48LCCOUPE Posted November 18, 2003 Share Posted November 18, 2003 O.K., I purchased a 1948 Continental Coupe, short version: previous owner sent out all chrome, replaced bad rockers,did body work, painted with black laquer (his specialty was body and paint so that part was his fun), sent V12 crankshaft out to have journals chrromed and polished, got sick and died in 1993. Engine sat on workbench for 10 years wrapped in oil soaked moving blankets, pan off, accesories in boxes along with the rest of the car in boxes. My plan: mechanical first, get it to make fumes, go forwards, backwards, start and stop. Then move on. 1st problem: engine turns over but with kind of a herky jerky about evry 1/4 turn or so. It's everything the starter motor can do to turn the engine even with 12 volts. Probably the bearings are wrong or installed wrong, the rings have created a ledge in the cylinder from sitting for ten years, the crank has warped (not likely just threw that in), crank is under and bearings are standard??? Tonight I sat looking at the engine as I have it standing at attention on it's rear end (don't have an engine stand that can hold it), pan and heads removed yesterday by yours truly along with oil pump, starter et.al. Have calipers and inside slides at the ready when my friend says, pull a rod cap and see if you've done any damage by the turning of the engine so far. I pull a cap. number three cylinder I believe and the bearing looks pristine, the chrome journal on the crank looks beautiful (in my eye and I am the beholder in this case), it really looks great. Now comes the people are amazing part. I say "where is the number on the cap?" "they had to have numbered the caps and rods!" finally found the number eyesight failing but it was small but there it was 4. Please review above cylinder pulled from (3). A simple mistake right?The rod was marked by the tried and true method of filing notches into the side of the rod, how many notches you ask? 9. I have pulled 6 so far and stopped. from number 6 cylinder we have number 12 rod and number 3 cap, from number 5 cylinder we have number 10 rod and number 6(or 9) cap etc.etc.etc. Haven't found anything matching anything yet. No wonder the engine wouldn't turn. It's not that rods and caps "should go together" they MUST go together. Boy am I happy we found this. Now I am forced to pull all the pistons, clean them up, check the gap of the rings and basically rebuild it. After finding what I found tonight, I think that is the best thing that could have happened- being forced to rebuild it "again". Side note, for those that don't know, connecting rods and caps are not cut apart or forged seperatley. they are forged as one solid piece and then broken or fractured along a scibe mark meant to be in the center of the crankshaft's focal point of stress. In other words the two halfs that used to be one piece, then broken apart, machined to accept two half shells along with rod bolts or studs MUST stay together as conjoined twins!!!! sorry I am losing it. Please be careful of what you find out there. I bought this car from the late owners son in law who had at least a hand in the motor assembly I believe. This man builds diesel truck engines for a living. And has a wonderful reputation for doing so. If you buy something rebuilt, maybe have it rebuilt again. Link to comment Share on other sites More sharing options...
DizzyDale Posted November 18, 2003 Share Posted November 18, 2003 Dear Dave,What do you think about the theory,it was just RAMMED together to sell.Just a thought.Now you HAVE to go through the whole engine for peace of mind.At least you will know what you have. GOOD LUCK,diz Link to comment Share on other sites More sharing options...
Rolf Posted November 18, 2003 Share Posted November 18, 2003 Hey Dave, sorry to hear about your tribulations, that is a nightmare when you had figured you had a good basic rebuild, but it also gives you the opportunity to align bore the crank and cam, resize the rods with the correct caps on them, and check the valves and hydraulic lifters, hopefully some of the work done previously will be right, and will not cost a fortune to repair, in case you didn't know, these V-12's are not your average Chevy 350, that can be slapped together any old way, and you either get them right, or you are doomed to a smoky, low oil pressure, mediocre engine, my advice, along with the other things mentioned, check your piston clearances carefully too, if there is any doubt have the pistons knurled or "expanded", making them a skose tighter, a critical factor in V-12's, sad to think that someone could put a V-12 together so incompetently, but there are so many sour running ones around, I am sure it has been done before, good luck, Rolf Link to comment Share on other sites More sharing options...
