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GSC Power Division Race Balance shaft

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clipto

10+ Year Contributor
2,317
5
Oct 8, 2011
Portland, Oregon
Very Subjective Question there man... .

For some I'm sure it's priceless of others Not needed. Depends what you are doing above all... . Good piece of mind regardless. In a 162mm Rod 2.2lr de-stroker revving to 11k Would it be a good Idle? Sure. Would you need it in a Stock lightly modded 1g or 2g... That's your call.

Adds the worry of a shaft spinning 2x the crank speed.

The Shaft whether it be a Stock stubby or this no matter what is going to be spinning... .
 
From my experience I have to say install the new race balance shaft,after witnessing 5 dsm's with oil pump failure due to stubby shaft fault I installed AMS balance shaft in both of my dsm's just to be safe.What happens is that some people install their timing belt to tight putting pressure on the oil pump gear which creates the stress on the stubby shaft causing it to fail sending all the metal shaving through the rest of the engine.4 out of 5 engines were ruined that I have witnessed due to this reason,the one was caught early and it was saved.New race balance shaft looks similar to your new one and gives it support that it needs and its oil fed just like your stock one.I believe the ones from ams are balanced up to 11k Rpm too.Go way to spend money especially if you have lots of money wrapped up in your engine.
 
The Shaft whether it be a Stock stubby or this no matter what is going to be spinning... .

Yes I said this once and was reminded that the stubby is just the gears riding on oil in the pump but the shaft spins on a bearing. Its true. Stubby isn't spinning on a bearing in the engine so no worry about spinning a bearing.
 
Stubby isn't spinning on a bearing in the engine so no worry about spinning a bearing.

Spinning is Spinning... Whether it be on it's own or in a Race

Be more specific what you are trying to say next time... Bottom like there is a trade of regardless.




Either way this is all subjective and dependent on too many things like many other question on here to ever be a simple yes or no... .
 
Spinning is Spinning... Whether it be on it's own or in a Race

Be more specific what you are trying to say next time... Bottom like there is a trade of regardless.




Either way this is all subjective and dependent on too many things like many other question on here to ever be a simple yes or no... .

Will do and thats what I was thinking. But I was told by someone with far more experience than me, not that I'm a newb, so I was inclined to believe so.

I pretty much said the same to him. But he still disagreed. Anyways it is subjective as you say.
 
From my experience I have to say install the new race balance shaft,after witnessing 5 dsm's with oil pump failure due to stubby shaft fault I installed AMS balance shaft in both of my dsm's just to be safe.What happens is that some people install their timing belt to tight putting pressure on the oil pump gear which creates the stress on the stubby shaft causing it to fail sending all the metal shaving through the rest of the engine.4 out of 5 engines were ruined that I have witnessed due to this reason,the one was caught early and it was saved.New race balance shaft looks similar to your new one and gives it support that it needs and its oil fed just like your stock one.I believe the ones from ams are balanced up to 11k Rpm too.Go way to spend money especially if you have lots of money wrapped up in your engine.

For what its worth I can second this statment after killing 3 oil pumps mysel.f I install a race shaft that I had a machine shop locally to turn for me and no problems since. Many say that the race shaft spin 2x as fast guess what the stub staft spins 3x if not 4x as fast being small in radius diameter. The thing to note is that the race shaft has no load on it like the rod and main bearings. therefore it can only fail if there is no oil in the pan to lubricate it. Its the way to go if you ask me:rolleyes:
 
Many say that the race shaft spin 2x as fast guess what the stub staft spins 3x if not 4x as fast being small in radius diameter.

The shaft speed of a race shaft is going to be the exact same as a stubby shaft. They're connected to the same thing.


I'm just curious how a race shaft is going to stop side-loading if it has no thrust surfaces. :hmm: I'm with TSIfreek, it's just something to sell.

You can get Mitsu stub shafts for $14, which Mitsu uses in multiple stock engines as well as their world class rally cars. Why would you spend $200 on some stock balance shaft that's been turned on a lathe?
 
