These New Big Block "truck engines"

[TimD]

These 26, 27, 28 engines that are appearing for "trucks" that seem to be big bore 21's - has anyone tried them in a 20 rigger yet and if so do they have enough power to pull much higher pitch? Obviously it can't race against the 3.5cc boats and would slot into 7.5cc class but I'm wondering if the light weight of a 21 boat plus the extra prop would make them competitive.

 

[Ron Olson]

In the 140 MPH in Flint thread that I posted, they guy named Dennis from Buffalo, NY had a .26 motor in his 'rigger with a water-cooled head on it and using a bored-out K&B 3.5 Gold carb. He was having teething problems with it but it did have potential. He was attempting to break a record in a class that isn't used too much, "C" Hydro. There are a lot of these engines coming out all the time with the T-Maxxes, Savage's, the new Losi and Associated trucks.

 

[nitrotoys]

THe Ofna .26 is a strong engine, Friend of mines got one in his assoc truck, and he can wheely on command. its about a 16lb truck. Im sure they can pull a pretty big prop for the size of boat.

i think that engines a 6 port one.

Tom

 

[DJT]

I will be trying the Dynamite .26 in my Dumas Hawk 3.5 this weekend. Two and three quarter horse power (manufacturer claim) for 140.00$, seemed like a good deal to me. I'll let you know haw it runs.

 

[TimD]

Thanks Derek - just what I was looking to hear.

Tim.

 

[TomMoorehouse]

i got one..... still testing the onfa .26

 

[Eric Perez]

Come on Tom, do you have any preliminary info?

Is it even worth looking into (For the Tinkerers I mean Sure would be nice to be able to test a 20 sized hydro with an engine that is close to a full bred race .21 yet cost half as much...

 

[TomMoorehouse]

i ran mine a couple times last year.... it worked ok.... did not get any speeds and it is far from broken in (3 tanks i think). i had big probs with the stupid slide carb. i got a k&b fit to it now but have not had it out yet this year..... im more worried about getting my .21 working first..... maybe next time i go out ill make some comparisons.

 

[Eric Perez]

Yea, does dam slides are a PITA to get right. It took me 3-days to get the slide on my small-block to work without sticking. It's got to do with the pivot point and the arm.

I ended up putting the pivot point almost flush with the carb-centerline. Had a super short servo-horn that I used to actuate the slide with. I'll post some pics tonight.

 

[Bob Kensill]

I've got a Sirio 27 in my Eagle SG. It pulls some really big props. To date,my best speed has been just a bit over 90mph. My goal is 100mph.

 

[TimD]

Bob,

Thanks Can you give me an idea on prop selection / pitch for an oval racer? You don't have to reveal any secrets B)

Tim.

 

[Bob Kensill]

For SAW I have been running an Octura 2047. The boat got right up on the pipe. I am using a CMDI 21S muffled pipe,set as short as I can get it. The boat takes a little to get up to speed,but I think prop area work will help that. I would rework an S15 or H10 for heat racing. I left the engine air-cooled but cut off half the fins and reduced the head diameter too. I am using a D&J carb with .350" bore and 65% Wildcat fuel. The motor is stock. The only trick is getting a flywheel on the SG crankshaft.

 

[TimD]

Thanks Bob!

What are people doing about the flywheel / hex on those cranks? Tom? Derek?

 

[TomMoorehouse]

i have a hacked os flywheel on mine

 

[DJT]

I am using an Octura .12 size flywheel with part of the back milled off so it would not hit the neck where the carb goes. I am also using a standard shaft not an sg shaft.

 

[Bob Kensill]

I'm using a cut down Nova Rossi flywheel. The engine doesn't seem to need much of a flywheel.