Is balance shaft delete worth it?

[Thecarfixerguy]

I’m getting ready to build my engine. I did some reading and I’m getting conflicting reports if balance delete is needed or not. I understand the concept of how it leaves more oil available for bearings, reduces moving parts, etc…

1) how much of a difference does it make as far as engine vibrations? Those of you who deleted, do you notice? More importantly will your wife notice? We both want to drive the car.

2) How much oil do you need? If stock oil pump is clean and healthy what is going to cause it to need more oil on a performance build?

3) With new Kevlar belts and good components do you really need to worry about the balance belt breaking?

As always, thanks in advance

 

[1990TSIAWDTALON]

You will notice more "buzzing/vibration" when you remove them. I have 2 cars that have them removed and one that still has them in it. The one with the shafts still in it is relatively quiet but the other 2 have more car vibrations.
Here is a good read to help you think about the issue.........

Jacks Transmissions

Jacks Transmissions is not only a top quality transmission rebuild company, but we also offer sales of transmission parts and have a fully operational general service center for automotive repairs.

jackstransmissions.com

 

[97egl]

If you want it for a daily or regular street car I would recommend keeping them.

1) The car does vibrate more. It really depends on how soft your mounts are as to how much will be noticed but at idle and cruising on the high seems to be the worst. How much your wife notices or cares depends on what type of person she it and what the car is being used for. My wife likes to drive my old beat up 1982 F150 4x4 wood truck to work sometimes just for the fun of driving an old truck and that thing vibrates and is loud. If she's driving some distance she will take her newer car with AC that doesn't vibrate.

2) You don't really need more oil. When you delete the balance shaft normally you have to port the OFH or shim the bolt to bring the pressure down. The only time you wouldn't is if you are running extra clearance bearings usually used on a race only application. Sounds like your goal is just a street car so you should have plenty of oil.

3)With a new belt I would not worry at all about the balance shaft belt. Normally I have seen the main belt go and the balance shaft belt is still fine. The only broken balance belt I have seen myself was very old and it broke and got caught in the timing belt and caused it to jump time. The Main belt appeared to be very new so someone did just the main belt and not the balance shaft belt. Others may have different experiences but I wouldn't worry about it at all if you replace everything.

 

[babyviper]

It's a common failure point, to me, it's not worth the risk. Balance belt often fails before timing belt. Balance bearings can fail and put metal shavings through your engine.

 

[slugsgomoo]

You will notice more "buzzing/vibration" when you remove them. I have 2 cars that have them removed and one that still has them in it. The one with the shafts still in it is relatively quiet but the other 2 have more car vibrations.
Here is a good read to help you think about the issue.........

Jacks Transmissions

Jacks Transmissions is not only a top quality transmission rebuild company, but we also offer sales of transmission parts and have a fully operational general service center for automotive repairs.

jackstransmissions.com

Honestly, that article still being up is infuriating since it's got so much wrong information.

I hate to link to Talk, but hey, here's a post where someone thoroughly debunks it, and scrolling up the thread, you can see Jack admit that there are many technical errors in it: Keep your balance shafts post #55

here's a post I wrote on the Galant boards in 2014:

it's the one place that I will categorically say that Jack's is wrong, and I think they're great otherwise.

Fact: Mitsubishi built dozens of 4gxx motors that came from the factory without balance shafts. If the motor can't live without them, wouldn't Mitsubishi's engineers be able to figure that out? Let's assume that some of them have a Masters in Mechanical Engineering (or better) and have an idea how torsional & harmonic damping work

Fact: The documentation from Mitsubishi says that the shafts are there to increase occupant comfort by reducing felt vibration from ~3-5k RPM. Felt vibration means your ass is happy, it has nothing to do with the mechanicals.

Fact: Even if replaced regularly, the balance shaft belt is very small, and spins a very heavy weight.

Fact: If you start pushing past factory 7,500rpm limit with balance shafts, you're a moron

Fact: for every revolution the crankshaft makes, the balance shaft makes two. This means that at the pedestrian limiter of 7,500, your balance shaft is spinning 15,000 RPM. If you push out to 8500, it goes to 17,000. I'm spinning to 9,500 RPM, or 19,000 RPM on a balance shaft, on a belt about the size of a power steering belt. This teeny belt has the ability to catastrophically self destruct, taking out very expensive engine parts.

I didn't have clutch drag with an ACT2600 in 2005 with a stock motor, or with a built 9:1 motor with no balance shafts (Same clutch, same shitty transmission). I don't have clutch drag now with a twin disk, aluminum rod motor, and no balance shafts.


