Engine mid plate questions

[d55dave]

OK, mocking up my car to make front mounts and I have the mid plate installed (The car had been set up years ago, but when I bought it as a basketcase all I got was the mid plate). I understand that a spacer needs to go between the crank and flex plate the same thickness as the mid plate (mine is 3/8"), to position the converter properly in the transmission but I have a few questions. What happens with the torque converter pilot area - does the converter just have less engagement in the back of the crank? What happens with starter engagement - the starter will now not sit into the pilot bore in the bellhousing all the way, and I am guessing may not properly engage in the ring gear on the converter?

Any thoughts or advice?

 

[440outlawdart]

i wasw thinking of installing a mid plate to this year as i might go with a powerglide,like to hear more on this too

 

[tubtar]

3/8th is pretty meaty for a mid plate. I have a CE one for my small block that had spacers included with it , but at .125" I don't thing pilot engagement would be as much of an issue.
I'd suspect with a thicker plate / spacer , the spacer would register in the crank and be machined to locate the converter precisely , but I don't recall ever seeing this done.
Not much different that a conversion kit I think.

 

[inkjunkie]

For the convertor, if you don't use an off the shelf unit, the issues can be "accounted for" when it is built.....

 

[1970 La]

I have a .125 mid plate if some one is looking for one. thanks

 

[d55dave]

On another note, what thickness are people using for front plates? I have made up my front mounts - to the typical water pump area, out of 5/16 aircraft grade 6061 t6 aluminum. Any thoughts?

 

[sst3193]

The mid plate on the friend's car doesn't account for the starter depth at all. His Tilton starter doesn't have a nose to register anyways. The flexplate bolts on top of a crank spacer that will capture the converter nose and take care of that.

 

[tubtar]

On another note, what thickness are people using for front plates? I have made up my front mounts - to the typical water pump area, out of 5/16 aircraft grade 6061 t6 aluminum. Any thoughts?

5/!6 " should work fine.....most are 1/4 " and I do see some 3/8 " out there too , so you are at the proverbial happy medium.
I have 1/4 front plate and am not going to use the mid plate at this point.
Just a good poly trans mount and the front plate should be enough for what I am doing.

 

[hemicop]

My front motorplate is 1/4 & midplate is only 1/8. As to converter "issues" when I order my converter I just tell them my midplate thickness & they add the appropriate length to the snout. I never really had any starter issues as my current & previous cars never had a problem.