ISO big valves and seats

After Kevin I will be in line as well. I would like some big valves. Someone told me that there are Nissan valves that work but not sure if that is a myth or true...:)
 
yep, they're Datsun/Nissan valves.

I had a PBS BV head, and it had the Datsun/Nissan logo cast into them. But they're modified to work in a Fiat head - they won't work out of the box. Not difficult to modify though.

Is PBS Engineering still around? If so, they "may" have a few kicking around?!?
 
Ironically PBS is across the street from my Interior guys place... I may have to swing by and have a quick chat....:)
 
Someone here..

had some for sale, and I missed them, gonna go beat my head against the wall now...... found my old machine shop guy, he said he'd plant seats and valves for 2 bills. He's a redneck circle track race engine builder, but he likes a challenge, and does really awesome work. He's reinstalling my aux shaft bearings right now- hard to find a guy that can do that. Wonder if the Costa Mesa guy knows where to get em?
 
PBS used a modified Nissan valve because that's all that was readily available. Now a days you can just buy stock replacement valves for a 90's Fiat from Rockauto. My machine shop supplied the seats.
 
DalaraX19 went thru this exercise recently...ie buy a pair of OE nissan valves and have them modified to replace some in a PBS compromised BVH?? wasn't cheap work.

http://xwebforums.com/forum/index.php?threads/18671/

Surely it is far more cost effective to begin with a valve that's already the right head size, stem length and has the collet groove already cut in the right place and the correct profile???

SteveC
 
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so please...

do tell, what should I be looking for? make,model engine? I can't remember factory valve size, 39mm is used for BVheads, correct?
 
1990's 1.6L intake valve, such as: AE Part # V91306 Valve stem diameter [mm]: 8.000; Valve Head Diameter [mm]: 39.500; Valve Seat Angle [°]: 45; Chrome-silicon-steel; Valve stem tip hardened; Length [mm]: 108.500
eng code [835 C1.000]

Kevin Cozzo said:
do tell, what should I be looking for? make,model engine? I can't remember factory valve size, 39mm is used for BVheads, correct?
Click to expand...
 
Chris. Are there larger valves than this that will work or is that the largest you can go on one of these engines? I thought I remember someone saying something about 42mm valves in one of their heads... I might be wrong. I am still new to the big valve stuff...:help:
 
I think...

39.5 is the biggest you can cram in there. Another thought is will the bigger valves still fit if I'm using 1300 pistons with the shallow cuts in them?
 
Not until you enlarge the flycuts, or else you will (probably) have issues ... issues being valves and pistons contacting....

If you have a higher lifting camshaft with a higher lift at TDC value, and / or a taller CH piston, and /or a cylinder head that has had a significant amount of material removed from the deck face, the clearances will have been reduced anyway.

SteveC
 
well crap

Wonder if there is enough material on those 1300 pistons to remove. I actually got over sized stock 1300 pistons and had the 1500 block bored for them. to increase my compression on a budget. The head has not been milled flat. I was planning on using a performance cam, but haven't checked the lift specs......
May have to blow off the big valve idea, as my 1300 pistons, were the maximum oversize- me thinks
so what do people with 1300 engines do if they want to use a BV head?
 
jjay911 said:
Chris. Are there larger valves than this that will work or is that the largest you can go on one of these engines? I thought I remember someone saying something about 42mm valves in one of their heads... I might be wrong. I am still new to the big valve stuff...:help:
Click to expand...

Jj,
My race motor has larger intake valves, I would need to check notes to confirm the size. It also runs larger exhaust valves...
Someone had done a lot of work when I got that head.
It's great, but a grenade. I would not suggest it for a street motor.
Chris Obert
 
No crap

You probably only have to enlarge the flycuts in DIAMETER, not in depth.
But do check this (flycut depth clearance) out when you dry build the engine.
Modelling clay on top of the pistons, assemble engine with used headgasket, turn engine over, disassemble, check thickness of compressed clay.
 
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