Is my head junk?

[straight6chevyguy]

Chevy inline 6 head
Purchased this as a completely rebuilt head from a machine shop.
Had been sitting for a while and had some light rust or so I thought.
Guess I didn't look at it close enough.
Found a crack on a valve guide stem (not sure of the proper technical term)
And the pitting from the rust on the head face is worse then I thought.

Here is some pictures.
So is it junk?
Im sure probably it's obvious but I thought it would not hurt to ask anyway...

[kwmech]

My first thought is yes it is junk, but I'm not a machinist. Also don't know how much of a cut the cyl head surface can take

[Dead Parrot]

Is this a rare or expensive head?
If it is one with replaceable valve guides, the cracked one could be replaced. But the interesting question is why did it crack?
You should be able to cancel out the rust on the deck surface by using a thicker head gasket.
BUT - the rust on the valve seats looks bad enough that they should either be redone or if money is an issue, hand lapped to clean them up.

Can it be salvaged? Probably but it looks like it needs a complete redo of a valve job, resurface and check/replacement of the valve guides.

If you just purchased it, might be worth asking the shop if they realized it had so many problems.

[vince1]

It seems obvious that someone pounded in a valve guide insert that was way too big. A .001" or .002" interference fit wouldn't have caused such a split. I don't know if it would cause a problem though unless a piece would break away. And after that insert was put in were the seats reground? If you purchased it as a rebuilt head they should at least resurface it for you, provided they could be even trusted to do it.

[straight6chevyguy]

So to answer a few questions:
I bought the head over a year ago from the machine shop I was having my engine block rebored at.
The guy at the shop told me that he had an extra head in the back that had been completely rebuilt and refaced but had been sitting for a few years.
I asked how much he wanted for it, he said $150. For me this was a heck of a deal for a chevy inline 6 head that had been completely rebuilt.
Before buying a gave it a looking over and it indeed looked like he said, completely rebuilt but sitting for a few years.
The Guy even tells me I can take it home and give it a better looking over before paying for it. Me, being happy with the other work the guy had done for me, said no I think its fine I'll pay now. This was my mistake on my part and cant really be mad at no one but myself. Whether or not the guy knew about the crack I dont know. Really not sure what to say as the guy seemed like a great guy and had done a really good job on my block and had even matched my rod caps back to the correct rods at no extra charge after I had foolishly gotten them mixed up without marking them.

So again, Im not really sure what to think or what to do at this moment.
Think Im going to just think this out for a few days.

I have another head but that needs to be completely redone and will cost me at least $250 to have it redone.

Or I can buy a new reman head online from summit racing for $500.

These heads seem to be getting harder to find and summit seems to be the last place online that I can get one cheap. (If you can consider 500 bucks cheap)

[vince1]

I'd try that head just like it is. Hand lap the valves and put it all back together. The most it should cost you if it doesn't work out is some time and an extra head gasket.

[straight6chevyguy]

So I did some more wire brushing and the head face looks a little bit better.
I think I will give it a try.
Also I think the valve seat will clean with some lapping.

But I do have a couple questions:
Should I use a thicker head gasket or run factory gasket?

I was also thinking about filling in the crack with JB weld, does anyone think this is a good or bad idea?

[vince1]

You could use a straight edge to see if that head surface is bad or not. I'm no expert but maybe have read that you don't want a feeler gauge gap of more than about .003". Or was that .006". I can't remember.
How much heat can JBWeld handle? It might not be a bad idea to try as long as it is not put on so thick that it interferes with the valve spring operation. Do all the valve guides have inserts?

[Dead Parrot]

For the crack, see if you can have it brazed. Likely means that insert is now permanent but would be a better repair then JBWeld.

[Joyridin]

I would be worried that the valve guide isn't straight or bent where the crack is located. When the head cracked, it probably pushed that guide off center. Can you easily slide a valve through the guide?

[straight6chevyguy]

Originally Posted by vince1

You could use a straight edge to see if that head surface is bad or not. I'm no expert but maybe have read that you don't want a feeler gauge gap of more than about .003". Or was that .006". I can't remember.
How much heat can JBWeld handle? It might not be a bad idea to try as long as it is not put on so thick that it interferes with the valve spring operation. Do all the valve guides have inserts?

Yes all the guides have inserts.

Originally Posted by Dead Parrot

For the crack, see if you can have it brazed. Likely means that insert is now permanent but would be a better repair then JBWeld.

