Machinist's advice sought

Verne_Frantz · #1 08-25-2016, 09:08 PM

Can these problems be fixed, and if so, how? (I didn't do it!)
Verne [img]<<GRAEMLIN_URL>>/rolleyes.gif[/img]

**Zman1969** · #2 08-25-2016, 10:08 PM

Verne the lower photo, it appears the head of the valve broke off. the seat may be saveable - may need to be replaced (probable) along with new valve but I cant figure out what the upper picture is of? or if its related?

**Spooky** · #3 08-25-2016, 10:32 PM

looks like a pinned rocker boss

Verne_Frantz · #4 08-25-2016, 11:26 PM

Pinned rocker stud boss - - - cracked

Verne

**Lynn** · #5 08-25-2016, 11:39 PM

The valve: no problem. Drive it out from the top and put in a new valve guide.

The stud: Depends on how deep that crack runs on the stud boss.

It may be possible to fix, but the question will be; is it worth it?

If I were to undertake fixing it, I would try to pry the pin out (in your first pic, looks like just enough room to get a small screwdriver in at the bottom of the pin and force it back out far enough you can get a pair of dykes on it to remove it. Have the head machined for screw in studs. Magnaflux to see if you got all of the cracked part machined off. If not, COULD weld and re-machine but now you are getting into serious money. Unless it is a REALLY rare head, you are miles better finding a new casting.

**earntaz** · #6 08-25-2016, 11:48 PM

If the head is not unique -- try to find another ... if one stud broke it is hard telling when another one will take a dump. TAZ

**SuperNovaSS** · #7 08-26-2016, 12:12 AM

I agree, the seat and guide are no problem as long as there is enough meat for a hard seat. Going to screw in studs is a good solution. Welding should not be crazy expensive. It is just very hard to find guys to do it. That type of repair with likely require pre heating the entire head and argon flood welding since its cast iron. Old school guys put the head on a charcoal BBQ to heat it, do the welding while on the BBQ and leave the head on the BBQ to cool as the coals go out which allows for even cooling. It's the quick cooling that causes cracks. Hearing a "tink" is the sound of death.

I believe there are also a lot of newer processes now as well.

Jason

68l30 · #8 08-26-2016, 01:03 AM

Had a stud issue like above on a set of 462's. I should have been running screw in studs. Have the mount milled down and threaded for screw in studs. Mag the boss after machining to make sure the crack is gone. The pin hole SHOULD have stopped the crack, I would be surprised if it went below the hole.

BIG

Verne_Frantz · #9 08-26-2016, 02:58 AM

Thanks BIG. I'll have to look close to see how far down the crack is. The pin goes all the way through the boss, so getting it out is as simple as driving it out from one side with a pin punch. Then is the fun of getting out what's left of the broken stud.
The head is worth the expense. '62 409 hi-perf.
Hopefully the valve seat replacement won't enter more problems (water). The rest of the valve is still help in by the retainer and keepers. It should just fall out and hopefully leave a good guide.

Verne
edit: The broken valve is an intake but the broken stud is the exhaust. I'll also need to correct this:

This engine was built (I was told) by Dan Jessel in '62 when he was working at Duffy's in Red Bank, NJ. It's a complete A/S spec engine so I'd kinda like to fix it.

**SuperNovaSS** · #10 08-26-2016, 03:33 AM

Maybe ask other 409 guys if they have installed hard intake seats with no issues. A buddy had a caddy head welded and had a seat cut in the welded material so that could be an option.

Jason