oldeskewltoy Posted May 12, 2015 Report Posted May 12, 2015 I've recently purchased a daily-able FX16 so I don't have to use Surreptitious(AE71) all the time... I named the FX "Skippy", and knew upon purchase that it didn't run. This is what was found when the head was pulled... something broke, and eventually got embedded - see arrow So.... OST-032 is Skippy's new head! stripped and ready for cleaning........ Can anyone tell me why one chamber is already clean???? More to come..... :D Quote
oldeskewltoy Posted May 13, 2015 Author Report Posted May 13, 2015 Can anyone tell me why one chamber is already clean???? More to come..... :D blown head gasket' date=' water jacket breach = steam clean. (?)[/quote'] normally this would be a great guess.... Ignition failure in number one.Un-burnt fuel soaked the chamber and over time it cleaned all the carbon off' date=' I saw this once in a 4AFE head. [/quote'] as is this..... But in reality this was a VERY loaded question - apologies. This chamber was the chamber used to make the chamber casting.... more to come...... :D Quote
oldeskewltoy Posted May 22, 2015 Author Report Posted May 22, 2015 So Skippy's head is back from cleaning and pressure checking. The chamber depths and the seat depth all look VERY good. There is some excess material that was left behind after the head was machined @ Toyota, that will all get cleaned up :thumbsup: It measures just about what an uncut head is suppose to measure - easily within the .001" tolerance of this caliper Work begins on chamber/bowls of #4 cylinder More to come.... :D Quote
ke70dave Posted May 22, 2015 Report Posted May 22, 2015 (edited) I'm going to ask a potentially stupid questiom. Why do you need the chamber casting? Edited May 22, 2015 by ke70dave Quote
oldeskewltoy Posted May 22, 2015 Author Report Posted May 22, 2015 I'm going to ask a potentially stupid questiom. Why do you need the chamber casting? no question is stupid... on the other hand some answers.......????? :yak: The chamber casting was teaching myself a lesson on how to do it! After I made the casting I sent it, along with a bunch of pistons to JE Piston to design a "new" piston for the 4AGE. I also use it to demonstrate the positive space view of my chamber work.... Quote
oldeskewltoy Posted May 23, 2015 Author Report Posted May 23, 2015 Work begins and continues....... :) @ cylinder #4.... deshrouding.... ...and working the exhaust.... 2 cylinders down' date=' [img']http://ost.ebeans.ch/albums/userpics/10005/normal_chamber_view_2_down.jpg[/img] 2 to go.... more to come.... :D Quote
altezzaclub Posted May 23, 2015 Report Posted May 23, 2015 After I made the casting I sent it, along with a bunch of pistons to JE Piston to design a "new" piston for the 4AGE. So they could forge a set of correctly sized pistons with over-sized unfinished crowns for you to finish as you wished? These are great threads, I'm sure a lot of guys just starting on motors are realising how straight-forward head work is and what can be done. A 4K benefits from the same work, a motor is a motor until you're down to the last few percent of extra bhp. Quote
parrot Posted May 23, 2015 Report Posted May 23, 2015 As I am sure you are aware, the TRD Group A manual says to polish the joggles (the areas around the deshrouding) until they yield smooth reflective surfaces, and not to polish the other portions (the areas not bounded by the deshroud). Looks like you have polished the whole chamber? Any thoughts on TRD's thinking there? Quote
kickn5k Posted May 23, 2015 Report Posted May 23, 2015 So they could forge a set of correctly sized pistons with over-sized unfinished crowns for you to finish as you wished? They use them to digitize the model to cut the forging, makes it easier to program the cnc. To do it like your saying "as forged crown" would be a min order of 500+ parts and an outlay of thousands of dollars in die work. It is a nice way to do it but not really economically viable. Quote
oldeskewltoy Posted May 24, 2015 Author Report Posted May 24, 2015 (edited) As I am sure you are aware, the TRD Group A manual says to polish the joggles (the areas around the deshrouding) until they yield smooth reflective surfaces, and not to polish the other portions (the areas not bounded by the deshroud). Looks like you have polished the whole chamber? Any thoughts on TRD's thinking there? Not the WHOLE chamber... but I have extended my work a bit beyond the original TRD joggles. Because of my experience with these heads I've found that the spark plug hole needs a bit of radius-ing, in addition the peak of the chamber will often times see a bit of work as well, BUT the areas between the paired valves is left as it was cast..... As to the why? It all has to do with how the head handles heat. The more heat you can remove, the higher the operational compression can be. By removing all the sharp edges we can raise the detonation resistance substantially From an earlier job.... So they could forge a set of correctly sized pistons with over-sized unfinished crowns for you to finish as you wished? actually.... so JE Piston FINALLY had accurate information as to what a "stock" 4AG was about. ALL the stocking 4AG pistons on the market are based on very suspect information (39CC chamber for one example). My purpose in sending the castings on was to get accurate information into the market. As to the piston above... look very carefully..... it is basically a TRD Group A piston crown...... but JE and I included full skirts...... As to how it all fits together...... many builders seem to forget the piston crown is nearly 50% of the combustion chamber... a good crown can raise compression and improve flame propagation all at the same time.... below shows a chamber over a 10.3 high comp piston, and over the TRD type crown - note the height of the crown isn't significantly different, while the compression change goes from 10.3 to 10.7 with just the piston change.... Add in a tighter head gasket for improved "squish" and a machined, DESHROUDED head and your compression jumps over 11 to 1, all inside a very effect chamber for dealing with heat..... Edited May 24, 2015 by oldeskewltoy Quote
oldeskewltoy Posted May 27, 2015 Author Report Posted May 27, 2015 It's far easier to take the direct path......then the path with the bend more to come....... :D Quote
oldeskewltoy Posted May 28, 2015 Author Report Posted May 28, 2015 It's far easier to take the direct path......then the path with the bend bends are gone...... more to come.... :D Quote
oldeskewltoy Posted May 28, 2015 Author Report Posted May 28, 2015 Now that the casting has been massaged... It'll go off to the shop on Monday to get its 3 angle, and have the head surfaced. More to come.... :D Quote
oldeskewltoy Posted June 19, 2015 Author Report Posted June 19, 2015 So... Skippy's head is back and it carries a fresh 3 angle valve job, and a minimal machining - .004". I only had the head cut .004" so I could keep some of the deshrouding volume - target chamber volume of 36.5cc. I did this so I could keep the static compression high, but manageable @ about 10.7 to 1, and tighten the squish gap by about 20% Specs 3.209" bore, 3.0315" stroke, .036 gasket, deck is .001 (under), piston volume 2/10 of a cc crown, with a 36.5cc chamber. preparing to check chamber volume.... note the wooden shims under the head to get it at a slight angle measuring chamber #1.... and the result......??????? Bullseye 36.5cc!! The chambers are now perfect, Skippy's head is now ready for reassembly.... "Perfect"? It appears that chamber #4 is tight, or so it seems in the photo. It WAS a bit tight, I worked the chamber walls a little adding a 1/10 of a cc to the chamber. This was a partial head when I began, the valves in this head were not originals to this head, so in this case although being re-assembled, I fully expect SOME dis-assembly of the valves for those needing to be tipped. More to come.... :D Quote
parrot Posted June 19, 2015 Report Posted June 19, 2015 I knew there was a reason why you wrap the head in bubble wrap, take it to the machinist, come back a couple of weeks later, hand over lots of money and put said head back on engine...... Quote
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