Trying to learn how to properly build a head

[race_me89]

I have been reading about what valve springs people recommend and what is beloved to be the best. But from my research I have concluded every cam should have a different seat prespassure and depending on rpm the seat pressure should be different. So I'm kind of lost as to how to put all this free information to use I read about all these different springs and their installed height, base pressure vs pressure at full lift.

I'm a little lost and I could use a nudge in the right direction

I am going to be running BC 280/280s. I believe first step would be find what the recommended seat pressure is (I thought the cam card but it just recommends a bc part number) so I sent an email tonight.

Then how do I actually use this information to build a proper valve train I'm lost

Please help

Thank you ahead of time
Matt

 

[crimsondragon]

First off, do you have proper precision measurement tools and tools to take apart a head completely?

 

[race_me89]

Yes I even have the tool to properly measure spring pressure at different heights. I work for a performance shop and I could just order kingly beehive or bee mad springs and be done with it but i am more interested in learning the proper way to select what springs are more suited for different applications

 

[killercolt]

Don't bother doing all of that measurements for that cam combos. Get a set of BC, Manley, Kiggly, or Crower springs and you are cover up to 8500-9000rpm. If you insist on being exact, you will need a sping pressure tester, sping install height micrometer, caliper, shims kit, and dial indicator. Check on you tube for video on how to do it.

Here are my recommendations for building the head:
-increase the drain hole size and debur any flashings
-unshroud the intake valves
-increase the oil feed hole to the head
-make sure the valve stems are not cut too low or the rocker arm will contact the retainer at full lift
-make sure the valve seats are not cut too deep or the lifter will bottom out which only not allow the valve to close completely. You can make correction by cutting the bottom of the lifters
-make sure the head is decked with a cbn/pcd mill for the best result. Avoid broach decking machine because it can be very uneven and inconsistent if it is an old cutter head.

-Check and lap the valves even if the machine shop did the valve job. Take the cams off and take the head into a completely dark room. Shine a small flash into each ports. If you see any light at the valve seat, you will need to do some lapping works. If you get a lot of light around the valve seat, your machine shop sucks and you will need to take it back because it might not seal at all.

-If you are sticking with stock size valves, you should just get lap in the valves yourself. This assume that your valve guides are not too worn out. Mitsubishi already put a 3 angles valve job on it. Lapping stainless valves give the best result because the stainless valves will not wear hardly at all during the lapping process. This make the valves seats look and seal perfect with eating a groove onto the stainless valves.

-make sure valve guides are driven in deep enough to account for the high cam lift so the retainer does not smash into the valve steal seals.

-use two sets of intake valve guides for the intake and exhaust side. The factory exhaust valve guides are too long and can extend too deep into the exhaust ports.

 

[BogusSVO]

Killer colt covered it pretty good.

The only real point I will disagree on is to measure each spring installed height and shim as needed.

You are correct about each cam and engine combo should be set up slightly different.

But learning where to play with spring pressures comes with experience and a few hundred tear downs and set ups, with a few failures mixed in,

I would say use the springs closed value for the installed height, and check to make sure the spring will handle the cam lift and not hit coil bind.