Also has some decent insight here click posts 6 & 7 seem relevant, but the whole thread, and jack's replies are worth reading.

I should add as a further case in point, the 4G61 does not have balance shafts from the factory. In fact, the proper parts to use for a BS delete come from Mitsubishi's parts catalog as OEM parts for the 4G61...

Realistically, this was ancient news when I got into DSM's in 2002...

vfaq - balance shafts


All that said, I would not run a non-SFI rated flywheel on anything I was beating on, especially at a higher rev limit. I ran a Fidanza in my 1g vs the ACT because supposedly the steel insert is less "slippery" than the chromoly ACT uses. The nice thing for me about the fidanza is that the replacement surface is $60, compared to a new ACT, or even resurfacing that's not a terrible deal. I've got ~35k on the one in my 1g, I did replace the surface when I put a new clutch in (even though it wasn't necessary, cheap insurance to me).

I think that keeping some weight is a plus, the ACT is a bit heavier than the Fidanza and may be a bit more fun to drive on the street. That said, I don't have any problem with the fidanza (clutch is CM FX-400 sprung six puck) and it's light years easier than the twin (though that motor also has steel rods...).

It's sad that a good shop has such an unhelpful article, especially after so much time. The truth is the engineers at Mitsubishi who designed the Sirius platform and then built millions of these engines without balance shafts would not have done so if it was a bad idea long term because the part was designed and very cheap, so risking warranty failures would be stupid.

Cliffs: Balance shafts are good for two things, removing felt vibration ~4500RPM, and snapping a belt, and taking out your valves/pistons.

 

[randman2011]

I'll say the same thing I say every time this question comes up. If you're keeping the factory engine mounts, toss the balance shafts. I wouldn't go out of my way to remove them, but since you'll already have the engine apart, there's no reason not to.

If you have or are upgrading to stiffer mounts, keep the shafts in a street car. I had a Talon where all of the mirrors were completely unusable due to the chassis vibrations. Switching from the stiff aftermarket mounts that came in the car back to the stock mounts fixed the problem. My current GSX has stock mounts except for a Prothane/Energy upper mount, and the extra vibration is very noticeable whereas before the mount change I didn't see an increase when I deleted the shafts.

 

[Sirius1995]

If you keep up maintenance on your car and build it properly (for street use) I would keep them for more comfortable drive, I did it re install BS's on mine after rebuild, but if you don't mind cons of BS delete at least it's one less thing to fail in your engine

 

[chrysler kid]

Every time I have to deal with a car that has had the balance shaft deleted, there is oil spewing from the main case of the oil pump to the block, you know that huge piece across the front of the motor. The increased oil pressure seems to find its ways to leak out of the motor

I dont recomend it. Unless you are the guy, and you are him, it creates more problems than it solves. If youre the guy with the race car that tears it down on your own, sure to for it. But deleting it isnt fixing any problems.

 

[gofer]

While I'm not agreeing/disagreeing (no way am I qualified to discuss engine harmonics/dynamics) I do want to pop in and say that there's a lot being left unsaid, everything should be taken into account. @Thecarfixerguy said he's getting ready to build his engine, we don't even know what engine he's building and for what car. Porsche 944's run Mitsu silent shafts, maybe he's building a 2.5l for a 944? @Thecarfixerguy, when you get a chance, create a profile for your car so when you post we don't have to make any assumptions.

Just because installing a BSEK works for 99% of the community and nobody reports issues it doesn't mean that there aren't unintended consequences that people don't initially perceive as the BS's being deleted as the cause. Here's an example of this and it has nothing to do with ride comfort and vibration and hopefully those that have a BSEK installed don't go "F*CK" when you read through the stuff below...

- 2g oil pump straight cut or helical gears​

- Two front cases, two blown oil pumps. Has ANYONE ever seen this before?​

These issues aren't necessary because the balance shafts were deleted, they were a result of how they BS's were deleted. So, OP, if you decide to delete your BS's take the advice in threads above about running the Mitsubishi BSEK and straight cut gears in your oil pump which, from what I understand, maybe hard to find.

I also recommend reading "To Stroke or Not to Stroke". Unfortunately, I can't link directly to pages but if you're not into reading a 60 page technical document and just want to understand engine balance and harmonics then you can get a good idea by just reading pages 22-25 & 41-43.

 

[CrackedDSM]

If you use a BSEK, make sure the shaft included has a groove cut out on it, that's a common point of failure for aftermarket/non-OEM BSEKs. If you just cut the shaft, be sure to either use a longer bolt for the head/oil pump gear portion of the remaining shaft that blocks the hole, or have the end of the shaft welded.


