the reason for not reusing gaskets is that when you tighten the bolts down the gasket deforms and fills all the tiny imperfections heat and time then sets the gasket for it to seal correctly you would have to get it to seat in exactly the same position as before which is impossible. also for the price of a gasket its not worth it. the labour cost to fix it again is much higher. plus lost time, cost of lost fluids, what has been damaged by the faulty gasket etc

i'm with Mike, curious as to how much bore wear there is, difference from top of ring travel to the bottom...easily measured with a ring level in the bore(end gap) and feeler guages..

-for those unfamiliar, the bore wears greater at the top than the bottom, so with more hours and wear the bore becomes tapered.
-also agree with Rome, somebody did a half@$$ rebuild job and sent it down the road (completely ignored the cylinder head??)
-never reuse a gasket (unless copper or something designed for multiple torque loads) just too much work and time involved to have a sudden failure
-lots of great advice in this thread!

trainzkid88 wrote:

not only should they be staggered they should not be on the wiped side of the piston ie when looking at the crank pulley if the crank rotates to the right the right side is the wiped side. in other words the ring gaps should not be on the loaded side. all reciprocating engines have a loaded side and they wear that side more hence why bores wear oval.
Chrysler and Toyota famously tried to counteract this by building slant engines.

as for gaskets needing sealants or not some engines do and actually acl bearing co recommend the use of hylomar gasket dressing on their gaskets. unless you have had the mating faces ground a dressing is reconmended and unless the surfaces are out of true i wouldn't get them ground. there is several gasket dressings on the market be sure to select the correct one for the application as there is different products for different jobs.

as for a cyl hone ball type hones cut faster flat stone type cut slower but less likley to over cut. both types should be lubed with a mix of kerosene and oil or diesel fuel. keep the surface wet while honing a (spray bottle works best) then scrub the bores with hot soapy water or water based degreaser to remove all the grinding fines wipe dry and oil with wd spray or lanolin spray immediately to stop rust.

AND NEVER REUSE A GASKET that is asking for trouble. the only exception your in the bush hours away from home and have no other choice but then when home you replace it.. do it properly the first time and you dont have to touch it for years especially if you dont use it much. dont skimp on oil changes bad maintenance is what causes most failures.
 

I can't say about Toyota's reasoning for a slant engine but Chrysler's was to reduce the engine height thus allowing lower hooded cars. Had nothing to do with wear. Also Ford had a diesel slant engine in some of their trucks that also had nothing to do with wear just the lack of room to get one in the engine bay.

I was taught at TAFE (although I already knew it at the time) that the first compression ring goes in 180 degrees from the exhaust valve as that is the hottest side of the cylinder. The next ring is 60 degrees from the first and the third if there is one is 60 degrees in the opposite side of the first ring. Either way rings rotate around the piston when the engine is running so ring alignment is mainly for wear in.

As for gaskets, I agree you should not reuse modern head gaskets but I have reused other gaskets many times and never had a failure. As long as the gasket is in good condition and the surfaces are clean it can and will seal again. Most gaskets though leave half on one surface and half on the other.

Hello John Gaunt, I was asking about how worn the old rings are, because I keep reading in this thread from the owner how nice this engine looks, but the evidence keeps suggesting not only are the valve guides completely knackered, but the rings quite possibly are too, I suspect there is a slight lip at the top of his liners too, looking at his photo's, and if your fingernail can feel it, you have to deal with it, or risk breaking your new top ring....

Quickest way to find out about the wear in old rings is place them one at a time at the bottom of the cylinder using a bare piston to push them down ensuring they are square in the bore, then measure the end gap with a feeler gauge, only takes 30 seconds to do, just a visual look and you will see if there is much of a gap, it's very obvious if it's even like a spark plug gap..

I've had badly worn rings here out of old Gas Cats like the 2 Ton with end gaps of 1/4", yet the engine ran great once I got her started, blowing very little oily smoke, better than this gentleman's newer Cat.           When you buy new rings, you do the exact same test to ensure you have sufficient end gap to allow for the expansion of the rings as they heat up, there is a spec for end gap and side gap for each ring position from top to bottom, obviously #1 ring at the top get's hottest, so needs slightly more room for expansion.

