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Cylinder head tricks/mods to do?


Drewpy_Dawg
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Galant VR-4 org Post #: 1246175 posted 05/24/19 10:59 AM     Remind Me!  Send Private Message   Edit Post      
My cylinder head will be going to the machine shop in the near future for a valve job and Iím 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 donít want to spend money on things that will be of no benefit for that goal.

Iíve 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 wasnít 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.

Itís 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 Iíll 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 Iím at it just to make it that little bit better?



1991 Eagle Talon Tsi AWD
in process of resurrection after 14 years

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CutlassJim
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Galant VR-4 org Post #: 1246177 posted 05/24/19 12:56 PM     Remind Me!  Send Private Message   Edit Post      
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!


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.



ALL DSM's are advanced and ALL Evo's retarded
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Drewpy_Dawg
Newbie


Galant VR-4 org Post #: 1246181 posted 05/25/19 08:28 AM     Remind Me!  Send Private Message   Edit Post      
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?



1991 Eagle Talon Tsi AWD
in process of resurrection after 14 years

Posts: 19 | From: Sachse, Texas | Member Since: 05/08/19 | IP: (47.184.184.7) | Report this post to a Moderator

thomcasey
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Galant VR-4 org Post #: 1246182 posted 05/25/19 08:51 AM     Remind Me!  Send Private Message   Edit Post   
I would open that port regardless.



Thom
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