Robby

Allright- I know this subject has come up before, but, I just did a search, and didn't come up w/anyhthing- at any rate, I'm hoping that there will be a little more up to date info on this subject...

My question- I'm considering deleting the balance shafts when I rebuild my engine- Any input on this subject would be greatly appreciated. Especially from those of you who have actually done so or have had some sort of experience w/cars that have had them deleted...


Thanks a lot,

tkacki

Hi,

Many people consider delete balance shafts. It sounds reasonable - more power and vibrations after detaching balance shaft belt are not noticeable.

It sounds like a good idea, but there is a bottom.

Many people form Poland, where I live suffered from improper setting of balance shaft or skipping the belt at all. Problem: Oil suction pipe located in oil pan was broken due to vibrations - oil pressure loss during the ride. Very painful consequences.

Robby

Thanks for that input- I'll look into that... Do you think it could have ANYthing to do w/the weather- maybe extreme cold? I ask b/c you said Poland...

Thanks,

tkacki

Hi,

Don't think it is weather related. Here winters are cold and summers hot. In case of my friend, who skipped balance shaft belt, oil suction pipe just broke above the oil level (near the place it is attached to block) and air was sucked by oil pump instead of oil.It has happened about 20k km after removing of the belt. Fortunately he finished with single rod bearing replacement. Now he uses the belt back.

But... we are not 100% sure that broken pipe is balance shaft related. However, it could be. That problem was reported by other users and mechanics as a common and related to improper balance shaft setting.

Regards,

Robby

That's interesting- I'm curious though- you said he didn't use the belt- does this mean that he simply did NOT use the belt OR that he completely deleted the balance shafts altogehter? I'm wondering then, if you have the balance shafts adjusted incorrectly, I would assume it COULD screw something up, but not sure about removing them altogehter- the whole reason for this thread, of course... Most of the stuff I've heard about deleting it is that the harmonic distortion is increased, etc, not about engine failuers- Scott told me that I should remove the belt right before I do the rebuild, to see how it feels- he says I wont notice a BIT of difference- Of course, he did NOT say to remove the belt & drive it for several months or anything- I think he just meant to drive the car for a few MINUTES, RIGHT before I drop the car off at the shop to start removing hte engine- just long enough to see if I notice any new vibrations, etc...

tkacki

Robby,

He just removed the belt and balance shafts were still on engine (they act as a balast). I don't think any differecne exists between removing shafts and only removing the belt (except the weight of the engine).

Robby

Okay- then is it possible to still have the belt connected & have something go wrong in there so the shafts get unbalanced & THEN cause probs? I've been looking over parts lists a lot lately & have seen balanced shaft tensioners, rollers, etc- I KNOW the timing belt has these items, but, if the balance shaft does too, then I would think something could possibly happen to mess things up IF the rollerr's stuck OR IF the tension changed, etc... BUT, I really don't know the first thing about all that...

Hasn't anybody out there ever removed the shafts &/or know more about this? I KNOW several people on the board have removed them- maybe it's still too early... :-)

josephsc

For what it's worth, David Floyd mentioned in the earlier thread that he had an SFR rebuilt engine w/o balance shafts -- maybe send him a PM?

https://rennlist.com/forums/showthre...9&pagenumber=2

SoCal Driver

Robby,

Remove the covers and remove the balance belt and drive the car.

You will not get far before you put the balance belt back on.

M758

Things can break without the balance shaft belt turning the shafts. I have not personally seen it happen, but I have seen Dyno results both with and without. The hp change was so small (3hp) that it does not seem smart to risk the engine even in race car for 3 measly hp.

David Floyd

Hey Robby,

10K miles on my engine with no balance shafts, but the engine was built with the delete in mind, knifed crank, lightened flywheel and balanced, car is smooth as stock.

Now just removing the belts or deleting the shafts without crank and flywheel work, don't think I would do that

Robby

Joe- that's wierd- I honestly tried a search & came up empty handed- I threw the word "balance shaft" in there too(?). Anyway, thanks for the link...

David- thanks a lot for the input- I've been trying to get in touch w/you about some of this- glad to hear it's running well. Do you know how they balanced you flywheel- to what # @ what rpm? Scottt goes to "0" @ 3800, whereas Porsche balances to + or - 12g @ ~700rpms, from what I've been told...

To everyone- Scott Gomes advised me to REMOVE the belt for a day or so to see how it felt- Socal said "You will not get far before you put the balance belt back on"- Scott swore to me that I would NOT notice a thing(!?)- He says he removes them ALL the time & no one could ever tell(?)- of course, HE usually does crank &/or FW work- although he acts as if it's not neccessary b/c of vibrations... There are several more reasons (other than just added HP) to remove them- all in all, it soundss like a GREAT thing, UNLESS it can cause vibration probs, etc...

Thanks,

David Floyd

Robby,

I do not know any of the balance info, the car is smooth as silk. I can't believe any damage is going to happen due to vibration, guess I will find out, but so far so good.

email me anytime

iloveporsches

Robby, my balance belt broke, and thankfully did not take out the t-belt. I didn't even notice.

Robby

Thanks guy's- I'm really wanting to eliminate it- not so much for HP reasons, but for the others- if I could just find a few more people who've done it, I would make my decision..

Also, I misprinted in my post to David- not sure if it matters, but what I meant to aws was- do you know what they balanced the CRANK (not FW) too? The 3's I quoted for Scott G were for that (not FW)...

Thanks