machined vs stub balance shaft elmin kit

[ZSpeed07]

well just like the topic sez. I just want opinions. AMS makes a good point about the required support to the oil pump but at the same time I know from my brother talking about it way back in the day everyone running the stub kit. I talked with a local guru and he told me to change to straight cut (1990) if i wanna run the stub but if i continue to run the helical gears that the machined one is better choice for me. I did search and found 1 short thread about the machined shaft aside from that the only thing I found was all about the stub. I also googled and didnt come up with much other then ams info about the oil pump needing the support

 

[DoyoFCT]

Honestly it would probably be cheaper to have your b-shaft machined yourself rather than buy the kit from AMS. I'm still not sure if I really believe the hype about the stub shaft causing problems. I think if you buy a brand new front case using the stub shaft is fine, but if you're re-using oil pump gears, and a front case with a lot of mileage on the b-shafts then I would consider machining the shaft or buying the AMS kit.

I haven't had any problems doing the elimination with the stub shaft, but every time i've done it with brand new oil pump gears/front case.

 

[ZSpeed07]

well im not 100% sure on what was all replace but I do know the motor was rebuild with less then 10k miles on it. only reason im doing the bse is cause theres something hitting my timing belt putting a groove in it. so i figured while doing a timing belt might as well do a bse

 

[Anger890]

My expierence is that the stub shaft does not support the driven oil pump gear. On one side the shaft goes out to a pulley and is supported by the t-belt, what keeps the other gear running true if there is not someting supporting it on its other end? It can and will deflect a certain amount as there is no force acting against it to prohibit the driven gear from tipping side to side.

When I dissasembled my 2.0 that used the turned down shaft, I found no wear on the oil pump case from where the gears could have contacted it. This was revving to 9,000 RPM reguarlly and 1 missed shift that went 10,500. Took apart a friends front case as it started making noise and found the case chewed up from the gears contacting it, he now runs the turned down shaft rather than the stub with no issues. Note, both cars were using new Mitsu front covers

Cost for getting a balance shaft turned down should be roughly 1 hours labor at your friendly local machine shop. Make sure when they are turning the shaft down they turn the weight off first, then cut the excess portion of the shaft off (past where the bearing is). Reason being is the stock shaft has a centering point already in it. Should cost $30-100 depending on the machine shops labor rate.

 

[DoyoFCT]

My expierence is that the stub shaft does not support the driven oil pump gear. On one side the shaft goes out to a pulley and is supported by the t-belt, what keeps the other gear running true if there is not someting supporting it on its other end? It can and will deflect a certain amount as there is no force acting against it to prohibit the driven gear from tipping side to side.

So your telling me that every 1.6L mirage is doomed to fail from the oil pump gear hitting the case? or maybe your telling me that there is a difference in the clearances vs. our front case? I really dont think either is true. This stub shaft is probably in other vehicles, but I figured i'd use the most common for reference. I just can't see them designing something that would fail in this manner.

When I dissasembled my 2.0 that used the turned down shaft, I found no wear on the oil pump case from where the gears could have contacted it. This was revving to 9,000 RPM reguarlly and 1 missed shift that went 10,500. Took apart a friends front case as it started making noise and found the case chewed up from the gears contacting it, he now runs the turned down shaft rather than the stub with no issues. Note, both cars were using new Mitsu front covers

There are other factors which can cause oil pump gear problems, so it would be a hard argument to specifically put blame on the stub shaft in my opinion. I have seen over tightened timing belts cause oil pump problems, I have also seen a oil sump gasket leak and cause the oil pump timing gear to slide into the case and cause all kinds of carnage.

I'm not saying your shaft does not work. I just don't believe it makes that much of a difference. I cant count how many people i know on hands and feet who use the stub shaft without any issues. So just be sure it's done right, and I bet the stub shaft/oil pump will out last your motor and/or car.

 

[Anger890]

So your telling me that every 1.6L mirage is doomed to fail from the oil pump gear hitting the case? or maybe your telling me that there is a difference in the clearances vs. our front case? I really dont think either is true. This stub shaft is probably in other vehicles, but I figured i'd use the most common for reference. I just can't see them designing something that would fail in this manner.



There are other factors which can cause oil pump gear problems, so it would be a hard argument to specifically put blame on the stub shaft in my opinion. I have seen over tightened timing belts cause oil pump problems, I have also seen a oil sump gasket leak and cause the oil pump timing gear to slide into the case and cause all kinds of carnage.

I'm not saying your shaft does not work. I just don't believe it makes that much of a difference. I cant count how many people i know on hands and feet who use the stub shaft without any issues. So just be sure it's done right, and I bet the stub shaft/oil pump will out last your motor and/or car.

