SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: horizon1 on April 26, 2012, 11:04:40 AM

Title: first jet need some help
Post by: horizon1 on April 26, 2012, 11:04:40 AM

this is my first jet project and need some help!  1   I need to find a flywheel cover/ rear motor mount for BBC   2  should i run a flywheel or flex plate? i ask because the motor im getting was hooked up to a drake pump and has a flex plate on it!   3  how easy should the pump turn over?    4  what is the best grade of oil to run stright 30 or heavier

thanks cant wait to get this thing in the water :sly:

Title: Re: first jet need some help
Post by: 75 fantasy on April 26, 2012, 12:38:15 PM

first off wecome to SCJB :thumbup:

1) do a search in the engine classified section, there's always someone selling a cover/mount.
2) flexplates allow the rpms to spin up quicker but i think you have to have an internally balanced motor but not sure maybe someone that know motors will chime in. i wanted to try a flexplate but sold boat before i could try.
3) if the pump is connected to the motor is not going to turn but if disconnected should spin freely with some resistance.
4) i used 30 but what do i know :screwy:

good luck :)

oh btw we like photos :D

Title: Re: first jet need some help
Post by: 74RogersBubbledeck on April 29, 2012, 07:10:39 AM

I bought my Rogers and it had a flex plate on it. Weak motor. When I built a strong Chevy 468 I learned alot from my research. When I had my short block put together by a good machine shop this guy explained to me it is necessary to run a flywheel and have the entire lower end balanced.

If you have a flywheel now it is possible its balanced with your crank and harmonic balancer. Taking it out and replacing with a flex plate might suck.

I've always run 20-50w with zinc like Valvoline VR1

I have a 04 Cobra that is stamped so I use what it wants, I can't remember what it is right now maybe 5-20

Title: Re: first jet need some help
Post by: mash on it on April 29, 2012, 10:17:10 AM

1) BBC 4 point rear mount are pretty easy to find, seen some on C/L last week
2) Flywheel or flexplate may already be determined on existing stringer mounting holes, I run an auto flexplate on 3 different boats, and if/when I have to replace one, I'll use an SFI approved one. If I rigged a boat from scratch, I'd use a junk aluminum flywheel.
3)Pump should have some resistance, but dont wory too much because replacing the bearing/pump refresh is pretty easy
4) 3 boats, 2 trucks and an xr600... Delo 15w40 (good sh!t)

Just my $0.02

Daniel
Mash on it