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S/C pulley and plumbing help PLZ....

2K views 14 replies 3 participants last post by  gn7 
#1 ·
Going from a 16 rib serpentine drive on a Gen 6 BBC with a B&M 420 mega blower to 8MM drive.

This may be two problems to solve or one if someone knows a slick way to do this???

I need to go from the old 1 1/4" rubber hose to 1/2" NPT on the BDS idler pulley set up.
Here's a pic of the old set up with the 1 1/4" rubber hose going onto a chrome tube bolted onto the water pump holes. I don't think there is a idler deal where the idler bracket bolt's onto the front of the blower with the B&M blower's so, I "think" I need to use the BDS style idler/water inlet spacers? Is there a nice way to get from the 1 1/4" rubber hose down to a T or Y with 1/2" NPT?

Next problem is pulley alignment.
My crank pulley has 3 grooves ( it's a 2 piece deal with 1 1/2 pulleys each half and get's bolted together) and I only need a two groove pulley for the alt and belt driven water pump.
As you can see in the pic, the idler pulley need's to go forward a lot and the crank pulley needs go back (losing 1 groove will help a bit) about 1 3/8".

Is there a easy way to do all this or not?

Thanks for any help, Jim
 

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#2 · (Edited)
yeah, after losing 1 of the bottom pulleys get the proper thickness spacer for the top pulley, all blower places sell them, so now both top and bottom line up. Then you just make some round spacers to move the idler plate where you need it to be. Ace hardware,hacksaw,3/8 drill. Now with the idler out there you may be able to use your 1 1/4 hose deal with spacers and not use the bds water plates. See you just run your ss plate and make spacers to move the idler bracket out, if your lucky there will be enough room to sneak your 1 1/4 hose in there.


Now if not i'd run 1/2 p to # 10 fittings from the bds plates to a common log below motor and plumb the 1 1/4 hose into that. So 2 #10 lines to the "log" and a 1 1/4 hose attached to it
 
#4 ·
OK, thanks guy's!!
Start at the bottom and work up.
I wasn't sure if stand off spacers would hold up to the stresses of the idler bracket. Just eyeballing things, I don't think the original chrome water tube will fit in there. Might be able to re-fab the tube to make it shorter.

1QuickCP,
where do I get the common log for the 1/2 NPT to # 10's to 1 1/4" hose? Make one?

Jim
 
#5 ·
OK, thanks guy's!!
Start at the bottom and work up.
I wasn't sure if stand off spacers would hold up to the stresses of the idler bracket. Just eyeballing things, I don't think the original chrome water tube will fit in there. Might be able to re-fab the tube to make it shorter.

1QuickCP,
where do I get the common log for the 1/2 NPT to # 10's to 1 1/4" hose? Make one?

Jim
You migh check jegs and summit I think I saw a radiator adapter from pipe to 1 1/4 hose, ya checked its fron 1 1/4 to 1" pipe. I would make one from a hunk of 1.5 alum bar stock.
 
#7 ·
You need to determine what your going to use for the water inlet before you get into the tube spacers. Yes the tube spacers are strong enough, and we just use stainless allens to hold the bracket. Our bracket is spaced off the block offs you have in your pics.



 
#8 ·
Got the 2 V pulley and I think it's made wrong????

BBC with a balancer on the crank snout, the pulley has a 2.250 raised register that goes into the dampener right? If so, the recessed holes for the 3/8" allen bolts are machined from the wrong side. Or, I am doing something really wrong?

Am I right that the 2 V pulley get's bolted on with the raised part going into the dampner then bolted on with the 3 --3/8 allen bolts going into the recessed holes in the front side of the 2 V pulley (can't do it with this pulley, recessed on the back side) and then the bottom blower pulley bolts on?

Here's a pic.


