Ive got a small crack on the cyl, where the oring wall connects to the water jacket. Its very thin here, the wall has pushed out a bit. Its not leaking. How did this happen? Detonation? Anyone seen this before? seems like a simple fix?

My cougar cylinder did that and had to be welded. Tim at titan racing is the one that fixed mine.

This is n2deep on my buddys name.

Think it was detonation? Defect? Hydroliced? I know I had some detonation a few times while tuning... I still would not expect that to do that....

It WILL be leaking, there could be many answers to "why" this happened, and you mentioned a couple of them....one more would be the o-ring groove size and the o-rings used, (or even the amount of grease used on one of the assemblies of the engine).
While the place where your cylinder is broken is the "weakest" area when the o-ring is concerned, it doesn't look like the outer o-ring has any "feathering" on it....so I would "assume" the inner and outer o-ring grooves were cut to the same dimensions....you may want to check for feathering of the inner o-ring.

It will need to be repaired, and they can check the groove size at the time they will be re-cutting the groove.

It cast !! As in any casting when it close to a passage it weak sure u could ship it to tim to have it tig welded and it be fixed for good but I say the heat will get to the plateing unless he weld it under water so it will not heat warp !!
I just know lot about casting and billet when comes to the steel and alum dep because I work on steel mills and other non ferrous metals mills and I sell copper ,alum,bronze,alum bronze and others casting to mills and to back this up so u don't think I am full of it www.eafrepair.com our web page it not good page I spend more time working on parts than on web !!

I am not trying to stir the pot with the cast billet thing we all know when u have a casting it a mold and u fill it in most cases they use sand for molds And the adv is u can make passages that u use to not be able to machine now days with endless edm and live tool machines u can make it happen with billet but the cost will be lot more because of the machine time
Here some info on cast alum
Aluminium alloys are alloys in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. About 85% of aluminium is used for wrought products, for example rolled plate, foils and extrusions. Cast aluminium alloys yield cost effective products due to the low melting point, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al-Si, where the high levels of silicon (4.0% to 13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.[1]

Alloys composed mostly of the two lightweight metals aluminium and magnesium have been very important in aerospace manufacturing since somewhat before 1940. Aluminium-magnesium alloys are both lighter than other aluminium alloys and much less flammable than alloys that contain a very high percentage of magnesium.

Aluminium alloy surfaces will keep their apparent shine in a dry environment due to the formation of a clear, protective layer of aluminium oxide. In a wet environment, galvanic corrosion can occur when an aluminium alloy is placed in electrical contact with other metals with more negative corrosion potentials than aluminium.

Aluminium alloy compositions are registered with The Aluminum Association. Many organizations publish more specific standards for the manufacture of aluminium alloy, including the Society of Automotive Engineers standards organization, specifically its aerospace standards subgroups,[2] and ASTM International.


I am not looking to start a pissing war with the cast / billet stuff I just talking about the auctal meterial used to make it

All materials start out at some point as a cast chunk. There is a big difference though in a cast part and a billet chunk of steel or aluminum. The actual naming convention is that a square or rectangular chunk is called a billet, and a round chunk is called a round, but the name billet in aftermarket circles has come to mean “strong because it is made from a block of metal”. This is not always true.
A cast part is made from material being forced or poured into a mold. The part will have thicker and thinner areas, and takes shape from this molten state. Therefore the material must have good castability. One of the main properties of a material that has good castability is that it does not form internal voids on cooling. As a material cools, it shrinks. If there are thick and thin areas, the thick areas will cool slower than the thin ones, and the thick areas can form voids, and the part can warp out of shape or crack, or worse, form internal stresses that come out when the part is used, then crack later. That’s why when you look at an engine block for example, they often have scalloped out areas to make the wall thickness more even. These materials are typically more brittle. A cast crankshaft is “weaker” because it is made from cast or nodular cast iron, not really because it is cast. It is cast because the material is very castable, but is impossible to forge. A billet may start out cast, but the shape is very very even and symmetrical, so the above concerns do not come into play as in a cast part of some odd shape.

