CMB 91 VAC

[Terry Keeley]

Finally got a look at my new 91 Vac, this after 24 runs or about 3 gals. of fuel, just starting to break in. Very impressed so far, it's gonna be a stump puller!

Specs here: https://www.intlwaters.com/gallery/albums/userpics/10068/2012_CMB_VAC_91.xls

Piston showed some evidence of hitting the head at 0.012", backed it off to 15.

As on the 45 the backplate to case showed rub marks, re-assembled with silicone.

Needles looked and miced good, put them back in.

Here's what happens if you're not patient enough during break in, interesting it galled on the cold side.

Completely my fault, pushed it too hard too soon...

 

[Thomas Hulbert]

Well Terry looks like you have run her hard.

Ill take it off your hands for A gold coloured coin ( not made out of gold ), made in Canada. LOL

 

[RodneyPierce]

the just starting to break in must have been sarcasm eh?

And are you making the aluminum ramp plugs that are pressed in?

 

[bermudadude]

wow dat some gouging .what u usin for oil?

 

[kcvnd]

What pipe are you running to pull the stumps Terry?

 

[Philmunsterman]

Is that normal wear for the Piston and Head after 3 gallons ? I have around 4 gallons on my 91HR. Thanks Phil

 

[Joe Warren]

Rich needle But High piston speeds cause them to stick on the COLD SIDE. (intake) also looks like the crank & rod needles are getting thrusted into the drum? are these stk length CMB rod needles?

 

[Terry Keeley]

What pipe are you running to pull the stumps Terry?

Just the 67/80 "Fat Belly" so far with stinger opened up to 0.430", it'll do better with a bigger volume pipe I think.

the just starting to break in must have been sarcasm eh?

And are you making the aluminum ramp plugs that are pressed in?

That's the first piston/sleeve I burned up, totally my fault. Ramp is factory!

wow dat some gouging .what u usin for oil?

Not enough, too soon!

Is that normal wear for the Piston and Head after 3 gallons ? I have around 4 gallons on my 91HR. Thanks Phil

I think so.

 

[Philmunsterman]

Interesting. My Head and Piston still look almost new. Would that mean I might have to much Head Clearance (.15 ) ?

 

[Joe Warren]

Interesting. My Head and Piston still look almost new. Would that mean I might have to much Head Clearance (.15 ) ?

Phil my engine came at .014. I have ran them as close as .010 on 60% & 18 percent oil

 

[Philmunsterman]

I guess I just need to start Running it Harder !

 

[Terry Keeley]

Interesting. My Head and Piston still look almost new. Would that mean I might have to much Head Clearance (.15 ) ?

Think it's prolly 'cause you're only running it WOT for a couple seconds at a time (it's in your SAW boat, right?)

My .67 in my SAW boat sees up to 80% with only 10% oil and it looks brand new too...

 

[Terry Keeley]

Rich needle But High piston speeds cause then to stick on the COLD SIDE. (intake) also looks like the crank & rod needles are getting thrusted into the drum? are these stk length CMB rod needles?

Stock needles, looks a lot worse than it is, barely feel it with your fingernail.

 

[Philmunsterman]

Interesting. My Head and Piston still look almost new. Would that mean I might have to much Head Clearance (.15 ) ?

Think it's prolly 'cause you're only running it WOT for a couple seconds at a time (it's in your SAW boat, right?)

My .67 in my SAW boat sees up to 80% with only 10% oil and it looks brand new too...

Ok. Thanks. Yep SAW Boat. What kind of gains do you see by stepping up to the 80 %

 

[Terry Keeley]

Ok. Thanks. Yep SAW Boat. What kind of gains do you see by stepping up to the 80 %

Jury's still out on that one, 70% is my "standard" SAW fuel.

 

[Philmunsterman]

Any tips for when I take off the Turn Fin this weekend ?

 

[Andy Brown]

Any tips for when I take off the Turn Fin this weekend ?

Slow down a little more before starting your turns and dial in a bit more rudder throw.

 

[Terry Keeley]

Any tips for when I take off the Turn Fin this weekend ?

Personally like a very small one, I wedge the LE so it helps the boat go straight too (thanks Andy).

Slow the thing down to a dead crawl before you try to turn, make sure you have lots of rudder throw, also you can blip the throttle to help get it around.

Looks like you have lots of water there, that'll help! :lol:

 

[longballlumber]

Thanks for sharing Terry. I know when I should listen and look (at the pictures)! B)

Later,

Ball

 

[steve wood]

Finally got a look at my new 91 Vac, this after 24 runs or about 3 gals. of fuel, just starting to break in. Very impressed so far, it's gonna be a stump puller!

Specs here: http://gallery.intlw..._CMB_VAC_91.xls

Piston showed some evidence of hitting the head at 0.012", backed it off to 15.

As on the 45 the backplate to case showed rub marks, re-assembled with silicone.

Needles looked and miced good, put them back in.

Here's what happens if you're not patient enough during break in, interesting it galled on the cold side.

Completely my fault, pushed it too hard too soon...

drill a .040 hole in the middle of the groove you ground in the drum housing