2.0 TS balance shaft question. - Alfa Romeo Forum
You are currently unregistered, register for more features.    
 
  Home Forums AO Club Member Gallery Classifieds Trade Directory  

Go Back   Alfa Romeo Forum > Supported Alfa Romeo Models > Technical & Vehicle Assistance > Engines (TS, JTS, JTD & V6)

Reply
 
LinkBack Thread Tools
  #1 (Post Link)  
Old 15-11-11
Status: New 156 v6 :) Happy chappy
AO Member
 
Join Date: Jun 2011
Location: United Kingdom
County: Dorset
Posts: 77

Member car:

Alfa Romeo 156 2.5 V6 Q

Help 2.0 TS balance shaft question.

Hey there.
Just wondering if anyone can help answer my question.

Yesterday i took the balance belt off just as a bit of a "lets see how it goes" kind of thing. Well ever since doing so, my gtv now feels a hella lot free'er through its rev. Before it felt as if something was making the engine work a lot more than it should.

So. Getting to the point. I think my balance shafts are bent or damaged in some way.
When i took the belt off, i gave the shafts a spin. Well one spins freely through about 90% of its travel then you have to forcefully turn it to "un-jam" it.
The other is worse! The only way i can think to explaine it, would be to break up one revolution in to 10% segments. Well every other 10% it jams like the other shaft.
Any ideas of why they are like this?
I would be happy to put the belt back on if they felt free and smooth. As this is not the case, for the moment its staying off. It has also stopped my revs bouncing free 1000 to 800 constantly.

Any ideas on this?
Reply With Quote
Sponsored Links
Advertisement
 
  #2 (Post Link)  
Old 16-11-11
gazza82's Avatar
Status: exhaust fitted ... not happy, blows
AO Gold Member
 
Join Date: Jan 2003
Location: United Kingdom
County: Buckinghamshire
Posts: 7,384
Images: 12

Member car:

'98 156 2.0, '09 MiTo 1.4

I think the balance shafts run in bearing shells like the camshafts, so it could be one is worn/damaged.
Reply With Quote
  #3 (Post Link)  
Old 17-11-11
Status: ALFA extremist
AO Member
 
Join Date: Mar 2010
Location: Australia
County: Victoria
Posts: 394

Member car:

n/a

that's the logical conclusion...

vibrationwise - how do you find it w/o the belt? if you like it, keep em off...

it's a low chance, but some BBs have come off and taken out the cambelt...

unless people insist on keeping it, i recommend leaving it off...

alfas meant to be rough & ready IMO...
Reply With Quote
  #4 (Post Link)  
Old 17-11-11
Status: New 156 v6 :) Happy chappy
AO Member
 
Join Date: Jun 2011
Location: United Kingdom
County: Dorset
Posts: 77

Member car:

Alfa Romeo 156 2.5 V6 Q

To be fair. Vibration wise. Long as your foot is constantly on the accelerator, there is no vibration at all. The only time there is vibration is either when youre coming down thru the gears instead of braking, or you take your foot off the accelerator and let it run under its own momentum.
Apart from that, no other vibrations at all.
I much much prefer it without the belt, feels more free and a lot, lot more responsive.
Reply With Quote
  #5 (Post Link)  
Old 17-11-11
OperationAlfa's Avatar
Status: -
Club Member
Membro Premio
 
Club Member Number: 118
Join Date: May 2007
Location: United Kingdom
County: Essex
Posts: 22,020

Member car:

GT 3.2 V6

I'd leave it off then.
Reply With Quote
  #6 (Post Link)  
Old 19-11-11
Status: ALFA extremist
AO Member
 
Join Date: Mar 2010
Location: Australia
County: Victoria
Posts: 394

Member car:

n/a

yea, don't forget BB seals are common problem w/ the TS... if you don't mind the little extra vibration

full oem BB kit damn near same cost of cambelt + aforementioned issues.... - i'd be rather done w/ them myself...

plenty of 4 bangers w/o it (including those in the TS range below 2litres!)
Reply With Quote
  #7 (Post Link)  
Old 21-11-11
Status: New 156 v6 :) Happy chappy
AO Member
 
Join Date: Jun 2011
Location: United Kingdom
County: Dorset
Posts: 77

Member car:

Alfa Romeo 156 2.5 V6 Q

Just an update;

The belt has now been off for week now, and I have had no problems at all with it being off.

