need advice on bbc

[aceofspades]

I just bought my first jet boat and iM rebuildin the engine,i have built many street car motors but never a marine motor,i hear people talking about the tollerence issues,i am having the block bored 30 over using flat tops,i guess what i'm asking is do i build it like a street motor or is there somthing different that i need to do.

 

[sturat]

you need to have the ring gap set diff due to the cooler temps we run

Someone with more know how than me will tell you excatly what to set the ring gap at

 

[Disturbed]

Please provide a little more information if you can.  Are you planning on forged pistons?  :smile15:  I think Duanehydro suggested .001-.0015 more piston to cylinder clearance than you would for a street engine.  You may give Tom at Jetboat Performance a call.  He's built a ton of Jetboat engines and he's very helpful and won't pressure you with any sales pitch either. 

 

[pro53]

Whos doing your machine work? I live in pinehurst, G&G PERFORMANCE in Tomball does real nice work, and he's in our area.

 

[TintMan]

Ive always used a cam with a 108 centerlobe if you are running hydraulic instead of most auto cams which are 112. I assume with flat tops you are building a hydraulic motor?Spend the money on good valve train components-they are usually what breaks first! :smile15:

 

[Patchman]

Give Joe or Chris a call at G&G. They are in Rosehill area. # 281-351-6202. Great guys to deal with! You basicly build the motors a little loose because of the prolonged high RPM they see. Nothing going on under 3,000 RPM unlike a street motor! :smile15:

 

[badblood]

I just bought my first jet boat and iM rebuildin the engine,i have built many street car motors but never a marine motor,i hear people talking about the tollerence issues,i am having the block bored 30 over using flat tops,i guess what i'm asking is do i build it like a street motor or is there somthing different that i need to do.

Ring gap needs to be determined on how its going to be run and if any power adders are in its future. (nos or blower)
Follow piston mfg recommendations on piston to wall clearance. Too much piston rock will cause excessive wear on pistons.
Use good head gaskets, (Cometic or Fel=pro mls work well) and brass freeze plugs, stainless valves, forged pistons, one piece pushrods, and good machine work are a minimum.