I'm saying that by supporting the driven gear you reduce the likely hood that the gear will "walk" and contact the case. Also look at your application of the 1.6l mirage, how high are they taking them RPM wise? What kind of torque is the engine producing and transfering via the timing belt to other components ie oil pump drive gear. Not every one has issues with the stub shaft, however they are not completly trouble free.

On the engine that ate the oil pump case, I assembled both front covers and timmed both engines, belt tension was right on the money, (initally I suspected it was too tight)

It comes down to insurance, if you can for a marginal amount of moeny buy yourself added reliabilty why not? Does everyone you know get the flu? Do you still get a flu shot? Same concept.

And a further note, Mitsubishi obviously thought this was an important thing to consider as it was recommended by Mitsu to Archer Racing that they run the turn down shaft for added oil pump support in their road race cars (they raced SCAA from 1990-1996). Turns out Mitsu had been using this shaft for 3 years in their rally car efforts after they saw issues with the stub shaft and oil pump wear in their engines.

And for even more fun, you can machine the oil pump case to accept a bearing for even more support.

 

[knochgoon24]

only reason im doing the bse is cause theres something hitting my timing belt putting a groove in it.

Have you had the oil pan off recently? There's a bolt or two that is/are shorter than the others. The longer bolts will go in far enough to groove the timing belt.

 

[DoyoFCT]

I'm saying that by supporting the driven gear you reduce the likely hood that the gear will "walk" and contact the case. Also look at your application of the 1.6l mirage, how high are they taking them RPM wise? What kind of torque is the engine producing and transfering via the timing belt to other components ie oil pump drive gear. Not every one has issues with the stub shaft, however they are not completly trouble free.

On the engine that ate the oil pump case, I assembled both front covers and timmed both engines, belt tension was right on the money, (initally I suspected it was too tight)

It comes down to insurance, if you can for a marginal amount of moeny buy yourself added reliabilty why not? Does everyone you know get the flu? Do you still get a flu shot? Same concept.

And a further note, Mitsubishi obviously thought this was an important thing to consider as it was recommended by Mitsu to Archer Racing that they run the turn down shaft for added oil pump support in their road race cars (they raced SCAA from 1990-1996). Turns out Mitsu had been using this shaft for 3 years in their rally car efforts after they saw issues with the stub shaft and oil pump wear in their engines.

And for even more fun, you can machine the oil pump case to accept a bearing for even more support.

I guess in the end it's " to each their own" but I don't like the idea of a machined shaft left in the motor spinning 2x the speed and riding on a bearing that "could fail". So i'll stick to slight thrust wear on my oil pump cases, which you see in cars with balance shafts.

 

[DoyoFCT]

Have you had the oil pan off recently? There's a bolt or two that is/are shorter than the others. The longer bolts will go in far enough to groove the timing belt.

Ditto, check for long bolts in the oil pan. This is a very common issue on 4g63 motors I can't count how many i've seen like this. I suggest converting over to studs if you have the ability/need to. It's much easier to deal with compared to bolts, and usually ends up solving most oil pan gasket leak issues if sealed properly.

 

[Anger890]

I guess in the end it's " to each their own" but I don't like the idea of a machined shaft left in the motor spinning 2x the speed and riding on a bearing that "could fail". So i'll stick to slight thrust wear on my oil pump cases, which you see in cars with balance shafts.

I agree, it will come down to personal preference and what you feel comfortable with. As a rebuttle to riding on a bearing, I guess I would rather have the potential for a bearing failure rather than the gears deflecting eating into the case and then pumping aluminum contaminated oil throught the block causing wear/damage to my crank, rods and plugging the squirters and or introducing an abrassive to take a ride on the piston/cyl.

I will aslo third the reccomdation to the OP to check the length of the bolts installed on the T-belt side as the others have suggested.

 

[ZSpeed07]

Have you had the oil pan off recently? There's a bolt or two that is/are shorter than the others. The longer bolts will go in far enough to groove the timing belt.

Ditto, check for long bolts in the oil pan. This is a very common issue on 4g63 motors I can't count how many i've seen like this. I suggest converting over to studs if you have the ability/need to. It's much easier to deal with compared to bolts, and usually ends up solving most oil pan gasket leak issues if sealed properly.

I personally havent had the pan off but the person that rebuilt the motor probably over looked that fact and put 2 longer bolts in. I did order a new bolt kit from STM cause I didnt relise they had studs available. Had I known that I would of gotten studs.

but thanks for all the input. I'm going to give AMS a call and order there machined shaft.

thanks for all the input you guys have given cause im sure theres others that wondered about this besides myself that are new to dsm's

 

[lacroixdp]

On the early DSM's this isn't an issue whatsoever. The early 1G engines have oil pump gears that are straight cut - oil pumps with this feature are the most resilient from my experience. The machined shaft is simply not necessary with these earlier oil pumps. The only time I could ever imagine this being an issue is with the later model DSM's with helical cut gears in the oil pump. Even then, there's plenty of people running stub shafts with no issues whatsoever. By running the stub shaft, you are eliminating one more bearing that could possibly wear in your engine.