Like I mentioned before, a little more vibration than usual, but I'm used to solid mounted engines so its no bother to me! Haha

So, the conclusion is - the belt is staying off while the car is in my hands! And that will be for a long time!!
Reply With Quote
  #8 (Post Link)  
Old 22-11-11
OperationAlfa's Avatar
Status: -
Club Member
Membro Premio
 
Club Member Number: 118
Join Date: May 2007
Location: United Kingdom
County: Essex
Posts: 22,020

Member car:

GT 3.2 V6

As long as you are happy!

I once had a 2.0 that the indie had put the balance shaft belt back on at 90 degrees out. Now that was interesting!
Reply With Quote
  #9 (Post Link)  
Old 22-11-11
Status: Hands too large...
AO Member
 
Join Date: Feb 2009
Location: South Africa
County: Northern Cape
Posts: 50

Member car:

2005 156 2.0 TS Veloce

I am also not a fan of these balancing shafts. It is a misnomer, and should rather be called gyro-shafts, or something like that.

In theory it is NOT able to counterbalance any imbalances that may be present, since it turns at twice the rate of the crank-shaft. Check the size of the pulleys to see for yourself. At the very best, it may have a gyro-effect, stabilizing any vibrations that may be present.

Lots of cam-belt failures have been caused by balancing shaft belt or pulley failures. IMO, it is not worth the risk. After removing the belt, I have not noticed any vibrations, but then again, this may be a false sensation, caused by the peace of mind that I now have.

What I did notice without any doubt, was the quicker throttle response. In the long run, you may also be able to detect an improvement in fuel economy.
Reply With Quote
  #10 (Post Link)  
Old 22-11-11
Mitch916's Avatar
Status: AROC 916 Registrar
AO Gold Member
 
Join Date: Nov 2002
Location: United Kingdom
County: Kent
Posts: 8,127
Images: 8

Member car:

156 2.4 JTD, GTV 2.0TS

At the end of the day, it's your car, it's your choice.

However, to suggest they don't do anything is daft. Balance, vibration whatever you want to call it, they do make the engine smoother. Maintained correctly, there is no danger to the cam belt.

I will be keeping mine.
Reply With Quote
  #11 (Post Link)  
Old 22-11-11
OperationAlfa's Avatar
Status: -
Club Member
Membro Premio
 
Club Member Number: 118
Join Date: May 2007
Location: United Kingdom
County: Essex
Posts: 22,020

Member car:

GT 3.2 V6

Originally Posted by Mitch166 View Post
However, to suggest they don't do anything is daft. Balance, vibration whatever you want to call it, they do make the engine smoother. Maintained correctly, there is no danger to the cam belt.
Yup, even my 2.0 track car had its balance belt.
Reply With Quote
  #12 (Post Link)  
Old 23-11-11
Status: ALFA extremist
AO Member
 
Join Date: Mar 2010
Location: Australia
County: Victoria
Posts: 394

Member car:

n/a

Originally Posted by Mitch166 View Post
At the end of the day, it's your car, it's your choice.

However, to suggest they don't do anything is daft. Balance, vibration whatever you want to call it, they do make the engine smoother. Maintained correctly, there is no danger to the cam belt.

I will be keeping mine.
who said it doesn't do anything? we're all in accord it removes a bit of vibration esp, at low rpm...

and how many 'maintained correctly' belts, cam or balance have still gone awry?

we're simply saying you don't harm anything by leaving it off and the benefits are:
1) improved economy and crank hp (however small)
2) reduced risk of leakage due to worn balance shaft seal wear (common issue)
3) completely removed risk of BB failure leading to cam belt failure
4) (optional) raucous and a bit more raw engine trait...

