Thread: OST-037: Under Pressure

There are some rebuilding specs in here that I'd like. Can anyone in here translate the Japanese? Ideally pages 36-41, and then 45-50.




Now for the bad news, I didn't see a deck measurement, nor did I see a stock chamber volume. I may have missed them, but I don't think so....


So I reassembled the as of yet untouched chamber 3 using the original valves from that chamber, and did a volume test on it





and here is a reliable chamber volume for a stock untouched SR20VE chamber





I also did a chamber test on #1





and the results.....




So my chamber work adds about .5 cc to a chambers volume, that was about what I thought it would.



Finally.... I measured the heads thickness....



... although 137.02 is confirmed(5.394"), there is a tiny amount of gasket residue, along with tool tolerances, I'm gonna go out on a limb and say an uncut SR20VE head measures 137mm.


More to come....

Shouldn't you be taking your readings at the meniscus?

Consistency/repeat-ability is the key, when I fill the burette, I have a choice to either use the top, or the the bottom of the meniscus, I use the top because it is easier to see from an angle(below) when I fill the 3' tall burette.

I understand completely! I was just making the note in the interest of reference material and definitely meant no disrespect.

what is not useful is the way the FSM is scanned in as photo pdfs.

so... I present something useful.

QR20 and SR20VET

Hastily and automatically translated by software.

https://drive.google.com/file/d/0ByPsC-cMs1-AbEtzYmdOYXdLZHc/view?usp=sharing

and can now be sloppily used as a reference point to the non-translated manual.

sorry, its the best I could do for now.

Thank you!!!

Hmmm, so I'm @ 40.6, and NISMO says I want to be @ 41.8. Any photos of the NISMO chamber

I might know where they gained a lot of that room, but I'd rather see... then guess :thumbup:

Concerning the piston volumes, are those NISMO pistons?

as to calculating compression - I use one of two calculators: 1) https://www.rbracing-rsr.com/compstaticcalc.html or 2) Engine Compression Ratio (CR) Calculator

lynchfourtwenty - what is the 10 to 1 pistons crown volume??

you may want to note that this info comes from a 3rd party book and is not directly from Nissan.

good point....

Well, my client has sent me the piston specs, and I believe I have the deck clearance - .0035" Not knowing for sure, but believing this is the piston down from the edge of the block by .0035". The other option would be the piston sticks above the blocks edge by .0035".

What is still unknown is the actual clearance. The pistons were made to have a clearance of .0035", but was that on a stock, unmilled block? The engine is going to be using a metal gasket, so it is fair to assume the block needs at least a minimal decking. So until the piston is fitted in the block, the actual deck clearance is still somewhat unknown.

The paperwork still doesn't seem to show a crown volume. It does show valve relief depths, it also shows a "dish depth" of .023", but that just tells me we have a dished(negative volume) crown, instead of a domed (positive volume) crown, it doesn't tell me the actual volume

So work begins on the exhaust seats-bowls-ports....

opening up the seat from a measured 24.9mm, to a measured 25.9



by pushing the bowls out this far I was are able to remove the lip in the seat (seen @ the 12 o'clock position on the bowl on the right)

along with the lip, by pushing the bowls we are able to actually make a round bowl to fit a round seat



Can you see the infringing areas where the bowl and seat meet on the unported side??



Here is a "creatively cropped" 2 panel to show continuity from seat, through the bowl, and out the port




and a final view showing a tight short radius, as well as the inner port walls





nore to come.......