[69Goat1]

I run an old Ed Pink 8-71 race blower on my GTO and a couple nights ago at cruise night I noticed the hub had slid out and my belt was dancing around. The hub is a BDS unit for pontiacs and I was using the factory crank bolt to hold it. It looks like it became loose and the hub was working back and forth on the key causing it to wallow out the keyway in the crank and then the bolt broke and it split the crank hub up through the keyway.

Since I am now having to change out a perfectly good crank is there a better hub or system than what I had? If this had been an exepensive forged or billet I would be really ticked but right now I am “only” looking at about $1200 to fix

[BruceWilkie]

Double key and use a stud instead of a bolt.

[69Goat1]

Originally Posted by BruceWilkie

Double key and use a stud instead of a bolt.

It was double keyed. I like the stud idea!

[mgarblik]

Originally Posted by BruceWilkie

Double key and use a stud instead of a bolt.

Really liked the stud idea but was unable to find the correct size made from the correct material. Talked to ARP a couple of times and it was going to cost upward of $500.00 to make a single stud/nut combination happen. So we switched gears and went with an L9 bolt from McMaster Carr for about $5.00. Has worked fine. Stud would probably be better, but the weird Pontiac size complicates matters.

[GTOGEORGE]

Originally Posted by mgarblik

Really liked the stud idea but was unable to find the correct size made from the correct material. Talked to ARP a couple of times and it was going to cost upward of $500.00 to make a single stud/nut combination happen. So we switched gears and went with an L9 bolt from McMaster Carr for about $5.00. Has worked fine. Stud would probably be better, but the weird Pontiac size complicates matters.

Having ARP make you something it like BEND over and here it comes! I tried and to get them to make a better grade head stud........damn it was a lot and then once we settled on a price they raised it on me! Seriously the Bolt they (ARP) make for the crank should be good enough...........i think his hub cracked at the keyway.


GTO George

[GTOGEORGE]

FYI......if a person is getting on and off the gas peddle during a 1/4 mile (or a blast down the e-way) attempt that will crack a hub or worse in a heart beat! Its that yank from the blower belt/blower.


GTO George

[mgarblik]

Originally Posted by GTOGEORGE

Having ARP make you something it like BEND over and here it comes! I tried and to get them to make a better grade head stud........damn it was a lot and then once we settled on a price they raised it on me! Seriously the Bolt they (ARP) make for the crank should be good enough...........i think his hub cracked at the keyway.


GTO George

The ARP crank bolt was way too short for our deal with the RCD hub, which is why we went with an L9 bolt from McMaster Carr. I had to buy a box of like 15 or 20 of them so I have a few spares if the OP needs one. He will have to make our super thick step washer for the whole deal to be the right length though. Custom one-off parts like the head studs you wanted or a special 5/8" fine thread stud can get crazy expensive. Places like ARP are set up for big production runs. Little odd requests, just seem to upset them.
Trivia: When Eric designed our billet Ram Air V heads, he designed them around ARP's EXISTING 9/16" studs to avoid the custom fastener issue. That was a smart move.

[GTOGEORGE]

If i’d known then what I know now I’d went with 9/16” head studs!
Diesels and Jap junks have better head studs!

GTO George

[69Goat1]

Originally Posted by mgarblik

The ARP crank bolt was way too short for our deal with the RCD hub, which is why we went with an L9 bolt from McMaster Carr. I had to buy a box of like 15 or 20 of them so I have a few spares if the OP needs one. He will have to make our super thick step washer for the whole deal to be the right length though. Custom one-off parts like the head studs you wanted or a special 5/8" fine thread stud can get crazy expensive. Places like ARP are set up for big production runs. Little odd requests, just seem to upset them.
Trivia: When Eric designed our billet Ram Air V heads, he designed them around ARP's EXISTING 9/16" studs to avoid the custom fastener issue. That was a smart move.

Hi, how can I get a couple of these bolts and instructions to make the step washer?

[GTOGEORGE]

Originally Posted by 69Goat1

I run an old Ed Pink 8-71 race blower on my GTO and a couple nights ago at cruise night I noticed the hub had slid out and my belt was dancing around. The hub is a BDS unit for pontiacs and I was using the factory crank bolt to hold it. It looks like it became loose and the hub was working back and forth on the key causing it to wallow out the keyway in the crank and then the bolt broke and it split the crank hub up through the keyway.

Since I am now having to change out a perfectly good crank is there a better hub or system than what I had? If this had been an exepensive forged or billet I would be really ticked but right now I am “only” looking at about $1200 to fix

Cant you just replace there snout of your crank?
I use loctite (blue) on my damper bolt.....never had one come loose. NOW I've broken the hub on my damper couple of times BUT I am a Bracket Racer so me getting off and on my throttle a couple of times a run is a BAD thing.


