Avoiding hotspots
Thread Starter
Race Director
Joined: Nov 2000
Posts: 16,416
Likes: 1
From: NC,USA
Avoiding hotspots
Hey guys...
I was inspecting my new pistons. Forged TRW's for the 355... Anyways, the valve reliefs are extremely sharp. You can cut your thumb nail on the edge!
I've heard that leaving something like this is bad for the motor, causing detonation when these edges get cherry red. My question... is what kind of toold do I need to use to knock them down? I was thinking a small stone, but i dont have one that is small enough to get into a valve relief! Maybe just slice it off with a knife? Its aluminum after all...
I just dont want to hack up my "EXPENSIVE" pistons... without a clue what I'm doing...
Thanks yall
I was inspecting my new pistons. Forged TRW's for the 355... Anyways, the valve reliefs are extremely sharp. You can cut your thumb nail on the edge!
I've heard that leaving something like this is bad for the motor, causing detonation when these edges get cherry red. My question... is what kind of toold do I need to use to knock them down? I was thinking a small stone, but i dont have one that is small enough to get into a valve relief! Maybe just slice it off with a knife? Its aluminum after all...
I just dont want to hack up my "EXPENSIVE" pistons... without a clue what I'm doing...
Thanks yall
Intermediate
Joined: Aug 2004
Posts: 42
Likes: 0
Pistons
Hi,
Don't know about anyone else, but I just use wet and dry
sandpaper, I use water.
I start with 400 to just round the edges and then use 600
to polish them off.
I really get carried away and remove all sharp edges in the
pin boss area inside the piston also. Sharp edges and cracks
go hand in hand.
(Do not round), Outside bottom skirt edge as this is also oil scraper.
Just polish the top sharp edges and you'll be fine.
I tend to get carried away sometimes
Later
jaykar
Don't know about anyone else, but I just use wet and dry
sandpaper, I use water.
I start with 400 to just round the edges and then use 600
to polish them off.
I really get carried away and remove all sharp edges in the
pin boss area inside the piston also. Sharp edges and cracks
go hand in hand.
(Do not round), Outside bottom skirt edge as this is also oil scraper.
Just polish the top sharp edges and you'll be fine.
I tend to get carried away sometimes
Later
jaykar
Thread Starter
Race Director
Joined: Nov 2000
Posts: 16,416
Likes: 1
From: NC,USA
The rods are already mounted to the pistons... so not much I can do about the undersides... unless I want to have them pressed back off!
I really do need to re-think whether or not I want to balance/align bore this engine!
I really do need to re-think whether or not I want to balance/align bore this engine!
Intermediate
Joined: Aug 2004
Posts: 42
Likes: 0
Hot Spots
Hi,
Don't even worry about the undersides.
Like I said I tend to get carried away. That was pretty much
when I was buildings race engines for myself and others.
They were seeing a whole lot more RPM and Comp 13.5 and up and were being run for along time under RPM and pressure.
Just wrap up the ring lands and down to keep water n stuff
out of the land and pin area since thier already hung.
Even if you were running floating pins wound'nt go to the
trouble to unlock them.
Besides rods give you something to hang on to while you work
P.S What did you mean Balance and align Bore. I Missed that one?
Later
jaykar
Don't even worry about the undersides.
Like I said I tend to get carried away. That was pretty much
when I was buildings race engines for myself and others.
They were seeing a whole lot more RPM and Comp 13.5 and up and were being run for along time under RPM and pressure.
Just wrap up the ring lands and down to keep water n stuff
out of the land and pin area since thier already hung.
Even if you were running floating pins wound'nt go to the
trouble to unlock them.
Besides rods give you something to hang on to while you work
P.S What did you mean Balance and align Bore. I Missed that one?
Later
jaykar
Last edited by jaykar; Nov 5, 2004 at 06:10 PM.
