m_ridzon

Question about the 2.0L LNF balance shaft sprocket bolts...

1. Are they "torque-to-yield," thus needing replaced every time they are removed?
2. If YES to #1, can someone tell me their part number? I can't seem to find it poking around the web.

Thanks in advance!
M Ridzon

donbrew

I don't know of any "torque to yield" bolts on the car. They are "Prevailing Torque" bolts; they may be reused if you can develop the minimum torque without bottoming out and there is no rust or other visible damage on the threads. The manual does not say which ones are. It does say to throw almost all bolts away with no reason given.

From Mitchell OnDemand

m_ridzon

Very interesting. I pulled up Mitchell's at my library for my engine repairs. In the specific sections pertaining to a certain repair (e.g., cylinder head replacement), I noticed that most major bolts (e.g., cylinder head, rods, mains, cam sprockets, balancer bolt, flywheel bolts, etc.) say to discard and replace, every time they are removed. And my understanding was because they are "torque-to-yield" (i.e., one-time use because they become stretched just to the point of no elastic return).

I'm going back to the library later today. On my previous trip, I had forgotten to look up information for the balancer shaft sprockets. I'll check that on today's trip and report back.

Oldblue

donbrew

There are no stretch bolts. They use those on iron engines with alloy heads. They stretch with thermal expansion so the heads don't crack by being too tight.

Somebody in the wayback decided that any bolt with an angle spec is a TTY. Now it is "common knowledge". GM would have you discard and replace every bolt that is not holding sheet metal; (I am thinking $$$$ and CYA). TTY actually means that the threads are deformed to lock them. Think about relative hardness for a minute; if you used bolts that are harder than than the block you would need to replace the block every time; if the bolts are softer what would be the use.

Neither AllData nor Mitchell identifies any bolts as TTY or prevailing torque. The prevailing torque fasteners are the nylon insert type and the squash nuts.

I daresay that your local mechanic has never thrown a bolt away on purpose. Unless they are stretch bolts.

m_ridzon

Hmm, the local dealership said the part number for these bolts is: 11516327
If you check that number on Google, Amazon, or eBay, nothing comes up but hits pertaining to front bumper bolts. No hits hint at balance shaft sprocket bolts. Weird.

Oldblue

m_ridzon

(thumbs up!)

donbrew

https://www.gmpartsgiant.com/parts/gm-bolt-11516327.html?Make=Chevrolet&Model=HHR&Year=2008&S ubmodel=&Filter=()

They say flange head need 2 engine assembly.

and these

m_ridzon

Now I'm scratching my head. @Oldblue said that the old bolts could be re-used, so I went to the library to look up their torque spec. In the infinite wisdom of Mitchell's Online ProDemand, it merely said "don't remove balance shaft sprocket bolts." Well isn't that just jolly! Duh Almighty Mitchell's, what do you do if they have been removed? I scoured everywhere in the manual but couldn't find anything more. So now the question is...does anybody know what their torque spec is for the balance shaft sprocket bolts?