48LCCOUPE Posted November 18, 2003 Author Share Posted November 18, 2003 Diz, that's what gets me. I know for a fact, that car and engine have sat for ten years. Always going to get around to completing it like the ole man wanted. Actually the car was willed to the grandson and when he got old enough to want it He didn't! Not advertised for sale, just sitting in the shop (is a customer of mine actually, truck parts and such). Maybe after the death in 93, someone said throw those parts together so they don't get lost? That was my benefit of the doubt until I realized they were all torqued and lock tabs turned up. Link to comment Share on other sites More sharing options...
48LCCOUPE Posted December 8, 2003 Author Share Posted December 8, 2003 O.K., the continuing saga, as stated above, rod caps did not match rods AND where not torqued to specs even tho lock tabs were all turned up. Removed all pistons, cleaned, measured, checked rings for spec, reassembled with correct rod caps to rods, torqued rods per spec and engine siezed. My current guess is that when the crank was sent out to have journals chromed and polished, the rods were not sent with it. Removed all pistons, assembled caps, removed crankshaft, now looking for reputable and recomended auto machine shop in area to fit rods to crank, and will need to (or should say insist that I) purchase new rod and main bearings. First have to determine for sure what size they should be, had STD mains and .010 over rod bearings. Two steps forward, seven steps back. This is where people cheer you up by saying, it's a good thing you caught it now instead of ruining something later. Link to comment Share on other sites More sharing options...
CBoz Posted December 8, 2003 Share Posted December 8, 2003 It's a good thing you caught it now instead of ruining something later. Oh geez, I don't know how many of those types of situations I've actually lucked out on -- something that might have gone *really* bad if I didn't catch it. That's why we read the directions twice, torque once, right?(Except, of course, for the time my wife put a gallon of Roundup on my bench. Looked just like the anti-freeze container, and it wasn't until I was pouring, looked down, and saw a whitish liquid, I said "Hmmmm!" and stopped. Never caused any problems though, and absolutely no weeds of any kind in the engine bay!) Link to comment Share on other sites More sharing options...
peecher Posted December 8, 2003 Share Posted December 8, 2003 It looks like you need to measure the diameter of the crank journals to find out where you are. The bearing inserts for the rods may be a size too small for your journals? the original (standard) diameters for your crank ('42-'48)are as follows: Main, 2.401" Rod, 2.250" If the journals measure greater than these dimensions it could be that they were not ground down to size after chroming. Normally they grind cranks under size in increments of .010" down to a max of .030" under size.While your at it, check the cam bushing for excess wear. Remove the cam and check the diameter of the bushings with an inside micrometer and the diameter of the bearing journals of the cam. The cam bearing journals shouldn't measure less than 1.7955". I believe the wear limit for bearing clearance is .005" total.Good luck. Link to comment Share on other sites More sharing options...
48LCCOUPE Posted December 8, 2003 Author Share Posted December 8, 2003 Peecher, thanks, already crossed many of those bridges but thank you. I think it's a combination of things, the bearings are correct, .010 over on rods and std on mains. It seems upon closer inspection that there are rods and caps from more than one engine, sides don't line up smooth. Took to a machinest who came very highly reccomended by some racing friends and was glad to see besides some high performance stuff, two Packards and a Buick straight 8 on stands being attended to. He is going to resize all the rods and machine for side clearance as well. After talking to him I decided to take the block up this weekend and have him check everything including cam bushings as you suggested, and have him put the short block together per specs. This may just work! Link to comment Share on other sites More sharing options...
48LCCOUPE Posted December 21, 2003 Author Share Posted December 21, 2003 UPDATE! Took engine to machinist and He had to match rods and caps by fit, markings were all wrong. Also had to resize three of the matches. Here's the good news, while checking things out, He could not get air blown thru the oil holes in the crank. After have to hand turn a drill bit in the galleys to get thru, brushing then blowing, He took out what He thinks is over 30 grams of metal trash that had not been cleaned out after machining. I guess the engine would have run pretty well for 4 or 5 minutes. Money well spent. Picked up engine today and took the heads with me- yep, warped and He now has those to resurface. I am going to have one fine V-12 when this is over. Link to comment Share on other sites More sharing options...
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