I would argue that on 10yo+ cars, it may be smart to remove it - unless you are keen on repalcing seals and expensive BB kits... (just as the cam belt kit it gets expensive to replace the lot, not just the belt)

NB: the 1.8 and 1.6 does not feature the BB at all, and really there isn't that much of a performance gap b/w the 1.8 and the 2.0... sooo... make of that what you will.

As pointed out - it's up to the owners of the cars - but i feel there is some slavish commitment to what alfa (or i should say fiat) did with the design... If you like it, good for you.... but there are tinkerers out there who like to experiment, and the insinuation that it is wrong to do so, isn't really what a technical forum is about IMHO..

we certainly shouldn't be scaring people off a harmless 'modification' that can bring reward and savings, if the owner doesn't mind a bit of vibration at low engine speed. A lot of people won't mind that at all - especially the kind on a technical forum.
Reply With Quote
  #13 (Post Link)  
Old 23-11-11
Status: ALFA extremist
AO Member
 
Join Date: Mar 2010
Location: Australia
County: Victoria
Posts: 394

Member car:

n/a

official figures for readers to decide if the whole extra 15nm or so of torque of the 2.0 vs 1.8 makes a BB essential...

from wiki's TS engine entry (4v)
1.8 L 1747 cc 103-106 kW (140-144 PS) @6500 rpm, 163-169 N·m (120–125 ft·lbf) @3500-3900 rpm
2.0 L 1970 cc 110-114 kW (150-155 PS) @6400 rpm, 181-187 N·m (133–138 ft·lbf) @3500-3800 rpm

obviously it is the 'eccentricness' of the motor that matters.. FYI the 1.8 was more or less square at 82 x 83mm with the 2.0 under @ 83 x 91mm

Last edited by wankski; 23-11-11 at 01:31.
Reply With Quote
  #14 (Post Link)  
Old 23-11-11
Status: New 156 v6 :) Happy chappy
AO Member
 
Join Date: Jun 2011
Location: United Kingdom
County: Dorset
Posts: 77

Member car:

Alfa Romeo 156 2.5 V6 Q

Being the original poster; I have to say I agree with wankski. Yes they do, 110%, remove some degree of vibration, whether it being a small ammount or, in my case, a fair amount.

But people, we have to remember that everything is opinionated. Some will say, my god why did I take my BB off! I've lost a squillion horsepower and I can only do 2 to the gallon! (figure of speech)
But then again, in my case and I expect maybe others, I dont know, I am 110% confident that I have gained a little more power and the car doesnt feel like its struggling.

That is just my 2 pennies
Reply With Quote
  #15 (Post Link)  
Old 23-11-11
Mitch916's Avatar
Status: AROC 916 Registrar
AO Gold Member
 
Join Date: Nov 2002
Location: United Kingdom
County: Kent
Posts: 8,127
Images: 8

Member car:

156 2.4 JTD, GTV 2.0TS

But your engine obviously has a fault.

If your engine was 100% I suspect the only difference you would notice is the extra vibration.

To my mind, the fact the 1.6 and 1.8 do not have the BB simply reinforces the point that the 2.0 needs it. Otherwise, why did Alfa bother?
Reply With Quote
  #16 (Post Link)  
Old 23-11-11
Status: New 156 v6 :) Happy chappy
AO Member
 
Join Date: Jun 2011
Location: United Kingdom
County: Dorset
Posts: 77

Member car:

Alfa Romeo 156 2.5 V6 Q

Mitch166 - I definitely agree with you about the 1.6 and the 1.8 not having them, but the 2.0 does. They wouldn't have just put it on the 2.0 to look pretty, it has a purpose, and that purpose is just for ride comfort (in my mind) but we will never know, unless we can find someone who was on the 2.0TS design team...

And yes, my engine does have a fault, I found out from Gazza82 that my shells could be worn/damaged, so I am most likely going to say yes they probably are damaged.

But fear not. I have got myself a new 2.0TS for Ł100! I got it from a friend in a garage, works perfect. The only work needing is a cambelt change as the one currently on it, was damaged (funnily enough) by the BB! Still runs fine, but obviously I'm not going to chance it, I'll change it.

