BS belt removal

[JuGs]

Ok I had searched this and getting mixed agreements. I have heard of people just cutting the BS belt and leaving the shaft in. How safe is it really. The post I had read had several people that did it and has done it for years and never had a issue. Now what is the worst case senario if I just got rid of the belt. I k now about the more felt vibration but thats all I know of. Id like honest opinions and if you know people thats doine it or your doint it you self please state how long it been like that and how the motor is running.

 

[1995gstr]

Heres a link to some info I have the bs elimination kit in my car so no first hand experience. But after reading this I will be replacing the balance shaft belt on my girls car when I do the timing belt ahh how fun. Oh yea heres the link. http://www.dsmtuners.com/forums/new...-7-cutting-belts-remove.html?highlight=merged

 

[JuGs]

That is the exact post I had read.

 

[DSMopar]

Don't do it

 

[JuGs]

I dont think Im going to but I was wondering just in case. Some how my balance shaft belt got completlt stripped of all the teeth. The shaft still spins freely so Im stumped how it happened. I also had to get a new crank gear. Im hoping to have everything in the next week, but funds are extremly low and it was a just in case situation.

 

[JAXWHITE1G]

I would suggest you look deeper into why the belt stripped. I would bet your BS bearings are bad even if you say it turns freely. A bearing can seize when hot but free up after it cools down. If it seized again you may not be so lucky to just strip the teeth. It could break and fowl the timing belt. This needs to be taken care of before you start the car again. I'm quite sure the bearings are bad.

Mike

 

[krkline2gdsm]

Listen... ignore all advice you have heard. Forget everything you have read. I will sum it up here. DO NOT remove just the belt. You need to do other things to make it safe. If your teeth on the belt are stripped, figure out why they are stripped (siezed BS bearing, old belt, etc). If you drive around with no belt, the balance shaft is spinning at 2x the speed of your engine (5000rpm on tach means 10,000rpm on balance shaft). Each balance shaft has weights. The front shaft counters the rear one and the cancel each other out. With only 1 spinning, it will wobble, chew up the BS bearing and damage your oil pump. You dont want to know what happens after that.

Here is the deal. If your rear shaft is siezing up and stripping teeth off the belt, that would mean your oil pressure would fall flat at 0psi and you would have other bearing issues so I doubt its the rear shaft causing issues. So I am willing to bet either it was a bad belt to begin with that stripped out or your having front shaft issues.

Here is the cheapest fix and also the safest fix to do. What I do is remove all timing components. Drop oil pan, pick up tube, etc. Remove the front case. You leave the front balance shaft installed! This stays here. You could remove it and put in a new bearing turned to block the oil oil but forget that. Just leave the front shaft installed the way it is. This will not move ever and also it will block off the oil hole resulting tin the same method as a turned bearing. Next, take the rear balance shaft and bring it to your local machine shop. Have them cut all the weights off it. Usually they put it in a lathe and make it a straight rod. Reinstall the rear shaft and put everything back together of course with new timing belt, tensioner, idler, and water pump. Do not cheap out and skip any of that stuff.

Now alot of people put in a stub shaft in the rear balance shaft placement but then you get really high oil pressure. Modifying the rear shaft will help stabalize oil pressure and also will prevent premature oil pump failure that the stub shaft is known to do as the stub shaft doesnt support the oil pump drive gear where as my method of modifying the rear shaft, does.

Either way, its not a job for the average mechanic. You need to know what your doing here. Also if you take the modified rear shaft method, its a good idea to put in a new balance shaft bearing although its not needed as long as your bearing is good.

In the end, your timing belt setup should look like this:

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And before the haters jump in here flaming me for modifying my rear shaft, please educate yourselfs before doing so. AMS uses this style now in all there motors and I have been using this style for 2 years on my 6bolt no problems. Stubby shaft method does work but it does have its flaws.

Proof is in the pudding:

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[Colt4G63 also]

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I really like this. What did you pay to have that machined down like that?

 

[krkline2gdsm]

$0 but AMS sells a kit for $150 or something like that. I would assume your local machine shop would charge $50 to do it. They just need a lathe

 

[jrohner]

You can pretty much get rid of the balance shafts for free anyways with a little modification.

I think the AMS shaft is mostly a gimmick.

 

[krkline2gdsm]

You can pretty much get rid of the balance shafts for free anyways with a little modification.

I think the AMS shaft is mostly a gimmick.