Jim
 

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#9 · (Edited)
Sorry Jim, but the raised pilot faces out. Just like the raised pilot on the blower. The pilot is always out, and anything you stack on it will sometimes have a pilot as well. The pilot is for the blower pulley. You can buy a pilot that goes between the damper and the v belt pulley. BDS carries them. My ATI damper has a pilot built into it. All the others tend to be flat faced. Not to worry though. I have run with the v belt pulley bolted flat to the damper without a pilot many times. Just bolt it on with the pilot out towards the blower drive pulley. The allen bolt will align it well enough. Not a big fan if the 3bolt/6 bolt adaptor arangement though. Hopefully your not spinning that blower too hard.



 
#10 ·
Hmmmm

GN, if I bolt it on raised pilot out, the crank blower pulley wont swallow the 2.250" raised pilot......
The hole in the blower pulley is too small. From memory, the hole in the blower pulley is 2.00"???

What was there with the 16 rib set up.......
Dampener--3 V pulley--steel drive hub--lower blower pulley. With this set up, the blower pulley was flush with the 3 V pulley. The drive hub sat inside the 3 V pulley and made the lower blower pulley sit flush.

If I go 8 MM.....
Dampener--2 V pulley--steel drive hub--lower blower pulley, the steel drive hub spaces the lower blower pulley back out where the 3 V set up was. I was hoping to shorten the "stack up" on the crank so I don't have to go as far out on the idler and upper pulley. Is there a 2 V pulley that is recessed so the steel drive hub sits inside the 2 V pulley? Or, can I machine off the 2.250 raised pilot and run the lower blower pulley flush onto the 2 V pulley? That would eliminate the steel drive hub.

Looking to make 10-12 lbs boost with this B&M 420 on E-85.

Jim
 
#11 · (Edited)
The easiest way to move the whole assembly back is to chit can the stock type damper. If it is actually stock, and appears to be, you REALLY need to can it. The face of an ATI is about 1/2-3/4" further back at the face than the stocker, and it doesn't require an adaptor plate, and has the correct pilot register built into it. Summit also sells a blower pattern damper that the face falls pretty close to the stock location. Neither are cheap, but Paul tells me your loaded. DON'T CHANCE A STOCK DAMPER!! That kind of boost from a 420 will break a stock damper at the worse possible time. And its going to tear things up when it does. How deep is the lake your boat on:))eek:))Reality

The register does not fit your pulleys because the 420 uses the old style 6-71 Crager pulley arrangment with 1/2" pitch belts. those pulleys had a 2 inch register. The new stuff has a larger pilot register. You have to open the hole up in the pulley. Or you can machine the pilot on the pulley if it doesn't have a receiver recess too deep on the back.



http://www.summitracThey are decent dampers. They are made by Cyco in Australiaing.com/parts/SUM-B74267/


CStraub on the boards here can get you one of these for a blower deal also.http://www.romac.com.au/
 
#12 ·
The register does not fit your pulleys because the 420 uses the old style 6-71 Crager pulley arrangment with 1/2" pitch belts. those pulleys had a 2 inch register. The new stuff has a larger pilot register. You have to open the hole up in the pulley. Or you can machine the pilot on the pulley if it doesn't have a receiver recess too deep on the back.

GN,

the new 2 V pulley is from Summitt (2.250") and the new 8 MM blower pulleys (2.00") are from BDS. I guess BDS sent me the smaller size register pulleys?

Good point on the dampener. This is a Paul Pfaff motor as far as I know. I wasn't going to mess with the dampener but.......If I stay below 6,500 do you still suggest changing it? If so, do you have a P/N for the ATI???

Thanks, Jim
 
#14 ·
I do have a Fluiddampener off a BBC dirt modified...... Yeah, I know.

Jim
 
#15 ·
I'd rather see you run a fluid damper than a stock type iron damper. Its not a RPM thing. Its a load thing. If the hub fails on that damper, it is going to make a mess of things. Its not the ring so much, its the hub.

http://www.summitracing.com/parts/ATI-917741E/

This one fits external balance. If you need an internal I'll see if I can find that number.



 
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