What would cause breaking a timing chain or timing gear?

[murse]

Doesn't take much to snap something I'd the engine is already moving. Somethings gotta give.

I ran stock components in my old big bore set up. But then there weren't a lot of upgrades back then. Think about all the stock 03/04's making big power with stock stuff. I'm thinking you have an oiling issue and the cams and journals are going to show signs of that.

That's kind of what I was thinking, all these terminators making big power and how many upgraded to all billet stuff???? I'll update this thread when I know more.

I had a built 3V with all new timing chains and guides. Decided to do a cam change shortly after and there was evidence the new guides had been deforming. Went with billet guides.

Guess I'll add the guides too lol

This break is not uncommon. Take notice of the pic you provided. They seem to break at the keyway point on the gear. I purchased a lot of experimental 4.6 dohc testing hardware in Michigan in 05. Also left over racing hardware. I probably still have some perpritory cam designs that showed where the gear key broke and spun around the end of the cam. I questioned the race engine builder. He said the bolts are one time use only. Good luck.

I'll have to see if he used new hardware or reused the old bolts. Thanks for the tip

 

[lOOKnGO]

I checked after my post, it didn't take much to confirm what I posted. Straight from LMR's web site, APR specs The cam sprocket bolts and washers are one time use torque to yield.

Sent from my SM-S506DL using the svtperformance.com mobile app

 

[murse]

I checked after my post, it didn't take much to confirm what I posted. Straight from LMR's web site, APR specs The cam sprocket bolts and washers are one time use torque to yield.

Thank you

 

[Turbo98GT]

whats the cam specs

 

[murse]

Should have updated this awhile ago, (actually just got the car back after 11 months being down) but the cam bolt just sheared off. NO clue why. Replaced with ARP bolts.

Also spent 3 grand on machine work. Ended up replacing 14 valves, pulled the pistons out to make sure they were ok and replaced the rings. Replaced crank and rod bearings, replaced oil pump, chains and replaced all valve seals while the head was out.

 

[P49Y-CY]

so they originally reused the oem tty bolts? that sucks. plus i think the 99-04 bolts are smaller and thinner than 96-98.

best of luck with it tho and thanks for the update

 

[murse]

so they originally reused the oem tty bolts? that sucks. plus i think the 99-04 bolts are smaller and thinner than 96-98.

best of luck with it tho and thanks for the update

I don't know, thanks.

 

[robvas]

Don't mean to get off topic but do you know why your car only made 600 on 19psi? What timing etc it had?

Seems like it should have made that on 15lbs (300 x 2) My stock headed 2V made 80hp less on 15psi on the same dyno (smaller blower though - S trim)

 

[Zemedici]

Don't mean to get off topic but do you know why your car only made 600 on 19psi? What timing etc it had?

Seems like it should have made that on 15lbs (300 x 2) My stock headed 2V made 80hp less on 15psi on the same dyno (smaller blower though - S trim)

Don’t get caught up in dyno numbers, could be 6294638 things affecting the number