I couldn't help but smile to myself when he shown me the damage from the BB, after the discussion we're having on here!
Reply With Quote
  #17 (Post Link)  
Old 23-11-11
Status: ALFA extremist
AO Member
 
Join Date: Mar 2010
Location: Australia
County: Victoria
Posts: 394

Member car:

n/a

i told you why the 2.0 has it even tho it's only marginally more torquey than the 1.8.... it has a more eccentric crank, with a much longer under-square bore/stroke ratio (see above) 83 vs 91mm..

the balance shafts are to cancel out the vibration and harshness from the more eccentric crank...

that's it... w/ the 2.0 being the premium 4 banger package - alfa did it for more 'luxury' and improved NVH....

at the time in the motoring press the 2.0 TS was highly regarded for its 'turbine' like smoothness.

my point is now, the BB requires a tensioner and pulley just as the cam kit... it's almost as expensive....most people don't correctly attend to it (just change belt at most) it can cause cambelt failure as it is not partitioned away from the cam timing system as it is in the v6 (fully enclosed by the pulley and cam covers away from the external accessory belt.

also now the balance shaft seals are old now and can, and often do, go wrong.. that's nothing to scoff at.... you need to crack the g/b to get at it...
Reply With Quote
  #18 (Post Link)  
Old 23-11-11
OperationAlfa's Avatar
Status: -
Club Member
Membro Premio
 
Club Member Number: 118
Join Date: May 2007
Location: United Kingdom
County: Essex
Posts: 22,020

Member car:

GT 3.2 V6

I got 171ftlb of torque out of my tuned 2.0 engine
Reply With Quote
  #19 (Post Link)  
Old 23-11-11
Status: Hands too large...
AO Member
 
Join Date: Feb 2009
Location: South Africa
County: Northern Cape
Posts: 50

Member car:

2005 156 2.0 TS Veloce

I fully agree with all contributions thus far. For completeness sake, I will add the following:

If all four pistons and con-rods have exactly the same mass (and center of gravity), they should cancel each other out, with two going up while the other 2 are going down, no matter what the bore or stroke is.

Crank shafts are only partially machined, and could have some uneven mass distribution over the length of the crank shaft, as a result of the roughness of the castings. In the old days, crank shafts were balanced by partially filling pre-drilled holes with lead, after spinning the crank in a balancing machine, much in the same way as wheel balancing.

Any imperfections in the above, are exaggerated by longer stroke engines (2.0l), causing more noticeable vibrations, in comparison to shorter stroke engines (1.8l & 1.6l). It may be that the balancing shafts were introduced by the designers in the 2.0l engines as a precautionary measure, knowing that components are not selected and exactly matched on an assembly line, as is the case when hand-building a blueprinted engine.

This boils down to pure luck when buying an assembly line engine: One engine may have all components closely matched, while the next may have one con-rod that is slightly heavier (but still within specifications) than the others, and now cause noticeable vibrations when run without the balancing belt.
Reply With Quote
  #20 (Post Link)  
Old 24-11-11
marlon
Status: - Update
Guest
 
Posts: n/a
The 1.8 16v doesn't have balance shafts and feels a bit "Free-er" than the 2litre in my experience. The balance shafts do weigh a bit.
Reply With Quote
  #21 (Post Link)  
Old 24-11-11
Mitch916's Avatar
Status: AROC 916 Registrar
AO Gold Member
 
Join Date: Nov 2002
Location: United Kingdom
County: Kent
Posts: 8,127
Images: 8

Member car:

156 2.4 JTD, GTV 2.0TS

I just don't buy it. On this logic, a car with air con won't feel as "free" as one without.

