Los_Control Posted January 24 Report Posted January 24 As a side note, you can check stretch by removing your distributor cap and rotate the crank back and forth. You want to see how much free play you have in the crank before the cam moves .. which moves the distributor rotor. Just a quick and dirty test when troubleshooting timing issues without tearing into the engine. Quote
ktb Posted January 24 Author Report Posted January 24 Thank you Los! I measured my slack to be ~3/8”, which is okay, I guess. I will have to consider replacing the chain and sprockets while I’m in here. The cam hub moved freely once I removed the cam sprocket, so I guess it has been the piston rings keeping the crank from budging all this time. Unless there are other suggestions, the next phase in trying to rotate the crank will be trying to free the pistons by removing rod bearing caps and pushing up from the bottom. In the meantime I have a lot of stuff to clean up and reassemble. Thank you all! 1 Quote
bkahler Posted January 24 Report Posted January 24 I don't know how true it is but, I was always told to replace the sprockets and chains as a set. 1 Quote
Los_Control Posted January 24 Report Posted January 24 13 minutes ago, bkahler said: I don't know how true it is but, I was always told to replace the sprockets and chains as a set. To be honest .... seems we always call it "the timing chain" When it is really a timing chain set. Not even sure it is possible to buy a new chain without the gears being included. Maybe, just never heard of it. 31 minutes ago, ktb said: Unless there are other suggestions, the next phase in trying to rotate the crank will be trying to free the pistons by removing rod bearing caps and pushing up from the bottom. I would remove all of the rod bearing caps and set them aside being careful to keep them in order so can be replaced where they came from .... then see that the crank turns. ... If not then start checking the main bearings. Then start moving the pistons by hand up and down. .... You should know very quickly if and how many pistons or a main bearing. I had one main bearing that locked it up from some mouse pee ... anything can have happened over the years of sitting. I would put some rubber hose over the rod bolts so they do not mark up the crank while working on it ... or some tape, anything for protection to save the polished crank surface. If you find a piston froze to the cylinder wall ... use a block of wood 2"x4" ripped down to fit. Then use a hammer and wood to tap them down. just to free them up. If it is a piston, now is the time to pull them out and install new rings and clean up the cylinder bores. Hopefully if it is pistons, a few sharp blows with the hammer/wood will free them up. Your cylinders do not look too bad and should not be a big problem getting the pistons free. 1 Quote
bkahler Posted January 24 Report Posted January 24 48 minutes ago, Los_Control said: To be honest .... seems we always call it "the timing chain" When it is really a timing chain set. Not even sure it is possible to buy a new chain without the gears being included. Maybe, just never heard of it. For some makes/brand you can. For my Triumph sports cars you can order individual parts. I never do, but I know you can. Quote
Los_Control Posted January 24 Report Posted January 24 5 minutes ago, bkahler said: For some makes/brand you can. For my Triumph sports cars you can order individual parts. I never do, but I know you can. Have to admit I never gave it much thought. A motorcycle chain is the same way ... replace the sprockets if you feel like it. Looking at RockAuto for my 1949, they have a crank gear but no cam or chain available .... dunno where we go when we need one ... I would check Napa first. On RA they also sell chains separately for a 1970 318, or in sets. So you can buy just the chain. The cheapest timing set for the 318 is $10.16 all the way up to $105 for a billet roller version. @ktb is measuring 3/8" play, I would not bother replacing it myself at this point ... If rebuilding the engine then yes. Quote
bkahler Posted January 24 Report Posted January 24 36 minutes ago, Los_Control said: @ktb is measuring 3/8" play, I would not bother replacing it myself at this point ... If rebuilding the engine then yes. Unless the gears so appreciable wear, I agree. 1 Quote
Young Ed Posted January 24 Report Posted January 24 I would suggest trying to turn it via the flywheel. There is a tool for doing that but I've always just used a decent pry bar. You get a lot more leverage using the teeth on the flywheel and only have to remove the inspection cover to gain access 1 Quote
ktb Posted February 4 Author Report Posted February 4 Freeing stuck pistons... Today I removed all the rod caps (again) and the front and rear main bearings (leaving the middle two to support the crank). I tried hammering a wooden dowel on top of each piston and pushing up from the bottom on a couple I could get to. Nothing will budge. So I'm back to soaking the tops of each piston with a diesel/ATF mixture. I tried a prybar on the ring gear long ago, but no crank movement. Is it advisable to try pushing up on the underside of a piston with a wooden dowel using a hydraulic jack? Also, is it okay to continue trying to turn the crank with no rod caps in place? Quote
John-T-53 Posted February 6 Report Posted February 6 Remove the engine from the truck, place on a stand, remove crank, valves, cam. Pound out pistons from the top with mallet and block of wood. Clean up cylinders with hone, then measure them to determine if it needs to be bored out, which it probably does. 1 Quote
ktb Posted February 6 Author Report Posted February 6 I would happily remove the engine if I had the means. I'll keep trying. Quote
JBNeal Posted February 7 Report Posted February 7 If that crankshaft is in a position where pistons are near TDC or BDC, then the crankshaft might be fighting any attempts to drive the pistons loose as the connecting rods have no mechanical advantage in the vertical position. Getting the crankshaft out of the way removes this restriction, though that is easier said than done. Another alternative to the MMO-style mix is DOT 3 brake fluid...itsa mess but it may make the magic happen 1 Quote
ktb Posted February 7 Author Report Posted February 7 That's interesting, #3 & #4 are in fact very near the top. Makes it so you can't get any appreciable amount of magical loosening fluid on top of those pistons. Today I tried to hammer a wooden plunger handle under #3, but it went nowhere. The handle got so stuck in there, I spent the next 5 hours trying to get all the pieces of it back out. It was not a great day. I may go ahead and try brake fluid. What have I got to lose? Quote
Los_Control Posted February 7 Report Posted February 7 Seems like it would be possible to rotate the crank out of the way with all the rods loose? 7 hours ago, ktb said: Today I tried to hammer a wooden plunger handle under #3, To me that sounds like a really bad idea .... good way to destroy a piston. You want to use a block of wood from the top. The wood needs to be wide enough to span across the piston and apply pressure to the sides of the piston equally. Probably need to measure and cut one to size. Then use a 2 pound sledge hammer and knock em loose ....after you rotate the crank out of the way. A wooden handle in the center of the piston top or bottom could easily just punch a hole through the piston .... you are counting on the sides of piston for strength. Lets hope the brake fluid does the trick. 1 Quote
John-T-53 Posted February 7 Report Posted February 7 On 2/6/2025 at 10:23 AM, ktb said: I would happily remove the engine if I had the means. I'll keep trying. You are doing it the hard way, I promise. Quote
ktb Posted February 7 Author Report Posted February 7 30 minutes ago, John-T-53 said: You are doing it the hard way, I promise. No doubt. I've got more time than money. Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.