4AF head prep and porting

[oldeskewltoy]

I'm doing an odd frankenbuild - from stock 4AFE, to superduty built 4AFE, eventually to 4AFZE. From research the SC12 supercharger may actually be a better "fit" with the "F" economy 16V.

Anyway, I'm beginning inside the head to improve what I can improve. The above chambers show my initial chamber deshrouding, removal of edges.....


My 1st question - I remember a post on varying the valve size to improve cylinder filling. The F head uses 30.0mm intake valves, and 24.5mm exhaust valves, the valve is about 8mm shorter then G valves, which are 30.5mm, and 25.5mm in diameter. So, would using cut down 4AG valves (1 intake and 1 exhaust per chamber) actually be a benefit??



SD 4AFE shortblock would be 4AGE 20V using 8.9CR 4AGZE pistons - under a 30.25cc F head chamber, 4AGZE pistons "become" 10.1 to 1 - (stock 4AGE chamber is 36.25cc)

[oldeskewltoy]

The biggest single problem to overcome....... Toyota changed the spacing of the exhaust ports when they went to the "F" head



they made the outer ports slant toward the center



now this wouldn't be a huge problem... EXCEPT - look at the chamber on the right, #1, well look along the head and you see a hole, the oil drain hole. This drain becomes a HUGE problem.....




Still not fully understanding..... here is the final pic showing why this actually is a problem....



the "new" photo in this series... is port #4... I believe the problem is not over stated......

[oldeskewltoy]

my initial idea is to "cheat the pillar" (coal speak for thinning the divider) on #1. a 2nd idea is to bring the current roof of port #1 to a more squared off shape with that drainside wall

[Grega]

OST.........depending on your budget why not take the head to a head reconditioners, get them to heat the head up, get a piece of ally slightly oversize to fill that drain hole (I'm assuming it is a straight thru drain from top to bottom of the head), get the ally piece frozen and put the two together as an interference fit.....weld the top side and underside of that ally filler piece then machine the surface of the head and then port away as per what you want to achieve? then, run an external oil drain like the 7rib 100kw??? just a thought?

[oldeskewltoy]

OST.........depending on your budget why not take the head to a head reconditioners, get them to heat the head up, get a piece of ally slightly oversize to fill that drain hole (I'm assuming it is a straight thru drain from top to bottom of the head), get the ally piece frozen and put the two together as an interference fit.....weld the top side and underside of that ally filler piece then machine the surface of the head and then port away as per what you want to achieve? then, run an external oil drain like the 7rib 100kw??? just a thought?

I've been giving this some thought.... with the engine in fwd(or in my case All-Trac) configuration, adding a drain to the back (intake side)of the head doesn't make sense(to me). And I'm not sure I'm ready to experiment with what in essence is my absolute daily driver..........

but it remains a possibility....

[oldeskewltoy]

doing a little work on the intake side... thinning the splitter @ the port roof(NOT thinning it on the floor). Carefully removing the casting flash, doing a bit of re-contouring around the guides....



that, and massaging the bowls and seats is all I plan to do on the intake side of this head

[Billzilla]

What I did to solve the angled ports on the F head was to add a bunch of metal to the outside of them #1 and #4 ports, then oval them out. It made them straight and also gave me the size I needed.

[trdee]

what are the benefits of using the F head to the G head?

[oldeskewltoy]

Bill... what did you do about the oil drainback crowding port#1?


trdee - I'm not sure there is an advantage..... my purpose is to use it in my All-Trac Corolla. I could swap the whole thing out for a managed 4AGE, and I'll NEED management once I go to boost, but in the mean time the engine is an exercise in how much i can massage from a 4AFE


btw... this is a 2nd generation F head - it was originally developed(2nd gen) for use in the heavier Celica base model. For more specifics - http://allanpalace.99k.org/4afe.pdf

dead link above, new link - http://home.exetel.com.au/seasalt/Resources/4afe.pdf

[oldeskewltoy]

[Billzilla]

Bill... what did you do about the oil drainback crowding port#1?

It was done a while ago, I can't remember it being a big problem though.

[Sam_Q]

I thought they had 31mm intake valves? or is my memory mistaken?

whats your plans for cams?

[oldeskewltoy]

I thought they had 31mm intake valves? or is my memory mistaken?

whats your plans for cams?

I remember you posting the lifts on your "F" cams... at well over 7mm, these are not even 7mm, their lift is .270"(6.9mm). Right now, I'm thinking if I can find a set of your generation "F" cam... and they still work in my generation "F" head, that they would be my best choice..... I'm trying to keep duration short to keep up the bottom end, this engine is going in my All-Trac Corolla daily, so a few more #/ft is far more important than a few more hp

[Sam_Q]

the cam lift on mine where 8.6mm and that was a while ago. Still quite the mystery as nowhere on any specs does it show a 7afe head to have more than 8mm of lift

[Hiro]

the cam lift on mine where 8.6mm and that was a while ago. Still quite the mystery as nowhere on any specs does it show a 7afe head to have more than 8mm of lift

What about the late-late model 7As that came out in the AE112s? Toyota claimed different figures for them (same peak power/torque but at different rpm) and I've seen better results on the dyno from them. They appear to have different part numbers for the camshaft too, compared to the 102s.