Larry Parker

Has anyone removed thier balance shafts?
If so how does the car idle/run? Is it much diff. than your car with them?.........................
regards

larry parker

Luke

Hi larry,

I was told the motor will shake itself to death if you let it idle (for any period of time)with-out balance shafts. Is this true?

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David Floyd

Larry

You might want to talk to John at Speed Force Racing, he runs without the balance shafts and is doing the same with my new engine and told me I most likely would not notice anything different.

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Luke

Here you go larry, in case you missed it.

Thank you p951s


[quote]Originally posted by p951s:
<strong>Ok guys heres the deal. I have REMOVED my balance shafts, i love it the car seems lighter, revvier, maybe not as silky smooth but certianly not rough either. The only way to do this is to have alot of work done to the block.

1.removing the shafts, covers, pulleys, tensoiner,ect.

2.Weld the oil drainbacks in the block shut these are six to eight 1x1/2 inch holes running from the shaft housings to the oil pan. To do this i believe you must completely dissaseble the engine and clean the hell out of it(if you have ever welded aluminum you know what i'm talking about)

3.Next I drilled and tapped the lower oil feed. It helps to make a flat with an end mill. Then i plugged it. This is important because that feed galley runs right from a crank main i think #2

4. Finally mill a 1 1/2 inch flat on the upper feed bearing surface then drill and tap for AN fitting. Then make a nice briaded steel line straight from oil feed to turbo ( which also needs to tapped, the hole is the correct size for an 1/8 inch pipe tap. i stuffed a rag into the hole first an used tapping wax so metal wouldnt fall into my turbo.) Now just get a pipe to AN adapter and you have a direct feed to the turbo.


I know this sounds involved. IT IS

Soime of you might say to just take of the belt and leave them in. I think this is a bad idea it will make the engine rough as hell. Because the harmonis will turn them but out of order. Just ask a mitsubishi 4G63 owner (Which these shafts are designed after, yes porsche bought the design from mitsubishi) So the only way is to remove them.

But heres what you get: Quicker rpm ,less lag, 30hp I have not dynoed, but this is what others have told me. It feels right. Better oil pressure to main bearings and turbo. No seals to leak, NO balance belt to break. Easy timing belt and water pump service, longer crank bearing life. (heres why! A balance shaft works by countering vibration from the large pistons, crank. Well the block has to absorb this. so every time the shafts and crank are fighting for the block it stresses the bearings. Not the scientific description but you get it. this doesnt seem to be a huge problem for Porsche, because they are built so well. But some chryslers will eat bearings until you remove the shafts. Its funny mitsubishi actually makes a balance shaft deletion kit, you can get it from the dealer. So it is a problem.

So let me just say that if i have a porsche that the engine needs to come out of then I will always remove the balance shafts. I feel it is an improvement. And i challenge someone to tell the difference at idle, i have non turbo cams and my car idles ok.

Good luck
arthur</strong><hr></blockquote>

Luke

bump

Larry Parker

Thanks luke.......get that old turbo out yet?

Luke

family is in chicago. Dad does'nt want me using the tabel saw. (lmao) I was gonna built the support. I have all the supplies to do so. I figured it'd be easier to get at with the rack down.
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BUt, YOu did knock alot off of the head with that dremel. I have a great cutting wheel for my drill, but I'm afraid. lmao. Think I'd rather be in the position to use vice grips.

Danno

Derrek told me that the balance-shafts were worth only 4-5hp. Just think of how slow the 944NA car would be if the balance-shafts sucked way 30hp out of its 147hp. That's a whole 20% of the power output, outrageous! Nah, I say the cam-drive easily sucks up way more power. Next time you change your timing-belts or water-pump, try spinning the balance-shafts by hand, then try spinning the cam by hand... heh, heh...

Luke

Good point, what about hte air you are compressing in there though?

Robby

Just curious, how much actual weight would you be removing if you did all of the stuff that Arthur said, while removing the balance shafts? How much do the shafts themselves weigh? Again, just curious- I have no idea (not the slightest clue), and have never even seen any of this up close....

Thanks,
Robby

Danno

Good point, what about hte air you are compressing in there though?

You're not really compressing any air, just operating the valves. You can get a sense of how much power is required to overcome the friction of the cam-lobes. Not to mention compressing the valve-springs. I seriously doubt that you could turn the cam by hand very far. Compared to how easy it is to turn the balance-shafts, you get the idea with the comparison. Now try spinning the cam at 6000rpm and you get the idea on how much power it takes. A lot of the V8 muscle-car crowd actually record power-savings of 20hp or more when go to roller-rockers and a lot less heat build-up as well. Even the newer Japanese & BMWs with roller-rockers claim savings of around 10hp.

Brian Wilson

Is it me, or does anyone else thank that arthur is crazy!!!

That does seem like a good idea though. Just think about it. You gain, what, 5hp for an ac delete. The balance shafts put quite a bit more strain on you car than a small ac compressor. I would like to see a after dyno of it though. Anyone want to volunteer??? If I could go from the 163hp to 17?, then that would be great. It isn't (sort of not) a lot of work to yank the engine if you have a long weekend and the right tools.

Someone give a shot. I have to sell my car in a year if I move back to the states. Maybe on the next one.

951Tom

I removed one of my balance shafts and I'm guessing it weighed about 10 pounds. Most of the weight is at the rear where the counter-weights are. Don't forget the balance shafts spin at twice crankshaft rpm, so if you're redlining it, your b/s are turning over 12,000 rpm. That's gotta take some power to do! I would never remove them from my car. I want the smoothness that they bring.
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doyle

I would imagine that someone could contact David Finch at Raetech. He races a purpose built 944 in SCCA. From what I understand, many full race motors get rid of the balance shafts because, of course, idling smoothness is not a major concern. He may have some experience with deleting the balance shafts.

One question, do you have to modify the block? Could you just remove the shafts and leave the carriers empty?

Ok, that was two questions.

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Danno

For the procedure and block-machining steps, go back up a couple of messages and read P951S's message that Luke quotes.