OST-056: Nasty.....

[oldeskewltoy]

Another first gen 4AG head, this one is a bit Nasty....




Btw, here is a photo showing the difference between a 1st gen TVIS head, and a 2nd gen TVIS head. A first gen is what came on the AE86, the 2nd gen is later





So, getting back to OST-056, the head is stripped, cleaned(?), and pressure checked. Once back, I deburr the casting




more to come......

[Sprite]

Thanks, Nice to see the comparison, looking forward to seeing the build.

[Rogue-AE95]

Btw, here is a photo showing the difference between a 1st gen TVIS head, and a 2nd gen TVIS head. A first gen is what came on the AE86, the 2nd gen is later

I have to wonder if Toyota had the MR / FWD mounting in mind when they (or Yamaha) designed the 4A-GE. I have one each of the big port heads and noticed this difference.

[oldeskewltoy]

Btw, here is a photo showing the difference between a 1st gen TVIS head, and a 2nd gen TVIS head. A first gen is what came on the AE86, the 2nd gen is later

I have to wonder if Toyota had the MR / FWD mounting in mind when they (or Yamaha) designed the 4A-GE. I have one each of the big port heads and noticed this difference.

I've yet to see a Toyota application that uses that mount...........






Work on the head proceeds.....



"Building" the intake side - blending the seat, bowl, and port





also working the exhaust side




more to come......

[Rogue-AE95]

I've yet to see a Toyota application that uses that mount...........

There's a small bracket that bolts to that part of the head. At least for the AE92 GTS. There's a hole in the top timing belt cover for it to stick out of. Then there's a plate which mounts from that bracket to the top of the alternator bracket. I have a pic somewhere of the pieces, I'll have to post it. There may be more to it but I forget. I pulled everything from a junkyard AE92 GTS.

Edit: here's a pic. The bracket is on the far right. I think the middle plate/bracket also bolts to the engine mount. There's 2 holes at that end, one of which bolts to the small bracket situated between the cam gears.

[oldeskewltoy]

I've yet to see a Toyota application that uses that mount...........

There's a hole in the top timing belt cover for it to stick out of.

Can you show me this /\ timing cover... all I've ever seen is the typical fwd cover \/...

[Rogue-AE95]

I'm sorry I derailed the topic with this, but I guess we all learn something new every day. And I always love to see your work!

OK, here are some better pics. I had pulled all of the timing covers for my (someday, someday, someday) engine build, along with that small "cam bracket."







^ Bracket looks smooth in parts because I've been taking off the casting lines & imperfections, so that I can get it powder coated along with other parts.

[oldeskewltoy]

new to me.....

[oldeskewltoy]

After learning about the timing cover from Rogue-AE95....

good lesson(for everyone)... even if you think you know it all....... you don't




Now, back to OST-056....

A facebook "viewer" asked if my work fits the stock gasket... I assured him it does......




Further progress... 3 down... 1 to go




more to come.......

[oldeskewltoy]

back from the machine shop wearing a new 3 angle, and back cut intake valves....





next, checking chamber volumes...







So if I want chambers down to 36cc, how much should I have machined from the head???



more to come....

[oldeskewltoy]

It's very late so my math might be off but I think about 1.5 thou (inches) sounds wrong but that's all I can come up with right now. I'm rusty with my numbers and a bit tipsy.

well, about .008" is about 1cc(+ or -), so @ .6cc over, that would be about .005"




and that's how much I had it machined.....


more to come....

[oldeskewltoy]

The head is now ready for re-assembly....