O 200 connecting rods?

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

4trade

Well-Known Member
Joined
Nov 1, 2010
Messages
527
Location
Lahti/Finland
Does anybody know how long is O 200 connecting rod and how big is STD lower end? My core is just jugs off in a storage, so i can`t measure it now.
 

PTAirco

Well-Known Member
Joined
Sep 20, 2003
Messages
3,667
Location
Corona CA
I have noticed this in a lot of aircraft engine rebuild manuals - they never give the actual dimension of the part! Only min/max tolerances or clearances. Very frustrating.
 

4trade

Well-Known Member
Joined
Nov 1, 2010
Messages
527
Location
Lahti/Finland
I have been try to find that in a net and manual. No mention for that... I cant tear my core apart for that dimension now, too busy. Like you say....Very frustrating
 

4trade

Well-Known Member
Joined
Nov 1, 2010
Messages
527
Location
Lahti/Finland
I am not happy to ask somebody to measure something i am not want to buy, too much hassle(hof) for my own satisfaction.
 

Dan Thomas

Well-Known Member
Joined
Sep 17, 2008
Messages
6,589
2.0625". Measured from an old rod I have here. That's with the bearings out. I suppose you want the crankshaft's crankpin diameter? 1.936".

Dan
 

Dan Thomas

Well-Known Member
Joined
Sep 17, 2008
Messages
6,589
He wants center to center big end small end if I am not mistaken.

Is he figuring on using auto rods instead? Most of those have bigger crankpin bores and are narrower. Between the holes I'd have to measure and do some figuring, but it's around 8 or 9". Longer than many auto rods. It has to keep that piston away from the opposing rod and crankpin and crankpin cheeks, see?

I had to replace the rod bearings in my A-65, which is pretty similar to the O-200. There were no auto bearings that were anywhere even close.

Dan
 

4trade

Well-Known Member
Joined
Nov 1, 2010
Messages
527
Location
Lahti/Finland
Thank you Dan. You got it. I am thinking is there good auto rod that can use. That is reason i am interest for center to center dimension.
 
Last edited:

TFF

Well-Known Member
Joined
Apr 28, 2010
Messages
16,130
Location
Memphis, TN
I am not sure about the 0-200, but most aircraft rods I have seen have the beams polished and then shotpeened. Race car quality. Carrillo will make any end size you want. I would not throw any $400 set of rods from Summit in there, though. How are you going to handle weights? The opposed weights will be match, but if it is not the same the counterbalance weights will be off on the crankshaft. I would expect the auto parts, especially the rods, are going to be too light. light is great for high revving short run engines, but slow turning high load engines need the structural strength.
 

4trade

Well-Known Member
Joined
Nov 1, 2010
Messages
527
Location
Lahti/Finland
I have been thinking engine, that run 3000-3200 rpm constantly. So i am aware that TBO is something like 1000 h if i squeeze 130-140 hp out of that machine. This is point where lighter masses inside engine are better. Carrillo rods are best one money can buy. I got set of those Carrillo rods for Chevy BB years ago. Those ones was exactly same weight (both ends too) and work of machining industry art. They dont give any rpm limits for BB.

I will balance that engine for lighter masses and higher rpm.
 

Dan Thomas

Well-Known Member
Joined
Sep 17, 2008
Messages
6,589
Thank you Dan. You got it. I am thinking is there good auto rod that can use. That is reason i am interest for center to center dimension.
When I get a minute I'll measure that rod, but be aware that these opposed-engine rods have the rod bolts installed in the other direction from auto rods. That's because you can't get at the nuts unless they're facing the piston end. Rod goes on crank first, piston is put on rod (maybe with piston partway into cylinder to hold rings) and then cylinder is pushed onto piston and up against crankcase.

Dan
 

pie_row

Well-Known Member
Joined
Nov 9, 2009
Messages
710
Location
salt lake city Ut
When I get a minute I'll measure that rod, but be aware that these opposed-engine rods have the rod bolts installed in the other direction from auto rods. That's because you can't get at the nuts unless they're facing the piston end. Rod goes on crank first, piston is put on rod (maybe with piston partway into cylinder to hold rings) and then cylinder is pushed onto piston and up against crankcase.

Dan
VW rods will work after market ones that is. And They have the bolts going the correct way.
 

4trade

Well-Known Member
Joined
Nov 1, 2010
Messages
527
Location
Lahti/Finland
VW rods is very short. There is 5.700 long ones aftermarket rods with Chevy lower end. Is there somebody that have actually test those rods in O 200?
 

jumpinjan

Well-Known Member
Joined
Oct 3, 2004
Messages
313
Location
Dayton OH
The 5.7 V8 rod is off-set ground on the big end, you don't want that one. If you want a 5.7 rod, use the I6 250 or I4 Mercruiser (Nova) engine. The I6 292 Chevy is even longer, I think its 6.0.
I use the 5.7 in my British car engine, its a pound lighter.
Jan
 

4trade

Well-Known Member
Joined
Nov 1, 2010
Messages
527
Location
Lahti/Finland
I was more like thinking that 5.700 is too short. There is mentioned that VW rod is proper one but i really don`t know. I know that all those V8 rods are offset ones, and i need avoid these ones.There is VW rod that use Chevy bearings, 5.700 long, build for aftermarket crank with Chevy bigger lower end. Seems like there might be no proper one, except those custom order rods, that cost a lot.

I keep on looking!
 

jumpinjan

Well-Known Member
Joined
Oct 3, 2004
Messages
313
Location
Dayton OH
Another important point is the small rod end can't be bushinged on the Chevy rod, there's no material there to support a bushing. What I do for my British engine mods, is hone the small end out to the stock pin clearance. Its steel on steel, but I haven't had any pin longevity problems yet
Crower does make a 5.7 rod, but its a little meater than stock, so there are interference issues over the stock rod.
http://www.crower.com/media/pdf/2008b/182-187.pdf
Jan
 

pie_row

Well-Known Member
Joined
Nov 9, 2009
Messages
710
Location
salt lake city Ut
The VW rods have the bolts going the correct way is what I was trying to say sorry for not being clear enough. Getting one the correct length well...
 
Top