A forged part is made from a chunk of metal. It is then usually heated, and it is pounded into shape in a forging die. The extra metal oozes out from between the forging dies and must be ground off. This is why there is a wide parting line on forged parts. A forged crank is stronger because of the steel it is made from. It could be an alloyed 4340 steel with .40% carbon, or a weaker 1020 steel that is not alloyed and has less (.20%) carbon. The early Chevrolet forged steel cranks crack so regularly mostly because of the weak material they were forged from. It was something like a 1020 (I’m not positive, but you get the idea). A forged piston is strong because of the material it is made from The steel used to make a forged part must have good forgability. It is forged because the material is not very castable. The forging process DOES add grain flow and add strength to the part as above, but it is primarily the higher material Ultimate Tensile Strength (UTS) and Yield Strength (YS) that make it strong. The yield point is the point at which a part first starts to plastically deform. Take a paper-clip, and straighten it. You can flex it to some degree without bending it. Once you permanently bend it, you have hit the yield point. The UTS is where the part actually breaks. The more brittle a material is, the closer together the UTS and the YS are. Also remember, steel can have a yield strength of as little as 40,000 psi, and as great as 300,000 psi. Now a forged part generally is more ductile than a cast part. 4340 steel is probably the most common material for connecting rod and crank forgings. One of the reasons is its balance of high tensile strength, ductility, and cost. It also responds positively to heat treating, so the surface hardness and the overall material tensile strength can be increased after machining. It is cheaper to machine the part when soft, then heat treat it hard.

Now the cost of a forged part would seem to be higher because of needing a set of forging dies and a bajillion ton forging press, but the cost or a forged part is generally much lower than a billet part because once the forging tooling is set up, you just go to town and pump out thousands of parts. Forged parts are always made in high quantity to justify the cost of the tooling. The cost of tooling amortized over 100,000 parts is small. If you had a half million dollars tooling costs, in this case the per part cost would be $5 per part. The parts are also close to finished shape, and do not need much machining. Machining generally must be done by workers with more skill and take more time than forging.

Now here is the key with billet parts... billet parts have the capability of being of higher strength than a forged part. It depends on what kind of steel the part is made from. A billet part is cut from a solid chunk of steel, so the material does NOT have to be forgeable. You can make parts out of superior strength materials to forging, because you do not have to pick a material that is forgable. Again, this does not stop the designers from picking a weak cheap material, knowing gearheads will buy the parts because the box says “billet”. The biggest drawback to a billet part is they must be fully machined. If producing 100,000 or 250,000 parts, the cost of the machining of all the parts will be much higher than the cost of forging and then finish machining an equal number of parts. The advantage is in low numbers of parts. You can set up a CNC program to mill out 10 sets of billet rods and make money on them. The tooling cost to forge something I’m sure is over $100,000. I do not know what it would cost, but I am just throwing out a number to give an idea of costs.

When shopping for parts in the future, remember what the terms "billet" and "forged" really mean. When shopping for the best of any product, the better you understand the terminoligy and the science behind the product, the better your decision making will be. When someone advertises a product as being "billet steel" or "billet aluminum", or "forged steel" you should be asking "what kind of steel?" or "what grade of aluminum?" or "what are the material properties?"

Just some info in case other didn't know about diff in process and once again I am not trying start a war with Calvin or and his ppl
But ur not going get billet parts for cast price so cp will still be leader because his price and fast production

Or you can just send it to millennium,they've fixed a lot worse

And they do plateing !'

Calvin, what does the grease have to do with it? I do use Vaseline to hold the orings in place during install....do you think the vasaline swells the Orings? Orings came from trinity....some folks say the black ones do not hold up good like the orange ones?

Well mine did the very same thing and Tim repaired it and have had no problems. This bike will be seen at gilbert this year as it has for the past 4 years. Needless to say it can be fixed buddy!

yup, its a simple fix.... but I dont want it to happen again if I am the one causing the issue... LOL....im about to put a whole ton of power through this cyl...dont want any issues. Ill proably buy a new one and get this one fixed and use it as a spare at the track.

