well as a training teacher in my Advance Sweeper Training class told me one time, "these machines eat dirt, thats what they are made to do" so 16hrs of 'eating dirt' is certainly enough time to start the chain reaction of wear inside the engine to cause that wear.

It's amazing how much wear dirt can do to an engine in a short period of time. I had come across a diesel engine at a customers facility wear out in a short time because of a air leak on the back side of the air cleaner that the servicing tech never caught. I just happened to get called out on it for a hard start issue and while i was diagnosing it i heard a rattle and found the rear horn on the air cleaner was broken off from the housing. We suspect it ran that way for 2 service intervals of 200hrs each so thats approximately 400 hrs of run time that it was eating dirt. Needless to say they were not pleased about that, we had to eat an engine over that incident.

i'm with bb on that.004 not being excessive warpage on the head surfacing, thats not that much to cause a head gasket failure issue like you have been having, unless the head was never re torqued after initial break in. Of course after the last gasket replacement if the same head bolts were reused that may have played a factor in the failures, once those bolts are stretched that may cause issues later on. Usually the main problem with bolts once they are initially torqued down is they never really retain their ability to hold the torque value and they keep stretching out so the head may have loosened up over time allowing for the failure(s).

It was mentioned about possibly using automotive pistons and rods? ehhhh... this is an industrial engine, theres not much on the inside that is 'equivilant' to automotive grade materials. Most of the components are made differently, heavier castings, their differences may be unnoticeable by the average mechanic but someone that has experience with engines would notice them, such as thicker skirts on the pistons and even the rods may be slightly different. So i would be weary of trying to supplement alternate parts other than industrial grade ones. ;o)

It is PM'ed every 90 days. with oil and oil filter changed.
The sweeper gets inspected every day.
The scratching and worn rings are likely due to a single event where we found the air cleaner cap had fallen off, or was deliberately taken off, allowing both air filters to drop out of place.
At that time, both air filter elements were replaced and the air ducting all the way to the mixer was cleaned out.
There was no apparent reason the air cleaner cap fell off and it has been suspected that a particular sweeper operator may have tampered with it for unknown reasons. There have been rumors from a few of his co-workers alluding to other acts of vandalism or damage to forklifts and other property. I recall installing a new seat on the sweeper once and the next day the seat vinyl of the back cushion had a slash all the way across it and it looked like the work of a utility knife or pocket knife. And the same operator was suspected of having done that, but no proof was to be found.
We have since been lacing a long plastic zip tie around the canister that keeps the latch buckles from being operated.
The sweeper could not have operated more than maybe 16 hours or so with the induction system unprotected (before being discovered and fixed), but considering the environment, that was likely enough to start the process. That happened about 3 years ago.
It's enough to have to deal with genuine mechanical defects/failures alone, but it seems we get a fair amount of employee inflicted vandalism occasionally too.

How often is this sweeper PM'ed? How many hours are on the unit? Sounds like allot of wear- although nothing to indicate a head gasket issue- the
.004" warp doesn't sound too bad. My concern is that the new engine will travel the same path if the cause isn't addressed

I believe that the one from Helmar is purchased out right as it is new and they do not do reman. I am thinking that you maybe able to use the pistons and rings from one of the automotive engines at the very least, not recomended but it maybe a option if need be. Will let you know on the manual.

Thanks Partsguy5. I would appreciate the GM breakdown if you can locate it.
I don't know yet whether we will need to turn in our old engine to Helmar or even if their is a core charge involved. I tend to leave the fiscal details up to my bosses as they don't really want input from the peons anyhow (no matter how much they say they want your ideas, they would really rather you just kept quiet).
I have never been much of a quiet person, and my thoughts are that we need to retain the old engine unless it must be turned in as part of the deal with Helmar. If we could source new pistons for 1/2 the Tennant price (or less) I think the engine could be used as a spare or a replacement for another sweeper elsewhere within this company if one is needed.

L1ftmech glad to hear that you got things sorted out. I know at one time GM was only selling gaskets and seals the pistons and other hard parts were not available. I believe I may have a GM break down from when they first used these in industrial applications. If I can find it I will send you a copy.
About 5 or more years ago you could google any of the GM industrial engines and find the parts manuals on line but it seems they have all been taken down.

Cylinder head tests OK, about.004" out of level diagonally across combustion deck. Machine shop going to do valve job and 1 spark plug thread insert (#4 cyl). All this was arranged Tuesday. Still no response from Cometic Gasket after a week since I sent them a query using their website contact facility.

