Harmonic balancer help!! URGENT
Thread Starter
Teching In
Joined: Jan 2015
Posts: 36
Likes: 0
Harmonic balancer help!! URGENT Just completed a lq4 swap into my 99 formula m6. having awful belt chirp, replaced all the pulleys on the car with the exception of the power steering pump. using an electronic stethoscope i was able to pin point the chirp coming from the entrance into the harmonic balancer as it comes off of the idler pulley. found some specs on the hb that it is supposed to be 2.4-4.4mm off the crank snout. pulled the pulley out to the 4.4mm then put the old bolt back in with some torque and started the car back up. no more chirp. so how do i torque down the new bolt but keep the hb at the 4.4mm so the chirp doesnt come back?? please help if you can, it would be greatly appreciated!!
I guess if you can get it in there. I would have thought you'd have no choose but to take the whole thing off. Whatever gets the thing in the right position and holds it there.
need to remove it. Some LS engines have a spacer behind the balancer but I am not sure how thick they are. I have torn a bunch of LS motors down, but have not come across the shim so I am unsure what vehicles came with them.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo it shouldn't. You might need a slightly longer bolt to make sure you have full thread engagement. 4.4 mm is around 3/16". Roughly
Here is some interesting info on the design, purpose and identification of TTY bolts:
http://www.enginebuildermag.com/2005...head-bolt-use/
Torque-To-Yield
Torque-To-Yield (TTY) is a term that you should be familiar with because it describes a type of head bolt that is used on many late model engines. Unlike ordinary head bolts, TTY head bolts are designed to deform – but do it in a controlled way. Like a standard head bolt, a TTY bolt will stretch and spring back up to its yield point. But once the yield point is passed, the bolt becomes permanently stretched and does not return to its original length. Because of this, TTY bolts should not be reused.
Why intentionally stretch the head bolts? Engineers discovered they can get much more even clamping on the head gasket if all the bolts are evenly loaded. Since variations in friction between bolts always causes some uneven loading, stretching the bolts guarantees all the bolts will exert the same clamping force regardless of the torque reading on the wrench. The result is improved cylinder sealing, longer head gasket durability and less cylinder bore distortion (for reduced blowby and more power).
TTY head bolts are typically used on engines with aluminum cylinder heads (where there is a lot of thermal expansion) and with multi-layer steel (MLS) head gaskets. MLS head gaskets are very stiff gaskets with much less compressibility than standard soft-faced composition head gaskets. On the other hand, MLS head gaskets are almost bullet-proof and produce much less bore distortion than other types of head gaskets because they require less clamping force. But to seal properly, MLS head gaskets require very smooth (almost polished), flat surfaces on the head and block. This, in turn, requires very precise and even clamping loads by the head bolts. That’s why TTY head bolts are used in these engines.
How can you tell TTY head bolts from ordinary head bolts? TTY head bolts are typically longer and narrower than standard head bolts. Factory service manuals will tell you which applications use TTY bolts, and you can often tell from the head bolt tightening procedure if the bolts are TTY or standard. TTY bolts typically have an angle tightening specification rather than a specific torque value (which requires using an angle gauge when tightening the bolts).
The torque procedure for tightening a TTY head bolt involves tightening it until a certain torque reading is reached. Then the bolt is given an additional turn to a specified angle (say an additional 45 to 90 degrees) to load the bolt beyond its yield point for maximum clamping pressure.
Torque-To-Yield (TTY) is a term that you should be familiar with because it describes a type of head bolt that is used on many late model engines. Unlike ordinary head bolts, TTY head bolts are designed to deform – but do it in a controlled way. Like a standard head bolt, a TTY bolt will stretch and spring back up to its yield point. But once the yield point is passed, the bolt becomes permanently stretched and does not return to its original length. Because of this, TTY bolts should not be reused.
Why intentionally stretch the head bolts? Engineers discovered they can get much more even clamping on the head gasket if all the bolts are evenly loaded. Since variations in friction between bolts always causes some uneven loading, stretching the bolts guarantees all the bolts will exert the same clamping force regardless of the torque reading on the wrench. The result is improved cylinder sealing, longer head gasket durability and less cylinder bore distortion (for reduced blowby and more power).
TTY head bolts are typically used on engines with aluminum cylinder heads (where there is a lot of thermal expansion) and with multi-layer steel (MLS) head gaskets. MLS head gaskets are very stiff gaskets with much less compressibility than standard soft-faced composition head gaskets. On the other hand, MLS head gaskets are almost bullet-proof and produce much less bore distortion than other types of head gaskets because they require less clamping force. But to seal properly, MLS head gaskets require very smooth (almost polished), flat surfaces on the head and block. This, in turn, requires very precise and even clamping loads by the head bolts. That’s why TTY head bolts are used in these engines.
How can you tell TTY head bolts from ordinary head bolts? TTY head bolts are typically longer and narrower than standard head bolts. Factory service manuals will tell you which applications use TTY bolts, and you can often tell from the head bolt tightening procedure if the bolts are TTY or standard. TTY bolts typically have an angle tightening specification rather than a specific torque value (which requires using an angle gauge when tightening the bolts).
The torque procedure for tightening a TTY head bolt involves tightening it until a certain torque reading is reached. Then the bolt is given an additional turn to a specified angle (say an additional 45 to 90 degrees) to load the bolt beyond its yield point for maximum clamping pressure.
Last edited by speedtigger; Oct 18, 2015 at 11:06 AM.
I have heard people say that, but what is that based on? Do the GM manuals say that? Here is some interesting info on the design, purpose and identification of TTY bolts: http://www.enginebuildermag.com/2005...head-bolt-use/ I wonder if the only reason it is recommended to replace the crank bolt is because there is sealer on the end.
Thread Starter
Teching In
Joined: Jan 2015
Posts: 36
Likes: 0
yes, i have bought a new bolt. just used the old one while i was jumping in and out of the car adjusting the hb. so i didnt have to buy 5 or six new bolts just to try and adjust it to a space where it wouldnt chirp.
UPDATE: replaced the hb to see if that would help anything since i had already purchased it and the old one was looking a little iffy. put on a new belt and the chirp went away!!.....for about 80 miles...
so I guess im going to have to shim it now and pray that it works! where would i buy a longer bolt from so i can get alll the threads engaged??
UPDATE: replaced the hb to see if that would help anything since i had already purchased it and the old one was looking a little iffy. put on a new belt and the chirp went away!!.....for about 80 miles...
so I guess im going to have to shim it now and pray that it works! where would i buy a longer bolt from so i can get alll the threads engaged??
I have heard people say that, but what is that based on? Do the GM manuals say that? Here is some interesting info on the design, purpose and identification of TTY bolts: http://www.enginebuildermag.com/2005...head-bolt-use/ I wonder if the only reason it is recommended to replace the crank bolt is because there is sealer on the end.
Install old bolt and torque to 240 ft lbs to seat the damper nice and flat
Install new bolt and torque to 37 lbs, then turn bolt an additional 140 degrees which I'm assuming makes it a TTY bolt at this point.
