"New Motor" MAC / CMB

[missbudpilot55]

Getting ready to take the plung and switch from CMB to MAC engines, "45" & "67",

what do I need to know about these two engines as far as mods or are they competitive straight out the box. "45" will be in Sport 40, "67" in 1/8th scale & rigger.

 

[gil sonsino]

Both are great out of the box engines but my personal preference is for MACS.

Gill

 

[Don Ferrette]

Getting ready to take the plung and switch from CMB to MAC engines, "45" & "67",what do I need to know about these two engines as far as mods or are they competitive straight out the box. "45" will be in Sport 40, "67" in 1/8th scale & rigger.

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ok this applies to both the MAC 45 & 67-

step #1- open the box

step #2- remove motor

step #3- install in boat

step #4- run a few tanks thru the motors for break in

step #5- twist that needle in & go like hell!

 

[missbudpilot55]

Was waiting on your reply "Oh Faithfull One", Don, now the next question, which pipe and how long? (AB67 or Parabolic) and which do you prefer the best?

TKS

 

[Joe Warren]

Bill I have 3 NEW CMD 67/84 Parabolic pipes for sale 50.00 ea. Perfect Condition.

 

[John Knight]

Was waiting on your reply "Oh Faithfull One", Don, now the next question, which pipe and how long?  (AB67 or Parabolic) and which do you prefer the best?
TKS

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Bill,

MAC 67, Parabolic pipe, stinger drilled, about 10.5" in length. You can go shorter.

John

 

[Don Ferrette]

Was waiting on your reply "Oh Faithfull One", Don, now the next question, which pipe and how long?  (AB67 or Parabolic) and which do you prefer the best?
TKS

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Go with the 45 parabolic on the sport 40, drill the stinger baffle to same i.d. as stinger. You'll probably end up at around 9 3/4" to 9 7/8" on the pipe length.

On the scale & rigger the 67 parabolic is probably a safe bet as well, drill the stinger baffle same way as above. I'd say 11" to 11 1/4" on the scale & 10 1/2" to 10 3/4" on the rigger. I haven't tried the AB67 pipe on anything smaller than a MAC84 but might test one on the S/J when I finish it. BTW- John Finch's SGX with a stone STOCK MAC67, parabolic pipe @ 10 3/4" runs 82 in true heat race trim. B)

 

[Jeff Lutz]

Bill I have 3  NEW CMD 67/84 Parabolic pipes for sale 50.00 ea. Perfect Condition.

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Joe, Do you still have those pipes for sale? Jeff Lutz

 

[jasonspeedy]

I've had great success with both the AB 67 & parabolic pipes, but here's a helpful note.

If you drill the the internal baffle on the AB 67, you'll need to insert a stinger. If you don't you may not have a sufficient amount of fuel being pushed back into the head, and you'll go lean. Trust me, I know...28 glow plugs and $50 in the cuss jar later...

 

[Don Ferrette]

I've had great success with both the AB 67 & parabolic pipes, but here's a helpful note. 
If you drill the the internal baffle on the AB 67, you'll need to insert a stinger.  If you don't you may not have a sufficient amount of fuel being pushed back into the head, and you'll go lean.  Trust me, I know...28 glow plugs and $50 in the cuss jar later...

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The AB67 should be run as is out of the box (using stinger bushings as needed). The only pipes I drill are the parabolics.

 

[jasonspeedy]

I agree, you should run the AB 67 as is. But, for a while, many people were thinking that the size of the baffle was creating some problems, and were consequently drilling them out. That's when you have the potential for a lean condition. Mine was drilled out, and I ended up needing a .410 stinger. I'm sure that if run as-is It would be perfect, I just didn't know that at the time. That's what you get for listening to people.