Legitimately every DSM that I have been a part of, either my own, or that I've rebuilt for friends/acquaintances has had the balance shafts removed. A lot of them being the old fashioned "just cut the shaft and use a longer bolt" method. Want to know two things to make sure they last and don't leak or have issues?


1) Either port the relief valve in the OFH, or use the oil relief valve spring from a Mirage/4G61 that comes without BS' from the factory. Oil pressure is perfect in all the engines I've PERSONALLY done this to, and all of them lasted longer than their setups, owners, cars, and none of them failed due to anything but a bunch of knock/tune failure or just too high horsepower for the piston/rod setup.

2) Please make sure the BS bearings are flipped 180* so the holes are blocked off. Do not use RTV, do not use silicone, do not use JB Weld. Just flip the bearings. Use the shaft you just pulled out of the other side, turn it around, and it knocks them right out. Easy peasy.



Long story short, is it worth it? Yes. From every perspective. Maintenance, power production, etc. People claim it makes the vibrations more noticeable but on anything other than cars with Prothane/solid mounts, I honestly didn't notice a thing. I will continue to do this all all future 4G63's I'm a part of as well. One of the best bang for buck mods for longevity, and power IMO that you can do for either free, or REALLY inexpensively. One of my favorite examples was a 6 bolt block rebuilt with 2G pistons, 1G Rods, ARP rod bolts, "cut the shafts" BSEK, and even had royal purple run in it for 60,000 miles that I had it. Guy who bought it off of me still has it to this day, and has put another 66,000+ miles on it with no issues. I still have pictures of it somewhere when he sent me pics of it with the pan dropped when he was just checking it to make sure everything was good. It looked new still. Nothing was that brown/oil color, it was all still black and silver/gray.


And for the record, I have legitimately never...not a single time had any engine that after I rebuilt it, had a leaky front case because of a BSE done. That sounds like 150% user error. Sealing the front pump isn't rocket science. There's a plug you have to block off with a freeze plug, and a hole that needs to be blocked off as well. The hole mentioned here, you can legitimately just bolt the BS pulley on the case and bam. No leaks. If you fail to do either of these two things, oil will spread its love all over the front case.

 

[Tina94]

I know substantially less than everyone else commenting here. But I will say that I’m doing my t belt right now, finishing it up tonight actually, and have opted to keep the balance stuff.

I trawled through probably 50 threads on this site and others dating from over the last 10-15 years looking for people’s experiences after deleting and looking for advice whether to delete or not.

The general consensus seemed to be:
Cruiser/daily/street car under 350, maybe 400 hp, keep it

Serious street car or autocross/drag/track build, delete it

Not sure how reputable any of the info is, but I read through a LOT of threads.

Edit: I should say I was immediately turned off by any mention of increased vibration. My camaros rum subframe connectors, poly bushings, and really stiff suspensions. And my big diesel rides like, well, a big diesel. So I wanted this to be a really pleasurable, smooth drive, especially with its (by my standards) plush interior and soft suspension. So maybe I was looking for the answer I wanted to hear.

 

[chrysler kid]

If you use a BSEK, make sure the shaft included has a groove cut out on it, that's a common point of failure for aftermarket/non-OEM BSEKs. If you just cut the shaft, be sure to either use a longer bolt for the head/oil pump gear portion of the remaining shaft that blocks the hole, or have the end of the shaft welded.


Legitimately every DSM that I have been a part of, either my own, or that I've rebuilt for friends/acquaintances has had the balance shafts removed. A lot of them being the old fashioned "just cut the shaft and use a longer bolt" method. Want to know two things to make sure they last and don't leak or have issues?


1) Either port the relief valve in the OFH, or use the oil relief valve spring from a Mirage/4G61 that comes without BS' from the factory. Oil pressure is perfect in all the engines I've PERSONALLY done this to, and all of them lasted longer than their setups, owners, cars, and none of them failed due to anything but a bunch of knock/tune failure or just too high horsepower for the piston/rod setup.

2) Please make sure the BS bearings are flipped 180* so the holes are blocked off. Do not use RTV, do not use silicone, do not use JB Weld. Just flip the bearings. Use the shaft you just pulled out of the other side, turn it around, and it knocks them right out. Easy peasy.



