by spencerforhire » Wed Aug 17, 2016 9:38 pm
If a timing chain breaks after only 6000 or 7000 miles, there's really only two possibilities-
1- It was a defective(and most likely cheap) chain.
2- It was installed improperly.
I once had a chain fail in a race engine; a double roller, I had visually checked it when I bought the engine used; everything was tight and appeared to be fine. But 30 or 40 passes later, the chain in a dozen pieces along with a pile of shrapnel had liberated itself out of the hole it tore in the front cover. A spectacular failure at 6000+RPM that also bent 11 valves and 5 pushrods.
Post mortem revealed the most probable cause- a 3-keyway aftermarket bottom gear, mated to an OEM chain and top gear. Obviously not compatible in some way(pitch, or possibly roller size) the chain had sheared ALL THE TEETH from the top gear before it failed. Somebody cheaped out, or possibly just didn't know any better and put some mis-matched parts together, with disastrous consequences.
The "fleet"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....
Visit http://www.spencerforhire.ca