steves86ta

iTrader: (5)

Hi

Let me start off with that I know aluminum blocks grow so we set the clearances up on the tight side of things...

However I'll be using my aluminum 5.3 block in a jet boat, and the coolant temp never gets above 140-160 degrees...

Knowing this should I still set this thing up on the tight end of things or should I set it up a little looser?

Will the block still grow as much with the constant cold water running through it?

Thanks

Che70velle

iTrader: (6)

I’ve seen .014” on main bearings with an aluminum LS7 rebuild, so different peoples idea of tight clearances can vary. Personally I’d try and get the water temp in the engine up toward 180-200 and set it up typical .002-.0024” clearance. Water temp will affect piston to wall clearances, lifter to lifter bore clearances, as well as valve to guide clearances among other things like oil temps which need to be upwards of 180-200. You can adjust water temps with a valving setup I assume?

steves86ta

iTrader: (5)

Yeah there's a valve but it's not an exact science...the water is moving in and out of the block so quickly it just doesn't have time to warm up.

On the hottest of days I think I've seen 180. But only at idle and once moving dropped down to 140.

I was planning to shoot for .0018 -.002 on the main clearances... My last engine (that lasted) was .0025 and seemed okay. But that was with an iron block.

brandon6.0

iTrader: (32)

Yea shoot for the clearance u posted. It will be fine. U can go to .0025 any maybe a melling pump if u choose.

Almuinum blocks do grow with temp. I always ahoot for .0020 and they seem fine. Factory clearance on some setups are usually tighter than tht as posted above.