Tick-tick noise: LS1 vs. Northstar

[Jack M]

This is going to be a little different approach to the same old LS1 question of why we get tick-tick noises in our engines during cold starts in the mornings.

These noises can be root-caused by lifters, exhaust manifolds, injectors, oil pumps, air pumps, and piston slap. All of these except piston slap can be corrected without great expense. GM has explained piston slap, and says it doesn't harm the engine. Some LS1 owners agree with GM, others don't.

My question is: Why is it that the 32 valve aluminum block Cadillac Northstar engine doesn't produce tick noises (assuming good care), and the 16 valve aluminum block Chevrolet LS1 engine does, at least on cold starts??

This may be somewhat of an unfair question because the Northstar is considerably more complex and expensive than the LS1. However, both are aluminum, which tends to transmit noises more readily. Yet, the Northstar does not, while the LS1 does.

So, excepting the well-explained piston slap issue, what are the technical reasons why one engine does not have cold start noises - and the other does?

Let me offer some background creditionals: I've owned six Cadillacs, ranging from Eldorados ('85, '89 (two), '95, and my present '01) to a '93 Northstar Allante. None of the three of these with aluminum blocks ever had a tick, nor have the other ones with cast iron blocks. I now own a stock 2002 Z-28 LS1 Camaro with 35k miles that performs great, and I dearly love it, but it does have that cold start tick.

Hope this post generates some interesting responses - and proves helpful.

Best regards,

[z28misfit]

My 99 z28 with 53,000 on it does the same thing. Once it is warmed up it goes away. I'm not too worried about, but I would love to stop it one day.