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Greetings,
My question is about stock connecting rod position in the piston in a 1972 350 chevy block. I tore down the engine and noticed #6 rod cap was facing to the front and all other even clys were facing back. Could this cause damage to the crank?
Thanks in advance
If it ran that way for any length of time its probably right. You have a notch cut into the top of piston that goes to the front of the motor. if the rod and caps have # on them then the #'s goes together, there is a tit made into the bearing that holds it in place in the cap and rod, the tits goes together. :cool:Quote:
Originally posted by zz1958
Greetings,
My question is about stock connecting rod position in the piston in a 1972 350 chevy block. I tore down the engine and noticed #6 rod cap was facing to the front and all other even clys were facing back. Could this cause damage to the crank?
Thanks in advance
Thank you for the reply.
This engine came out of a truck that had been rebuilt aprox. 5000 miles ago. Then stolden and the sheriff said they run until the engine quit running. When I tore it down we sent rods to machine shop to be resized and replaced the crank. That was when we noticed the difference in the caps. the bearings and cap are in correctly the beefy side of the cap is facing front, all others in that bank are facing back. The caps in the other bank are facing front.
When you mate the caps to the rods like Mike said, with the bearing tangs together, then the rods are installed on the crank with the tiny little oil hole at the parting line of the cap and rod facing the camshaft, not the oilpan.
Didn't the machine shop catch that?
I really appreciate your comments,
All oil holes are inward, all bearings are in tangs facing out, the situation is one cap appears to be wrong (backward) when compaired to the others, will this damage the crank.
Well, it won't do it any good, depending on the radius of the fillet at the corner of the rod journal. Take it apart and do it right, or you're gonna have some explaining to do to the cam lobes that don't get oiled as a result :)
If I had 1 cap that looked dif. from the others id want to know why. If you could post a pic. of the 2 caps I might could help you, if not id go back to the machine shop and let him look at it. :HMMM:Quote:
Originally posted by zz1958
I really appreciate your comments,
All oil holes are inward, all bearings are in tangs facing out, the situation is one cap appears to be wrong (backward) when compaired to the others, will this damage the crank.
Heres a picture
This picture shows caps both facing front, all other cap pairs are opposite each other
I think maybe Mike went to bed and I can't tell much from your photo. If one of them has the oil hole aimed toward the oilpan, it's wrong. The caps and rods usually have a deeper chamfer on the side that mates to the cheek of the rod journal to allow clearance for the fillet. Pull the cap off the one that looks wrong and see if the wider chamfer is toward the other rod or toward the fillet. If it's wrong, you probably won't be able to get the proper side clearance on that pair and you ain't gonna like it down the road, cause the shallow chamfer is gonna dig into the fillet and the extra heat generated could grow the big ends enough to spin a bearing.
Thank you techinspector1, I will try that. None of the oil holes face the oil pan I took all off and checked earlier before my first post. With the picture I was trying to show the rod caps have a small part of the casting almost like a point sticking out on one side, on this journal (photo) the points face the same direction on all other journals the even clys. face back and the odd cyls. face back.
It could just be an oddball rod that was used to replace an original for some reason during a rebuild at sometime in its life. Check the chamfers.
Guess I should read what I type!
what I meant was on the even cyls. the points are to the front and on odd clys. they point back
I still got it backwards. Its late I quit Ill just walk to work tomorrow. Good night all. Thanks again. zz
Rod side clearance should be 0.014" to 0.016" on each pair.
Cant tell much about it zz1958, but if the piston is in the right way and the cap bearing is tit to tit, you have good side clearance then it should work. If the rod is on backwards like teck said the side clearances want be right. you can put the rods in backwards but they will be to tight. Other wise I don't know why you have 2 dif. caps. are the beraing tits at the same place on all of the rods? :HMMM:
Looks like just the cap is on backwards. Disaster in the making. I'd get a rebuilt rod.
. if the cap or rod is on backwards then you should be able to see it. take one you think is right and check where the notch in the piston is, compare where the #'s on the rod and cap is, compare where the bearing tits in the cap and rods are, which way is the rod offset. and where the oil holes are, if every thing match up then its should be right. if you still cant make up your mind then put a new rod in. if its backwards it want last. :HMMM:
problem solved. thanks again for all your help gearheads! rod was backwards origanal builder is in hiding, won't admit his mistake. well hell it just cost us time and money, and learn us some about people.