The shaft speed of a race shaft is going to be the exact same as a stubby shaft. They're connected to the same thing.


I'm just curious how a race shaft is going to stop side-loading if it has no thrust surfaces. :hmm: I'm with TSIfreek, it's just something to sell.

You can get Mitsu stub shafts for $14, which Mitsu uses in multiple stock engines as well as their world class rally cars. Why would you spend $200 on some stock balance shaft that's been turned on a lathe?

Good point on the thrust loading!
 
The shaft speed of a race shaft is going to be the exact same as a stubby shaft. They're connected to the same thing.

Its smaller in radius which means its has more revolutions/min than the race shaft being that its larger at the bearing area, although they are connected to the same thing:cool:
 
I also prefer race shaft and I would never work on engine unless stubby shaft has been replaced with race shaft.Biggest reason to that is that I don't want to be responsible why your engine failed using stubby shaft.People I am trying to help you here,I witnessed this 5 times.I would hate to see you blow up your engine I would love to keep seeing dsm's on the road.All this big companies making these race shafts are doing it for the reason and its definitely not just something to sell.
They race these cars more than we do and I am sure they experienced these problems before.
 
Even if you use the race shaft, you need debur he oil pump gears to avoid cutting into the case. Only use the straight cut oil gears to avoid excessive side movement at high rpm. The tiny oil pump gears and stubby shaft are not the problem.

The problem is the big oil pump gears that is attach to the timing belt. This big gear is pivoted on the front and rear parts part of the oil pump case. Ideally, it is center perfectly between these two points and spin freely. In the case with a helical gears or tension from the timing belt, there is a lateral and twisting movement perpendicular to the axial movement. This case the gear teeth to angle toward the case. This cause the big gear to shave the case and send shaved aluminum directly not the big gear pivot parts of the gear. You are pretty much screw after this. The shaving can also be cause by the small oil pump gears but it is more like when you use a helical gears.

Mitsubishi and Hyundai actually make different versions of the big gear aside from the obvious helical and straight gear pattern. Some gears are perfectly flat from the teeth of the gears to the pivot shafts of the gears. Some gears are flat near the teeth and and raise up about .003-.001" from the roots of the teeth to shafts of the gears. This bump up I believe is to keep the big gear from cutting into the case when the gear angle toward the case. The two types of smaller gears do not have this step up.

It is extreme crucial that you debur the gears and use the straight cut gears. Even if you have the gears with step up, I recommend tossing them for the straight cut gears.

If you are building engine for people, you will save your reputation by charging to debur the gears. If your engine builder don't know or refuse to use the staight cut gears and debur the gears, run like hell. Your butt might be sore if you don't get that "it's a race engine warranty".


If you think what I am saying is bs and the trolls are ready to send me hate pm, there is simple test that you can do. Take your new oil pump gears and case parts and assemble the oil pump without the gears debur. Make ire you use your favorite oil. Spin the oil pump by hand and take it apart. Apply a little lateral for e like the force cause by the timing belt. Take the pump apart and examine the cases for any scratches. I will guess that you will have a scratched up case. Imagine this shaving action when the engine is on.

This is the step in the gears I am talking about.
See the ring after the roots of the teeth. Notice how the teeth are rounded out from the deburring process.

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Without the raised area on this straight cut big gear. However the straight cut big gear does come with the raised area.

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The small gear is debur too.
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This is what happen when your oil gears shaved the case. The little stubby shaft is seize in the case. The big gear did the same.

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When I debur these gears, I press each one against an old case very hard and spin it. If they do not shave or scratch the case then I am confident they are good to go. I only use wd40 for this test since it is a close to zero oil as possible. Hope my rant will help you guys out.
 
Last edited:
Thank you for the post,
I can see what you are saying but I am still not 100% sold on it.All the engines that I have built never came back after race shafts being installed.
You said that this is NOT stubby shaft problem and I believe otherwise.I believe that is caused by stubby shaft not being supported by anything and not being oil fed through the shaft,like the stock balance shaft or race shafts are.I do believe that shaving gears might help from rubbing into the case which I also witnessed but I believe that major problem lays in the stubby shaft.Thank you for your input,I will definitely add gear grinding to my list when doing next engine build.

