Newbie Auto 'Box Installation Help Please!

plastic orange · Post by **plastic orange** » Sun Feb 24, 2008 11:03 pm

My BW 65 flex plate fitted my 3.9 engine. I don't think the bolt spacings are different between cranks. Are you sure you have the correct flex plate to fit the converter? Did you trial fit it before fitting to engine?

Pete

bigdawgv8 · Post by **bigdawgv8** » Mon Feb 25, 2008 9:32 pm

plastic orange wrote:My BW 65 flex plate fitted my 3.9 engine. I don't think the bolt spacings are different between cranks. Are you sure you have the correct flex plate to fit the converter? Did you trial fit it before fitting to engine?

Pete

Was the engine from a manual or auto Pete?
I'm sure the crank flanges are different.

My 3.9 came with the flex-plate and 1-inch-thick spacer bolted on as it came out of the donor. This flex-plate has a larger centre hole.
The spacer bolts onto the crank (using allen bolts sunk into the spacer)and the flex-plate bolts onto the outside edge of this spacer.
The BW65 plate has the same bolt pattern as the crank but needs to be spaced out by 1 inch (in my case).
I can't use the above spacer because of the countersunk bolts and the oversize holes they are in.
I tried to use the Range Rover flex-plate (fits engine) with BW 65 torque convertor (fits gearbox) but the 4 bolt holes don't line up.

Is there a spacer available the same as the one I have but without the countersunk allen bolts and with longer bolts to suit??? (BTW - these bolts would need to be pretty long 1.5 inches?)

What are the flex-plates made from? Sprung steel? If so It's going to be impossible to machine or drill if I have to modify the BW65 to fit in the same way as the Range Rover item.

Thanks again for the help.

Martin

Post by **katanaman** » Mon Feb 25, 2008 9:38 pm

I cant help you much but what I can say is that the cranks are exactly the same whether auto or manual. Daft comment coming up but you do know the bolts aren't equal spaced? you need to spin the flex plate until the holes line up as it only fits one way. See told you it was daft but u never know.

Quick other question, are you using a BW65 flex plate or a 3.9 plate?

bigdawgv8 · Post by **bigdawgv8** » Mon Feb 25, 2008 10:15 pm

katanaman wrote:I cant help you much but what I can say is that the cranks are exactly the same whether auto or manual. Daft comment coming up but you do know the bolts aren't equal spaced? you need to spin the flex plate until the holes line up as it only fits one way. See told you it was daft but u never know.

Quick other question, are you using a BW65 flex plate or a 3.9 plate?

Thanks.

I'm using the 3.9 plate and spacer with the BW65 torque convertor.

The holes I'm referring to are the holes in the flex-plate where the torque convertor bolts on - are you saying that these aren't equally spaced???

Cheers

Martin

Post by **katanaman** » Mon Feb 25, 2008 10:34 pm

no the crank holes arent equally spaced. The 3.9 engine never used a BW 65 auto box that I know of. so far as I know it uses a 3-speed Chrysler Torqueflite A727 or a ZF 4HP22 4-speed I am not even sure if the 3.9 actually used the 3 speed but it might have. Others will know better than me on that front. I would doubt very much that your flex will be anywhere near the 65. Use the proper flex plate and your sorted. You might need different spacers or something which wont be hard to find but it will fit your crank.

plastic orange · Post by **plastic orange** » Tue Feb 26, 2008 8:22 am

My 3.9 was a manual, so I don't think the cranks are different. From memory, I think the thick spacer was used on the GM 180 box (possibly others) - but I don't think the 65 had this.
I don't think you are using the correct flex plate/torque converter combo.
If you get everything from a 65 it will fit.
Any spacer I have seen just bolts up to the crank through the flex plate - not as you describe with peripheral bolts.

Pete

bigdawgv8 · Post by **bigdawgv8** » Tue Feb 26, 2008 9:09 pm

Once again thanks for all the replies guys.

I'll strip it down again and work with the flex-plate from the BW65.

To fit this and have the correct flex-plate to torque convertor clearance I need
1) the correct spacer ( I have a selection of spacers but nothing suitable)
2) the correct length bolts ( as I said these will have to be long!)

Anyone know where I can get these?
I might be lucky and be able to get the bolts from work but the spacer?

Cheers

Martin

bigdawgv8 · Post by **bigdawgv8** » Tue Feb 26, 2008 9:21 pm

Up-date,

Just had a quick look at 'Rimmers' site and both spacer and bolts are currently unavailable.

bigdawgv8 · Post by **bigdawgv8** » Sun Mar 16, 2008 9:53 pm

Hi,

A final up-date.

I bolted everything together today and it works fine.

I used the BW65 flex-plate with a modified 3.9 spacer ( I had to machine up some sleeves to fit the recessed bolt holes ) all held onto the crank with high-tensile bolts found at work.

Thanks for the help guys.

BD