All about my heavily modified m20 head.

[Spaz]

No access to flow bench.

:'(

[StereoInstaller1]

Jordan, do you plan on CC'ing the head?

Luke

[Jordan]

Already have. Everything was +-4cc. I adjusted until they were within +-1cc. Real easy.

[Alecs MacDonald]

They are smoothed to the valve pocket for increased flow.

On my planned head work, I thought about doing that but was advised not to on a street motor for reliablility/durability issues of the valve guides. Should I worry about this?

[Jordan]

It's about 2-2.5mm of valve guide.

I dropped the head off at the machine shop today to get the head resurfaced, and do a valve grind. I opted for a 5 angle grind on this head :)

The machinist said its totally not a problem. Very common practice. Most heads have alot of valve guide exposed, where as m20's only have a tiny bit.

[Alecs MacDonald]

Cool, thats what I wanted to hear. How much did the that 5 angle valve grind run you? You arent holding anything back on this one.

[Jordan]

You arent holding anything back on this one.

Well... there are 2 ways to do things. Right, and again.

Look what I am doing again ;)

Resurfacing, 5 angle grind, and resleeving the guides to be toite is going to be around $200. I don't know what their "retail" rates are, as this shop hooks up TSA employees :)

[Jon325i]

I like the hi-res photos.....clearly shows the amount of 'before & after' effort involved. Knowing the M20 head is a huge bottleneck in the flow path, these changes have got to make a significant difference with the other mods employed (cam, intake & exhaust). As usual, good work :-D

Jon

[AndrewBird]

What tools did you use for the majority of porting and polishing? Did you use rotary files or grinding stones? How about for polishing? What kind of rouge did you use?

[Jordan]

Standard Abrasives Deluxe porting kit. Absolute must for this job. (same exact kit pros use) $38 shipped from Summitracing.com



Requires a good straight die grinder and an adjustable pressure regulator to slow it down for best media life.

I used white rouge to polish the exhaust ports and chambers, although that is NOT pictured here. What is pictured here is the dull satin finish from the very fine cross buff included in the Standard Abrasives kit.

[diegom6]

Standard Abrasives Deluxe porting kit. Absolute must for this job. (same exact kit pros use) $38 shipped from Summitracing.com



Requires a good straight die grinder and an adjustable pressure regulator to slow it down for best media life.

I used white rouge to polish the exhaust ports and chambers, although that is NOT pictured here. What is pictured here is the dull satin finish from the very fine cross buff included in the Standard Abrasives kit.

Is exactly wat I bought, with some some spare parts, but it arrived after I polsihed my head :curse:

[mspiegle]

holy crap, i've been thinking about your M20 head for the past week because i've been gathering info/parts for my track car. All the info here is exactly what I needed.... THANK YOU.


So wait... Isn't your car pushing out around 200rwhp as it is? What head was that with?

[Jordan]

170rwhp/176rwtq.

Slightly/mildly modified head. All stock exhaust.

I hope to see 185/190rwhp/tq after I'm done, and I retune.

[mspiegle]

ah. The 200hp number I thought I saw must have been flywheel then. Eitherway, that's freakin' awesome. Way to go and get the most out of a 2.8.... it seems most people just don't do it "right" and make the most out of their strokers.

[diegom6]

how much money have you invested to get hsoe 170 RWHP?