My thundercat - Page 10

Roflhat · 11 May 2016, 19:45

Put the 70 carbs back on to try get some better acceleration

The 50hp stacks fit on these too. Also painted the cowl, getting some custom stickers made

Also got another prop, 11x18p Merc Cleaver but the newer kind. Absolutely mind condish

Roflhat · 16 May 2016, 09:26

Ran terribly with the stock carbs yesterday, going to order 3x carb rebuild kits and take it from there. Took about 40 pulls to start and would die every time I put it into gear. Getting around 120psi with the TSR head, less than I was expecting but hard to judge anything by static compression.

Roflhat · 25 June 2016, 13:11

Got the stickers on, looks alright IMO

Also got a new prop, 16p Radice in brass, set a world speed record in 1979 on a Yam 55

Engine is running properly, the gasket on the carb bowl on the bottom carb wasn't seating properly and one of the spark plug tips had come undone. Still dropping onto 2 cylinders occasionally so need to have another look but it's running really well, finally! Dropped it down to 10mm off the transom and tried some of the smaller props to check acceleration.

Got 46 knots with the 14p vengance, acceleration is very good.
49.3 knots with the 10 3/8 x 19p overhub cleaver, acceleration isn't great because the exhaust isn't drilled. Great top end pull though
SOLAS 15p cupped ran ok but not as good as it did on the tohatsu, 46.5 knots with decent acceleration
The 16p Brass needs a different washer at the nut end, the hub is slightly different.
Best of the bunch was definitely the 15G Yamaha, 47.6 knots with incredible acceleration and unreal grip through the turns. Think I'll get this one worked

Roflhat · 11 August 2016, 09:43

Bit of an update, engine started dropping onto 2 cylinders, then onto 1. Took the plugs out and it was fouling badly (oil). So I'm now running 50:1 with a set of new plugs and it's running much happier now, plugs are perfect.
Engine is now completely standard, even got a standard airbox for it. Runs awesome, feels very smooth thanks to the balanced crank, much more so than the tohatsu at low RPM.

More props and more testing, got a 2 blade brass prop, 10 3/8 x 17p. Unfortunately first time out it spun the hub... so it will be getting sent off to get a new hub.

Best prop is still the 15G yamaha, now getting a consistent 50 knots with it. Really nice prop, although I'd still like a 16G for a bit more top end, the 70hp has no problem spinning up the 15p. Weather hasn't been too great but got out to little Bernera with it.

Also a few more props to try,
18p merc cleaver (another one)

a cut 15G yamaha, meant to be closer to 16p

And this funky looking thing, 9 3/4 x 17p 4 blade Ron Hill

Roflhat · 01 November 2016, 20:34

Engine has been running perfectly recently, got the 90hp carbs on too. 99kmph with the modified 15G Yam. Also ordered a new boat, brand new Ceasar F10 from South Africa, should be here around the end of the year. Took a while to decide on colour but in the end I went for all black with carbon nose cone -

(that's not it, but same hull)

Also sending the powerhead to BDK Race Engineering to get it ported and some reed block stuffers. They also might CNC new head chambers for the TSR head.

Tore the whole engine down, and I came across this -

the remains of an exhaust pipe..

So currently trying to have that replicated in stainless. Makes me wonder how fast the engine would go with a functional exhaust pipe!
Think I'll get the whole engine painted while it's apart, all satin black with grey decals, stay tuned...

Squid Boat · 02 November 2016, 05:05

Really fun and knowledgeable threat mate.

Cheers

Roflhat · 02 November 2016, 18:03

Quote:

Originally Posted by Squid Boat

Really fun and knowledgeable threat mate.

Cheers

Glad you're enjoying it!

Roflhat · 24 December 2016, 19:53

Bit of an update, powerhead is still away getting worked on. Got a new exhaust made, looks the goods and is very similar to the original shape.

Had some time while everything was away getting painted to give the trailer a coat, in black of course. With mudflaps too, going to replace the carpet with black.

Photo of all the props:

The new hull is now finished and on it's way, should hopefully be here in February some time. There's a thunderbolt (5.3m) coming up here too, 90hp yamaha going on it.

Looks alright, but not as good as the F10 Ceasar

carbon nose cone and honeycomb boards

Got the engine put back together today, new mounts and exhaust plate gasket. Whole thing was done in satin black with custom decals

Squid Boat · 25 December 2016, 02:47

Sick.

Cheers

fel2 · 20 January 2017, 22:13

Did you receive your thunderbolt yet ? Can't wait to see some good picture

spartacus · 21 January 2017, 07:08

Nice job. Your range of props is outrageous!

Roflhat · 25 January 2017, 20:04

The boats are in the UK, going through customs just now. Still no powerhead though!
Hopefully soon so I can get testing

Fair selection of props now, I might sell a few once I've done some testing, the 70hp likes different ones to the tohatsu

lukewhiting · 30 January 2017, 22:55

Quote:

Originally Posted by Roflhat

The boats are in the UK, going through customs just now. Still no powerhead though!

Hopefully soon so I can get testing

Fair selection of props now, I might sell a few once I've done some testing, the 70hp likes different ones to the tohatsu

If you think of getting rid of any over hub exhaust props let me know! Wouldn't mind trying something different

Roflhat · 01 February 2017, 09:21

sent you a PM Luke

Boat is now in the uk, powerhead should be done soon too, here we go!

fel2 · 06 February 2017, 22:35

Give us some
Picture !

Roflhat · 07 February 2017, 16:35

Quote:

Originally Posted by fel2

Give us some
Picture !

Go on then

Hull arrived yesterday, got it inflated and on the trailer and got the shell of the engine on. Just waiting on the powerhead now!

The boat looks absolutely amazng, very pleased with it. Love the carbon nose cone. The floorboards are unbelievably light, can easily hold them both with one hand, must be 6-7kg lighter than the old thundercat.

The transom on the Ceasar is very short, 570mm from the top of transom to bottom of hijackers compared to 640mm for the Thundercat. So I've set the engine up at 50mm above the transom just now which should be good for semi cleavers. Issue is I can only get the lower two bolts in, so I've designed a jacking plate which I'm hoping to have made.

The all black fuel tank in place:

It's got a raised section underneath which means it doesn't sit flat. I'm going to look into getting it cut off so it sits better, and also the filler cap isn't stainless, so that might want changing too.

lukewhiting · 07 February 2017, 16:52

Looks the nuts!! Love it! You'll have to bring it down south one day!

Roflhat · 07 February 2017, 17:24

Quote:

Originally Posted by lukewhiting

Looks the nuts!! Love it! You'll have to bring it down south one day!

Yeh would be good to get out for a run with some other thundercats, thinking about organizing a race or cruise of some sort up here too

fel2 · 07 February 2017, 17:54

What about the thunderbolt you had bought before x-mas

Roflhat · 07 February 2017, 17:58

Quote:

Originally Posted by fel2

What about the thunderbolt you had bought before x-mas

That's not mine unfortunately, it's coming up to the island though. It's down in Southampton just now getting a custom trailer and the Yamaha 90hp fitted, should be here before the end of the month