Boxman Posted September 7, 2011 Report Share Posted September 7, 2011 So about a month ago, I was here with a question about my engine rebuild. Not long after that, I got stuck. Apparently, the H-beam conrods I ordered from Maxspeedingrods, are too wide for my block. I installed one piston, and tried to turn the crank, but after about 110 rotational degrees either way, it got stuck. So they are too wide, and collide with the bottom of my cylinder wall. The rods do fit B5234T engines of >'99, but as mine is pre-99, they don't fit completely. They are the right length and all, but just a bit too wide. The seller now agrees to take them back and hone them to the correct size - but here's the question. Does anybody know the exact measurements of a pre-'99 B5234T block? Or does anyone know what the allowed dimensions of the conrods should be? Maxspeedingrods wants me to tell him how much should be honed off - but I have not the slightest clue to be honest. Does anyone know? Link to comment Share on other sites More sharing options...
Che'_Moderator Posted September 7, 2011 Report Share Posted September 7, 2011 You against more machining work? If not there is an easy fix. Link to comment Share on other sites More sharing options...
Boxman Posted September 7, 2011 Author Report Share Posted September 7, 2011 Not necessarily. But it's gonna cost me. I heard that an option was to cut out notches from the block, so the rods would be untouched. The engine shop that did my engine earlier, didn't want to correct my conrods, and said they'd have no time to cut my block (because they have to write a new program in their machine, which would only be beneficient if they had 5+ blocks to do, they said.). They said it'd cost me 500 euro's. I heard from another buyer (whom I contacted because I wanted to know if I got the wrong rods) that he used a dremel to cut out notches in the block. At the moment I do not have too much time to spend on my project, so proper rods would be the easiest for me. I'd have to disassemble the midsection and crankshaft again. But if all else fails, it is ofcourse an option. Link to comment Share on other sites More sharing options...
BlackT5 Posted September 7, 2011 Report Share Posted September 7, 2011 What did they charge you for a set of rods? Link to comment Share on other sites More sharing options...
Boxman Posted September 7, 2011 Author Report Share Posted September 7, 2011 I paid around 500 USD i think.. Dunno exactly, I haggled with them in British Pounds, but paid with Euro's It was something like that. They weren't cheap, and the machine shop that worked on my engine told me they were of very good quality (although they didn't notice that they were too wide for the actual block). Link to comment Share on other sites More sharing options...
lookforjoe Posted September 7, 2011 Report Share Posted September 7, 2011 I think it's easiest to machine/notch the block. That was done to mine, when I bought H-Beams from LG Speed a couple of years ago, I had the same issue. The machine shop didn't have to fabricate any fancy jig, they just cut away what was needed for clearance. If you modify the rods, they will have to be much more careful, since the balanced weight will come into play. Link to comment Share on other sites More sharing options...
Che'_Moderator Posted September 8, 2011 Report Share Posted September 8, 2011 Jig..... LOL. Yeah for this there is not need to set up steps or CNC. You can just run it down an endmill. If you were were here I could do it in under 30 minutes. Link to comment Share on other sites More sharing options...
lookforjoe Posted September 8, 2011 Report Share Posted September 8, 2011 Last time I personally used any type of milling machine was in high school Metalwork class, '78. Don't know anything about computer controlled mills. :lol: Link to comment Share on other sites More sharing options...
Che'_Moderator Posted September 8, 2011 Report Share Posted September 8, 2011 Oh I got it, Thats why I ed and +1ed you. Link to comment Share on other sites More sharing options...
