Distributor gear problem - help me figure this out...

General Engine Discussion

Moderator: John_Heard

Post Reply
Message
Author
User avatar
wikd69
Posts: 2067
Joined: Sat Feb 23, 2008 12:42 pm
Location: Rocklin, CA
Contact:

Distributor gear problem - help me figure this out...

#1 Post by wikd69 » Sun Mar 09, 2014 4:35 am

Ok, so with the last build I went with a steel gear at the recommendation of Crane.

Today I was be-bopping down the freeway today, spinning about 3300 rpm when *BAM POP WHAAAAAM*...

Distributor gear gave up the ghost... The weird thing was how it went - the distributor gear wore on only one side - the gear splines wore thin on one side and then one broke off and the cam gear chewed up a bunch more. Weird.

Could I have maybe bent the distributor shaft ? I'll set it up and check it with a dial indicator, but that's the only thing I can think of that might cause the wear pattern I'm seeing. I'm running a Melling high volume oil pump and I've been running VR-1 50Wt oil. Thick oil, high volume, when it's cold it runs up around 70 psi or more. It's only when the motor gets hot that the oil starts to thin out and the oil pressure drops to a more reasonable range.

I'm in the middle of pulling the cam now - it appears to have goobered up the cam gear as well. Dunno if it can be salvaged.

What don't I know about how to align the distributor to the cam ? This old blower manifold is not too precise in that department. And, there isn't a good way to square the manifold to the heads - I just eyeball things to get the manifold set in place.

Any advice on this ? When I put this booger back together this time I don't wanna have to have the distributor go south again...
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

User avatar
wikd69
Posts: 2067
Joined: Sat Feb 23, 2008 12:42 pm
Location: Rocklin, CA
Contact:

Re: Distributor gear problem - help me figure this out...

#2 Post by wikd69 » Mon Mar 10, 2014 1:34 am

Ok, so I ended up pulling the cam - the gear is chewed up and I'm not going to be able to use it. And, I don't think this cam has a pressed on gear - its a full billet stick so unless Crane can work some magic with it I'm gonna have to eat the damn thing.

The bigger question, at least at the moment, is the distributor. I pulled it out and put a dial-indicator on the gear - it's almost .010 out when I spin it. This doesn't seem like it would cause the wear I see in the distributor gear but it certainly wouldn't help. Unless the gear itself is out of true, it looks like the distributor shaft is bent. Could this come about from too much RPM (throttle blip) on a cold motor running 50WT motor oil and a high volume oil pump ? I could see where a throttle stab on a cold motor could *maybe* bend the distributor shaft out of true, but man, that's a damn scary thought !!!! This motor just doesn't have a lot of time on it. I guess it's better it came apart at low rpm on the street instead of in the middle of a high boost run on the track, huh ?

Have any of you guys had issues with bent distributor shafts ? And, am I in danger with the gear chunks now lying in the pan ? I'll sweep the pan with a magnet when I get under the ride by going in through the drain plug hole. I should be able to get a bunch of the debris out of there, but how worried would you be with what I don't catch that way ? I blocked the bypass at the filter so it's not going to let stuff flow around the filter, but it's possible it could toast the pump mebbe. What do you think ? I'd prefer not to pull the motor to drop the pan.

The odd thing is the opposite side of the gear doesn't look bad at all. All the really bad wear is on just one side. That is what made me run the dial against it. The one gear spline in the picture looks like it broke off at the root and wasn't just worn down first. Very odd. Here's a shot of the distributor gear. *ouch*

Image

Something I was pretty happy with were the 'lifter hangers' I made to hold the rollers up off the cam. This allowed me to get the cam out without pulling the blower and intake to get to them. I cut up a bunch of hangers from moms closet to make these and they worked pretty slick. These will go into my special tools box when I get done here (just don't tell mom) :smt003

Image

And it's a bit fuzzy, but I *just* had room to pull the cam out. It cleared the center support in the front grill only after I spun the cam to clear the first lobe. Being able to pull the cam without pulling the hood, blower and intake was a pretty big deal.

Image
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

User avatar
mytmouz
Posts: 643
Joined: Thu Sep 21, 2006 1:00 am
Location: Pelahatchie,MS

Re: Distributor gear problem - help me figure this out...

#3 Post by mytmouz » Mon Mar 10, 2014 10:11 am

To me, it looks like the oil pump locked up...
Trucks are for haulin...

Image

bracketchev1221
Posts: 155
Joined: Fri Oct 11, 2013 7:59 pm
Location: Mountville PA

Re: Distributor gear problem - help me figure this out...

