Machinist's advice sought
 

Can these problems be fixed, and if so, how? (I didn't do it!)
Verne [img]<<GRAEMLIN_URL>>/rolleyes.gif[/img]
https://www.yenko.net/ubbthreads/pics...3-eng.stud.jpg
https://www.yenko.net/ubbthreads/pics...lve_pocket.jpg

Re: Machinist's advice sought
 

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?

Re: Machinist's advice sought
 

looks like a pinned rocker boss

Re: Machinist's advice sought
 

Pinned rocker stud boss - - - cracked

Verne

Re: Machinist's advice sought
 

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.

Re: Machinist's advice sought
 

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

Re: Machinist's advice sought
 

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 &quot;tink&quot; is the sound of death.

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

Jason

Re: Machinist's advice sought
 

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

Re: Machinist's advice sought
 

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:
https://www.yenko.net/ubbthreads/pics...ton_damage.jpg
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.

Re: Machinist's advice sought
 

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

Re: Machinist's advice sought
 

That's why I'm afraid. Some went ok and some hit water. Not much meat there, I guess.

Verne

Re: Machinist's advice sought
 

Well, I took a close look at the stud. The crack only goes down to the pin hole. Surprisingly, (or maybe not since it was built as a race motor)the studs are threaded and there's no damage to the threads from it breaking off. I'm seriously thinking about just replacing the stud and living with the crack. I would drill it and re-pin it. The crack has no where to travel because it stops at the pin hole and it's only the top 1/8in. Am I crazy??

Verne [img]<<GRAEMLIN_URL>>/dunno.gif[/img]

Re: Machinist's advice sought
 

I think it all depends on your spring pressure. Anything above stock I would be concerned. Make sure you have plenty of thread engagement under the cracked area.

BIG

Re: Machinist's advice sought
 

No heavy duty springs BIG. Just OEM. These '09s don't like to rev that high anyway so they don't need a ton of pressure (stock cam).

Verne [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]

Re: Machinist's advice sought
 

Should only drill and pin off to the side of the stud to remove minimum stud material. Threaded stud is best and needs nothing else. If all have been replaced with threaded studs and also pinned, I'd remove the pins &amp; drilled studs (scrap them) and replace with new studs only.

Paul

Re: Machinist's advice sought
 

Verne, FIX THE HEAD! Weld up the crack or you're just asking for trouble down the road. It's not a big deal. BUT send it to the best head guy you can find, maybe Dave Mills will help???

Piston is an easy fix. Take it out and get it checked for cracks. IF NONE FOUND, just sand off the sharp edges with a dremel or similar tool and re-use the piston. Deburr any and all sharp edges and you will be fine as long as the gouges are not too deep. But being a 409 there should be a ton of meat there.

Good luck, John

Re: Machinist's advice sought
 

Thanks for the opinions. As for the piston, that was my plan (as long as its not cracked). The stud broke for two reasons. One is that it was weakened by the pin hole and two because the Intake valve head got caught under the exhaust valve. I don't plan on drilling the new stud.
As for the crack, I'm still not convinced it might cause more problems. It can't go anywhere because it ends at the pin hole and there should be no side to side thrust on the stud. Once the old stud is removed, I'll see how far down the threads go.

Verne [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]

Re: Machinist's advice sought
 

Threaded and pinned is like belt and suspenders. Actually worse since the pins cause stress risers. I agree on pulling the pins...

Re: Machinist's advice sought
 

There was no real reason to pin a threaded stud. That was usually only done on push in studs for some that had higher than stock spring pressures.

Re: Machinist's advice sought
 

These heads were made about a month after the factory started pinning them so the pins were already there. I guess someone decided to replace them after adding the screw-in studs.

Verne