Thunder Tiger outboards

[gary cuppels]

Hi I have the opportunity to aquire a new .21 o/b. What is their story? I have not seem much about them. what about reliability and parts?Any thoughts will be appreciated.

 

[camaroboy383]

well they are nice over all engines... slow and heavy stock but sure do haul the mail when modded correctly.... PARTS,,,,,well they are gettin perdy hard to find... some esier than others,,, but most of the internals are scarce...

i run the heck out of tt's and thats all i run... cheap and effective...

gotta say i love em ..... tim duggan, jerry wyss,myself and marty slater all run them.. some others too... its just not a hot topic to all the outboard guy's...

alden

 

[Valet]

is there any easy mods to do to them and can you put a tuned pipe on them?

well they are nice over all engines... slow and heavy stock but sure do haul the mail when modded correctly.... PARTS,,,,,well they are gettin perdy hard to find... some esier than others,,, but most of the internals are scarce...

i run the heck out of tt's and thats all i run... cheap and effective...

gotta say i love em ..... tim duggan, jerry wyss,myself and marty slater all run them.. some others too... its just not a hot topic to all the outboard guy's...

alden

 

[camaroboy383]

the only easy mod out there for a tt is reducing the skeg surface... cutting the lower for a pipe is relatively easy but,,,i hate to say it,, the pipe will do nothing for you unless the timing numbers are changed...all this along with a good modified button and your on your way to a way faster engine...

here is a pic of a tt lower cut for a pipe,,, but the key part in the pic is look at the reduced skeg.....

imo,, i would buy a $189.00 tt and mod it any day,, over buying a $600.00 cmb/nova..... just my opinion.... if done correctly they will sing the magic note,,,and take some w's.....

alden

 

[Tim_Duggan]

Cheap (free) easy mod to do to them is take the head off and dig out the aluminum head shim. The head clearance and bowl volume are ultra-conservative. If you have access to a lathe, you can adjust the head button even further.

Another cheap and easy mod is restrict the water flow down to a trickle by filing most of the angle out of the water pick-up and putting a restrictor in the water line.

Also, try an Octura X637 or X640 reduced to 38mm. The stock P215 prop isn't bad, but in some cases the Octura is a better choice.

 

[camaroboy383]

ohhhh ya,,,, for sure the X637.. you will like that prop...totally forgot about the head shim removal,,, and the water pick up restriction,... i run no water to mine... the lower acts as a major heat sink and the water on those engines flow alot, cooling the engine even further..cool it with fuel,,, it will run hotter so you can run a fatter needle to cool it,,,and think about it..more fuel,,,more lube...

if anyone knows these engines it would be tim or jerry for sure...

alden

 

[Jerry Wyss]

I have come to favor "air cooling" using lower nitro over pinched down water flow. Its just that it's less plumbing to monitor,, and I'm a plumber,lol. The problem with that is the availability of car/buggy air heads. Those that are out there are the 21 Mac buggy engine, the discontinued O.S.21 RG and 21 Thunder Tiger buggy engine heads. All have six bolt patterns that fit the TT O/B case but all have to get cut to fit the button and reduce fins on a lathe.

Pinching down the water is a much easier thing to do but the plumbing has to consistantly stay in place or you'll

suddenly go too lean when something pops off.

High nitro (60% and up) is a different story,, it's tricky to get them hot enough without burning the thing up at full throttle,, and the TT O/B sleeve is one thing that burns up easily. Not a branch in the road that I would recommend due to the TT's poor parts supply like it is now.

They are a fun/practice motor with the addition of a pipe and car header, shim out and pinch the water down to about 1/4 of full bore and run O'Donnell 30%. The props listed above are good, the geared TT lower like the X6 series Octura props and "break the engine in well". Its boring as watching paint dry but essential to the longevity of the engine.

You will likely break the small "shear pin" fairly soon and I work in a appropriate size piece of paper clip and peen the ends for a fix. Next will likely be a flexshaft breaking so keep your thottle jabs to a minimum.

Flexshaft lube is important, remove the nipple on the upper right side of the lower where engine oil residue was meant to go to the gears for lubrication. I use a thin grease, specificaly, NAPA Engine Assembly Grease, pumped in there with a "grease pistol" thats made to grease the sprocket on the nose of a chain saw bar. The light grease will "travel" very well all the way down to the flex easy.

j-dub

 

[camaroboy383]

another thing to add is that the tt's like the k&b 1L plugs #7311... it will tighten up the bubble volume slightly...

alden

 

[gary cuppels]

guys : Thank you for the discussion.By the sounds of it they are not a terrible motor. BUT where can I find spare parts. and is $100 reasonable for a moror?