Regarding the re-use of head gaskets, when all Cats head gaskets were made from copper, it was Cats recommendation / suggestion in their tech literature, that it was perfectly acceptable to re-use a head gasket provided it was in good condition, so it's very important we share the right information on this forum, because not everyone has deep pockets full of cash for their toys, and is happy to spend hundreds of dollars on new parts they might not need.

I agree with PhilC, nowadays Cat seem to use either steel or laminated single use gaskets, and those are not always suitable for re-use, interestingly I've replaced two professionally reconditioned D4 heads on two older D4 crawlers using new steel head gaskets from Cat the past couple of years, and even after a light coating of Aviation Gasket Sealer, still had some minor external weeping in a couple of spots 1/2" long, not bad, but noticeable.

After a few hours run time, I re-torqued the heads and the minor leaks disappeared, even though there were some "Experts" on here saying you don't need to re-torque new Cat head gaskets, I've proven that baloney to be poor advice, and thank goodness I ignored it, because on average each head nut picked up around 30 degrees extra rotation on the second torqueing, I even shared photo's of it here.

From memory I paid about $60 for the new genuine Cat D4 head gaskets, and at that price, it's a no brainer to use new if available, but if new wasn't available, or money super tight, I'd definitely re-use a good steel head gasket cleaned spotless with a suitable sealant, what's the worst that can happen, I get a minor leak like happened with my 2 brand new head gaskets, and I need to re-torque, or in a worst case scenario, remove the head again, no big deal.

Regarding hones, interesting opinion I read was the stones in a worn bore will not give as good a result as a ball or "toilet brush" style hone, because the stones will ride only on the high spots of the bore, leaving the worn hollows less hatched, while the ball hone because of its flexibility, is able to more evenly cross hatch a worn bore.

In a new cylinder I'd be using a 3 or ideally 4 stone hone because it will run true and even, but in a worn bore, if you can afford them, or can borrow one the right size, a ball hone is great, because typically you spend very little time creating a good cross hatch when honing, otherwise it becomes a re-boring! LOL 
 

John...why would it require a new ring to measure bore taper(wear)?

-the bores wear much less at the bottom than the top...so what really matters is the differential reading....that's the taper...

-of course a bore gauge would be better, but this is super quick and easy to get a rough estimate..

yep it wouldnt matter if it was new or old the difference top to bottom is what your checking. yes to tell is that bore out of spec you would need a new ring or a bore guage.

mike nearly all gaskets need a re-tension after a few hrs only mono torque gaskets are different. like i said heat changes them. a torque wrench is rather inaccurate simply because a human being operates it. to get it close to the same you need to pull from the same angle and at the same speed every time hence why the best position is side on to the engine.
the best is a tool that tightens every head bolt at the same time slight problem to my knowledge they only exist in the Ferrari engine plant.

the slant does cancel out the sideways forces to a degree hence why vee engines are so smooth also their compactness. ships drive shafts are offset 7 degree from centre for the same reason it counters the side pull of the prop.
if you want to be able to reuse a paper intake, trans or inspection plate etc gasket smear both sides with grease it will release easier and the grease can help it seal. you would be surprised what you can seal with a cornflakes packet and some grease

Hi guys.
I shot a video, for those interested in seeing the disassembly and hd details of this engine.

Oil rings are shot, bores are glazed, notice the cross hatching at the bottom of the bore, that is what the whole bore should look like.

I'll ask again, please show us some pictures of the old piston rings sitting in the bottom of the bores they came from, #1 to #4, include top compression rings and oil rings.

You need to measure your bores with a bore gauge, there is a good chance they are worn out too.

Do you have a small element filter in the big air filter I had a guy who rebuilt his 955k motor but and did't change the small element he said he was clean and he had trouble again and he call a CATERPILLAR dealer and a mecanic guy came inspecte the motor and found the probleme it was the small pré cleaner filter was no good