But, at the end of the day, if it feels (psychosomatic) good, do it!
Reply With Quote
  #22 (Post Link)  
Old 24-11-11
David C's Avatar
Status: -
AO Platinum Member
 
Join Date: Aug 2003
Location: London, England
Posts: 26,160

Member car:

Audi TT 3.2v6 DSG

Originally Posted by marlon View Post
The 1.8 16v doesn't have balance shafts and feels a bit "Free-er" than the 2litre in my experience. The balance shafts do weigh a bit.
The main reason it will feel "free-er" is that the 1.8 has a shorter stroke.
It also has a smaller bore, so lighter pistons, than the 2.0
The 1.8 also makes it peek BHP 100rpm higher than the 2.0

I could feel the same differences between the different size Sud engines many MANY years ago.
Reply With Quote
  #23 (Post Link)  
Old 01-12-11
Status: -
AO Member
 
Join Date: Jun 2010
Location: Romania
County: Bucuresti
Posts: 13

Member car:

Alfa Romeo 156

Try this:
2.3 DOHC Overview

balancer shafts use a bit of power, wiki says about 15hp, but it seems a bit exagerated.
Reply With Quote
  #24 (Post Link)  
Old 02-12-11
Status: GTV for sale ...
AO Silver Member
 
Join Date: Jan 2011
Location: United Kingdom
County: Warwickshire
Posts: 1,842

Member car:

GTV 2.0

Originally Posted by DawieS View Post
If all four pistons and con-rods have exactly the same mass (and center of gravity), they should cancel each other out, with two going up while the other 2 are going down, no matter what the bore or stroke is.
Hey, Dawie I gotta disagree with this because even a perfectly balanced (component mass wise) inline 4 cylinder, 2 stroke engine, will be unbalanced when the cylinders are firing.

Edit: although you are exactly correct, 2 pistons go up while 2 go down

The inbalance isn't very serious, and it happens at twice crank speed. Hence, the balance shafts spin at twice crank speed to correct it.

I bet they consume less than half a horsepower.

Last edited by Turtle4288; 02-12-11 at 15:27.
Reply With Quote
  #25 (Post Link)  
Old 04-12-11
seadart's Avatar
Status: -
AO Silver Member
 
Join Date: Oct 2010
Location: United Kingdom
County: Hampshire
Posts: 2,144

Member car:

GTV ts lusso Ph 1

As Turtle says the power consumption will be negligable.. there is viltually no resistance when turning them by hand.. I guess pick up would improve as there would be less mass to accelerate.. my only concern would be that any vibration in any engine can lead to unwanted stresses/fatigue.. the 2 litre TS engine is oversquare.. the longer the stroke, the higher the piston velocity at any given frequency/revs.. the smaller engines are square or under square.. lower piston velocity, therefore less vibration..
so for the stroked 2 litre, any reduction in vibes is good.. maybe the balance shafts aren't just about driver comfort ?? crankshafts do not like vibration.. When engines have been 'stroked' to increase capacity.. the red line has to be reduced a grand or so.. four cylinder engines are inherently unbalanced and the crankshaft will flex.. work hardening at a stress raiser.. usually at the main journal/web.. = snapped crankshaft or increased bearing wear.
In other words.. removing the balance belt MAY reduce the engine life..

unless of course you are a complete nutter and have had to get rid of the BB to fit a blower.. in which case.. go for it!!

I may sound all old and sensible but there was a time when I used to drill holes in con rods.. based soley on the premise that a hole weighs less than metal..

Last edited by seadart; 04-12-11 at 21:44.
Reply With Quote
Reply

Go Back   Alfa Romeo Forum > Supported Alfa Romeo Models > Technical & Vehicle Assistance > Engines (TS, JTS, JTD & V6)

Tags
balance, belt, question, shaft

Thread Tools


Recently 'Read'
No History to show

Useful Links
Lost Password?
AO Merchandise
FAQs
Register

External Links
Alfa Romeo...
Alfa Romeo GTV 2.0...
2004 ALFA ROMEO 147...
2011 Alfa Romeo...
Alfa Romeo...

Alfa Romeo

Recent Image

Alfa 159

View paul.o's images

Search

Forums

Classifieds
   

Gallery

Social Groups
   

Members
   


Did you know..?
Did you know..?
Within your User Control Panel, you can change the way AO works:
For example, to change the number of posts per page, go to Edit Options and scroll down to 'Thread Display Options'. In the section 'Number of Posts to Show Per Page' select a desired amount.


New To Site? Need Help?

All times are GMT. The time now is 10:42.


Powered by vBulletin®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2011, Crawlability, Inc.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733