Dan the liquid in the gland will hydrolic the wall out, put the oring in there dry, if you do weld it install a greased piston in the bore and fill it with water and then weld it the plating will be perfect, if it needs plating millennium will fix the gland no problem

i would muchy rather fix the gland than a billet head bolt boss lol

Obviosly you have not seen my welding LOL, ill just send it to millenium as the cyl needs replate anyway from a lean sieze a while back...need the cyl to be like new for the turbo build.
Thanks everyone! You have a PM Tim.

If this is a "Cheetah" as in the powervalve style cylinder, Then that could be caused by running the domes Trinity sent you. If your not running domes cut by a good builder. (Note: anyone but Trinity) Than you will get detonation no matter what your timing of jetting. (squish is NEVER suposed to get tighter towards the center of the piston, or you'll send all that force out the O-ring!) Check it and see....

Trust me....been there done that.
Have Tim at Titan Racing cut you some domes. It will be the best money you ever spend on that motor. They are KNOW for having major issues on the 4 mill cheetahs, and on a few of the 10 mills depending on your cc's and fuel choice.

yup, the domes were negitive squish...I had to run race gas to keep it from detonating. On my other engines I built I had customs domes made..this engine is the first time taken apart... knew about the problem...did not use it much. You are correct! always check squish!!!

was it pushing your plugs out also?>

Hell ya... I took it out and herd the detonation... got off it.... one plug was loose..... retarded the piss out of the timing...still got detonation....put race gas is it and it was fine... put a few miles on it until I built a 441 cub and swapped out the engine....now im rebuilding this one... lots of folks warned about the PV motors having negitive squish... I did check the squish when building it... im like hmmm I dot like it but trinity says its fine....LOL... now I run much larger squish on all my engines... Tim from titan is making me some new domes.......nice helpful guy.... so are the other vendors here on the forum...

Dan, is the black material between the failed groove and the cylinder bore o-ring material? It looks like it to me. I am going to say the o-ring used was put in an o-ring groove that was just a little to small to accept it.
You may want to consider having an o-ring groove machined into the dome (maybe .010 deep) to make room for the o-ring to fit??

My saber did the same thing, its on its way to be welded right now and my dome's (all 3) will be getting o-ring grooved .010.

I really think mine did it due to detonation. I was trying to fiX the detonation issue...had lots of detonation lol. I had mine fixed, then beefed it up on the water jacket with a little job weld to support it. Mine was much thinner than yours... You think you might have had detonation?

No detonation, very low compression. 11.1
I drained all the coolant and run it without any o-rings.
LOL, it ran quite well.... track pass

Good luck with your setup.

need to use viton o-rings on those. they are usually a dark brown color.

Looks like what I did to my old dm a few years ago. Mine was a detonation/lean condition that caused it. had it fixed and sold the cast cyl and went billet!!

who cut those domes?

My thinking too Tim....."pretty domes" like that and he blames the casting for detonation.....?

now, I am just asking, because his problems are not cast vs billet here, that would have destroyed more than an oring groove

LOL.. yeah the domes wern pretty i had to run them in a pinch. We will leave names out of it you know him calvin.. No im not going there with cast vs billet. I actully sold the billet and am running a cub now so im back where i started and loving it sofar. Just put it out there because it looked similar to my prob which was me being new,setup not right etc.

Oh I wish I would just go back a few years to lmbo

have liners made at NW sleeve, then good domes cut and ride it.

I know detonation cause my issue... tim had some new domes made for me.. the stock trinity domes are nasty.
Anyone ever use copper head gaskets and ditch the orings?

The domes should seal to the cylinders.
The O-rings should not be seeing forces strong enough to be a failure point.
Your thinking the way you are due to having dealt with the Trinity experience.
Trinity builds have been known in the past to use PIANO WIRE in place of the O-ring!
But when you have a company who think that the more compression you have, the more power you will make....then why stop at 200PSI? Maybe the real power is made at 250PSI.
Once your domes are cut correctly, you'll be fine.

Everybody here knows your feeling about Trinity......even though they did everything to fix your problem that you had MANY years ago.......let it die......you are getting close to sponsor bashing....IMO