 

[Anger890]

On the early DSM's this isn't an issue whatsoever. The early 1G engines have oil pump gears that are straight cut - oil pumps with this feature are the most resilient from my experience. The machined shaft is simply not necessary with these earlier oil pumps. The only time I could ever imagine this being an issue is with the later model DSM's with helical cut gears in the oil pump. Even then, there's plenty of people running stub shafts with no issues whatsoever. By running the stub shaft, you are eliminating one more bearing that could possibly wear in your engine.

The engine that ate a case with the stub shaft was using 1990 straight cut gears in a new OEM front case. You are correct in saying you are running 1 less bearing in the engine, but on the other hand the gears deflecting inside the oil pump introduces a point of failure/contamination not formerly present inside your engines oil pump.

My opinion of the stub shaft is kind of like smoking, not everyone who smokes gets cancer, but those that do wish they had never lit up. I think there are not as many stub shaft failures talked about for a few reasons.

1. RPM, I don't think most people take the engines up over 8K out of fear, most failures are high RPM, many might write it off to running high RPM and never get to the root issue.

2. There is always something else to blame, timing belt tension, oil pump priming, oil pressure, etc.

3. Herd Mentality, its worked for everyone else, it can't be my problem. Has anyone ever taken a front cover with the oil pump gear attached and applied pressure to 1 side of the gear? Nobody measures this type of stuff, so we go with what has been done in the past.

 

[ZSpeed07]

well on that thought im planning to build a 2.3 stroker motor when the time comes just from the fact of high rpm revving scares me

 

[Mr PopUps]

Ditto, check for long bolts in the oil pan. This is a very common issue on 4g63 motors I can't count how many i've seen like this. I suggest converting over to studs if you have the ability/need to. It's much easier to deal with compared to bolts, and usually ends up solving most oil pan gasket leak issues if sealed properly.

We dont use oil pan gaskets....

 

[ZSpeed07]

We dont use oil pan gaskets....

odd... I just bought one from local parts store

 

[My1GLaser]

odd... I just bought one from local parts store

Well don't use it. Use Ultra Grey RTV and follow the directions in the FSM. Some have probably had good luck with the gasket and others haven't...similar to the whole stub shaft issue.

 

[DSM98GSX]

Ill agree with "to each his own". I currently have a stub with no issues in either a 6 or 7 bolt. Each has the pros and cons, its up to you to decide which one outweighs the other. As for the oil pan gasket, I dont run one either, PITA. So good luck with your decision, take what everyone has said and you decide.

 

[ZSpeed07]

Well don't use it. Use Ultra Grey RTV and follow the directions in the FSM. Some have probably had good luck with the gasket and others haven't...similar to the whole stub shaft issue.

ahh ok well I will just take it back then. where are these directions that you speak of. Im still new to this forum so I dont know where everything is yet.

 

[My1GLaser]

Factory Service Manual. I believe if you search you can find it on the forum somewhere, but I'm not positive. PM me your email addy, and I can email you just the engine manual section, which is 3.57mb. The whole service manual cd is 722mb.

 

[ZSpeed07]

I pm'ed you my email... I was thinking... since I'm going to do the machined balance shaft should I still replace the bearings or would it be safe to leave them? Just curious incase I have trouble getting the bearings out.

 

[My1GLaser]

They are tricky to get out, but getting them back in without damage is the key.

As far as if you should replace them or not, I really don't know. I guess it depends on how they look, and what you have to install the new ones with.

I replaced mine, but they were just block-off bearings. I wouldn't feel comfortable driving them in the way I did with a screwdriver and hammer if the BS was going to be spinning inside it.

 

[ZSpeed07]

well I got bearing race drivers and stuff of that nature. I guess I will just have to wait and see once I get the new stuff and tear it down and see how the old ones are

 

[dsmfa9nutter]

Take balance shaft out, turn it around, put it in straight, tap it STRAIGHT and the bearing pops out, rotate it, tap bearing back into hole STRAIGHT. That easy. Just did this to a friends engine (and mine a year ago). All you have to buy is the stub shaft.

 

[donniekak]

When i do a bse i tap the oil pump shaft for a longer bolt and run it past thebearing journal and loctite it. Free stubby shaft. I usually don't remove the front shaft either, just the belt. This way i don't have crazy high oil pressure.