Saving Old Seagulls

Does anyone have the technical specs for the 170 conrod?

Thinking of getting one made, been putting it off for years but now motivated to at least explore the idea. Seems some custom fabricators can make a rod just from the specs instead of copying an existing one, this would be easier than finding one to borrow/copy.

Not using this company but here’s an example of the specs I would need to get one made from scratch without copying existing one. https://www.cp-carrillo.com/files/1-Lan ... heet-1.pdf

Thanks all

speak to Charles.

Your in luck Andrew I found a picture of one I remanufactured years ago.

The one with the bronze big end is mine the ally big end was the last new Seagull one.
Remember if you make any mistakes in the specs it's your fault & you still have to pay!

I do have some unmachined 170 rod castings (I had to buy the minimum order) if you want to try getting the machining done where you are.

That bronze cap should last a life time, and it saves having to put a bearing shell in it.
looks like the bush you put in the small end has a smaller hole than the original one? Or is it just a thicker bushing.

Both fit a 13mm wrist pin, though it does have much smaller chamfers to increase the load bearing area.

Can't get much past you Kiwis!

did the bronze cap with its extra weight put any shake on the engine?

These rods were conceived under the supervision of Max Nightingale at Alpha who sadly is no longer with us.

He did all the balance sums, I only tested to about 6500, as the revs increased it got smoother.

I made a similar one, never managed to break it.

I found there was no more vibration than usual.

That's a very impressive piece of work, H-A !!!!!

Yes very nice, and I like the way you held it on the lathe.

Looking at the photos of original rods, I notice that they appear to have had bronze bushings both top and bottom, but the big end caps were plain aluminum on the bearing surface? Is that the case and if so is that part of the original design flaw with these?

Wondering if anyone ever tried upgrading the big end cap with a bronze bush. Maybe that would just further weaken the cap though, with the aluminum that would have to be removed.

I’ve found 2 original rods in what I am told are operable condition recently, from different sources. We will see how they look when they arrive, I’m hoping at least 1 is good enough to use on a limited basis without any modification. Once I get them in hand I will post photos and also try to get some detailed measurements to post here.