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Rod cap ??
https://slantsix.org/forum/viewtopic.php?t=55589		 Page 1 of 2
Author:  Rick Covalt [ Thu Jun 12, 2014 1:11 pm ]
Post subject:  Rod cap ??
I have a line on some 198 rods but they apparently do not have any caps on them. If I am going to have them resized anyway can I just use caps off another set of rods?

Thanks!
Rick
Author:  Joshie225 [ Thu Jun 12, 2014 2:08 pm ]
Post subject: 
You'll probably have to go through quite a few caps in order to find 6 that are close enough to be resized to fit. How many rod cores do you have available for sacrifice?
Author:  Rick Covalt [ Thu Jun 12, 2014 4:40 pm ]
Post subject: 
Josh, I have a broken rod from my engine disaster last fall and one rod that has a small mark in it from flying parts. I can pick up 2 rods but they do not have the caps. I don't have any rods to get caps from. I was really hoping to just be able to pick up a couple caps, install ARP rod bolts, and have them re-sized and be ready to go.

Rick
Author:  Joshie225 [ Thu Jun 12, 2014 5:44 pm ]
Post subject: 
That's highly unlikely, sorry. My machinist went through 4 rear main caps to find one suitable for resizing to fit a 340. These old parts simply aren't that accurate.
Author:  kesteb [ Thu Jun 12, 2014 10:14 pm ]
Post subject: 
That doesn't sound right. When they resize rod ends, they take a few thousandth off the cap, bolt them together and then bore them out to the proper size. So I don't see what difference it makes where the caps and rods comes from.
Author:  SlantSteve [ Thu Jun 12, 2014 11:59 pm ]
Post subject: 
I was "lucky" enough to buy a set of 198 rods on eBay .... What can I say
:oops: anyways,they turned up with the caps mixed up,some rods weren't numbered and some were. I believe they were a mixed set. The numbered rods were an easy job to sort,but the un numbered rods were a whole different story. It was guess work to see what cap was the best fit with each rod....eventually I got them right,but it's a lot of hassle,not only do you need to get the bearing bore lined up,but the bolt alignment was different between rods and some caps had poor bolt alignment on some rods making it very hard to even assemble them to check the bores. With six rods,I'm betting you will need quite a few spare caps to get something close...I wouldn't gamble it on a hi po engine.....especially when you consider that by the time they are aggressively closed and honed back to spec you'll probably have a rod that's possibly a lot shorter.....
Author:  Dart270 [ Fri Jun 13, 2014 4:25 am ]
Post subject: 
I probably have 20-40 rods from 170 and 225 that could be used to try caps. I have not done this.

By the time you rebuild/fix those 198 rods, isn't it almost the same to get K1/Molnar rods? Figure $300+ for buying and rebuilding the 198 rods with good bolts? Just sayin...

Lou
Author:  Joshie225 [ Fri Jun 13, 2014 10:29 am ]
Post subject: 
Quote:
That doesn't sound right. When they resize rod ends, they take a few thousandth off the cap, bolt them together and then bore them out to the proper size. So I don't see what difference it makes where the caps and rods comes from.
Try this test. Take two rods, exchange the caps. Run your finger nail across the parting line.
Author:  Rick Covalt [ Fri Jun 13, 2014 11:15 am ]
Post subject: 
I have 5 rods and pistons that I want to use in the future. I can pick up another rod for $25 but it has no cap. If/when I find another single rod I will have a set of six and will do another big bore engine probably for my truck. This is probably years away.

My big bore engine for my race car will be K1/Wiesco and they are already on the shelf. I just don't want to scrap the 5 rods and pistons out of my blown motor.

Rick
Author:  CNC-Dude [ Fri Jun 13, 2014 12:00 pm ]
Post subject: 
Swapping rod caps is much different than main caps on a block. While you can sort through a pile of main caps that can fit close enough to work on another block most of the time, a rod cap from another rod usually has too much of a mismatch between the rod and the cap in both a side to side orientation as well as a front to back relationship where the side clearance is involved, and both of these issues have to be corrected to allow you to use it. And most shops just don't feel this is a worthy investment of time on there part to have to charge you for. Then you will also have to blend the chamfer on both sides of it too so there will be no mis-match there(which is often overlooked). You will just need to search for another rod that has the original cap on it.
Author:  Dart270 [ Fri Jun 13, 2014 1:56 pm ]
Post subject: 
Or, you could just run one 225 piston and rod in your 198 rod/short piston motor!! I bet Charlie has done this and run 13s... :roll:

Lou
Author:  slantzilla [ Fri Jun 13, 2014 3:17 pm ]
Post subject: 
:shock:
Author:  DadTruck [ Fri Jun 13, 2014 3:32 pm ]
Post subject: 
If there was non clean up when re sized due to a mid matched cap, I would have the shallow area filled with braze material then re machined to size. Common fix for rods with bore damage.
Author:  SlantSteve [ Fri Jun 13, 2014 3:54 pm ]
Post subject: 
If you only need one rod,and it's only $25 it's not a huge investment....worth a gamble? Maybe? Guess it depends on how many caps you can locate and try. Still wouldn't push them too hard......


Dadtruck.....brazing up a rod bore to repair?? Never heard of it....seen oversize bearing shells,but never a brazing process,sure it wasn't a journal repair?
Author:  CNC-Dude [ Fri Jun 13, 2014 4:58 pm ]
Post subject: 
Quote:


Dadtruck.....brazing up a rod bore to repair?? Never heard of it....seen oversize bearing shells,but never a brazing process,sure it wasn't a journal repair?
Might work for a diesel rod, but for a $25 dollar rod, it's too much effort, then you still have 2 more mis-matches to correct. That sounds like one of those tricks you do when your trying to trade off a lemon to a car lot.LOL
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