1FZ trans swaps 6R80 10R80 and more (3 Viewers)

[cruiserbrett]

Hello,

I have thought about this and run some numbers on clearances versus what Toyota designed in stock for the starter bolts.

The minor diameter of an M12 x 1.25 thread is 10.65 mm. Since these bolts are 70 mm long, the bolt will not be fully threaded and the portion under the head of the bolt will be run around 9.9 mm in diameter. This yields a nominal diameter difference for an M10 bolt passing through a threaded M12 x 1.25 hole of .75 mm. Radially this is .375 mm of clearance. Stock, Toyota had a 12 mm hole with and a M12 x 1.25 bolt with a major diameter in the range of 11.9 mm. This yields a diameter difference of 1.1 mm and a nominal radial clearance of .55 mm. There are three hole patterns to align. The holes in the starter, the block, and the adapter plate, with their own tolerance for location.

I think I am more comfortable with the larger radial clearance if we drill out to 13 mm and stay in the design range that Toyota came up with . The difference in radial clearance is not great, but I cannot do a full tolerance analysis for fit of the three hole patterns, as I do not know the tolerances that are held for the start or the block.

Thanks for the suggestion.

Mike

Very late to the party, but why not machine a relief on the transmission side of adapter to depth of the adjacent socket head cap screw, and put a stud in the starter, and use a nut on the stud?

 

[PIP]

I machine a bunch of transmission adapters. Some of them I've designed use Toyota starters. Several of these adapters use M10 studs through M12 threaded holes intended for a bolt from the transmission side. It works great, no problems whatsoever.

 

[ProjectTrinity]

Anyway to solve the CEL issue to smog?

 

[OutlawMike]

Anyway to solve the CEL issue to smog?

I have two paths on that to try. One is to trick the stock ECU to think it is in Neutral and then it will not throw codes. The other is to use an OBD2 ECU from a 1996 or 1997 Supra, manual trans, non turbo. I need to get off my butt and try them.

 

[hazard]

FIY
US Shift has finally released their 10R80 transmission controller. Now we can use this awesome trans. Just need adapter to 1FZ. I have one made that also mates to the stock transfer case but it will be a while before I try it. This is the best possible trans for our use. Super low 1st and lots of overdrive with many gear steps. Should be great for crawling and economy. I will post when I get it in, probably 6 months.
The trans is the biggest holdback if you want to use the 1 FZ and want economy and drivability.
Cheers

 

[Marvelicious]

The trans is the biggest holdback if you want to use the 1 FZ and want economy and drivability.

I've always felt that way. I'm not afraid to rev the nuts off my 1FZ when appropriate, but it gets THIRSTY. I'd really like to do one of these swaps at some point, but honestly.. 8 or 10 speeds, either one is great. If the adapters are all available when I decide to go ahead, it'll likely come down to price.

 

[OutlawMike]

I've always felt that way. I'm not afraid to rev the nuts off my 1FZ when appropriate, but it gets THIRSTY. I'd really like to do one of these swaps at some point, but honestly.. 8 or 10 speeds, either one is great. If the adapters are all available when I decide to go ahead, it'll likely come down to price.

FIY
US Shift has finally released their 10R80 transmission controller. Now we can use this awesome trans. Just need adapter to 1FZ. I have one made that also mates to the stock transfer case but it will be a while before I try it. This is the best possible trans for our use. Super low 1st and lots of overdrive with many gear steps. Should be great for crawling and economy. I will post when I get it in, probably 6 months.
The trans is the biggest holdback if you want to use the 1 FZ and want economy and drivability.
Cheers

Make sure you get a 10R80 with the updates. The CDF drum has a press fit defect from 2017 to 2022. Also, the outer shell (or trash can) has issues with the F clutch gouging divots in it. The updated 10R80 has a hard anodized finish on the outer shell. My 2017 10R80 in my F150 s*** the bed in December 2024 at 62k miles. I had an 8 year warranty, so Ford put a remanufactured transmission in.

 

[CJK]

FWIW — 8HP and 10R80 both have a 1st gear ratio of like 4.7 so the difference is negligible. It seems like the better choice is whichever is more reliable, more plentiful parts (OEM and aftermarket) and lower cost.

If it wasn’t like $10K to do the swap, I would be all over it.