Now for the report on the block and pistons.
All 4 pistons show some heavy scratching and signs of slight galling on the skirt thrust side. The cylinders themselves show scratching bad enough that you can just barely feel the scratches when dragging a fingernail across.
Cylinders are from.003" to.005" worn on taper.
Pistons worn down about the same average amounts (.003" to.005").
Piston top rings were placed into the cylinders and end gap checked. The least end gap was measured at about.035" and the most was near to.048". Specs for ring end gap of top and second ring on this engine are.011" to.020". Like Neil Young once said in a song, "That hound dog is history."
My local engine parts warehouse is unable to find any info about pistons for this engine and alluded that if I came up with a GM part number they might be able to search for it as a cross ref.
The only source of part numbers we have is Tennant, and Tennant has adopted the practice of assigning a Tennant part number to everything they sell. Tennant price for a single piston kit (piston, pin, and rings) is $136 USD.

I went back through my notes and realized that I had omitted Helmar from the list of potentials I gave my boss when we first decided to replace the engine with a new one.
He contacted Helmar and Helmar said our new engine would arrive at our location within 14 business days.
Thanks Partsguy5.

The JXLD isn't a bad engine- it's a flat head 6 similar to a Continental 6- the b*tch is parts- engine was discontinued at least 20 years ago. Everything has to be custom made- doable but time consuming & expensive. Still cheaper than buying a newer 25,000lb unit for the usage it sees.

I'll see what kind of response Cometic Gasket offers and what kind of lead time they need. I was told that the cost of renting the replacement sweeper to fill in is about the same as a new engine would have been.
Kinda makes a guy scratch his head and wonder why we don't own a "back up" sweeper.
Hercules JXLD! Oh God I feel your pain. Unless that one is better than the Hercules G-1600, it is not, well....up to date.
The G-1600 proved so sorry in our fleet of the late 1980s that I would mockingly brag that Hercules builds their engines with the very latest and most innovative technology available......in 1925.

The engines I modified due to excessive head gasket issues were Mitsubishi 4G63's. Apparently this engine is available turbocharged in some sort of Mitsubishi car & it eats head gaskets in that application. Cometic had a "heavy duty" head gasket which fit perfectly & has been in service ever since. In speaking with them they said they could make a "heavy duty" head gasket for any engine as long as they could have a sample gasket to get the specs from.

They even made a straight 6 head gasket for a Hercules JXLD in an old Clark that I service- Installed it 2 years ago with no issues.

yep headbolts can be found just about anywhere
as for the cosmetic head gasket?
just make sure it is basically the same thickness, without shaving the heads or block down to compensate the thicker gasket will affect how the engine runs, it may not run correctly because of the extra space, compression or fuel delivery/consumption issues. A few thousands of an inch makes a big difference in how it runs :o)

Thanks BB. We do have a pretty good internal engine parts store locally. I will probably be checking with them on availability of the head bolts.
I placed a query to Cosmetic regarding the head gasket.
We'll see what they say.

I have a local vendor supply the head bolts.

You understand why I added it's easier to ask forgiveness than to ask permission?

if you're going the short block way
yes machine work should be done, its imperative
checking the rings and piston bore also is imperative
why halfazz a job?
if you don't do these things that engine won't last 6 months to a year if you're lucky.

i tell you this, if my boss tried to make me half azz a job like that i'd flat out refuse to do it. Heck if i'd want that coming back on me down the road.

I already sense at work that there may be some resistance to my intentions to do a comprehensive check of the block.
I already told my boss that I want to pull out the pistons, remove the rings and slip them back into the cylinders to measure ring end gap. And that I also mike out the cylinder bores and the pistons. I got a fairly long pause and then was told that he didn't know if he wanted me to go that far. ????WTH???
Sometimes it is easier to ask forgiveness than to ask permission.
I will check out Cometic Gaskets Inc. Are they also your source for the head bolts?

I feel your frustration when presented with a failure which management doesn't allow to be repaired properly. A cyl head should always be checked when replacing a head gasket- but what do we know?

If you're going to reuse the block- make sure you to check the flatness of the block where it meets the head. I have seen these warp as well right at the coolant passageway.

