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Car Forum / Volvo Cars / March 2007cam shaft swap
The no run issue turns out to be a broken camshaft retaining bolt with half of the bolt still in the cam. I have a spare in an 86 and was going to swap it Good idea, bad idea. Should I swap out the whole engine. I was going to do the rear seal and engine mounts too. I might also be getting rid of it. Could part it out and be satisfied that I found the problem. Ran fine before breakdown. Wagon with 160K. Old lady wants to get rid of it, too many in the yard. > The no run issue turns out to be a broken camshaft retaining bolt with > half of the bolt still in the cam. [quoted text clipped - 6 lines] > Ran fine before breakdown. Wagon with 160K. Old lady wants to get rid > of it, too many in the yard. Camshaft swap is easy enough, why not give it a shot? > The no run issue turns out to be a broken camshaft retaining bolt with > half of the bolt still in the cam. [quoted text clipped - 6 lines] > Ran fine before breakdown. Wagon with 160K. Old lady wants to get rid > of it, too many in the yard. Why not just remove the remainder of the bolt and put in a new bolt? Much faster, and the cam lobes and followers are already mated to each other. Moreover, unless the spare engine is an exact duplicate, the spare cam's lift, duration, and overlap timing are all likely to be different. (That could be a good thing...or not!) Try this: Get a spring-loaded center punch. Use it to tap the remaining bolt a few times to loosen the threads. Then use a pick to back out the bolt. This is a bit finicky and might take as long as 30-45 minutes, but it CAN be done. If all else fails, drill the center of the bolt to a depth of 1/4" or so and use an extractor, *after* the tap-tap routine to loosen the threads. Since the bolt should be fairly free at that point it should be easy to extract. Then replace the bolt and re-time the engine. Done! JRE >> The no run issue turns out to be a broken camshaft retaining bolt with >> half of the bolt still in the cam. [quoted text clipped - 17 lines] > Get a spring-loaded center punch. Use it to tap the remaining bolt a > few times to loosen the threads. fwiw, I find the spring loaded center punch can be used to remove the bolt completely... If you snapped the bolt by over torquing it or the head got popped off by a malfunction and they're not bottomed out or baked in place by the exhaust, they will spin out. Problem is turning them. Position the center punch off center of the bolt and angle it the direction to unscrew the bolt. Keep snapping around in a circle until it's out enough to grab. > > The no run issue turns out to be a broken camshaft retaining bolt with > > half of the bolt still in the cam. [quoted text clipped - 28 lines] > > JRE Yeah, I don't know about the Volvo specifically, but in general cams and whatever rides on them in any car are considered to be parts that mate in to each other in the breakin period, and swapping is not conducive to a long future life. There is a lot of pressure and sliding friction between the two surfaces, and the parts are designed so as to wear together when new, as I repetitiously said before. > Yeah, I don't know about the Volvo specifically, but in general cams > and whatever rides on them in any car are considered to be parts that > mate in to each other in the breakin period, and swapping is not > conducive to a long future life. There is a lot of pressure and > sliding friction between the two surfaces, and the parts are designed > so as to wear together when new, as I repetitiously said before. Camshaft swaps are not uncommon, you often have to adjust the shims but I've not heard of people having trouble with wear. I know more than one person running non-stock Volvo cams they found in junkyards, usually the "hot" K cam. > > Yeah, I don't know about the Volvo specifically, but in general cams > > and whatever rides on them in any car are considered to be parts that [quoted text clipped - 7 lines] > person running non-stock Volvo cams they found in junkyards, usually the > "hot" K cam. Good to know, since that's on my "maybe someday" list. >> > Yeah, I don't know about the Volvo specifically, but in general cams >> > and whatever rides on them in any car are considered to be parts that [quoted text clipped - 9 lines] > > Good to know, since that's on my "maybe someday" list. 'Break in' is actually a misnomer. It should really be 'wear in' because the process allows for parts that don't fit well (because of variation in manufacturing tolerances) to get to know each other. If everything were machined right on spec and assembled correctly (as in, properly built race motors) the only break in required is get the motor up to temperature and run it! When it comes time for a rebuild, all the bits go in a basket. Rods and pistons are numbered (for balance reasons) but everything else ends up wherever it ends up. If I were swapping used cams, I'd probably try to keep the followers (rockers, whatever) on the same lobe they were on. If that didn't happen, oh well... run it. I'm going to try backing out the bolt and replacing it. > I'm going to try backing out the bolt and replacing it. It should come out okay, now that the torque has been relieved. Mike |
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