 

[camaroboy383]

they are 189.00 new plus shipping,,,depending on if its used and how much its been used,, its worth 100.00...obviously at your discretion...

like stated parts are tough to find,,,but if properly cared for will last a long time..if you ever need anything i could possibly help,,, i have alot of parts here...

alden

 

[gary cuppels]

they are 189.00 new plus shipping,,,depending on if its used and how much its been used,, its worth 100.00...obviously at your discretion...

like stated parts are tough to find,,,but if properly cared for will last a long time..if you ever need anything i could possibly help,,, i have alot of parts here...

alden

thalk you for the offer

 

[Karl Grabowski]

dear guys,

i want to introduce myself, because i am a new member in this forum.

my name is ralf-karl living in germany. my newest project is a tunnelboat

with a thundertiger engine.

take a look in this swiss forum threat:

RC Powerboat-Forum.ch

its my first tunnel, and i want to mod the engine a little bit. i read many topics about this

here and have any questions:

Cheap (free) easy mod to do to them is take the head off and dig out the aluminum head shim. The head clearance and bowl volume are ultra-conservative. If you have access to a lathe, you can adjust the head button even further.

tim, what do you think is a good measure for the head clearance of the PRO-21M-OB ?

thank you very much.

greatings ralf

 

[Martin Meijer]

Hi Guy"s

I love TT outboard too,it is a great engine.

Run a stock tt on a dumas sprint not a fast engine but very reliable.

Put my other TT outboard on a O.S lower unit it is a full tune engine.

For tt parts look at http://www.thundertiger-europe.com/

Ooh I,am Martin living in the Netherlands

Best regards

 

[Tim_Duggan]

dear guys,

i want to introduce myself, because i am a new member in this forum.

my name is ralf-karl living in germany. my newest project is a tunnelboat

with a thundertiger engine.

take a look in this swiss forum threat:

RC Powerboat-Forum.ch

its my first tunnel, and i want to mod the engine a little bit. i read many topics about this

here and have any questions:

Cheap (free) easy mod to do to them is take the head off and dig out the aluminum head shim. The head clearance and bowl volume are ultra-conservative. If you have access to a lathe, you can adjust the head button even further.

tim, what do you think is a good measure for the head clearance of the PRO-21M-OB ?

thank you very much.

greatings ralf

Welcome to IW Ralf!

On 21 engines & 50%+ nitro, I set the head clearance in the region of 0.006" to 0.010" at Top Dead Centre.

I hope this helps.

Tim.

 

[Tim_Duggan]

Hi Guy"s

I love TT outboard too,it is a great engine.

Run a stock tt on a dumas sprint not a fast engine but very reliable.

Put my other TT outboard on a O.S lower unit it is a full tune engine.

For tt parts look at http://www.thundertiger-europe.com/

Ooh I,am Martin living in the Netherlands

Best regards

Hi Martin,

That is an interesting conversion - the TT engine on the OS lower. Were all of the parts interchangeable (crankshaft / PTO)?

 

[camaroboy383]

tim,, martin was telling me about this conversion some time ago,, and jerry and i had talked about it some... i would like to see it run... martin you have any video??.. interesting conversation piece..

karl,, welcome,, good to have another tt guy around here..lol...

alden

 

[Martin Meijer]

tim,, martin was telling me about this conversion some time ago,, and jerry and i had talked about it some... i would like to see it run... martin you have any video??.. interesting conversation piece..

karl,, welcome,, good to have another tt guy around here..lol...

alden

Hi Guy"s

I use the crank and the conrod from the O.S engine,it fits perfect.

Sorry Alden i don"t have a video,i will make one but it is winter here in the netherlands lots of ice hehehehehehe.

Martin

 

[Karl Grabowski]

thanx to all for your nice reception.

yes tim, this is what i want to know. *tup*

martin, very interesting your custom TT . good to know what is possible.

here in germany the same... no water ... only ice.

... the TT is my first outboard engine. i think the quality is more than ok and the price was low.

that was the reason i bought it.

ralf

 

[Martin Meijer]

thanx to all for your nice reception.

yes tim, this is what i want to know. *tup*

martin, very interesting your custom TT . good to know what is possible.

here in germany the same... no water ... only ice.

... the TT is my first outboard engine. i think the quality is more than ok and the price was low.

that was the reason i bought it.

ralf

Ooh use fuel with 16/18% oil,your tiger motor will love you for that hehehehehe

Alden,if you give me your e-mail adres sent you a nice video from my big tunnel with 16cc K&b outboard.

Martin

 

[Tim_Duggan]

Ahhh the dreaded oil contnet debate.

I'd go so far as suggesting at least 5% castor oil + 15% synthetic such as KL200 in a TT PRO21M O/B. The crank seal is less than ideal and the extra oil seems to help it somehow. Saw significant results with more oil in that motor.

Jerry W, what are your thoughts?