How is it a gimmic? Its exactly what I said it was and does exactly what I said it does. They cut all the weights off the rear shaft and put it in a lathe resulting in being able to run a full rear shaft without the belt and front shaft to counter. Stabalizes oil pressure without porting porting oil filter housing and also doesnt cause premature oil pump failure from an unsupported stub shaft.

 

[jrohner]

How is it a gimmick? Its exactly what I said it was and does exactly what I said it does. They cut all the weights off the rear shaft and put it in a lathe resulting in being able to run a full rear shaft without the belt and front shaft to counter. Stabilizes oil pressure without porting porting oil filter housing and also doesnt cause premature oil pump failure from an unsupported stub shaft.

I'm think you just like to argue so I shouldn't even reply, but what the heck:

As in, that whole theory, as you just stated is to sell the gimmick. Even if they do believe in it, it still doesn't prove it really is necessary. Has anyone but AMS claimed there is an issue? Has even AMS physically seen the problem AND had real issues because of it? The next time I see Brent Rau, I'm going to try remember to ask him if he runs that or a normal stub shaft. If he doesn't need it, none of us do -- 1400whp, 11000+ rpms, yeah.

The biggest reliability issue with these engines, IMO, is the BS's, not just the belt but the bearings as well. They (the bearings) seem to like to die and destroy engines, so doing it AMS's way, potentially keeps part of that issue.

 

[krkline2gdsm]

I'm think you just like to argue so I shouldn't even reply, but what the heck:

As in, that whole theory, as you just stated is to sell the gimmick. Even if they do believe in it, it still doesn't prove it really is necessary. Has anyone but AMS claimed there is an issue? Has even AMS physically seen the problem AND had real issues because of it? The next time I see Brent Rau, I'm going to try remember to ask him if he runs that or a normal stub shaft. If he doesn't need it, none of us do -- 1400whp, 11000+ rpms, yeah.

The biggest reliability issue with these engines, IMO, is the BS's, not just the belt but the bearings as well. They (the bearings) seem to like to die and destroy engines, so doing it AMS's way, potentially keeps part of that issue.

Im not trying to sell a gimmick. Answer me this, how many failed full rear shafts have failed? 0 How many syb shaft have failed? Countless!!! Need pics for proof? If you think for one second that AMS are the only people claiming failure of the stub shaft, you live in a closet. There are countless cases of stub shaft failure. Usually what happens is the oil pump fails because the oil pump drive gear isnt supported. This digs a grove into your front base and causes failure. Its a known problem before AMS came out with there design. Why do you think they came out with it to begin with? And maybe you should search about porting the oil relief hole in the OFH. You must do this on a stub shaft. On a full rear shaft, you do not. Stabalizes oil pressure much better.

And your comparing apples to ornages. Brent Raus car is a race car. It doesnt ever get driven. It maybe driver 10 miles a year and thats all track time? In case you didnt notice, the stub shaft does fail over time, not in 10 miles. Again, apples to oranges. If your going to argue with me, atleast back it up with some real life examples. Some people have success with the stub shaft. But thats like rebuilding a 7bolt. Its hit or miss. Why not go with what works?

And your arguement about bearing failure is irrelavant. Do you know why the rear bearing of the shaft fails? Because people remove the belts or the belt snaps and then the bearing fails. In very rare cases, the rear bearing can fail but if you replace with a new one on a new shaft with no weights, your chances are much better of having a running driving car over the stub shaft.

End of story.

 

[TunaTalon]

Each balance shaft has weights. The front shaft counters the rear one and the cancel each other out. With only 1 spinning, it will wobble, chew up the BS bearing and damage your oil pump.

At the risk of being picky, the balance shafts rotate in opposite directions and cancel out each others horizontal imbalance. Their vertical imbalance forces add and the total vertical imbalance of the two shafts cancel out the vertical imbalance of the engine at two times RPM frequency.

The forces on the bearings of either balance shaft are not affected by the presence or absence of the other shaft. All imbalance forces are transmitted to the block through the bearings. That’s why the bearings wear our so fast; they are heavily loaded.

All else from your post is right on.

The biggest reliability issue with these engines, IMO, is the BS's, not just the belt but the bearings as well. They (the bearings) seem to like to die and destroy engines, so doing it AMS's way, potentially keeps part of that issue.

Yes the AMS style full length shaft without the eccentric weights still has a bearing in use; but without the imbalance loading from the weights the bearings will last much longer. The main bearings on my Talon were “like new” after 183,000 miles while the balance shaft bearings were in bad condition.