#4 Post by bracketchev1221 » Mon Mar 10, 2014 2:35 pm

Just start pulling the motor out now. If it ate the cam gear, all the shavings are going to eat the bearings and everything else. And if you truly are having cam gear alignment issues, the best way to set it is looking through the cam plug at the rear of the block.

User avatar
wikd69
Posts: 2067
Joined: Sat Feb 23, 2008 12:42 pm
Location: Rocklin, CA
Contact:

Re: Distributor gear problem - help me figure this out...

#5 Post by wikd69 » Mon Mar 10, 2014 11:03 pm

bracketchev1221 wrote:Just start pulling the motor out now. If it ate the cam gear, all the shavings are going to eat the bearings and everything else. And if you truly are having cam gear alignment issues, the best way to set it is looking through the cam plug at the rear of the block.
:smt005 :smt005 :smt005 :smt005 :smt005

Yeah, I started pulling the motor earlier today....

I still don't know why the distr gear wore in such an asymmetric fashion. Really weird - the only thing I can figure is the distr shaft is bent - and the dial seems to indicate that. And if it is bent, I can only wonder about how that happened.

So tell me - if the oil bypass is blocked off (and it is) how does crap get past the filter ? I've heard bad stories about wiping bearings when you get crap in the pan - how does that occur ? What am I missing ?
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

User avatar
wikd69
Posts: 2067
Joined: Sat Feb 23, 2008 12:42 pm
Location: Rocklin, CA
Contact:

Re: Distributor gear problem - help me figure this out...

#6 Post by wikd69 » Mon Mar 10, 2014 11:05 pm

bracketchev1221 wrote:Just start pulling the motor out now. If it ate the cam gear, all the shavings are going to eat the bearings and everything else. And if you truly are having cam gear alignment issues, the best way to set it is looking through the cam plug at the rear of the block.
:smt005 :smt005 :smt005 :smt005 :smt005

Yeah, I started pulling the motor earlier today....

I still don't know why the distr gear wore in such an asymmetric fashion. Really weird - the only thing I can figure is the distr shaft is bent - and the dial seems to indicate that. And if it is bent, I can only wonder about how that happened.

So tell me - if the oil bypass is blocked off (and it is) how does crap get past the filter ? I've heard bad stories about wiping bearings when you get crap in the pan - how does that occur ? What am I missing ?

And you know, it never occurred to me to check cam gear alignment from the back. Mebbe I'll double-check that while I have it out this time...

Crapola, I'm about to put a zipper on this damn thing, it seems to rotate in and out of the car on a very frequent basis.
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

bracketchev1221
Posts: 155
Joined: Fri Oct 11, 2013 7:59 pm
Location: Mountville PA

Re: Distributor gear problem - help me figure this out...

#7 Post by bracketchev1221 » Tue Mar 11, 2014 6:58 am

It doesn't have to be the big pieces that eat the bearing. Your oil filter can only filter so far to not stop oil flow through it. When thousands of those little pieces get through the filter it is like having fine lapping compound running through the motor. Generally the bigger grit will get caught in the filter. But some oil filters have internal bypasses too. A wix racing filter for example has a micron rating of 61. A micron is .000039". Multiply that by 61 and you get, .002379" Not much room left on a .002-.003 bearing clearance huh?

User avatar
wikd69
Posts: 2067
Joined: Sat Feb 23, 2008 12:42 pm
Location: Rocklin, CA
Contact:

Re: Distributor gear problem - help me figure this out...

#8 Post by wikd69 » Mon Mar 24, 2014 11:25 pm

Ok, so I have the hotrod back together and it's acting strange.

My temperature spikes pretty quickly when I back down on rpm on the street, but it seems to do it randomly. Could it be the thermostat starting to go bad or sticking ? It hasn't had heating problems in a long time. If it persists I'll try replacing the thermostat.

I also have a new oil leak somewhere on the back of the block, up high. I've not found it yet.

GRRRRRRRRRRRRRRRRRRRRRRRRRR....

This thing is getting to be a pain in the ass. Running this level of performance on the street is getting to be more trouble than it's worth - I spend a lot more time on the street than I do on the track and it may be time to scale this motor back down after this year.
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

bracketchev1221
Posts: 155
Joined: Fri Oct 11, 2013 7:59 pm
Location: Mountville PA

Re: Distributor gear problem - help me figure this out...

#9 Post by bracketchev1221 » Tue Mar 25, 2014 12:12 pm

I would change the thermostat, and fill it through the water neck as high as you can to purge all the air out of it. Then put the new thermostat and neck on and fill it up the rest of the way. I give you credit for trying to run something like that on the street. I don't have the patience to do that.

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests