High compression head question

[Spudenater]

Hey all, I recently acquired a "high compression" head and pistons locally, and I'm hoping some 3tc vets can help me out. So the head has been shaved, no word on exactly how much though. It's just to the bottom of the smog ports. Anyways, I was wondering about the shape of the combustion chambers. As you can see in the attached pic, my stock head (Jan 1980 3TC) has round chambers, but this otherd (Unknown date of man.) sre oblong. My questions are such:

Will the shape of the combustion chambers be a problem with stock (flat) pistons?
Will I have any problems if I bolt this on to an otherwise stock motor? (weber 40 and header not withstanding)
Any clue why it has an additional hole/port next to the spark plug inlet, whereas my stock head does not?

Also, I was given accompanying pistons, and I'm a bit puzzled by them. They have the old TEQ logo on the inside, as well as Aisin, and a part number (18010), and I can't figure out what the hell they're out of. I was told they "go with" the heads oblong combustion chambers, but as I'm somewhat new to motor building in a general sense, I'm having trouble figuring out if they're "required" to have a properly functioning motor if I bolt on the head. Any insight would be greatly appreciated, thank you!

Stock head


Shaved head


High compression pistons

[NME308]

Hi there mate,
You have my friend been sold the ugly duckling smog head with pre combustion chamber. It was Toyota's very short lived venture into extremely lean burn mixture 'technology'. Those pistons are specifically to suit that head of course.

Can your standard head be reused?? Have it CC'd & shaved to suit a 'normal' set of pistons would be my advice...

Cheers,
Jason

[VG214]

That cylinder head and pistons are for 13T or 12T engine.

[Spudenater]

I don't see a reason why my stock head couldn't be reused. It's got a stripped exhaust bolt hole, but I have a helicoil kit to repair it. After a cleanup it oughta be fine. However, is there any tangible benefit to running 12t/13t equipment? If there is, is it worth my effort to replace my pistons? (head I'm already doing obviously).

[Toyota1515]

Those heads are not good at all for performance purposes, the tend to crack and hydro-lock your engine making it ready for a side window in the block!

[Spudenater]

Well alrighty then, thanks for the info. I suppose I'll try and sell this off to someone whose just looking for a non-performance oriented replacement. What do y'all suppose is a fair price?

[Toyota1515]

Well alrighty then, thanks for the info. I suppose I'll try and sell this off to someone whose just looking for a non-performance oriented replacement. What do y'all suppose is a fair price?

I always said i never put a price on what is not mine but i can tell you right out of the bat, whoever is looking for 3t parts i am 100% sure is not looking for smog environmental friendly parts thats for sure, with that said, imo they are worth its weight in aluminum scrap!

[oldeskewltoy]

Well alrighty then, thanks for the info. I suppose I'll try and sell this off to someone whose just looking for a non-performance oriented replacement. What do y'all suppose is a fair price?

I always said i never put a price on what is not mine but i can tell you right out of the bat, whoever is looking for 3t parts i am 100% sure is not looking for smog environmental friendly parts thats for sure, with that said, imo they are worth its weight in aluminum scrap!

true.... BUT.... if they are trying to restore a model that used those parts... then those parts are rare and difficult to find.... If you are going to attempt to sell them, pull the valves and clean the head up some so it looks more purchase-able

As far as price.... $250 for a head and 4 pistons is pretty cheap... and you can always post it as OBO

[Spudenater]

Okay, I appreciate the input. I suppose I'll have to wait for the right buyer, but I'm not hurting for cash so I have time. Maybe I'll post them up on JNC, see if any of the people with the Carinas or international Corollas want them. Thanks a bunch guys.

[slaus]

Okay, I appreciate the input. I suppose I'll have to wait for the right buyer, but I'm not hurting for cash so I have time. Maybe I'll post them up on JNC, see if any of the people with the Carinas or international Corollas want them. Thanks a bunch guys.

THAT IS DEFINITELY 13T OR 12T EQUIPMENT BUT I WOULDN'T GO TOO FAR AS TO WRITE IT OFF AS WORTHLESS OR RUBBISH. I NEVER EXPERIENCED ANY HEAD CRACKS IN MY EXPERIENCE BUT I GUESS IT DEPENDS ON HOW FAR YOU GO WITH IT..

A FEW YEAS AGO, I SUPERCHARGED A 13T-U ENGINE AND RAN 17 PSI OF BOOST ON IT WITH GOOD RESULTS. NEVER DYNOED BUT DID SNIP A LOT OF SR20 AND RB20/25 TURBO CARS ON THE STREETS...

SEE LINK : http://www.youtube.com/watch?v=YYudIV2V9ac

WHAT I DID HOWEVER WAS REPLACE THE SAME PISTONS THAT YOU HAVE UP THERE WITH SOME FLAT TOP 21R OVERSIZED PISTONS WHICH DROPPED THE COMPRESSION AND MADE THE HEAD USEABLE (SO TO SPEAK)...

WHAT I CAN SAY HOWEVER IS THAT THE ORIGINAL 12T/13T HEAD + PISTON COMBO THAT YOU HAVE HERE DOES HAVE HIGHER COMPRESSION OVER THE 2T/3T ENGINE AND BEFORE I BOOSTED THE ENGINE, WITH JUST SLAPPING ON A 38/38 WEBER AND ISOLATING THE EGR SYSTEM WHICH IS CONNECTED TO THAT HOLE YOU ARE ASKING ABOUT NEXT TO THE SPARK PLUG HOLE, THE ENGINE WAS QUITE IMPRESSIVE IN NA FORM...