I changed to an electric water pump and a double aftermarket roller chain is a fraction of the price of the GM high performance one (which is a single roller and the difference in cost will by the electric pump). Stock chain is junk (stamped steel) and GM should be ashamed to have ever installing it in a flagship car. Mine was giving me a P335 code because the cam was walking and causing the CKP sensor to see it as a miss fire. Drove me crazy finding it until I gave in to doing the big job to change the timing chain (while the motor is in the car). Intake has to come off to get at the stub oil pump drive and the pan has to come off to put in a new one piece gasket which gets destroyed removing the timing chain cover. Rad, condenser and tubs all come out. Then motor has to be lifted to allow the damper to be removed and the cam clear the cross bar. On top of that, the power steering rack was unbolted and pushed forward as far as it will go. I did mine on a lift and doing it on jacks would be insane!
So, a double roller is the same center to center as any SBC but the reluctor grinds on the chain. You can see how the high performance lower sprocket is cut to make it clear. I'm having spacers cut on a hydrojet to move the cover and reluctor ( and accessories) out 1/8" and then everything should be happy. This motor kept the GM single roller and the crank vibrations returned to better than normal (above 1500 RPM with Hot Cam. Below 1000 RPM, the cam has enough vibration to set the sensor off so I raised the sensing RPM with the tune-up). I'll post the new rumble sometime if can get a video done. To quote the kids... wicked!
|UPDATED|8/27/2013 6:41:52 PM (AZT)|/UPDATED|
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Adams' Apple
jimmymack
nice job, well done!
