I have a '97 A4 C5. Installed a Comp Cam 224/224 .567/.567 lifr LSA114. Have Cadillac Racing lifters (suppose to lessen the sewing machine sound), 7.425 push rods, Harland Sharp 1.7 roller rockers, LS6 ported intake.
After these mods were installed the sewing machine sound is louder than the stock valve train.
I used a stethoscope and the valve train sounds fine, the noise is coming from the injectors (30#) and the valve train through the intake runners and top of the LS6 intake. Would installation over the top of the intake quieten this noise?
Another question; is how come some engines with a bigger cam have less of a sewing machine sound? Is it because of the cam maker; isn't all after market cams grind by Comp Cams?
Also; is it true with a lift of less than 550 the sound isn't as loud?
I'm told that this is the sound after a after market cam is installed and just get use to it.
Thanks for any input.