The Golf Ball shaped pistons in 2TC TE56 Project build.

Webers, Cam selection and Ignition upgrades.

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VinceG2
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Re: The Golf Ball shaped pistons in 2TC

Post by VinceG2 » Fri Nov 29, 2013 8:36 am

I have a 1975 TE31 with a 2T-C engine from California. It has the Golfball pistons. They are indeed 9.0:1 compression.
Piston.JPG
Golfball Piston
Piston.JPG (110.18 KiB) Viewed 5720 times
The people who previously worked on the engine did a terrible job. It looked like they used a wire brush to clear the gasket before and made a right mess of it. As a result, the head gasket had blown, the surface of the head was all scratched up, and the valves were messed up. You can see what a mess the bottom of the engine looks like in this picture:
Engine.JPG
2T-C engine
Engine.JPG (38.82 KiB) Viewed 5720 times
Just got the head resurfaced, the valves relapped. The head looks all nice and pretty again, just have to find the time to clean up the bottom half of the engine before I put the new gasket and head back on. The engine is currently all stock, with automatic transmission. I have added power windows, power locks, and 6x9 speakers to the rear deck and a stereo. Oh, and I changed the dash lights to LEDs.
Head.JPG
Head
Head.JPG (77.28 KiB) Viewed 5720 times
I had previously heard about these pistons, so it was neat to take the head off and actually see them.

BTW, Starting in 1975, all cars are required to have a Catalytic Converter in California. Pre-cat Corollas would be 1974 and earlier.

82te72
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Re: The Golf Ball shaped pistons in 2TC

Post by 82te72 » Sat Nov 30, 2013 5:14 am

heres a read relating to this so if it is correct as i assume it to be. the golf ball pistons are not as good as typical 2tc or 3tc ones and actually have a lower compression ratio due to lower dome volume

http://www.dorikaze.net/showthread.php? ... ion-ratios

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73GTV
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Re: The Golf Ball shaped pistons in 2TC

Post by 73GTV » Sun Dec 01, 2013 4:53 am

Thanks for that link. So if the emission Carburetor meters less fuel to a setup that has less volume per face of each piston would use less fuel with the same stroke, which would mean that its emission output should be less than the previous years pistons.

Now add twin carburetors to this. Less cc's than the stock, well, could that not equal a higher compression since it is less volume? Same stroke, compressed in a smaller area = more fuel ignited in less area via good hot spark!

Quote: The golfball piston came in everytime with a dome volume of 20cc. The surprise here was the flat-dome with a volume of 22.9cc.

I don't know, it equalled a fast engine and I know that the carburetors couldn't be the total reason for this improvement in performance back then.

82te72
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Re: The Golf Ball shaped pistons in 2TC

Post by 82te72 » Wed Jan 01, 2014 8:38 pm

73GTV wrote:Thanks for that link. So if the emission Carburetor meters less fuel to a setup that has less volume per face of each piston would use less fuel with the same stroke, which would mean that its emission output should be less than the previous years pistons.

Now add twin carburetors to this. Less cc's than the stock, well, could that not equal a higher compression since it is less volume? Same stroke, compressed in a smaller area = more fuel ignited in less area via good hot spark!

Quote: The golfball piston came in everytime with a dome volume of 20cc. The surprise here was the flat-dome with a volume of 22.9cc.

I don't know, it equalled a fast engine and I know that the carburetors couldn't be the total reason for this improvement in performance back then.
The carbs have nothing to do with static compression ratio. Since the flat top pistons have a wider dome the volume numbers seem realistic. The change in squish due to piston shape could increase performance. But i have a hard time believing there 9:1

When i calculated it out myself for 2t i came up with 8.5:1 for golfball and 8.8:1 for flat top. I used their values in the link for dome volume and an assumed .04 inch hg thickness

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73GTV
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Re: The Golf Ball shaped pistons in 2TC

Post by 73GTV » Sat Jan 10, 2015 1:53 pm

82te72 wrote:
73GTV wrote:Thanks for that link. So if the emission Carburetor meters less fuel to a setup that has less volume per face of each piston would use less fuel with the same stroke, which would mean that its emission output should be less than the previous years pistons.