I have had custom head gaskets made (Cometic gaskets Inc) which have worked out well for troublesome engines. Combining the thicker gaskets w/ thicker head bolts (non- stretch to yield) has worked well on a couple of older units I service.

yep that sounded too good to be true, and as was said earlier, retro-fitting another engine into that frame would of been a huge headache and nothing but trouble afterwards.

As for the internet sites? well i was just relaying what i found, i myself would be doubtful about dealing with ebay too....
but my suggestion for EPS (engine power source) is not a fly by night company, they are very well known here in the south and rebuild and sell prebuilt engines, they do ALL engines.

If you boss wants to stick his head in the sand and deal only with chicago engines then so be it. Get your short block and heads and have at it... its nuttin but time and money right? chuckles

good luck on your repair

I will say if YOU are the one that gets the job of pulling that engine and swapping it out just be very careful with the propulsion pump and drive coupling when you take it apart and reassemble it.... warping one of those is bad bad bad.... will come apart on ya later on ;o)
And pay attention to the seals on the control solenoids in the manifold control blocks throughout the unit, if it has run hot i'm sure those seals are hard and will cause the unit to malfunction due to internal bypassing on the hydraulic circuits. :o)

good luck

OK, the rumor about the existence of a retro kit for 6600 is false.
No such animal.

My employer has a company policy that there is to be no business conducted with ebay or other online market places.
Chicago Engines is one of the firms we contacted and we were told that they no longer have any long block nor complete 1.6 engines.
Short block and separate head are the only way we have been finding the engines available.
It is easy to be misled by visiting a website and see that a lot of stuff is "offered" only to get the real story when contact by phone or e-mail is made.

Right from the start of this I have had the gut feeling that this specific engine (the one in our sweeper) may have suffered a warped head during the events leading up to the very first "head gasket" failure in 2009.
Though this is a Tier II engine with overheat limp mode provision, that does not guarantee the engine cannot be subjected to damage causing overheat conditions. If the machine is placed out of service and repaired properly AT THE FIRST INDICATION of trouble THE VERY FIRST TIME it goes to limp mode, there is a chance that no major damage will be incurred.
But, knowing the "denial mentality" of the average dock worker or dock supervisor regarding vehicle maintenance, it is very likely that back in 2009, the engine could have been subjected to multiple overheat events before the sweeper was presented to the shop with an issue.
Realize that each overheat event can expel coolant from the radiator into the recovery bottle, overflowing the recovery bottle and spilling some coolant out.
Repeat that several times a day and pretty soon you have so little coolant in the engine that the ECM temp sensor bulb is not submerged in coolant (which means the head is dry) and the temp signal of overheat will be late in reaching the ECM.
I have a scene in my mind of the operators simply shutting off the engine and letting it cool down a while and then going right back to sweeping some time later and never reporting the problem. They detest using a push broom, and there's really no way a push broom could replace a sweeper machine realistically.

The repair work that was done in 2009 was done by a different tech (since retired) and a different regime of supervisors.
In 2009, the head was not sent out to a machine shop for testing/checking. In 2010, the head gasket blew again and same tech replaced it again without having head checked.
In 2012, I removed the head to extract a broken spark plug (broke while trying to remove plug) and I detected the early signs of head gasket failure on cyl #4 between the back edge of cylinder and the coolant riser passage at the rear of the block/head. That was the cylinder having the broken spark plug too. I was able to extract the remains of the plug without resorting to an insert and management would not OK to send the head out for testing/checking.
The head gasket failure this time is precisely at the exact same place I saw when I had the head off in 2012.

We now have a different group of managers including the GenMan, so things are being handled a little differently this time.
The hours on this engine are into the 16,000s and considering the multiple head gasket failures, it was suggested that a new engine would probably be the shortest path to return the sweeper to service.
Having met with some frustration trying to find a drop in engine, we have now decided to repair this one, but not following the previous methods.
Monday, the head is going to a qualified automotive machine shop for thorough testing and if it passes muster, it will get the valves refaced and new stem seals.
I am going to pull the pan and look at the rods and mains.
Thanks all and I will update on how it goes. A sweeper has been rented to cover the down period (I told you a broom does not fit their hands).

What is the inherent problem with this engine- just head gaskets (not that a head gasket gasket problem isn't enough) or are there other issues with this engine?

If the problem is head gaskets- what's the cause? Perhaps a custom head gasket or head bolts could cure the problem- just a thought.

The thought of retro-fitting another engine just makes me cringe. I've done that & it's off the chart with time & all the little things you don't think about that really add up.