For my blacktop/silvertop engine build I needed to know what my compression ratio would be after I put the ae111 head on. I knew the ae111 head had a more open chamber and therefore I would lose compression, but I didn't know how much. Add to that some combustion chamber mods I will have done which would lose volume again. So I have to work it out, to do this I decided to measure the volume of the head, aka: CCing the head. Heres how I did it:

 

 

 

The final result was that it had 37.8cc. I already know for the arias website that a silvertop has a 34.5cc head. This works out well for me and my plans. I will now work out what I need to do.

I would have never thought of doing it that way, Certainly one clicked on person.

hey heres the bets bit- a burrett costs $150+, an oral syringe cost me $5!!

 

oh also I tried the whole hole in the middle thing and it didnt work, I had to do it off the side, just for anyone else who wants to try this

well I have finally fixed up all the pictures and the links as far as I know, if I have missed something please let me know

In my frustration of breaking coil mounts on the side of my engine I decided to do something drastic:

 

 

 

so I thought I would solve the vibration problem once and for all.... it didnt work...

 

A few weeks later after doing this it failed again from vibrations and in a way I once again wouldnt expect, I will post pictures of how I think I finally fixed the problem, well even though I have already said that 4 times already I think its ok now!

well what happend a few weeks later is I was doing something to my engine and I saw something loose, I looked closer and I saw that one of the allthreads that went into the block snapped off after the lock-nut. After that I cried enough, i decided no matter what I was no longer going to put the coils on something apart from the engine. Also just before that I once again re-did my wiring loom for the engine harness. Heres how I did it all:

 

 

- Mounted on the strut brace with a single welded bracket. I tried to make it as low as posible so it actually leaves enough room for a tri-brace in the future. I also cable tied the loom to the brace, I will weld on proper brackets later but the ties will do for now. For the end I made it so the whole coil electrical power plugs in via a 3 pin auto plug. This is because I regually take my strut brace off for maintenance/modification and I don't want to undo my electrical connections every single time so this plug makes it easy for me to do so. I initually thought that this was causing a misfire on my engine being so close or something however I was mistaken and by sheer conincidence I ripped 2 wires off my alternator plug, so my ignition system was under-volting. The plug replaced I was back red-lineing as usual.

 

 

 

- Notice my new T connector as part of my new loom, the lower part has my dash temp probe and the oil pressure. I plan for all my looms to be in loom-tube with heat-shrinked ends in due time

Very nice work as usual. Care to make me a front strut tri-brace just like yours? Ill pay you. lol. Yours looks like the stiffest one Ive ever seen.

hehehehe, no chance, besides even if I did have the time the only way to make a brace like this is to weld it together as its bolted to the car.

 

 

 

Also in other news I forgot to mention this but I might be ditching my blacktop head and upgrading to a 4afe or a 7afe head for more power. I am sure some people would be horrified by this but I have done my research.

just a bit of an update:

 

I have bought an ae112 head off a 7AFE and i plan to use it instead of a 20v head as an upgrade in power through the whole rev range. I have most of it worked out so far and I am waiting on some tools to continue with it. For anyone who is shocked, upset or otherwise please feel free to question me.

I whipped up this diagram to give a rough idea to people why the F head has more theoretical potential than a G head:

 

 

Notice the valve angles, inlet port angles and shapes and the combustion chamber shapes

Edited October 7, 200718 yr by Sam_Q

just some updates, I was playing with my 7AFE cylender head, test fitting it to a 3 rib block I had laying around, it helped me do a few measurements and get a rough idea for how I plan to do things. Pictured on the engine is a 20v exhaust cam gear off a blacktop, I will at this stage be using a T3 4AGE 16v vernia cam gear if it actually turns up. I have no idea what belt I will need, maybe a 4Ac or some other single cam engine?? If I actually used the original cam gear I could use a 4AF belt but the 4age gear does fit on and can be easly shimmed to the right spacing but is a smaller diameter. I chose this option because I can easly get a vernia cam gear and I can also use the stock 20v bottom gear drive.

 

Anyway the pics:

 

 

 

The cooling system will be very simular to my 20v and shouldnt pose much of an issue, although I am planning on doing the heater piping a bit different this time.

so what mods have to be done to the 7afe head to make good power? we bought my wife an ae112r a few weeks ago

I whipped up this diagram to give a rough idea to people why the F head has more theoretical potential than a G head:

 

 

Notice the valve angles, inlet port angles and shapes and the combustion chamber shapes

 

 

Actually, the 20v intake port design is pretty similar to that of the Formula 1 head and the Toyota F head.

 

 

That's a cross sectioned 20v head -- the first one that you posted is from a 16v.

JC807: some pretty serious work is involved, the biggest problem is the camshaft shape and theres no easy solution to that. I may be importing some camshafts from Malaysia to take care of that but I will see. I can very safely say thats my biggest problem right now.

 

bryson: indeed your right, well atleast from that point of view anyway, I should of said "more poential than a 16V G head. However if you had a scross section thoughout the legth in a horizonal plane you would find its not as close. The Intake path looks nice from that angle but its not that good, the shape is still far from ideal. Apart from the bleedingly obvious of having a provision of an extra valve the FE and the F1 head keep a pretty consistant shape and cross sectional area all the way to the valve. he 20v head on the other hand starts off as an oddly shaped oval before flatening out and going into an open chamber and then to 3 valve openings. The ae111 head is much better in this design but it still has a relatively sharp change in shape and I suspect size. What does this do for perfomance? well if it does change in cross sectional area then it losses air speed which has an effect on low to mid rpm cylender filling, in theory anyway. Other than that I have no problem saying I have no idea at all.

 

other than that the 20v engines have a bad squish area size and shape, a 5v in inferior over a 4v in a bore thats 400c, valve angle is till too wide, intake as previously mentioned and the list goes on. I can be more specific if needed. Also not relevant to me but 4age 20v engines are very limited in how wild a cam can be run because of the cam bucket limitations.

more updates, this is off a post on toymods:

 

http://www.toymods.net/forums/showthread.php?p=582306

 

 

cams in place showing scissor gear arangement

 

 

 

 

comparasin for a 20v flange vs the FE head, the two outer ports on the FE head curve inwards. There is access to add material and realign the ports if wanted, I wont bother.

 

 

 

 

exhaust of a 7afe vs a 20v

 

 

 

 

intake of a 7AFE vs a 20v, the 20v being modifed however in the height of the injector releif.

 

 

 

 

a dial gauge on the intake measuring real intake lift, unlike many claims I found my stock ae112 intake cam to have 8.6mm lobe lift and about 8.35mm actual lift

Edited October 22, 200718 yr by Sam_Q