Trim cylinder threaded eye size and thread pitch?

[_diesel_]

I have learned an incredible amount from this forum and finally registered to see if I can get some info I have had no luck finding. I'm trying to fab an extension for my trim cylinders. I did the sei conversion and my cobra cylinders are too short to lift the merc drive up enough for trailering. I would appreciate any info. I'm looking for the thread size and pitch for the end of the ram where the eye threads on.

 

[Bondo]

Ayuh,..... Welcome Aboard,..... I have no idea, but suggest you mike the shaft, 'n use a thread pitch gage to see what the threads are,.....

You do realize, it won't trim in as far when you extend them, Right,..??
Does Sei have an answer for this question,..??

 

[_diesel_]

Ayuh,..... Welcome Aboard,..... I have no idea, but suggest you mike the shaft, 'n use a thread pitch gage to see what the threads are,.....

You do realize, it won't trim in as far when you extend them, Right,..??
Does Sei have an answer for this question,..??

Thats what I tried but i get .6625in or 16.83mm. I am able to thread a 5/8-18 bolt into the eye fairly nice, but 5/8-18 nut will not thread onto the ram. And the thread pitch sure seems to be m1.5 although the 18 does fit well with minimal slop. Maybe it's a 17mm? Nowhere near me with that kind of fastener selection.

I asked sei about using mercruiser trim cylinders but they claim it won't work. He said the cobras didn't have much travel as it was and now the rear mount is an additional 4 inches back. I have 4 or 5 inches of shaft still remaining when I'm trimmed all the way down because of the conversion bell housing, they notch the drives to allow full down trim. I'm just trying to add 4 inches to the shafts so it will lift the drive higher, it drug my skeg out of the shop when the tongue was nearly on the ground.