B&M 250 refresh
 

Guys I need the low down on replacing the seals, bearings and teflon strips on my B&M 250's. I've read a few threads on the internet and it doesn't seem to be to be too complicated.

Anyone have a technical component breakdown sheet laying around.
Thanks,
Jason

Jay, I know the rear bearings and seals are piece of cake, as is the snout bearing.

I may have the literature you seek. Ill dig thru some stuff tomorrow.

Are you finally gonna bolt those babies on??? :santa:

Maybe I'll just pack up some booze and head down to Chicago and see if they'll refresh themselves... lol

It might be cheaper to just send them out to california. We like to drink around here! :drink:

That's a relative term.I've probably bought less for more $$$.

Were you able to find any literature? Do you know what bearing and seal part #'s?
No hurry, just curious.
Thanks

seal kit
http://www.jegs.com/i/Weiand/925/91167/10002/-1

seal kit without the base gasket and carb plate gasket

http://www.jegs.com/i/Weiand/925/9598/10002/-1

coupler

http://www.jegs.com/i/Weiand/925/7063/10002/-1

bearing set
http://www.jegs.com/i/Weiand/925/9592/10002/-1

Shaft /coupler /bearing
http://www.jegs.com/i/Weiand/925/155272/10002/-1

carb plate to blower case gasket

http://www.jegs.com/i/Weiand/925/91185/10002/-1

Shaft/coupler kit

http://www.jegs.com/i/Weiand/925/155272/10002/-1

Sorry Rook, cant find the book I had with the breakdown of parts and diagrams.

The bearings themselves, I would buy from a bearing shop. From what I remember, they are nothing more than a very common industrial style bearing. 188 bucks for the bearing kit from jegs is alot. Prob get them from a bearing supply for way less than that.

As far as the blower to manifold mounting. They used an o ring setup on some, and some just a paper gasket. I can tell ya, forget the o ring setup. It flat out leaks. B&M actually had a bulletin on them, to basically go back to the regular gasket. The best gaskets I found are these from RBS superchargers. Good price and they are thick, and dont leak. The B&M 4 bolt mounting setup is not the best, compared to like a GMC blower.


http://www.rbssuperchargers.com/Prod...-0017&pID=7956

They also have the carb plate gasket, and much cheaper too.
http://www.rbssuperchargers.com/Prod...-0026&pID=7408

I see they also now have a bearing AND seal kit for them as well.

http://www.rbssuperchargers.com/Prod...0-038&pID=9131

Lol, I'm sorry I can also use Google. I just thought you might have had the part#'s handy. RBS give you the bearing #'s on their site. Looks like SKF or Timken are about $6ea. I thought there might be some seal inside the ends. I have the intake and carb gaskets already. And I've already been warned to sealant, gasket sealant the intake and blower together. And that the Orings stuck... Literally!

Thanks once again,
Jason

And so it begins...:)

Apparently there was no shame with red loctiting everything in place. The front bearings did not want to come off the shafts. And there was some slop in the rear needle bearings.

An honest days work.

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Front Bearings NTN 5204 $22ea
Rear Needle Bearings INA 1612B $5ea
Seals TB2 149 100 $ still looking

I assume there is no adjustment for gap and timing. No shims were found.

Nice work bud. How was the coupler/shaft? Any play in the splines?

Good question, didn't even look at the snout or check the play. Maybe I'll head back out to the shop tomorrow and try to disassemble that. I think I left it sitting in the solvent tank, lol.
Any idea on removing and replacing the Teflon strips?

Mild, or anyoune else, have you ever re-Teflon stripped any rotors? The Teflon looks to be in there good. That looks to be this weekend project.
And I found the best deal on bearing kits for our Power Chargers. The bearings are a little more than my ebay quotes.
http://www.theblowershop.com/store/b...1bd7c3f6cccff7

I have not had to replace them in my 250's or 420s, as they were still pretty good, esp on my 420's. The blowers had very little time on them. I think mike tkach has replaced teflon strips over the years.

i used to do a lot of them,different brands use different stripping so it,s important to get the right material.i had a fixture for holding the rotors,that really helped,i would put the new strips in really hot water to make them pliabel and pull the strip in with some heavy duty pliers.you leave an xtra 3/4 of an inch hanging past the end of the rotor as it will shrink up a little,the next day you cut it off even with the end of the rotor.it should be a fairly easy job being as the rotor only has 2 lobes and they have no twist.forgot to mention,i used atf for a lube to assist pulling the strips in.

