470 Stroker build

The bent flexplate is creating an unbalanced situation and likely doing damage . Were there any issues during transportation or installation that could have bent the flexplate?

 

Was the transmission rebuilt for this new engine?

 

73stage2, no issues with the engine etc. The flex plate was part of the balanced short block from a project someone in the Tacoma area started in 2010. I knew the flex plate was slightly warped when I installed it….approx 0.060 on the one mounting foot of the converter. I thought it wouldn’t be a big issue…..maybe it was. the tranni was built 3 years ago with this 470 build the goal at approximately 575 hp. Same with fuel system, drive shaft, rear diff…..all planned for this 470.

 

Talked to my tranni builder, he claims to put the restriction in to limit fluid flow to the torque converter.

just checked the end play on the stock 455 i ran for 3 seasons with the same turbo 400, 9.5 inch converter, end play on crank 0.006

Motor comes out week of the 21st

 

Larry, thanks for this info. I have read this article and several others. I think installing the heavier Transgo orange relief spring for the pump was a mistake. I will be taking tranny out, changing this spring, will also ensure that there is a .110-.125 restriction in the converter feed. I will be looking at a pressure relief system that is tee’d into the cooler line, dumps fluid back to the pan once set pressure is exceeded. Hutch transmissions in Ontario sells a simple relief valve.

 

Another interesting article on converter pressure and thrust bearing

 

It’s amazing the power of fluids under pressure.

 

Motor out on the stand. So the investigation begins…

 

Rear side of thrust worn. Looks like ive caught it before it damaged the crank. Ill have the crank polished, make sure thrust surfaces are mirror smooth. And deal with my turbo 400

 

Here’s where the converter restriction goes. I tapped it for a brass set screw and drilled it out to .125”. Get rid of the orange spring use a stock one with shims and replace your flexplate. Glad you found it before the thrust contact area on the crank wore all the way through the bearing and started grinding on your block, crank would be toast, be sure to check your thrust clearance.

 

Thanks 73 stage 2. With the turbo 400 mods you spoken to, I will be adding an adjustable relief valve in the cooler line. Not doing this again.

 

Here is s pic of the crank thrust surface - tranni side. Needs to be polished.

 

Looks fine to me

 

Mark,
Taking crank to machinist this morning. He will polish the thrust surface just like the journals. Im sure my thrust issue all comes down to the excessive internal pressure in the turbo 400 from the heavy pump relief spring from Transgo that was installed in my turbo 400. That will be changed out to a stock spring, a restriction installed in the converter charge/cooler circuit, an adjustable relief valve in the cooler circuit to ensure I dont ruin another thrust bearing. Doing whatever possible to prevent reoccurrence.

 

Fortunately your bearings took the hit like they’re supposed to instead of the crank.
Was the end clearance in the trans checked when the trans was rebuilt?

 

Dont know the answer to that Mark.

Do you know what the tolerance is? As tranni is on a dolly.

thanks

 

No I do not.
I’m sure someone on here does tho.
Since the trans is out now would be the time to find out