Long story short, is it worth it? Yes. From every perspective. Maintenance, power production, etc. People claim it makes the vibrations more noticeable but on anything other than cars with Prothane/solid mounts, I honestly didn't notice a thing. I will continue to do this all all future 4G63's I'm a part of as well. One of the best bang for buck mods for longevity, and power IMO that you can do for either free, or REALLY inexpensively. One of my favorite examples was a 6 bolt block rebuilt with 2G pistons, 1G Rods, ARP rod bolts, "cut the shafts" BSEK, and even had royal purple run in it for 60,000 miles that I had it. Guy who bought it off of me still has it to this day, and has put another 66,000+ miles on it with no issues. I still have pictures of it somewhere when he sent me pics of it with the pan dropped when he was just checking it to make sure everything was good. It looked new still. Nothing was that brown/oil color, it was all still black and silver/gray.


And for the record, I have legitimately never...not a single time had any engine that after I rebuilt it, had a leaky front case because of a BSE done. That sounds like 150% user error. Sealing the front pump isn't rocket science. There's a plug you have to block off with a freeze plug, and a hole that needs to be blocked off as well. The hole mentioned here, you can legitimately just bolt the BS pulley on the case and bam. No leaks. If you fail to do either of these two things, oil will spread its love all over the front case.

thats because youre "him" . Youre the dude who does it right. I would forsure pay you to do it


Lets ask a general question if youre on the fence about the delete kit, if the added vibration caused your sunroof cover to rattle lightly at the stoplight, would that annoy you enough that your regret the delete? Would your wife be ok with the rear cargo tray rattling while trying to have a conversation with her in the car?

I probably have seen the worst ones done though, there were quite a few shady performance shops back in the day doing these deletes on stock cars

 

[1990TSIAWDTALON]

The prothane/non-stock motor mounts DO have A LOT to do with feeling ANY engine. Tina, you seem to have a nice variety of vehicles and I tend to agree with what you experience. Our Camaros have subframe connectors/solid or welded mounts etc and they vibrate like, well, a race car. When DSM owners, even me, delete those shafts, we are looking for the Max HP without having to worry about the extra belt. I run a racing balance shaft belt on the 90 GSX that is mostly stock. The other 2 have prothane mounts and are stiff everywhere so maybe most posts about the increase of vibration is because more than just the shafts were taken out. I don't RIP the GSX. I DO rip the other 2 and they dont have shafts so I don't worry about the belt at 9k+.
I like the car with BS's still in it for a good daily fun car tho, to the OP.

 

[Dericsh]

My balance shaft bearing failure. There are several others I’ve seen in build threads that failed similarly. Was it low on oil? Over revved? I’m not sure, I bought it this way 3 years ago and it’s still broken.

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[enriquez2000]

Tons of answers here so my experience..

1. No extra vibration until I swapped to torque solutions mounts. Now it feels well.... like a muscle car

1a. I recently had my oil squirters back out(2 dropped out, 1 loose and 1 tight) vibration was probably part of the culprit however if they had been installed with new lock washers and loctite it would have been fine.. lesson learned to not have someone help me put things together next time

2. I ported my OFH and had oil pressure of 30psi at idle

3. I had no oil leaks other than a crack in my valve cover

I daily drove mine for a while until I decided to pull it down and get my auto trans beefed up to handle more power and boost but I still enjoy a spirited cruise here and there.

 

[Thecarfixerguy]

Great replies everybody. Thanks! With all the different input I’m still just as on the fence as before though . It’s a street build looking for up to 400HP, but I want my block all set up in case I decide to go bigger in the future. I don’t want to pull the block out again for future desires. I’d rather have it done once done right. I’m hoping to make my decisions soon. I’m tearing Down the running block I have for inspection this weekend and then ordering parts soon. I’ll be asking more questions I’m sure.

 

[babyviper]

This is due to you running an oil pan gasket and not RTV

My balance shaft bearing failure. There are several others I’ve seen in build threads that failed similarly. Was it low on oil? Over revved? I’m not sure, I bought it this way 3 years ago and it’s still broken.

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But, to be honest, I have seen this failure many times. Hence the reason I don't think it is worth it to run them. There is also a third option, you can run the race shaft to provide support better than the stubby shaft.

GSC Power-Division Race Balance Shaft for all 4G63 Evo's and DSM > Evolution 4-8 (4G63) Build Components > GSC Power Division: Performance Camshafts and Valvetrain

Mitsu 4G63t DSM/EVO1-9

www.power-division.com

 

[gofer]

But, to be honest, I have seen this failure many times. Hence the reason I don't think it is worth it to run them. There is also a third option, you can run the race shaft to provide support better than the stubby shaft.