Now add twin carburetors to this. Less cc's than the stock, well, could that not equal a higher compression since it is less volume? Same stroke, compressed in a smaller area = more fuel ignited in less area via good hot spark!

Quote: The golf-ball piston came in every-time with a dome volume of 20cc. The surprise here was the flat-dome with a volume of 22.9cc.

I don't know, it equalled a fast engine and I know that the carburetors couldn't be the total reason for this improvement in performance back then.
The carbs have nothing to do with static compression ratio. Since the flat top pistons have a wider dome the volume numbers seem realistic. The change in squish due to piston shape could increase performance. But i have a hard time believing there 9:1

When i calculated it out myself for 2T-C, I came up with 8.5:1 for golf-ball and 8.8:1 for flat top. I used their values in the link for dome volume and an assumed .04 inch hg thickness
Sorry, I have been busy. Nice calculations, however, have you completed the experiment of the addition of twin carburetors to this engine and posted the results? I'm asking this question because I want someone to prove me right or prove me wrong, and not in theory. I will be able to eventually test this again soon. I believe that I have located the correct head from that engine and I'm toying with building as near as possible That exact engine this winter and will post the build on the progress. The combination was that 1976 Emission Cylinder Head, Twin Carburetors, specifically duel 2T-BR downdrafts, and those specific pistons.

I want to cc that combustion chamber to see if there was a difference between production runs of that Cylinder head since it was a one year only production build. The actual secret could be the camshaft for that year. The original purpose was to provide a source for where the over-sized pistons could be purchased, since then the stock was so limited.

Image
Last edited by 73GTV on Sun Nov 01, 2015 5:41 pm, edited 1 time in total.

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73GTV
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Re: The Golf Ball shaped pistons in 2TC

Post by 73GTV » Sat Jan 10, 2015 2:13 pm

[quote="82te72"]heres a read relating to this so if it is correct as i assume it to be. the golf ball pistons are not as good as typical 2tc or 3tc ones and actually have a lower compression ratio due to lower dome volume. (This is the conventional method of calculating the cr and as you can see, Toyota lied. )


Sorry to borrow your quote, but it was to actually try and correct a point that you had made, and possibly also an error on both our parts concerning pictures and perceptions: Please Observe!

2T-C (1976) 3T-C pistons and 2TG Piston:




Just a sideways view for the Pin in the connecting rod:

Your picture was very good, but taken at an angle not to show the difference in the height from the pin, as well as the difference in height between the two pistons. Humm!
Last edited by 73GTV on Wed Dec 27, 2017 4:14 am, edited 3 times in total.

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73GTV
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Re: The Golf Ball shaped pistons in 2TC

Post by 73GTV » Sat Jan 10, 2015 2:25 pm

Just for info sake, 3T-GTE Turbo Pistons:


Looks like the same design only, well you tell me.
Last edited by 73GTV on Wed Dec 27, 2017 4:15 am, edited 1 time in total.

slaus
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Re: The Golf Ball shaped pistons in 2TC

Post by slaus » Sun Oct 25, 2015 11:30 am

Anyone know where i can get these golf ball pistons with rings???

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73GTV
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Re: The Golf Ball shaped pistons in 2TC

Post by 73GTV » Sun Oct 25, 2015 10:21 pm

slaus wrote:Anyone know where i can get these golf ball pistons with rings???
I purchased an oversize set from a parts store in Sacramento, Ca. that speclized in obsolete engine parts which was also a machine shop, however I can not recall the name of the place and then he had only one complete set left. I had posted the name of the place in a earlier post.
Update:
Repco: Part Number RY6069 .030
Toyota Part Number: 13101-26021

Dana Motors
2319 Lexington Street
Sacramento Ca. 95815
916-920-0150

slaus
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Re: The Golf Ball shaped pistons in 2TC

Post by slaus » Mon Nov 02, 2015 3:30 pm

Ok thanks..

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