1997 vortec piston slap?!@#

[1Bradymichael]

Was wondering if anybody has ever heard of any issues with the 350 vortec when starting cold? I have one that sounds like it has a bit of piston slap which goes away after about 30 seconds. It is not a lifter,but I suppose it could be a bearing. The motor has 130,000 miles on the clock,but runs like new.It does not burn any oil,and I run 5w-30 synthetic(Valvoline). I had a 97 Venture that had the same thing and more than one GM mechanic said it was perfectly normal for this motor becuase of ceramic skirts. Any input would be appreciated.Thanks
Mike

[1Bradymichael]

Anybody out there have any ideas?

[tooltimetech]

I have had 2 97's with 350 vortec's and one had 104,000 on it, now my newest purchase has 120,000 on it. Both have slight knock in cold start up, actually the one with 120,000 sounds a little better than the one with 104,000 before it left me, (sold it to the ins. co. after totalling it out). Any way I am not concerned about the noise, a little piston slap is to be expected after so many miles. As long as it runs good, doesn't burn oil, doesn't overheat, and is maintained properly it will likely go for a very long time. Haven't heard of any ceramic pistons, the 350's have normal pistons in them. When the noise goes away in a short amount of time (30 seconds to 2 minutes) is good, if the noise persists for a very long time or doesn't go away at all then it is starting to get a little loose. A scored or collapsed piston will make noise cold and warm, a piston with an extra thousandths of clearance will just make a little noise until it gets some heat in it and expands a little.

[1Bradymichael]

Thanks for the info.This is kinda what I suspected but it is always nice to here another point of view from somebody else!