Another thing is please stay away from aftermarket oil pumps/front cases I know they are much cheaper $90 versus $230 ,Aftermarket oil pump gears feel much more loose than Mitsu,it will work for a while but you'll be back doing it again and lets hope you didn't run it for too long and have pumped the shavings throughout your engine.
 
Its smaller in radius which means its has more revolutions/min than the race shaft being that its larger at the bearing area, although they are connected to the same thing:cool:

This is incorrect. Shaft speed (rpm) stays the same. Larger radius will however increase surface speed.

You may want a refresher course in basic physics, in this case.. dealing with angular qualities like tangential velocity and angular displacement.

[ame]http://youtu.be/9QDKnQm_poI[/ame]
 
Even if you use the race shaft, you need debur he oil pump gears to avoid cutting into the case. Only use the straight cut oil gears to avoid excessive side movement at high rpm. The tiny oil pump gears and stubby shaft are not the problem.

The problem is the big oil pump gears that is attach to the timing belt. This big gear is pivoted on the front and rear parts part of the oil pump case. Ideally, it is center perfectly between these two points and spin freely. In the case with a helical gears or tension from the timing belt, there is a lateral and twisting movement perpendicular to the axial movement. This case the gear teeth to angle toward the case. This cause the big gear to shave the case and send shaved aluminum directly not the big gear pivot parts of the gear. You are pretty much screw after this. The shaving can also be cause by the small oil pump gears but it is more like when you use a helical gears.

Mitsubishi and Hyundai actually make different versions of the big gear aside from the obvious helical and straight gear pattern. Some gears are perfectly flat from the teeth of the gears to the pivot shafts of the gears. Some gears are flat near the teeth and and raise up about .003-.001" from the roots of the teeth to shafts of the gears. This bump up I believe is to keep the big gear from cutting into the case when the gear angle toward the case. The two types of smaller gears do not have this step up.

It is extreme crucial that you debur the gears and use the straight cut gears. Even if you have the gears with step up, I recommend tossing them for the straight cut gears.

If you are building engine for people, you will save your reputation by charging to debur the gears. If your engine builder don't know or refuse to use the staight cut gears and debur the gears, run like hell. Your butt might be sore if you don't get that "it's a race engine warranty".


If you think what I am saying is bs and the trolls are ready to send me hate pm, there is simple test that you can do. Take your new oil pump gears and case parts and assemble the oil pump without the gears debur. Make ire you use your favorite oil. Spin the oil pump by hand and take it apart. Apply a little lateral for e like the force cause by the timing belt. Take the pump apart and examine the cases for any scratches. I will guess that you will have a scratched up case. Imagine this shaving action when the engine is on.

This is the step in the gears I am talking about.
See the ring after the roots of the teeth. Notice how the teeth are rounded out from the deburring process.

You must be logged in to view this image or video.


You must be logged in to view this image or video.



Without the raised area on this straight cut big gear. However the straight cut big gear does come with the raised area.

You must be logged in to view this image or video.


You must be logged in to view this image or video.



The small gear is debur too.
You must be logged in to view this image or video.


This is what happen when your oil gears shaved the case. The little stubby shaft is seize in the case. The big gear did the same.

You must be logged in to view this image or video.


You must be logged in to view this image or video.


When I debur these gears, I press each one against an old case very hard and spin it. If they do not shave or scratch the case then I am confident they are good to go. I only use wd40 for this test since it is a close to zero oil as possible. Hope my rant will help you guys out.
Do you have a pic of before and after ??? I for the life of me cant remember what a stock one looks like
 
Even if you use the race shaft, you need debur he oil pump gears to avoid cutting into the case. Only use the straight cut oil gears to avoid excessive side movement at high rpm. The tiny oil pump gears and stubby shaft are not the problem.

