Balance Shaft Delete?
- Thread starter jcdman
- Start date
ccannx
Goblin Guru
Did neutral balance shafts and 82lb valve springs to run the motor at higher rpm. I believe the idea is the spinning counter weights progressively increase in effect the faster the engine operates to a point it is beyond engineered countervibration. Less rotational mass also helps parasitic hp loss and acceleration. Also installed a size down ATI super dampner to help cut down and centralize rotational mass
Dsteinhorst
Well-Known Member
As one of the few people who have drove my Goblin both before and after the balance shaft delete with no other mods, I can say the vibration is noticeable; mostly at idle and certain harmonic frequencies. I used the old school delete kit, didn't do the neutral shafts. I decided to as part of a noisy timing chain replacement. It was a bit of a PITA with the motor in the car.
For a street Goblin, I wouldn't do it again.
For a street Goblin, I wouldn't do it again.
Desert Sasqwatch
Goblin Guru
Let me ask the question differently, is vibration caused by the stock balance shafts noticeable at high RPMs? Say like 6000 RPM or higher? I know the extra weight swinging around will be a limiting factor for upper end RPM, thus the reason for putting in the neutral shafts.
Many 'early' 4 cylinder engines didn't incorporate balance shafts and they operate just fine without excessive vibration occurring from the secondary balance harmonics. Seems that removing the Ecotec balance shafts would not cause much harm, but allow for a raised redline for a few more HP - including the necessary tuning and intake/exhaust modifications.
Many 'early' 4 cylinder engines didn't incorporate balance shafts and they operate just fine without excessive vibration occurring from the secondary balance harmonics. Seems that removing the Ecotec balance shafts would not cause much harm, but allow for a raised redline for a few more HP - including the necessary tuning and intake/exhaust modifications.
Iwanttogofast
Well-Known Member
I don't know for sure, but what I've read elsewhere seems to be a general consensus that neutral shafts are best for street and occasional track use, and delete is for racing. Again, not sure yet but I think the neutral option still offers some benefit with reduced rotational mass. I've seen people who used a delete kit state that it is not great on the street and they wish they hadn't gone with a full delete.
Desert Sasqwatch
Goblin Guru
So a balance shaft delete is preferred over installing neutral shafts?
Mayor West
Goblin Guru
I re-read the posts above and realize that he in fact does mean removing of the shafts all together... I didn't think people actually did that in non full-race capacity.
I deleted my posts above, so @Desert Sasqwatch 's reply might not make sense.
I deleted my posts above, so @Desert Sasqwatch 's reply might not make sense.
Rauq
Goblin Guru
I think the balance shafts vs delete are two different ways to accomplish the same thing. You can't just remove them, as they have oil galleys feeding the bearings, and the water pump and balance shafts share a chain. ZZP sells neutral balance shafts which are essentially just balance shafts with no weights on them, and OTTP sells delete bushings plug the oil feeds to the balance shafts. With the delete you either have to run an electric water pump or use part of the original balance shaft as an idler for the water pump drive chain.
Ross
Goblin Guru
I have read that the balance shaft delete only saves less than 1hp on a dyno. But if you eliminate the water pump from the crankshaft, you can gain more hp... maybe 5 or 7 hp? The stock shafts are 4.2lbs each, about 10" long, so you can save some rotating weight.
The neutral shafts are $280 from ZZP, and are easier to install.
The full balance shaft delete kit is ~$150, or the half kit is about $40, but takes more time to install. You also get to choose if you are installing the sprockets as idler gears, so that the stock water pump is powered by the chain, or if you are going with an electric water pump, and removing the chain driven water pump.
Each of the 2 balance shafts have 2 bearings, numbered 1 and 2 here.
The pressurized engine oil enters one side of the bearing, and leaves out the other side, thru passages in the block.
So to maintain the oil pressure without a balance shaft, something has to fill the bearing.
On a neutral shaft, the front bearing (#1) uses the stock part around the bearing, and the stock sprocket. (those stock parts are in the image above)
the rear bearing #2, is filled with the rotating neutral shaft.
On a balance shaft delete kit,
the front bearing uses the stock part around the bearing, and the stock sprocket is bolted to the supplied part 1 (below). Some kits don't include this part, as they expect you to cut it off of the stock balance shaft. The front sprocket is only supported by the front bearing, as there is no shaft going to the rear bearing.
The rear bearing, is filled with the supplied part 2. It doesn't rotate, but the oil can travel around it, maintaining oil pressure. I have seen youtube videos pounding these aluminum rings in place with loctite, but others just use dry ice to shrink them before inserting in the block. If it falls out, your engine will loose oil pressure, so don't goof this up.
The neutral shafts are $280 from ZZP, and are easier to install.
The full balance shaft delete kit is ~$150, or the half kit is about $40, but takes more time to install. You also get to choose if you are installing the sprockets as idler gears, so that the stock water pump is powered by the chain, or if you are going with an electric water pump, and removing the chain driven water pump.
Each of the 2 balance shafts have 2 bearings, numbered 1 and 2 here.
The pressurized engine oil enters one side of the bearing, and leaves out the other side, thru passages in the block.
So to maintain the oil pressure without a balance shaft, something has to fill the bearing.
On a neutral shaft, the front bearing (#1) uses the stock part around the bearing, and the stock sprocket. (those stock parts are in the image above)
the rear bearing #2, is filled with the rotating neutral shaft.
On a balance shaft delete kit,
the front bearing uses the stock part around the bearing, and the stock sprocket is bolted to the supplied part 1 (below). Some kits don't include this part, as they expect you to cut it off of the stock balance shaft. The front sprocket is only supported by the front bearing, as there is no shaft going to the rear bearing.
The rear bearing, is filled with the supplied part 2. It doesn't rotate, but the oil can travel around it, maintaining oil pressure. I have seen youtube videos pounding these aluminum rings in place with loctite, but others just use dry ice to shrink them before inserting in the block. If it falls out, your engine will loose oil pressure, so don't goof this up.
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TheNuker
Goblin Guru
Pounding those aluminum sleeves in was a PITA! Once you get them started it was not too bad, but getting that first lip in.... I 3d printed a holder to position these in the hole as its about 6-7 inches inside the block. i then used a dowel and dead blow to knock those suckers in. They are never coming out lol.
Nuker-
Nuker-
Dsteinhorst
Well-Known Member
I had a similar experience with the solid aluminum threaded version. Definitely not coming out.
jirwin
Goblin Guru
The vibrations are negligable in my opinion. I don't even notice them hardly except at idle a bit. It may make a difference that I'm not running solid trans mounts like some. If you're building it, go for it, but its not necessary. You kinda need a cam to truly take advantage of the higher (8k) RPMs anyway.
Desert Sasqwatch
Goblin Guru
...cam to truely take advantage of the higher (8k) RPMs anyway...and stiffer valve springs, and (for LNF) forged pistons and connecting rods, and (at least) port matching the intake manifold/head, and possibly larger fuel injectors (Opel injectors for LNF), and better turbo (stock K04 runs out of huff after 6000 RPM)...and probably a bunch more stuff too.