GTO George

[69Goat1]

Originally Posted by GTOGEORGE

Cant you just replace there snout of your crank?
I use loctite (blue) on my damper bolt.....never had one come loose. NOW I've broken the hub on my damper couple of times BUT I am a Bracket Racer so me getting off and on my throttle a couple of times a run is a BAD thing.


GTO George

Never heard of replacing a snout! It’s a factory 455 crank...

[GTOGEORGE]

Originally Posted by 69Goat1

Never heard of replacing a snout! It’s a factory 455 crank...

CAST crank.......that would be the problem!



GTO George

[mgarblik]

This is an area we have put considerable time and effort into and so far, no failures. We use a double 1/4" keyway with hardened steel keys. We use an RCD blower hub for a 385 series Ford application that is NOT fully finished. You need to call them and tell them exactly what you are doing and they will pull a Ford unit off line before final hone which will give you a nice .001-.0015 press fit on a Pontiac crankshaft. Then we use a hard steel very thick custom step washer Eric designed but can be made fairly easily on a lathe. PM me and I can scan and send you a blueprint for the washer. Then we use an L9 bolt tightened to 230 Ft. Lbs. to hold it all together. So far, it has been a very simple and reliable set-up. I have the bolts and blueprint for the washer if you decide to go this route. As George said, if it was a billet or forged crank, I would consider cutting the nose off and putting a new one on. Cast N, crank, time for a new one.

[BruceWilkie]

George you mentioned foreign having better fasteners lol ...

13mm is just slightly over .5" (.5118")
14mm (.5511")slightly more and just barely less than .5625"(9/16)

Might be worth investigating.

[GTOGEORGE]

Originally Posted by BruceWilkie

George you mentioned foreign having better fasteners lol ...

13mm is just slightly over .5" (.5118")
14mm (.5511")slightly more and just barely less than .5625"(9/16)

Might be worth investigating.

Noooooo, I guess I need to spell it out.......”ARP” make better fasteners for jap junks and diesels the Pontiac’s!
Yes as always I’ve been way ahead of you on the other sizes, thank you.



GTO GEORGE

[bad69bird]

I agree with the above posts, your next crank definitely needs to be doubled keyed. I've replaced two snouts on my crank. The side load from the side-slinger blower is brutal when you're pedaling the car.

I have a crank support that is for sale that would help with that, but it would need to be modified for your application. Mark at Luhn Performance hooked it up for me!

Good luck with your car!

[69Goat1]

Originally Posted by bad69bird

I agree with the above posts, your next crank definitely needs to be doubled keyed. I've replaced two snouts on my crank. The side load from the side-slinger blower is brutal when you're pedaling the car.

I have a crank support that is for sale that would help with that, but it would need to be modified for your application. Mark at Luhn Performance hooked it up for me!

Good luck with your car!

My crank was double keyed...lots of goosing it around on the street probably did the key ways in...need a better bolt setup...

[GTOGEORGE]

Originally Posted by 69Goat1

My crank was double keyed...lots of goosing it around on the street probably did the key ways in...need a better bolt setup...

Honest.....on.....off.....on......off the Loud Pedal is a BAD thing with a supercharger, crank snout does not like it!!!! I’m the only Pontiac out there Bracket Racing a Roots Blower, a Bracket Racers is ALWAYS on and off the Loud Pedal......it’s the nature of the beast!


GTO George

[69Goat1]

Got it fixed and 220 lbs of torque on an L9 bolt...



I originally built this engine in 2007 and at the time it had 10.25/1 compression and it was naturally aspirated. It has a small solid roller with lift numbers in the 5’s, 250 @ .050 and 110 LS. It made 550/550 on the dyno and was a fun little motor. I bought the blower setup shortly thereafter and have had it on this block a couple times in the past with the high compression.



I decided to lower the compression so I could run pump gas so I lowered it to 8.4/1 with new pistons. I have been driving it around for over 2 years now and then the snafu this thread is about happened. I had never dyno tested it with the blower so we decided to do it after the crank was fixed. They put it on as I had it setup and it made 710 HP but was pig fat. They dropped the jets in both carbs 6 numbers and it responded with 751 HP @ 5800 RPM 5% underdriven and 11 psi. On the dyno we had the alternator on it because the belt runs the water pump and we left the blower scoop on it. Plugs look great and it starts like it’s fuel injected.



I also have nitrous on it to cool it but didn’t dyno it that way so the 150 I hit it with while Mexico racing should really wake it up. They made the pulls at 28 degrees of timing and I pull more with a boost retard box when I am spraying.



Can hardly wait to get it to a track with 40 more Hp and 50 more FP of torque and a brand new converter that maybe my heavy pig won’t drive through...

[mgarblik]

Looks good, lots of power. The blower pulley does stick out way farther than ours. The extra clamp load on the bolt will help for sure.