 

[krkline2gdsm]

At the risk of being picky, the balance shafts rotate in opposite directions and cancel out each others horizontal imbalance. Their vertical imbalance forces add and the total vertical imbalance of the two shafts cancel out the vertical imbalance of the engine at two times RPM frequency.

The forces on the bearings of either balance shaft are not affected by the presence or absence of the other shaft. All imbalance forces are transmitted to the block through the bearings. That’s why the bearings wear our so fast; they are heavily loaded.

All else from your post is right on.

Hmmmm I always understood it that with both balance shafts spinning they cancel out each other and balance themselves and also absorb the vibrations of the motor. I could be wrong but the way your putting it, I am 100% wrong about how they work. Doesnt change the fact about what I said and the reason for a full shaft. Could you explain a little more how they balance shafts work?

 

[TunaTalon]

Could you explain a little more how they balance shafts work?

My best effort at explaining the why and how of balance shafts is in the “HARMONIC BALANCE OF IN LINE FOURS” section of http://www.kidzuku.com/StrokeOrNot.pdf.

 

[JAXWHITE1G]

I have read of many stub shaft failures and agree that turning the weight off the balance shaft is the best possible solution and have done mine that way. The long shaft and 2nd bearing reduces the load on the front bearing

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I disagree with leaving the front shaft in place. If the bearings are worn there will be leakage around the shaft and lower oil pressure. While you have the front cover off I would remove the front shaft. It will have to be cut if the engine is in the car. You can drive out the old front bearings and turn them 90 degrees and reinstall them. Zero cost, just a little more work. Seal the hole in the front case with a bolt and nut.

 

[krkline2gdsm]

I disagree with leaving the front shaft in place. If the bearings are worn there will be leakage around the shaft and lower oil pressure. While you have the front cover off I would remove the front shaft. It will have to be cut if the engine is in the car. You can drive out the old front bearings and turn them 90 degrees and reinstall them. Zero cost, just a little more work. Seal the hole in the front case with a bolt and nut.

Correct me if I am wrong but in a car with both shafts installed and the belt, oil lubricates the bearing anyways and oil comes out of the oil hole to lubricate. By leaving front shaft in, the same thing is happening except shaft isnt turning so oil leaks around the shaft bearing and falls into the pan... no more than what normally would happen if both shafts and a belt were installed, correct?

I understand what your saying but I dont think a tiny oil hold leaking a little more oil out of it than normal is going to reduce oil pressure by anything more than 1psi.

Of course I did the job with motor installed and if I had the motor out, I would of done it the other way. But just trying to understand the way you are thinking

 

[JuGs]

In all honestly I have no clue why it stripped the teeth. I can spin the BS freely by hand so like stated could be bearing. Right now Ill be keeping all the BS in. Where I live I cant pull another motor and work on it so when I get to working again that will be on the to do list with all the other small odds and ends. Thanks alot for the very discriptive write up on keeping the BS and cutting the other one. Im getting a new BS and timing belt tomorrow or monday depending how things go.



All in all what would the estimate cost of getting a timing belt and the rear shaft cut?

 

[JAXWHITE1G]

Correct me if I am wrong but in a car with both shafts installed and the belt, oil lubricates the bearing anyways and oil comes out of the oil hole to lubricate. By leaving front shaft in, the same thing is happening except shaft isnt turning so oil leaks around the shaft bearing and falls into the pan... no more than what normally would happen if both shafts and a belt were installed, correct?

I understand what your saying but I dont think a tiny oil hold leaking a little more oil out of it than normal is going to reduce oil pressure by anything more than 1psi.

Of course I did the job with motor installed and if I had the motor out, I would of done it the other way. But just trying to understand the way you are thinking

There are 2 oil holes and with worn bearings there is a lot of clearance to leak oil by. With the shaft spinning it somewhat centers itself in the bearing floating on oil reducing the clearance by half. The non spinning shaft will settle on the bottom of the bearing and allow more space for oil to leak by. A new bearing won't loose much pressure with the shaft just sitting there but a worn bearing has the potential to leak a lot.

 

[jrohner]

I just don't think that it would offer much 'support', with how far away the bearing is from the oil pump. The only support it could offer is from the stub shaft 'cocking' in the hole; it can't really offer full side-to-side support. If you believe in it, that's just fine, I just don't care for the idea. Who knows maybe someday my opinion of it will change.

I like to leave the front BS in place without the belt on, and I just cut off the other one to make my own stub shaft and weld the oil hole shut. It costs $0, and I have not noticed oil pressure issues either too high or too low. I drive my car hard on the street with as much boost as this little E3-16G can hold and everything on my car takes a beating.