wizzard_al Posted September 8, 2011 Report Share Posted September 8, 2011 You asked how wide the rods are, and you seem to be discussing not the thickness at the journal, but the distance from one rod bolt to the other. If you are talking about how thick (wide) the rod is on the actual bearing journal, here is what both VADIS and VIDA say about the rod end journals: Diameter, standard¹........50.000 +0/-0.016 Bearing recess width........26.0 ± 0.1 mm - this is the width of the rod between the crank counterweights, typically called the cheeks of the rod or the crank. I guess you'd say this is the measurement if you are looking at the rod edge on. Maximum out-of-round........0.004 mm Maximum taper........0.004 mm ¹The variation in diameter for each bearing journal must not exceed 0.008 mm Neither VADIS nor VIDA give any dimension for the rods other than the length (139.5 mm), the piston pin diameter (23mm) and the journal sizes. What I think you want is the rod sitting on a table, with the crank journal "O" shape flat on the table, and how wide the rod is at the heads of the rod bolts, and how wide it is where the rod splits. Only an actual measurement will do that. If you want, I have a spare engine now at the shop being honed, and the machinist has my rods and pistons, but since the place is about 1/4 mile from my house, I can go over tomorrow evening and measure one. It is a B5234T3, from about 2000/2001, and I checked VIDA; the rod for the 850 and S70 turbos is part #9135984 through 1998, but that was replaced by part # 1270483 in 1999 through 2001, and the newer part number is shown as superceding the earlier part number for all the earlier cars. That tells me that Volvo was replacing the earlier style rods with newer ones, but was that replacing them with the fractured rods? I know for a fact that the rods on my spare engine are NOT fractured rods and that makes me wonder when the rods changed to fractured rods, because it is a sold lifter engine, and only a couple hundred thousand engines away from mine, which I thought had fractured rods when built. I know that the 1999 engines had major changes at engine 1817653, where they went to solid lifers, and I originally thought they might have changed to the fractured rods at that same time. Unless the fractured rod didn't arrive until 2002 because the rod number changes again starting that year? VIDA doesn't give me a clue on that change, so make your own guesses. Let me know if that is the measurement you want, and I can do it tomorrow evening, if someone doesn't beat me to it. However, I think the advice to grind out the block is the best advice, the rings never go that low in the cylinder, and as long as you don't have any major ridges or sharp edges left from your grinding, you won't have a problem. Link to comment Share on other sites More sharing options...
Johann Posted September 8, 2011 Report Share Posted September 8, 2011 Problem used to be at the shoulder just above the big end. From what I recall 29 mm was the correct width and the wrong rods were 1.5 mm wider. Clearing the block with a dremel should do. Link to comment Share on other sites More sharing options...
wizzard_al Posted September 8, 2011 Report Share Posted September 8, 2011 Thanks Johann, that is exactly the type of measurement I thought he wanted, just thought it might be a bit lower where it needed to be measured. On all the big block domestic engines, it is usually the are right at the rod bolts that seems to be the problem in all the articles I remember looking at. Link to comment Share on other sites More sharing options...
ozzimark Posted September 8, 2011 Report Share Posted September 8, 2011 Unless the fractured rod didn't arrive until 2002 because the rod number changes again starting that year? VIDA doesn't give me a clue on that change, so make your own guesses. From the research I have done, this is the case; the fractured split shows up with the change from 139.5mm to 147mm. Link to comment Share on other sites More sharing options...
Boxman Posted September 8, 2011 Author Report Share Posted September 8, 2011 The rods I have are actually 32mm wide, but that is not necessarily the problem. The problem is, that they widen too soon at the big end. I can turn the crankshaft more than 90 degrees, which means that the stem of the rod is actually good at maximum sideways distance. After 110 degrees or so, the curving part of the rod seems to hit the metal. It is ofcourse very difficult to get measurement for this, I'm not even sure how I'd measure my rods now. I guess you'd have to have the blocks dimensions in digital form, and run a dimension to determine the maximum dimensions of the rod inside the cylinders. I don't really know what to tell the guy that made the rods. @Johann; those notches seem actually doable to carve out. Is that really all it needs, even for the 32mm wide rods? Also, this is the picture the seller of the rods sent me, as for what should happen to the rods And these are the actual measurements of the rods And the following pictures is me illustrating the problem (dont mind the bolts, i know they're out because I was just about to disassemble them again. The bolts do not actually hit anything. Link to comment Share on other sites More sharing options...
Boxman Posted September 8, 2011 Author Report Share Posted September 8, 2011 Run a simulation I meant, instead of "run a dimension" (i can't seem to edit my post). Link to comment Share on other sites More sharing options...
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