GMC-IH

[idahovette]

What about the exhaust valves?

 

[dragstews]

What about the exhaust valves?

Both sets of heads have the 1.880" valves ..

• #435 .... This post should have the answers ..

If not, what do you want to know about the ex. valves ?

 

[idahovette]

Ok, sorry I missed that post

 

[dragstews]

Not sure if I mentioned the valves going in my 781 heads having 11/32" stems instead of the factory's 3/8" ...

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Used one piece bronze guides for doing the smaller stems ...
Some weight was lost and a bit more flow was the results ..

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[squaredeal91]

Are you doing any port work on any of these builds?

 

[dragstews]

Are you doing any port work on any of these builds?

.... Buku ....

The PP heads that will see duty on the stoker 496 motor is in the Seat & Guide machine at the moment getting major work done on em ...

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I'm only building the big block motor for the 1962 C-10 ...
The owner is doing a wild Hot-Rod build to the rest of the truck ...

And a very nice frame-off job he's got going on ..

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Here's what he's starting with ...

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Had a bit of rust in the old girl !

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[dragstews]

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Brand new crank. brand new Hi-Po balancer and brand new tool ...

Well, being I'm dealing with new parts I assumed they would be a plug & play fit ..

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Had the need to install the balancer to do the balance job to the crank, that didn't go all that well !

The push was way to much, snap the tool right from the start ...
What the %*# ?

Ok, alright time was at hand to fine out why ??

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Had a GM crank that I mic-ed the snout, then mic-ed the aftermarket crank ..
Both was dead nuts the same size ..

The balancer was next to eyeball ..
Got a inside measurement from a factory GM balancer, and there it was !!

The aftermarket balancer was .0023" smaller ...

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[dragstews]

Had to order a ball hone to take some meat out of the new balancer's hole ..
(1-5/8")

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Taking out .002" with a ball hone will be slow go at it's best ..
I called the company and they pulled a few from the shelf, found one that was on size ...

They said it would not be a problem to do a trade out ..
Shipping would take days, I don't want to wait ....
Soooooo, a honing we will go ..

 

[dragstews]

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Been working on the exhaust wall of the chambers ... Hadn't got to doing the intake wall yet ...
Giving some room for the O.S. valves to do there thing will enhance the breathing in the chamber, also on the table to do is notching the cylinder bores ..

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Bore notching is said to be worth about 30hp or so ..

squaredeal91 said:
"Are you doing any port work on any of these builds?"

This chamber work falls within the realm of added flow ...

Valve shrouding is an airflow restriction within an engine's combustion chamber where the chamber wall or deck is too close to the valve's edge, preventing a smooth flow of air and fuel mixture into or out of the cylinder.

This creates turbulence, limits airflow, and reduces engine performance. The problem is especially prominent in engines where the combustion chamber is larger than the cylinder bore, causing the chamber to overhang the deck.

 

[dragstews]

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The shiny shi .. errr .. stuff won't do a thing for HP, but just might get him laid ..

 

[dragstews]

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Well, let's try doing the push again ...
Might be having better luck this time around ..

( Sure do hope so cause I borrow a installer, mine had a one way ticket to valhalla )

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[dragstews]

Exhaust valve seats are pretty much cut in ..
Moved on to doing the intakes ...

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Oversize here we come ...

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[dragstews]

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Working the exhaust is coming along nice ..

 

[dragstews]

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Looks like a problem .. ?

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A bit tight with these fittings ...

 

[dragstews]

Got a much better fit with these fittings in play ..

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