oldeskewltoy

Not enough :yes: likely going to make my own tray... likely have 75-100 1/8" holes, and a 15-20 3/32" holes

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

I have a 4AGE powered AE71 too... Springs I'm running are custom...5.3kg/mm front and 3.5 kg/mm rear, fronts are in stock strut housings, I'm running full stroke HTS model 112s. I'm running Recaros... they are very nice seats. Are you still running the AE71 strut? The AE71 uses solid rotor disc brakes... fine for 50-75hp, but a bit lacking with over 100hp. One solution is to run AE86 struts, but the AE86 has a steeper strut angle then the AE71, so although the AE86 struts may bolt in... you will automatically get positive camber from the swap. One way is ajustable upper top mounts, the other is adjustable lower control arms..... OR... using the stock AE71 strut - fabricate a new caliper mounting bracket and mount what you want........

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

bends are gone...... more to come.... :D

It's far easier to take the direct path......then the path with the bend more to come....... :D

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.... 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.....

Why I insist on insuring the finished product for its shipment back to it's owner...... I've been told the head itself did not sustain any damage... but this shows significant intrusion.... so when I say the insurance adds $20' date=' or $30 to the return shipping cost... its just to [u']COVER YOUR ASSets.[/u]

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

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....

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

if you crank your neck 85 degrees to the left.... ;) you can see intake valve #2 is currently @ .010" (spec is .008"), with a .1122" shim. This means replacing with an .1142" shim should get me to spec. The other 2 intake valve, 5 and 6, are currently @ .008" with the .1122 shim. The other 13 were significantly tighter, and if I had a full stock of thin shims (.0984" through .1024") I might just shim it... but I TRY to think of the client/next guy... and if I keep common shim types in there, when this client goes for camshafts in his future... he should still be within standard - common size shim distances.

The dance continues.... although now I'm dancing with the valve clearances... with 13 valves headed back to the machine shop to get tipped...

port work - about 30 hours : chamber deshrouding' date=' and equalizing chamber volumes - 6 hours : waiting for the machine shop to do their thing - 2 weeks Found another suspect retainer... swapped it out [img']http://ost.ebeans.ch/albums/userpics/10005/retainer_flaw.jpg[/img] The head is now ready for its cams..... More to come....... :D

With OST-030 heading back to its owner, and OST-032 at the shop getting cleaned and pressure checked, there is a window of time to check chamber volumes on OST-031, and then re-assemble. This time I got 35.6 on #1, and #2, #3 was 35.3, and #4 was 35.5 Soooo... I did a little adjustment on chambers 3 and 4 and got both to 35.6 Chamber and bowls... before.... and after Assembly to follow......

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

I typically set the flowbench to test @ 25". Yes... I know the norm is 28"

yes...... I don't test each head I do, unless the client wants(spends for) verified results. I typically experiment on a mule, then test the work I do. Once I find an area or procedure that is effective, I incorporate it into my work. 4AG.... 7MG SR20DE As to the accuracy/consistency of my work... this chart shows less than a 1.5% difference between the flow of 4 exhaust ports

Valves @ full lift... Exhaust.... Intake...

not disputed.... BUT.. the time required/amount of work involved makes it significantly less desirable. Also to consider is the irregularity of the "flaw"s occurance. chamber #1 has no "flaw"... chamber #4 has only a minor "flaw". Do I weld up chambers 1 and 4 and shape them to equal the finished chambers of 2 and 3? My typical finished head goes out the door for under $1500' date=' some under $1000 so... to again answer your question... Yes... these heads would have better pressure recovery, but the work involved makes it less affordable/attractive. "Pressure Recovery" - is a concept researched by Darren Morgan (Induction Research and Development expert). In essence..... to simplify this even more(to better visualize)... think of the valve opening inside a funnel..... :bounce:

;) thanks... Showing off her angles....

So with OST-031 now @ the machine shop getting its valve job and surfacing we delve back into OST-030 I've gotten the head back from the machine shop, they have provided a minimum resurfacing .003", to add to the previous clients report of a .008" resurfacing, the current surface is not quite @ .011, closer to .0102". This head is now 115.74mm thick, having had a total of .26mm removed. Typically with a 10 thou cut you can expect chamber volumes to drop to about 35cc, the deshouding adds about .4cc, to gain volume I had the valve seats machined an extra .003" to gain 1cc in chamber volume, this lowers the valve on the seat allowing for a bit more volume in the chamber. The valve tips were cat an equal amount so use of more common shims sizes is retained. So right now the chambers sit @ 36.4cc (1/10cc tolerance)

As per FSM specifications(AE86 and AE92) 4AG valve springs are to be checked @ 34.7mm(1.366") 1.366" (34.7mm) This is our standard. All spring were brought to this point, and from this point on coil bind was found. On advice from Loynings, .050" off coil bind is maximum "allowable" VALVE lift. I capitalized VALVE lift because it is different from cam lift* in this situation. From an unknown source - *Coil bind doesn't change - with heating, valve stem length can "grow", but with the stems "growth", so will the spring, BUT when compressed, the coils will still bind at the same point - thus for purposes of valve springs - valve lifts, and not cam lifts are being referred too. OEM stock (USED) - 35#s @ 34.7mm(1.366"), full bind comes in @ .349", subtract .050" and you are left with .299" before "effective coil bind". Pressure @ "effective coil bind - 96#s - Spring was bound @ 1.017" Since for this test I didn't have any new OEM springs I used 2 used springs. For point of fact... I recently did have some new OEM springs, and only 14 of the 16 springs actually met the minimum height in the FSM, the other 2 were within .03mm or less - spec is 41.09mm The two used ones I have measured out to 40.92, and 40.90. So they were pretty close. HKS - 30#s @ 34.7mm(1.366"), full bind comes in @ .415", subtract .050" and you are left with .365" before "effective coil bind". Pressure @ "effective coil bind - 120#s - Spring was bound @ .951" Toda - 42#s @ 34.7mm(1.366"), full bind comes in @ .419", subtract .050" and you are left with .369" before "effective coil bind". Pressure @ "effective coil bind - 128#s - Spring was bound @ .947" BC 7MG valve spring - 58#s @ 34.7(1.366"), full bind comes in @.486", subtract .050" and you are left with .436" before "effective coil bind". Pressure @ "effective coil bind" 168#s - Spring was bound @ .880"