Author Topic: 44 Intek Twin  (Read 560 times)

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Offline HMCTAS

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44 Intek Twin
« on: September 16, 2018, 01:11:47 AM »
Gday from Tasmania  :D

We're just getting into mower racing down here in Tassie, have been doing it for about 12 months so far. I run a Greenfield mower with a 26HP (44ci) Briggs Intek V'twin.

I have strengthened the original chassis, lowered it, widened it etc. It runs a clutched belt drive with a 3.5" front pulley to a right angle drive with a 7" pulley on it, so I get a 2:1 reduction to the right angle drive. Then it is sprocket driven to a kart rear end.

At the moment it performs pretty well, could be better but there's more stuff to do to the front end.

Engine is stock, it was running at 4500 on the governor. I've got a billet flywheel coming from the USA so I can remove the governor. Rods are next on the list or can stock rods do the job? I would like to get about 5500/6000rpm out of the engine.

What will I need to get for the heads? I've just got some new stock heads for it so I have a couple of bare canvasses to play with lol

Cheers,
Shane




Online PJG56

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Re: 44 Intek Twin
« Reply #1 on: September 16, 2018, 04:19:06 PM »
Not knowing the age and condition of your motor,i would put ARC rods in it as soon as possible.
the 49 rod is a much better rod and your motor might already have them from factory,but I have seen them fail at stock 3650 rpm,i just wouldn't risk it,unless it was a stock grass cutter..
Paul Guptill  (oppy) #238modX
2012 slmra mowstock champion(builder/owner)

2013 slmra mowdified champion(builder/owner)
2013 ARMA national champion Mod-X(builder/owner)
2014 ARMA national champion Mod-X(builder/owner)
2014 All American Champion Mod-X/CP(builder/owner)
2014All American Champion FXT (engine builder)
2014 All American 2nd place SP(builder/owner)
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Offline rotten ron

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Re: 44 Intek Twin
« Reply #2 on: September 16, 2018, 08:58:50 PM »
How did you get 4000 on the governor? It is a wonder a rod has not come out already. As for the heads you will need better springs and retainers and if you put a higher lift cam in it you will need to take the valve seals off and shorten the valve guides


Offline HMCTAS

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Re: 44 Intek Twin
« Reply #3 on: September 17, 2018, 03:35:31 AM »
How did you get 4000 on the governor? It is a wonder a rod has not come out already. As for the heads you will need better springs and retainers and if you put a higher lift cam in it you will need to take the valve seals off and shorten the valve guides

I removed the stock governor linkages and built one to take a throttle cable hooked onto the governor spring with more adjustment. I hadn't planned on a cam (yet lol). As for the valve springs, will the EC dual valve springs and retainers do the job? I'm guessing stronger pushrods have to be in the mix as well.

Not knowing the age and condition of your motor,i would put ARC rods in it as soon as possible.
the 49 rod is a much better rod and your motor might already have them from factory,but I have seen them fail at stock 3650 rpm,i just wouldn't risk it,unless it was a stock grass cutter..

The plan was to get the rods at the same time as the flywheel, however the flywheel was $630AU to my door so the rods have to wait until the piggy bank is a little fuller. I haven't had the engine apart properly yet other than to replace a leaky sump gasket. Engine is in overall good condition but I'll rebuild it once I get rods for it.

Thanks for your help so far, as I get more into it i'm sure i'll have more questions  :lol:

Offline rotten ron

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Re: 44 Intek Twin
« Reply #4 on: September 20, 2018, 08:24:36 PM »
The EC springs and retainers will work fine and you should do a performance valve job and maybe some porting while you are working on the heads also machine some off the surface of the heads to help the compression ratio

Offline HMCTAS

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Re: 44 Intek Twin
« Reply #5 on: September 21, 2018, 03:50:50 AM »
The EC springs and retainers will work fine and you should do a performance valve job and maybe some porting while you are working on the heads also machine some off the surface of the heads to help the compression ratio

That was in the plan of attack Ron, just ordered some burrs for the die grinder last night :D How much would you take off the heads? I was going to face them off to make sure they were flat but that was about it. 

Offline rotten ron

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Re: 44 Intek Twin
« Reply #6 on: September 21, 2018, 09:42:32 PM »
Check the CCs of the heads so you can figure out the compression ratio then you might take up to .100" .You might have to flycut the pistons for valve clearance and if you use a higher lift cam it will be closer <if you have race gas or alcohol you can run near 14 to 1 compression ratio  Intek heads don"t flow well it would be better if you ad a Vanguard 38 cubic inch with 23 HP heads probably good for about 75 hp at 11000 rpm


Offline HMCTAS

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Re: 44 Intek Twin
« Reply #7 on: September 22, 2018, 01:37:41 AM »
Check the CCs of the heads so you can figure out the compression ratio then you might take up to .100" .You might have to flycut the pistons for valve clearance and if you use a higher lift cam it will be closer <if you have race gas or alcohol you can run near 14 to 1 compression ratio  Intek heads don"t flow well it would be better if you ad a Vanguard 38 cubic inch with 23 HP heads probably good for about 75 hp at 11000 rpm

.100" is a fair wack at it. I don't think I'll be going that far :lol: To be honest, i just want something that I can run reliably with no governor. It'll be running on pump fuel for convenience.

Vanguards sound the goods but I'll work with what I've got. Even as it is now, there's a bunch of us that are sort of evenly paced, so If I can bump this engine up a little, that'll do me :D

Offline rotten ron

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Re: 44 Intek Twin
« Reply #8 on: September 22, 2018, 10:28:50 PM »
I understand.I have a friend who raced with a club but he made his tractor go lots faster than the other guys in the club so they didn't want to race with him because he made them look slow so he left them and started his own club with other guys that wanted to go fast and that club is still running.

Offline HMCTAS

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Re: 44 Intek Twin
« Reply #9 on: September 22, 2018, 11:54:49 PM »
I understand.I have a friend who raced with a club but he made his tractor go lots faster than the other guys in the club so they didn't want to race with him because he made them look slow so he left them and started his own club with other guys that wanted to go fast and that club is still running.

It's early days where we race so we have a race to see how everyone goes then we send the fast guys to the back of the field in a handicap style. This system has been working well so far. As we get more numbers up then we can start breaking it into classes.