RE: Thunder Cat 31
 

Here is some pics of what broke sorry they aren't the best but you get the idea, Horizon said $185 for the parts to repair..................... lol like I'm gonna spend that for this.


Paul


p.s. Sorry it took so long been working on a little rigger.

RE: Thunder Cat 31
 

Wow that thing came apart good!! How old was the motor? What are your plans on a new power plant?

RE: Thunder Cat 31
 

I am not sure, I don't want to spend a lot of money I might consider a decent .21 but a .45 isn't out of the question either. Its all a matter of money at this point.

RE: Thunder Cat 31
 

Thanks for the help on the drive gear guys!.

Gooeycheese, those carnage picts are cool[:-]. I never thought nitro motors came apart like that. A TC with a .45 would be crazy fast[8D]. Good luck!!

RE: Thunder Cat 31
 

can someone post a picture of a octura m prop i was just wondering the difference between the x and the m

RE: Thunder Cat 31
 

The "M" series has less tongue area than the "X" does.
Yeah, I'm too lazy to get my camera out right now........

RE: Thunder Cat 31
 

losifiend

Most motors break either of over reving ore hydraulic lock when taking in water check this CMB 90 how it broke after taking just a little to much water. Nitro is wonderfull evel.

RE: Thunder Cat 31
 

Back to newbe questions. Motor to prop shaft alignment issue. My motor seems to have come from the factory dead on. How ever there the cowlet axis and the motor crank shaft axis are not, such that the flex shaft can be seen wobbling slightly within the flex shaft tube entrance. Anyone else see this? Suggestions?

RE: Thunder Cat 31
 

when you say "tongue" where is the tongue part of the prop

RE: Thunder Cat 31
 

Wish granted:D...m440 is to the left.

the "tongue" is the leading edge(the part close to the boat transom when installed)

RE: Thunder Cat 31
 

When you "seal" an engine what joints/seams are sealed? What is the preferred sealant?

RE: Thunder Cat 31
 

Thankyou for the picture. I assume the one on the left is the m and the x is on the right because all the ones I have look like the ones on the right and they are the x.

RE: Thunder Cat 31
 

Probably should have read before assuming what one was what.

RE: Thunder Cat 31
 

depends of the motor to seal but mostly the backplate and the carb to the block , by using any hi temp silicone gasket seal from automotive store.

RE: Thunder Cat 31
 

Well, I blew up my motor today...I'll have pics posted in a few hrs...gotta tear it down, see what is broke and order a new .32. I think they are only like $119.

I have thought about putting a bigger motor in my TC...has anyone done this? I would assume a larger motor is going to need a different mounting plate...

RE: Thunder Cat 31
 

poor dynamite .32:(:(...how it happened?..check back few pages C. Aldana posted tc31 pics with os .46 engine and uses stock mount, actually boat looks stock at all,,neatly done.

RE: Thunder Cat 31
 

Alright, looks like my .32 threw some bearings, which put the crankshaft out of balance...thus scraping the walls of the block and sending metal shavings everywhere. I didn't find any loose bearings in the case but I am guessing they were crushed and became part of the mess I found on top of my piston. There appears to be 8 or 9 balls missing from the bearing.

Here is the carnage:

RE: Thunder Cat 31
 

I blew my rear bear also, last fall. It didn't cause very much damage so I replaced bearings and ran it until last weekend. You really need to take it totally apart and see how bad it is, unless you can see its beyond repair already.


Paul


p.s If its not that old you could try the warranty path (90days or less)

RE: Thunder Cat 31
 

Yea, the crankshaft really dug into the crankcase...I think it is toast. The cost for the parts I need is about $100....its more economical just getting a whole new powerplant and breaking it in myself. I bought the boat used...1 yr old, so no dice on the warranty. I could have been running it a little lean as well, so...Thats the way it goes...

RE: Thunder Cat 31
 

That was going to be my first question as it looks like a lean out failure.

Something I keep reminding myself everytime I am tuning this engine etc is that it gets all of its lubrication from the oil in the fuel, and too lean really can be mean if you know what I am getting at.

RE: Thunder Cat 31
 

How do you know when you are running too lean or conversely when you are running just right ie not too lean?

RE: Thunder Cat 31
 

as far as i know by how the glow plug element looks after running decent laps....run the boat for laps pull it out, take out the glow plug,,the perfect one is element is slightly pulled out, kinda dull looking, rich is element is shinny and wet, lean is element is dull, deformed element needs shim to be added.

RE: Thunder Cat 31
 

Do I understand correctly that if the tune is correct the glow plug element is "slightly pulled out" and if too rich or too lean it is not "slightly pulled out"?

If too lean then the "element is dull" and if the element is "deformed" a shim needs to be added to what? Richen it back up? Or other/what? Just trying to understand.

RE: Thunder Cat 31
 

Rageman,

Keep an eye on the exhaust trail when running. If you can see bluish smoke, it is not running too lean. If the boat has good smoke from the exhaust but performance seems to be lacking, then it is probably running rich. When tuning for performance, make sure the motor has warmed up and make small HSN adjustments....1/16th to 1/8th turns at a time. When you no longer see smoke from the exhaust, it is getting to the too lean area. When you get too lean, the boat will be going faster, but you are running the risk of burning up the motor.

The Shims that wavewaker was referring to are thin metal washers that are factory installed around the piston sleeve, under the cylinder head. They were installed to decrease the engine compression during break-in. After break in, you may remove all but one shim....it's not required, but it does give the motor a little more power. If you do remove shims, the motor will need to be richened up a little and re-tuned since the added compression will create higher motor temps.

If you go to the Dynamite website, they have pdf versions of the motor and boat manuals for download which will give you some info and exploded views of the motor. You can also do a video search on "Nitro motor tuning". YouTube or google video have several tutorial videos on nitro motor tuning.

RE: Thunder Cat 31
 

It is very dangerous to tell a novice boater to remove head shims. It is common tuning fact that without measuring a motors squish band (excuse the spelling) it is impossible to say whether to remove 1 or both head shims. My motor after measuring had a perfectly acceptable squish band of .015" without any shims. This squish band is still farely big for such a small motor taking in consideration that we run the same squish band on our CMB 45. Arrie one of the guys in our club's motor squish band is at .019" with the shims removed. He still begging me to machine his head button to .015", but I think I will only do it after winning a few races. His driving skills are much better than mine so I have to do something to beat him.

Looking at smoke trails are a dangerous whay of tuning your motor. Getting a temp probe and RPM guage is the best way of tuning a engine. And ofcourse listen to what the engine is doing. Is it "four stroking" the motor is rich, is it dropping off when doing tight turns it is most likely lean at top end (provided your bottom end is set right).