GSC Power-Division Race Balance Shaft for all 4G63 Evo's and DSM > Evolution 4-8 (4G63) Build Components > GSC Power Division: Performance Camshafts and Valvetrain

Mitsu 4G63t DSM/EVO1-9

www.power-division.com

I'm not sure how much the OP picked up from the links I posted about running the straight cut gears if you do a BSEK but, if that was missed... I've seen a few posts lately about the straight cut gears being obsolete/discontinued so, if you can't find them, running the race shaft is the recommended route if you're running helical gears like @babyviper linked to above to prevent side loading.

@Thecarfixerguy you never gave any details about your build like I asked but, if you read the "To Stroke or Not to Stroke" document about harmonics of a stroker engine I wouldn't recommend deleting your BS's at all. If it's a 2.0 then it's 50/50... Most of the reputable engine builders that build 2.3 short blocks won't build them w/o the BS's.

 

[MattHDSM]

...but, if you read the "To Stroke or Not to Stroke" document about harmonics of a stroker engine I wouldn't recommend deleting your BS's at all. If it's a 2.0 then it's 50/50...

I did read this document, thought it was very interesting. I did end up deleting my balance shafts, but still have factory bore/stroke. I ended up getting a fluidampr in the hopes that any harmonics that those balance shafts were helping with, that the fluidampr could potentially pick up some of the slack that the balance shafts used to handle. I haven't noticed any increased vibrations, and oil reports are showing normal wear levels. I am not pushing crazy power though so maybe that's why.

I have no evidence to back it up, but I think a fluidampr or an ATI damper is probably a smart upgrade to have if you delete balance shafts. At best, they absorb some harmonics of the lost balance shafts, and at worst they do nothing for harmonics, but at least they won't separate like the factory damper might eventually do.

 

[jesse12345]

I did my first delete of the balance shafts, and I've had zero issues. Oil pressure is a little high when cold but no oil leakage. I to bought an extra engine off of a guy and the bs bearing was in the pan, so that's why I eliminated them.

 

[1990TSIAWDTALON]

Really guys, if we are that worried, I think a professional internal balance would be beneficial when deleting the shafts. One of my rotating assemblies is and it wasn't expensive (but it seems like everything about these little hobby cars IS).
I think my shop charged me about the same as when they did some of my SBCs, around $400.
Just some thoughts.

 

[Dericsh]

This is due to you running an oil pan gasket and not RTV


But, to be honest, I have seen this failure many times. Hence the reason I don't think it is worth it to run them. There is also a third option, you can run the race shaft to provide support better than the stubby shaft.

GSC Power-Division Race Balance Shaft for all 4G63 Evo's and DSM > Evolution 4-8 (4G63) Build Components > GSC Power Division: Performance Camshafts and Valvetrain

Mitsu 4G63t DSM/EVO1-9

www.power-division.com

That thing was like plastic it was so old, broke off in chunks!

 

[Thecarfixerguy]

.

@Thecarfixerguy you never gave any details about your build like I asked but, if you read the "To Stroke or Not to Stroke" document about harmonics of a stroker engine I wouldn't recommend deleting your BS's at all. If it's a 2.0 then it's 50/50... Most of the reputable engine builders that build 2.3 short blocks won't build them w/o the BS's.

I thought I had my car built in my profile. I’ll look in to that. It’s 2G DSM. Building for street use ~400HP. Just getting started. I bought the car with a stock engine out of it so I’m building it up before it goes in. If there’s any merit to better harmonic balancers helping with vibrations I’ll definitely look in to that. My biggest concern about vibrations is if it will make the car uncomfortable if we take it on longer trips or drives, like a few hours.

 

[enriquez2000]

I thought I had my car built in my profile. I’ll look in to that. It’s 2G DSM. Building for street use ~400HP. Just getting started. I bought the car with a stock engine out of it so I’m building it up before it goes in. If there’s any merit to better harmonic balancers helping with vibrations I’ll definitely look in to that. My biggest concern about vibrations is if it will make the car uncomfortable if we take it on longer trips or drives, like a few hours.

How do you feel riding in an old muscle car?

With poly/solid mounts and BSE thats what it reminds me of. Personally I love it... but everyone has their preferences.

 

[babyviper]

In the late 90's to early 2000's cars weren't running that smooth compared to now. Compared to most economy cars I owned back then I couldn't tell much of a difference. Especially after the turbo-back exhaust, cams and motor mounts. Unless you plan on keeping the factory motor mounts, stock cams and installing a super quiet exhaust, I can't imagine you'd notice it either.