Thanks, I'll order the strips when I order the bearings. So, installing the strips is just like installing rub rail. Lol

One thing I just found out is to fill the front with the proper amount of fluid...NOT till it comes out the front plug. I have been doing it wrong all these years. Just figured it out while talking to a tech at The Blower Shop. It is to be filled above the front plug.

Thanks greencard.

Removing the Teflon strips was easy. I know they are not the same size as new strips, but the old strips were pretty easy to reinstall. I also dug into my pulley selection to see what I have laying around. I'll be placing an order probably Monday.

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No play in the splines at all!

Andy how the heck are ya?

Show-off . Now there are 3 of us in the known galaxy with the oddball half spline snout b&m 250. Now i have to go tear mine down . I am inspired .

Details please. I'm ignorant about the different types of snouts. I have another blower on the shelf that the strips appear to be good, the blower is tight and rolls over smoothly. I wasn't planning on getting into it, but now I might remove the snout to see what I have.

It's been a pretty easy project so far. The only thing to note is the gears and bolts were red loctited on. Also, when using the gear puller make sure you put a small washer between the puller and the rotor ends. I used the taper end on the puller and it got into the first thread on the rotor. No big deal, I just had to chase the 1 hole with a tap. I learned from the first one.

I have pretty good luck with a air hammer . Dont laugh . Have a shank with a brass drift fitted on the end make sure its supported so the back side give it a little blip 90% time it will get going .you would definetly want to try it on something junk first.
they had half spline full spline and keyed for that style blower . You hit a stump or burp the engine with a grippy belt ona half spline it often fries the splines.thats whhere a lot of people get wild with loctite too lol

Its off the boat on the bench was going to tear it down tonite another guy here has a spare shaft .but once i sat down on couch that was it for me

Ok, I tore down my other blower to just restrip it. Looks like some JackWeed center punched the damn strips in! Also, looks like confirmation that I have 2 identical half spline snout blowers.
Also, the difference between a 250 and 420 manifold, Oringed and non Orined. And 2 Dominators 1 with velocity stacks.
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Ok, I tore down my other blower to just restrip it. Looks like some JackWeed center punched the damn strips in! Also, looks like confirmation that I have 2 identical half spline snout blowers.

Looks like a busy weekend for me, my components have arrived. Bearings, seals, gaskets and 20'of Teflon stripping.

Great Thread... so what did you do with the stakes in the rotaors holding the strips? i have the same thing on my 250. mine was send out and rebuilt 2 years before i bought the boat. maybe like 2003 by the previous owner when he rebuilt the motor.. He ran it for a year or 2 and i ran it for one summer. it has been on the shelf now for 7 or 8 years. going back together with the motor and thinking about this charger or selling this and going with a procharger set up.

any conclusions on this project ??

also when assemblying the blower snouts make sure you use some really sticky spline grease,,oil just dont cut it to keep lubed.

FIXX on the grease for the spline to coupler grease... wont the gear oil disolve and wash out the grease ? or does the level of the oil not come up that far?

It was mention earlier about the correct amount of oil is not when it comes out the frt cover hole, so what is the correct amount?
If i read correctly, It looks like we should be using 75-90 syn gear oil, is this correct?

thanks Bill.

gear has no protection when it comes to splines unless there is plastasizer which is micro pieces of pcv to keep the gears and splines from rubbing each other..merc 101 is good for splines..if the splines dead stop on the gear then the oil wont get in between the splines..the spline grease keeps a cushion between the splines and keeps them from wearing out.. ever see a prop shat that has not been greased..they eventually get beat to a point from no grease..

Bringing back an old thread...

I have a local guy here that will re-strip my blower for $250 (I bring the seal kit), but looking at the project, it doesn't appear to be that big of a thing to do. I like doing my own stuff where I can, and this doesn't seem too difficult. My questions:

1. How hard really? My blower other than the strips doesn't appear to have any other issues. It would just be seals and the strips.

2. Special tools?

3. How did you set up the strips once you had them in the rotors? Did you have to put them in a lathe to set the clearance, or was it good to go with the strips that you purchased.

Thanks in advance!

I've used Merc 101, Merc Spline Grease and STP Engine treatment to dress the splines in the past.

I can't get the backlash/timing set on my gears. I've shimmed the crap out of it every which way.

That's not good.

To set timing you will need to shim one or the other rotor gears outward. Not both. The gears are angle cut so moving one outward from the other slightly adjust the rotor timing.

Hi, I just got a 39 scorpion with 250,and 454s plugs black and dirty,one motor fresh,had blown head gasket, one with 4 hrs.Help! how should I set this up?