View original topic: What about 1602 74x83mm 40 hp? Page: Previous  1, 2
Bub Tue Sep 27, 2022 10:20 am

Busted-bolt wrote: I guess this belongs here . My 1602 . It's almost done ! Lol

Is that CIS on a 40hp? What is that all about?

What did that turbo come from? A key chain?

Holy SH*T I bet that will absolutely rip.

Alstrup Tue Sep 27, 2022 10:25 am

I donīt see the point, - except for the "challenge" If you go 69 or 74 stroke even with the stock 1200 rods and pistons, the stock 1200 tin doesnt fit anyway. If you go with 1300 sgl port heads, the tin needs to be altered too. 13/1500 tin is easily adaptable of course.
There are H beam rods on the market already which fits the 1200 "40" hp crank, for those who absolutely want that.

Busted-bolt Tue Sep 27, 2022 1:22 pm

The big bore 83 mm piston's were modified to be semi hemi just like the heads . I did use a .075" shim for the barrels to get my desired compression ratio .

Busted-bolt Tue Sep 27, 2022 4:17 pm

You can be rest assured I'm using the 40 Hp upper tin when I'm stale air all the way ! 🙃

henry roberts Wed Sep 28, 2022 2:46 am

Is that twin turbo?!?

So Frankenstein and so much custom fabrication! I love it!

earthquake Thu Sep 29, 2022 9:54 am

I thought when you built a 1602 on a 40hp you used 36hp rods that are profiled machined on the big end of the rod so it would work on the 1600 based crank, this way you would still have 20mm pin bores to fit the 83mm BB pistons.


Busted-bolt Thu Oct 06, 2022 9:13 am

I used 40 hp rods that had about .020" milled from each side of the big end . The stock 40 hp cylinder holes on the block and cylinder heads remain stock size as a factory 40 hp . I just have a set of slip in 40 hp big bore jugs in there as well . I need to find those copper stale air rings for the cylinder head to barrel seal . The aftermarket ones are junk because they are to hard and will not allow the cylinder to seat in the head correctly . When all of the mock-up is done on the prototype parts the top end will be removed , cleaned thoroughly , reassembled and adjusted . I just need to source some O-G stale air 40 hp head to cylinder rings ! 👍

earthquake Fri Oct 07, 2022 5:26 pm

If the sealing rings are solid copper heat them with a torch until they are a dull red to anneal them, then they should work.


thomas. Sun Oct 23, 2022 6:32 pm

I used the copper rings from a new box of good quality gaskits from WW in my 40hp 1385 bb.I didn't have any trouble with sealing & I use the stale air heater boxes with no smell or emissions. I switched the heads to the late '65 40hp heads.

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