Thread: OST-037: Under Pressure

When you try going to big cams, you will see why that is annoying to have rocker arms mounted on a shaft such as that. And there is the always anytime you float a valve, the entire head looks like a grenade went off vs sometimes when a rocker arm is tossed, the worst thing that happens is a shim gets into your oil pan and the rocker stuck somewhere clear of all moving parts. (when Lady Luck strucks )

Sometimes having one powerband is better than two.

I do think your work should really consider expansion into the 54C since there is more than what you have been exposed to in that cylinder head.

Always pluses and minuses. Devilish details should not escape you, either.

So before I sent the head out to be clean and pressure checked, I took a pic of the chambers....



Hmmmmm, I've got work to do in those chambers.... they aren't as "clean" as the DE chambers I worked last year....

here is a closer look @ one of the VE chambers...




and from last year... a pair of DE chambers








So while the head is out getting cleaned and pressure checked, its time to clean the valves....




While cleaning the valves, I thought there was something a bit odd. So I picked out an intake and exhaust valve from the DE head and viola.....



The VE valves are smaller......????? The intake isn't considerably smaller, but the exhaust is nearly a full millimeter smaller....



and with that... does anyone have a spare pair of VE exhaust valves?? It relates directly to the chamber work... I need a spare pair of valves that will fit, the DE intakes will fit, the DE exhausts don't

From what I remember it had something to do with velocity.

It might be tuff getting additional valves as these engines are imported, so usually they have to either be bought new or from someone parting an engine out or someone who has upgraded valves..

Ok... then I'll have to get a pair of DE valves cut down and then ground to have a sharp edge for a margin..... I'll know more once I get it back from being cleaned and pressure checked.

I wasn't real happy with the head once it came back, there are some serious flaws in the chambers, VERY sharp edges!!



Note the seats are "deeper" then the DE head, the resulting machining have left us with sharp edges in the chambers.... not good. Sharp anything inside the combustion chambers may lead to detonation, aka ping. This wasn't a total surprise to me, I had trolled the net, and it seems many (most?) of the VE heads have the seats deeper in the head and the residual machining left behind.

Not only are they sharp, but they will cause havoc, as they disturb flow past them.

So this head will see extensive chamber work. Besides the flaws in the above view, we see that the intake short radius can be improved, and the exhaust large radius has been machined from the factory. Can anyone see anything else???



Chamber #1 as it goes through its transition





1 chamber down (far right) 3 chambers to go...




More to come....

It isn't obvious... but there is something missing..... anyone know whats missing?

... and no I don't mean the valves

Theres like a baby dot near the spark plug hole ?

Definitely following this thread! My VE is down for awhile so it'll be interesting to see the before and after. Side note, if you still are needing to borrow ve intake valves, I can loan you a couple since it'll probably be at least a few months before my motor is back together

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No need, but thanks for the offer, I had a couple of DE valves purposely "shrunk" so they would fit deep in the seats, the reason I wanted the exhaust valves was so I could use them to shield the seats as I remove the sharp edges inside the chambers. I'd rather use a pair of reground DE valves, then risk damaging a VE valve







The intake seats are missing a 3rd angle on the seats!!




The red arrows are pointing to the valve to seat contact points, on the exhaust side you can see the seat has 3 angles, but the intake seats only have 2 angles. We shall fix that later when we do the valve job.



#1 intake now re-worked, the short radius is smooth with no discernible edge from port floor to the edge of the valve seat, just one continuous curve



Each bowl has been opened up at 2 points to allow additional filling. Finally, the seat has been opened up to 88% of the valves diameter - 30.10mm from a nominal 29mm.


More to come......