Lifters, piston slap, or normal?

ls1frc

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I had piston slap in my 5.3, the 6.2 does not sound like piston slap to me. The sound is too metallic/tappy for piston slap. Piston slap is a hollow sound. Both my 5.3 and my old G8 did it. And it goes away quickly, not after 20 minutes of warming up. I honestly think these lifters are just defective at this point. I am going to throw in the super long pushrods as a hail mary.

Other than cam/lifters, what else could a VT noise be? I hope not cam bearings? I'd imagine bad cam bearings would be opposite, as in quieter when cold and noisier when hot like a rod bearing would be.

Other things I can think of would be oil aeration but I'd think I'd have issues warm as well. Motor is very quiet warmed up....


Listen to this at 30 seconds, this is what piston slap is. Mine doesn't sound anything like this.
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Geotrash

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I had piston slap in my 5.3, the 6.2 does not sound like piston slap to me. The sound is too metallic/tappy for piston slap. Piston slap is a hollow sound. Both my 5.3 and my old G8 did it. And it goes away quickly, not after 20 minutes of warming up. I honestly think these lifters are just defective at this point. I am going to throw in the super long pushrods as a hail mary.

Other than cam/lifters, what else could a VT noise be? I hope not cam bearings? I'd imagine bad cam bearings would be opposite, as in quieter when cold and noisier when hot like a rod bearing would be.

Other things I can think of would be oil aeration but I'd think I'd have issues warm as well. Motor is very quiet warmed up....


Listen to this at 30 seconds, this is what piston slap is. Mine doesn't sound anything like this.
You must be logged in to see this image or video!
The only other thing I can think of is a lifter bore that's wallered out, but I would also expect that noise to grow as the engine warms because aluminum expands faster and to a greater degree than steel.
 

ls1frc

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The only other thing I can think of is a lifter bore that's wallered out, but I would also expect that noise to grow as the engine warms because aluminum expands faster and to a greater degree than steel.

I have read that Johnson lifters
The only other thing I can think of is a lifter bore that's wallered out, but I would also expect that noise to grow as the engine warms because aluminum expands faster and to a greater degree than steel.

I have read that someone measured johnson lifters as slightly smaller than stock causing lower oil pressure than factory.

I went ahead and measured every pushrod for zero lash. Ranged from 7.260 to 7.275. I had 7.325 pushrods so within spec everywhere.

I put in the stock 7.4 pushrods while I was there just as a test to see if maybe the lifters are gunked up somehow and this could potentially free them up since the plunger is so far preloaded now.

If it still sounds like shit tomorrow morning im gonna swap lifters. The 20 minutes of awful sounding VT noises everyday ruins all the hard work.
 

Geotrash

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I went ahead and measured every pushrod for zero lash. Ranged from 7.260 to 7.275. I had 7.325 pushrods so within spec everywhere.

I put in the stock 7.4 pushrods while I was there just as a test to see if maybe the lifters are gunked up somehow and this could potentially free them up since the plunger is so far preloaded now.

If it still sounds like shit tomorrow morning im gonna swap lifters. The 20 minutes of awful sounding VT noises everyday ruins all the hard work.
Hmmm...as I understand it, one of the signs of pushrods that are too long is more valve train noise. I'm wondering based on your measurements, if you might be better off trying a slightly shorter pushrod than you had in there.

One of the steps I took in putting my engine back together during my 2nd cam swap attempt, was to mark the top of the valve stems with a sharpie. When the valve train geometry is right, the rocker arms will reach the exact center of the valve stem tips at half valve lift. I spot checked 2 cylinders this way and it was within spec.
 

ls1frc

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Hmmm...as I understand it, one of the signs of pushrods that are too long is more valve train noise. I'm wondering based on your measurements, if you might be better off trying a slightly shorter pushrod than you had in there.

One of the steps I took in putting my engine back together during my 2nd cam swap attempt, was to mark the top of the valve stems with a sharpie. When the valve train geometry is right, the rocker arms will reach the exact center of the valve stem tips at half valve lift. I spot checked 2 cylinders this way and it was within spec.

As I understand it, in a hydraulic setup with fixed rockers there's no way to adjust it so the wipe pattern changes. The only thing you can change is where the plunger sits in the lifter body by adjusting pushrod length.

Total travel on the lifters is .200. I am down about .140 in the lifter body, which is way too much however should not have any bearing on noise and I am only doing it as a test run anyway to see how it reacts over the next couple of cold starts. The theory is there is now less space needed to fill with oil, so it should fill quicker on a cold start.

It was noisiest with the 7.300" I had in there a couple months ago, which I can see why. I only had .025" preload on some lifters.

I've had dozens of cammed setups and never had noise like this, that's why it's so frustrating.
 

Geotrash

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As I understand it, in a hydraulic setup with fixed rockers there's no way to adjust it so the wipe pattern changes. The only thing you can change is where the plunger sits in the lifter body by adjusting pushrod length.

I've had dozens of cammed setups and never had noise like this, that's why it's so frustrating.
Good to know! I'm learning every day. Hope your experiment this time pays off and you won't have to pull the lifters.
 

ls1frc

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Good to know! I'm learning every day. Hope your experiment this time pays off and you won't have to pull the lifters.

Me too! I heard similar complaints about people with Morel 5206 lifters. One guy switched to insanely long pushrods and it quieted down his setup.

I got so good at pulling heads, it would just be a day's work not a huge deal just annoying when you spend $430 on lifters.
 

ls1frc

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No change with the longer pushrods. MAYBE slightly quieter when warm. The engine sounds perfectly fine when warm, maybe I do just need to live with it ugh.
 

Geotrash

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No change with the longer pushrods. MAYBE slightly quieter when warm. The engine sounds perfectly fine when warm, maybe I do just need to live with it ugh.
Maybe so. I get why it would annoy you though. It would me, too. My Morel 6504's are definitely louder than stock lifters when cold but quiet down quickly.
 

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