, the last week in December I found what I was looking for in TN and drove up there and came back with new 2019 6.7 F250.

Still got my 7.3. It is in my shop. My daughter has been saying she wanted my "Big Truck", she called it since she could talk, when she turned 16. I've been letting her drive it down at the lake and hunting club for over a year. Heads have now been rebuilt. I'm fixing to pull the motor and and get it to a machine shop to get checked and reworked. My plan is to have back together and it breathing again by July as my daughter turns 14 then. I think she knows she is going to get it. But mom keeps say heck no. So we are working hard on her. I want her to have it to keep it in the family. I bought it new in 2002 and it was the first new vehicle I ever had. And I know every breath she took except for those that brought her down. Except for one little recall I'm the only one ever to have worked on that truck. So hopefully I will get it back again one day.

Sorry for the long rant. But if you have any other questions let me know.

Blue

 

Bless you for your answer. I will have more questions for you. But first I need to pull the passenger side head. Carry on...

 

Last post kinda of got me sad and got me to thinking of the good days I had with my 7.3 before this nightmare started. I thought I would share this last picture I took of my 7.3 before I started taking it down to pull the heads. This is a 17 year old truck. And I took excellent care of it.

You can't see it under the jack and degas tank but when the original radiator blew out in the end cap seams, the start of this problem, from the time I left the 4wd shop and parked in my garage it was leaking, I decided to upgrade. There is a really nice heavy duty all aluminum Mishimoto radiator under there now.

A couple years ago the original water pump stated to leak so I replaced it with a new factory water pump. At the same time I did a serious coolant system clean and flush and switched coolant over to DELO ELC coolant. At the same time I put a nice new pretty clean factory degas tank in. So degas tank and water pump were about two years old. Well, after the radiator fix, a few weeks went by and was towing boat to the lake for my daughter's weekend birthday celebration and the new degas tank was leaking when I got down to the lake. Was able to make it back home stopping and putting coolant in it along the way. So, I decided to upgrade and ordered an all aluminum degas tank from Mishimoto. Did not like the aluminium look in the engine bay so I had it powder coated black to make it blend in better. You can see it there in the attached picture.

What you can't see is another nice new water pump that came afterwards. And the nice new chrome finished XDP oil cooler down under there that came not long after that.

Well, wish you luck on your project. I hope it goes better than what I had to go through.

Blue

Last picture before taking her down to check the heads.