The problem is the big oil pump gears that is attach to the timing belt. This big gear is pivoted on the front and rear parts part of the oil pump case. Ideally, it is center perfectly between these two points and spin freely. In the case with a helical gears or tension from the timing belt, there is a lateral and twisting movement perpendicular to the axial movement. This case the gear teeth to angle toward the case. This cause the big gear to shave the case and send shaved aluminum directly not the big gear pivot parts of the gear. You are pretty much screw after this. The shaving can also be cause by the small oil pump gears but it is more like when you use a helical gears.

Mitsubishi and Hyundai actually make different versions of the big gear aside from the obvious helical and straight gear pattern. Some gears are perfectly flat from the teeth of the gears to the pivot shafts of the gears. Some gears are flat near the teeth and and raise up about .003-.001" from the roots of the teeth to shafts of the gears. This bump up I believe is to keep the big gear from cutting into the case when the gear angle toward the case. The two types of smaller gears do not have this step up.

It is extreme crucial that you debur the gears and use the straight cut gears. Even if you have the gears with step up, I recommend tossing them for the straight cut gears.

If you are building engine for people, you will save your reputation by charging to debur the gears. If your engine builder don't know or refuse to use the staight cut gears and debur the gears, run like hell. Your butt might be sore if you don't get that "it's a race engine warranty".


If you think what I am saying is bs and the trolls are ready to send me hate pm, there is simple test that you can do. Take your new oil pump gears and case parts and assemble the oil pump without the gears debur. Make ire you use your favorite oil. Spin the oil pump by hand and take it apart. Apply a little lateral for e like the force cause by the timing belt. Take the pump apart and examine the cases for any scratches. I will guess that you will have a scratched up case. Imagine this shaving action when the engine is on.

This is the step in the gears I am talking about.
See the ring after the roots of the teeth. Notice how the teeth are rounded out from the deburring process.

You must be logged in to view this image or video.


You must be logged in to view this image or video.



Without the raised area on this straight cut big gear. However the straight cut big gear does come with the raised area.

You must be logged in to view this image or video.


You must be logged in to view this image or video.



The small gear is debur too.
You must be logged in to view this image or video.


This is what happen when your oil gears shaved the case. The little stubby shaft is seize in the case. The big gear did the same.

You must be logged in to view this image or video.


You must be logged in to view this image or video.


When I debur these gears, I press each one against an old case very hard and spin it. If they do not shave or scratch the case then I am confident they are good to go. I only use wd40 for this test since it is a close to zero oil as possible. Hope my rant will help you guys out.

I disassembled my engine and found the same condition - circular scratches on my oil pump case from using angle-cut gears. Could that be why my number 1 rod bearings are almost trashed?? Can the gear sets be deburred by hand or is machine work and balancing required?
 
Last edited:
I disassembled my engine and found the same condition - circular scratches on my oil pump case from using angle-cut gears. Could that be why my number 1 rod bearings are almost trashed?? Can the gear sets be deburred by hand or is machine work and balancing required?
You will have some scaring in that area the thing you want to check is the inside where the gear inserts into the pump housing and see if its egged shaped! It will be hard to say if the pump caused the rod bearing to fail it could be the other way around.
 
You will have some scaring in that area the thing you want to check is the inside where the gear inserts into the pump housing and see if its egged shaped! It will be hard to say if the pump caused the rod bearing to fail it could be the other way around.

Thanks for the reply. I'm a returning member from a LONG time ago and couldn't shake the itch of having a 'somewhat' fast car.
I'm trying to evaluate my parts, how I can improve my next build, and what NOT to do again in the future. I've been away and didn't even know about a race balance shaft until recently. I used to rev my last build to 7000 RPM quite frequently and didn't really notice anything until around 23000 miles or so. I'll take pictures one of these days and let you see.
 
Take your pictures now, so we can all see the damage.
Here are the pictures of the oil pump gears, case, and an almost trashed #1 rod bearing. All other bearings had no deep grooves with only minor wear of the 1st later of material.
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Sorry -bump

Any good way to maybe clean this pump/case assy up? I'd like to reuse it over spending $400 for new parts.
 
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