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Cylinder head tricks/mods to do?

Joined
May 8, 2019
Messages
19
Location
Sachse, Texas
My cylinder head will be going to the machine shop in the near future for a valve job and I’m trying to finalize a list of all the little things to do that will help this head perform its best. This is not a big power build or a drag car. It will be a fun street car making 350-380 hp max, so I don’t want to spend money on things that will be of no benefit for that goal.

I’ve decided to stay with stock size valves. I know 1mm oversize on the intake side could be helpful, but considering that I got a new set of stock intake valves for far less than a set of oversize I decided it wasn’t necessarily cost effective. I already have EVO exhaust valves (the sodium filled ones) and EVO beehive springs and retainers, and of course the revised lifters. The casting flaws inside the ports have been cleaned up and things smoothed out a bit but no actual porting/enlarging of the ports. Still need to look at gasket matching the ports. Exhaust ports will be polished, intake ports left slightly rough.

It’s my understanding that at this power level a 5 angle valve job has no advantage over a 3 angle. Unless somebody can give me good reason to go for the 5 angle I’ll save the money and stay with 3 angle. Seats and guides will be replaced as needed based on the machinists inspection.

What is the benefit of polishing the combustion cambers?

Anything else I should consider doing while I’m at it just to make it that little bit better?
 

CutlassJim

Well-known member
Joined
Jul 17, 2006
Messages
1,698
Location
Manchester, NH
Polishing the chambers eliminates any risers that could turn to hotspots and cause pre-ignition. I also polish the tops of my pistons even though some people think I'm crazy for doing it.

Markings like these on the tops drive me crazy and are just asking for trouble. And those sharp edges from the valve relief machining? Gross!
81RI1aqFUAL._SL1500_.jpg


Clean up the casting flash on the topside of the head and port the oil drain backs to help oil get back to the pan as fast as possible.
 
Joined
May 8, 2019
Messages
19
Location
Sachse, Texas
Thanks. I'll polish the combustion chambers while I'm at it. Won't cost me anything except some time and a couple of buffs for the die grinder. Think I'll leave the pistons alone though lol.

What's the consensus on opening up or radiusing the oil passage at the head bolt? Only for a head that's been shaved?
 

thomcasey

Well-known member
Joined
Sep 24, 2014
Messages
907
Location
Indianapolis, IN
I would open that port regardless.
 
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