schreurs1

Just bought an L92 for my fox. Motor is a core that broke a valve spring, bent a valve and pushrod, broke the lifter and tray and scuffed the piston. Piston looks ok but when the valve bent, it cracked the guide and put a hairline crack in the surrounding aluminum. My question is what should a guy do with that crack? Weld it? Leave it? Machine the guide support out completely? On our aluminum headed sprint car engines, the guides have no surrounding aluminum support where the guide enters the runner so that makes me wonder if I can't just leave it or grind it down. It's only cracked on one side so I don't think it will drop a chunk of aluminum into the motor, but I'm also not an engine builder either. So what would you do?

litle88

iTrader: (20)

Pics?

schreurs1

Here is a pic of the guide. Obviously the guide itself will need to be replaced. To left of the guide is the hairline crack in the casting.

schreurs1

will try to get a better picture tonight

1989GTA

Welding is an option. However you just might be better off buying a new head. Will wait for a better picture.

schreurs1

schreurs1

Our ASCS engines don't have the aluminum where the crack is, just a guide hangin out in the runner. And that's a lot more abusive environment as well.

schreurs1

Any input?

KCS

iTrader: (20)

I'd pop the guide out and then take a look.

If it isn't too bad, you may be able to just grind it out and keep material removal to a minimum to keep the crack from spreading further. If it gets to where you have to weld and then remachine the guide boss, it may be more cost effective to find another head and chalk this one up as a practice or mock up head.

1989GTA

This ^^^^^

schreurs1

that's kinda what im thinkin too Im going to see how it acts when we take the old guide out and go from there

hellbents10

iTrader: (10)

Weld the crack then pull the guide and put a new one in.