I have been planning on learning how to braze not sure I want practice on this lol.
I could try to find someone that could though.

Originally Posted by Joyridin

I would be worried that the valve guide isn't straight or bent where the crack is located. When the head cracked, it probably pushed that guide off center. Can you easily slide a valve through the guide?

Yes the valve slides easily.

[geezer#99]

Sometimes you gotta waste money to save money!
You could glue it back togethor and then drop that valve and spend a few grand replacing your new boat anchor.
Call it a lesson learned and look for another head.

[burnin oil]

Valve is your call. For the head gasket I would try and find a felpro perma torque blue gasket. They are a little thicker but seem to seal any backyard rebuild. Never had one not seal, even on a wavy deck.

[straight6chevyguy]

So today I was thinking about just laying down the money and buying that new reman head from summit, Well I cant seem to find a head for a 250 inline 6 on there website.

Well, the option of a new head is gone. I guess that narrows my choices down.

[vince1]

Another option would be to break off those two halves and ream a new hole for a guide made to fit, no big deal for a machinist. Could be a bit pricey though.

[mattfranklin]

A good shop can completely bore out that old guide housing and replace with a hardened replaceable guide. As long as the crack hasn't progressed. Mine didn't have cracks, but my machinist recommended doing that and then replacing the seals. Positive seals + hardened guides makes for long lasting valve guides and seals without oil consumption. Like modern engines do.

EDIT: "False guides" was the phrase used by my machinist to describe those things. He set it up on a "seats and guides" machine and then bored about a 0.500 hole with drill and reamer. And then pressed in the new hardened guides. He did all the guides that way. I think they might have been a couple of bucks each from Summit.

EDIT2: I'm not talking about the silicon bronze split valve guide liners, but complete hardened iron guides.

['68OrangeSunshine]

Originally Posted by straight6chevyguy

I was also thinking about filling in the crack with JB weld, does anyone think this is a good or bad idea?

JB Weld is a bad idea in this application. It's just an epoxy with metal shavings.
It will not handle heat and pressure.
I had a crack in a stock cast iron exhaust manifold on a 454 BBC in a '67 K/10 Suburban. So I JB-Welded it. Looked fine for a couple of months, then the epoxy burned away.
You want a skilled welder.

[cadillac_al]

Since the OP bought the head from a machine shop, I would have brought it back to him and ask him what he would do. He probably didn't notice the crack and will feel bad and fix it for you and probably resurface it too for dirt cheap.

[crazy longhorn]

Originally Posted by mattfranklin

A good shop can completely bore out that old guide housing and replace with a hardened replaceable guide. As long as the crack hasn't progressed. Mine didn't have cracks, but my machinist recommended doing that and then replacing the seals. Positive seals + hardened guides makes for long lasting valve guides and seals without oil consumption. Like modern engines do.

EDIT: "False guides" was the phrase used by my machinist to describe those things. He set it up on a "seats and guides" machine and then bored about a 0.500 hole with drill and reamer. And then pressed in the new hardened guides. He did all the guides that way. I think they might have been a couple of bucks each from Summit.

EDIT2: I'm not talking about the silicon bronze split valve guide liners, but complete hardened iron guides.

Yes, I have have .500 guides pressed in after machine work....as said , if the crack is just on the top (what we see), it should not be a problem. I would however ask the machinist, if he would fix the problem& resurface the head to remove the pitting from the rust. Maybe let him do the valve job.....if he wont work with you, walk away Crazy L

[straight6chevyguy]

Hi guys, So I Finally decided to talk to the guy at the shop where I got my head.
According to him the crack is not a problem and said that it just happens sometimes and its only a cosmetic thing.

I might be taking a chance but I'm gonna take His word for it.

I am having him re-surface the head. It's at the shop now He said it should be done within a week.

['68OrangeSunshine]

That's cool if he stands behind it. I don't know enough about auto machining to venture an opinion. Like Oddball in Kelly's Heroes, ''Oh I don't know nuthin' about what's inside 'em, Man. I just drive 'em.''
Sometimes, it all comes down to trust.
I would make sure my AAA dues were paid before taking a motor with that head on the road.

[geezer#99]

At least when you hear the tick, tick, tick you’ll know where to look.

[GSP7]

Have a good engine machinist put 12 complete new guides in it. That whole piece that is cracked can be replaced. It has guide inserts sleeves in it as it is.