4AG headwork, now block too

[oldeskewltoy]

As per TRD spec........





Original combustion chamber volume (pics on top) between 36.25 cc to 36.5.0 cc. Finished combustion chambers between 37.00cc and 37.25cc. That is about a 2% difference. It is also important to note that this head has yet to see a milling machine.

[toddw]

Very nice job. Is this a bigport of a smallport head (unsure if they are the same volume in the combustion chamber).

[oldeskewltoy]

this happens to be a smallport head... but everything I've ever been told says the combustion chambers never changed on 16V 4AGEs

[allencr]

And the point is... better flow, less CR?
Please show the transition from the seat's 45 to the head's alum., without the valve.
Thanks.

[oldeskewltoy]

And the point is... better flow, less CR?
Please show the transition from the seat's 45 to the head's alum., without the valve.
Thanks.

Much improved flow... the penalty was .75cc(3/4 of 1 cc), or less than 2% increase in volume. The ability to run substantially more compression with much less chance for pre-ignition since the sharp bits have been removed and polished

The 3 angle valve job has not been done yet,

Here might be a better photo showing the advantage of removing the shrouded section - this was my "practice head"... no work was done to the seats... this head was used for demonstration only




The above photo shows the valve at 7.4mm lift and 2mm lift
When you deshroud the valve(area around the valve), there is little if any step the air has to flow around....

[Sam_Q]

ah the old deshrouding trick. I am about to do the same on my 7afe engine

good work by the way

[Grega]

thats a fairly decent trick is that de-shrouding idea...
how would a polished area in the combustion chamber there help with flow?
thinking about the 100kw pistons they are raised in that centre section i'm wondering if the polishing has anything to do with the resultant flame front at combustion time ; ie; removing all the dags/burrs etc helps with a more consistent flame...?
i don't know much about heads ect (except for where to take it to when it needs reco) so this is all quite interesting

[rick q]

oldeskewltoy,

Can you post a link to where you found that info please. I've Googled myself silly and can't find one - I'm looking for similar info for the Silvertop 20 valve.

Thanks in advance.

Rick Jones

[JP]

the 16V info's in the "TRD Bible", it doesn't have the same sort of info for the 20V.

http://cgi.ebay.com.au/COROLLA-LEVIN...QQcmdZViewItem

[roadsailing]

looks pretty good

somethign i have wondered ever since reading the L&T bible

what the shit is a joggle?

also, only the bigport stuff is translated to english from memory, the smallprot and 20 valve info is all in japanese, and from memopry it is a bit light on fot the 20 valve engine.

[-GT-]

I'd be quite interested to hear info on the 20V too, i haven't found much at all in my travels around teh interweb either.

[Grega]

shinybluesteel...........i can only think a joggle is that section of the head/chamber?
only joggling i've come across was a tool to do something with panel work...

[oldcorollas]

take a better pic of the japanese characters above where it says "joggles" on the diagram?

[Grega]

stu it probably says joggles in japanese mate

[Ben Wilson]

I'm thinking perhaps 'ridges'?

[fixeruperer]

ahh it means must where "goggles"

i bought a pack of undies in bali and on the intructions (becuase i forget how they work) they said "do not tumble fry" i thought it was funny.

[Sam_Q]

theres very little shrouding on the 20V engines so you would be lucky to get anything out of it even on a flowbench.

[Sam_Q]

heres how I was thinking of doing my chamber initually:



not quite the same thing as the 4ag drawing posted earlier but instead a general deshrouding. I believe one of the thoeries is from the valve to the chamber is 85% of the valve lift and 65% for the exhuast. Quoted from the four stroke tuning guide.

[Dimmy]

Very nice! That's the next step left on my 16v Probably do it in a few months.

Anyone willing? hehe

[oldcorollas]

top left says

の範囲で滑ら
makes somethings area slippery?

top right is too small to read

btw, there are no joggles in japanese... in english it measn "dowels" ? (bits sticking out?)