# O 200 connecting rods?

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##### Well-Known Member
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 cant measure it now.

#### pie_row

##### Well-Known Member
Nope google didn't turn it up with a reasonable amount of effort.

#### ezaviator

##### Member
The rebuild manual doesn't provide those dimensions, only the minimum and maximum clearance.

#### PTAirco

##### Well-Known Member
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.

##### Well-Known Member
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

#### pie_row

##### Well-Known Member
I did see one on sale on Ebay ask him maybe?

##### Well-Known Member
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
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

#### pie_row

##### Well-Known Member
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
He wants center to center big end small end if I am not mistaken.

#### Dan Thomas

##### Well-Known Member
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

##### Well-Known Member
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.

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#### TFF

##### Well-Known Member
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.

##### Well-Known Member
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
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
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.

##### Well-Known Member
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
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

##### Well-Known Member
I was more like thinking that 5.700 is too short. There is mentioned that VW rod is proper one but i really dont 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
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
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...