Technical Punch marks in Double Hump exh seats??

Well, got these 461 Double Humps today, and there's punchmarks around every exhaust seat??
Precautionary or a sign of loose seats? Even though i have a hard time beleiving that all seats in two heads are loose.....
Otherwise, how good is this in respect of heat and pinging??

/Stefan

 

Thats a common way to expand the metal to hold the seats tight

 

PM squirrel and ask him.

 

Lots of the "Old Boys" did that as a matter of course when installing seats in flatheads and such. Some carry it over into newer stuff, like your Chevy. Might cause hot spots and pinging in a high perf engine. I never had any luck with inserts in a head that wasn't designed for them. More than once the inserts were rolling around in the truck box on the way home from the shop!

 

That's what i'm worried of.... and to grind it down adds cc's

 

I don't think the 461's had 'seats', the valves rested on the castings. Are there seats in yours? Really don't look like it but hard to tell with the goo in there. Lots of things were done back then, those holes might have been a 'speed secret' to swirl the exhaust gas or something.
I wouldn't care for them as the thin metal will act as a heating element promoting preignition.
One thing is for sure, those valves are sunk way too deep. They should be sitting up on top of the seat not down in it. Kills the flow.

 

Somebody had hardened seats put in. The punch marks are old school way to retain the seats.

 

If you plan to use them as is, mark each valve as to which hole, pull the valves & closely inspect for loose or leaking seats. If you can have them pressure tested, do so. Chev V8 replacement seats have to be small OD & depth by design - cutting too deep can cause seepage or worse. I'd take a tool to the edges of the chambers & peen the staking flat ....
Once the valves are out, you'll know more.

 

and those punch positions aren't even close enough to the seat insert to actually be doing anything.

 

I think I see the seat inserts and yes was very common in the old days to help keep seats in... they made a tool that piloted off the valve guide and you hit with a hammer and it swedged some material over the outer edge of the seat. That was the "High tech" method back them but the punch marks you have were very common. They shouldn't cause any issues.

 

Thanks for all replys!
Removed the valves today and soda blasted the chamber and this is how it looks now

 

Looks like there are seats down in there. I would take a p*** on these heads. They are too deep. Although if you are just puttin around on the street it may not matter much. But if you want performance you'd want a better set to start with.

 

The peen is EXACTLY for that reason ...to hold the seat in.
what size are the valves ....

 

Staked valve seats I have done it for years. Look how the metal around the punch marks is deformed pushed against and over the seat. I have never had a seat come loose using this method. When I install seats, sleeves, or core plugs put them in the freezer wipe them with a little KW block sealer and press them in.

 

My 71 Pk big block 402 some previous idiot owner had hard seats installed in the exhaust. And one came loose dropped the valve and ruined the engine. I wouldn't use those heads if you paid me. I run old engines and add a pint of diesel to every ten gallons of corn gas. And that works very well for me..

 

They are 1.94 and 1.50

 

and some of us even HEAT the heads to 200* -n- chill the seats/insert -n- they just about fall in...lol

 

and so by installing 2.02-2.05 or even 2.08's along with some 1.60 ex valves ...
will bring them back up or NOT sunk IN so bad....
just as well check and install screw in studs -n guide plates as well( if that hasn't already been done.)
don't forget to check for CRACKS 1st or ANY work may be a setback, or a waste of time -n- money.
it LQQKs like they have replaceable guides in there ALREADY that an EASY check -n- replace.

 

Yep...first thing on to-do list is to check them for cracks....bringing them next week to a friend working at Volvo Aero that got the machinery to do just that

 

Hmm, 1.94 & 1.50 - thats too small for those heads, I'm quite sure the 461 head is supposed to have 2.02 & 1.60, that explains the large gap between the valves. They might be ok, mock up a pair of valves and see how they set up, also flip the head over with the valves in place and they should be deadnuts even. With all the valves in the head you should be able to lay a straight edge across the lot and touch all of them, that means all the are set up equally in the combustion chamber ie the volume is the same. If one valve is sunk here or there your compression will suffer in that cylinder and play hell tuning.

 

Those are '65 - '66 327 250 - 300 hp heads, used 1.94 / 1.50 valves.

 

Well....stems are different heights all over. All intake valves is higher as could be expected

 

You're right, my memory is wonky. I was thinking that was the head used on the 327/365hp. I ran 461X heads with 2.02/1.60 converted to angle plug for many years.

 

If you'll look at the picture of the chamber with the valves installed, the exhaust valve sits pretty high on the seat. That would make the stems shorter when you laid a straight edge across them. If it were for an "all out" engine. you could probably open up the seat a little more for more flow. You'd need to use some bluing and lap the valves in to see where the seat actually hit valve face. I'll bet right now, it would be on the inside portion of the valve face. Then you'd need to blend the pocket where the hard seat bottoms out on the head. Looks like you have a pretty good lip in there.


The heads are factory 1.94/1.50 valve heads. The factory high performance head had a factory cut to unshroud the exhaust valve with the bigger valves.

 

i'll get a picture ... there's a set of 2.08's with 1.60's and
still NO touchie (on each other)...

in a PERFECT world yes the straight edge is the PREFERED END result...
some are set / adjusted / sunk / for REASONS ...

some of the reasons might be cc in chamber....
another reason might be to make the OTHER side have CERTAIN
valve spring height (length of valve) because a cam/springs
dictated 2.0 installed Spring height and not 1.7...

the engine builder (slash) machine shop (slash) valve grinder guy...
can make things RIGHT.

 

Kind of drifting off topic, but 2.08/1.60 will fit stock valve centers without hitting.

Back to the original post, it doesn't hurt to stake the seat but I hope that's not all that holds it in.

 

as i said before the head can be heated and the new seats KQQLed for
easy installation....

 

looking at the heads, they are used, and they've been working fine....I would just leave it alone and run it. If you want to buy another pair of heads for peace of mind, you can. It will be expensive, in Sweden.

 

When I read the ***le of this thread, the first thing to come to mind was Singh's grooves/dimples; grooves and dimples cut into heads to increase turbulence and direct flow. Ya'll can look it up if you're interested, but it follows the same basic theory of dimples on golf balls.
I am Butch/56sedandelivery.

 

Yea. Could be the machinist in question stakes them all. They should not have to be staked. if the tolerances are correct the seat should stay by itself.