Really dumb question!
Thread Starter
|
Fleet Mechanic
Joined: Jul 2000
Posts: 1,494
Likes: 347
From: SE Iowa
Really dumb question!
Okay, I knew my good friend was a cheap-A$$, but this one really takes the cake. I wasnt even going to post this, but he bought over a 12-pack to talk me into it.
Question: He's building a 400 for his '76 F150 and has the motor completely bolted up and ready to install. He somehow got a wild hair up his A$$ and decided he now wants to grind off emissions bump in the exhaust ports...only he want to do it without taking the heads off, just unbolt the rockers to close the valves then blow out the mess. I told him to just go buy another gasket set and chalk it up to " I told you to do it in the damn place!"
So what the crowds opinion? Is this "safe" or will he get shaving in the cylinders?
Stryder
Question: He's building a 400 for his '76 F150 and has the motor completely bolted up and ready to install. He somehow got a wild hair up his A$$ and decided he now wants to grind off emissions bump in the exhaust ports...only he want to do it without taking the heads off, just unbolt the rockers to close the valves then blow out the mess. I told him to just go buy another gasket set and chalk it up to " I told you to do it in the damn place!"
So what the crowds opinion? Is this "safe" or will he get shaving in the cylinders?
Stryder
Post Fiend
Joined: Jan 2003
Posts: 8,600
Likes: 4
From: Iowa
Really dumb question!
I wouldn't, and I've been known to do some pretty stu..., uh, wild things. It'd probably be ok, the exhaust would probably blow them out, except on the cylinders with the exhaust valve open when he grinds them. Why risk it? He probably doesn't even need the new head gaskets. Just pull the heads, grind the emmisions bump off, wipe 'em off good, and slap it back together.
Edit: even if the exhaust valves are all closed, there's still a small overhang on the valve, and some could get sucked in when the valve opens.
Edit: even if the exhaust valves are all closed, there's still a small overhang on the valve, and some could get sucked in when the valve opens.
Posting Guru
Joined: May 2003
Posts: 1,393
Likes: 0
From: Thomson, GA
Really dumb question!
And if he has a decent cam, it will have some overlap, meaning both valves are open, and it *could* pull some back in. It would be easier with the heads off anyway.... but its not your motor, and if your buddy is always giving you a hard time, let him do it, and give him a light "i wouldn't do that if I were you"
Elder User
Joined: Aug 2001
Posts: 508
Likes: 0
Really dumb question!
Even if your buddy gets all the valves closed, the grinding residue still might find a way into the engine. I once sand blasted a bare engine block prior to painting. Even though all the openings were heavily duct taped shut, lots of sand somehow got inside. (The block still needed to be honed, thus the sand didn't hurt anything. However, I did spend a long time pressure washing it to make sure there was no sand in an oil passage.)
Thread Starter
|
Fleet Mechanic
Joined: Jul 2000
Posts: 1,494
Likes: 347
From: SE Iowa
Really dumb question!
Thanks guys. These are all the EXACT same things I told him, but he insists that by unbolting the rockers, all valves are completely closed and he can use an air nozzle to blow them out. Maybe he'll change his mind when he reads this.
Side question of my own: I thought that once you torqued the head gaskets down, they are "used" and should'nt be used again?
Stryder
Side question of my own: I thought that once you torqued the head gaskets down, they are "used" and should'nt be used again?
Stryder
