noise in engine

[trex1270]

Ok, I have an LS in my 69. after I drive it a while I get a noise that sounds like a lifter....so I replaced them..twice. Noise came back and I thought, maybe a valve spring, so replaced those. It was good all winter. Now the noise has came back...I have no idea what it can be...any ideas? there is no power loss and it drives fine...

[Chevelle598bb]

Is the noise only when the engine is cold or does it also make noise while warm. If its cold it could be piston slap and if warm it could be a lifter bore that is too large causing excessive lifter bore to lifter clearance.

[trex1270]

it only does it when the engine is warm, after I have driven it about 10 miles...I forgot to mention, the noise comes and goes...

[Chevelle598bb]

More than likely a worn lifter bore. I have seen a few out of spec in early aluminum block ls engines.

[trex1270]

Fix?

[Chevelle598bb]

If it is an oversized lifter bore which you can't tell without pulling the lifters and measuring there is only a few options. Trash the block or have the offending lifter bores bushed (expensive) or have all the lifter bores bushed (very expensive).

A good practice is to mic the lifter bores on an lsx engine before sending the block to the machine shop.

[trex1270]

I went back and re read some of the post...this is an Iron 5.3 block that I had bored do 5.7

[Chevelle598bb]

Well let's dig a little deeper then. What cam, brand of lifter, length pushrod, valve springs and rocker arms are you using.

[trex1270]

Comp torquer v2, lunati( tried two sets of ls7), Texas speed valve springs on prc stage 2 heads. I'll check on push rod length tomorrow. It only makes noise on drivers side. I'm wondering if there is an oiling issue letting a lifter bleed down... Oh stock rocker arms. Thanks

[Trevor @ Texas Speed]

You definitely need to check your pushrod length. We recommend using an adjustable pushrod length checker to verify proper lifter pre-load on any new setup. You can have the same exact grind cam, but if two different cam cores were used to grind each cam you can see a variance by as much as .050" in pushrod length! You will also have varying lengths in lifters, amount milled off of cylinder heads, thickness of head gaskets, etc. that all play into the final pushrod length required to attain proper lifter pre-load. If you have the Lunati 72232 lifters, they will have a normal travel range for the plunger. You typically want to be somewhere in the .040" to .080" pre-load range, ideally being somewhere in the middle.

Let us know if we can help!

Thanks!

Trevor
Texas Speed & Performance

[trex1270]

There are 40 thousands per load. Stephen at east Texas muscle cars built the engine.

[trex1270]

Changed viscosity of oil went to 20-50...noise gone

[Riggs 74]

Any updates? Was the sound like a rod knocking?
How long did you drive the car with the new oil before the noise disappeared?

Riggs

[trex1270]

Not a rod, top end noise. Noise is gone, not returned. The noise was gone immediently.