Is it even possible for those chains to jump?It looks almost impossible for such a big chain to jump 1 tooth, i know timing belts can i find them from time to time on my customers engines...But this looks strange...ou: :error:
The chain doesn't look like it jumped. It does look like it was lined up wrong, if you're sure that the piston is at top dead centre. The bottom sprocket only fits one way; roll it up to the top position, (TDC) and I'll bet you'll see the top gear will line up. There's probably nothing wrong with that set up.
I have been turning crank many times and it wont line up the marks.And position you see on the photo is TDC,so it might be wrong assembled during rebuild wich has been done by previous owner in US( i have found invoices under floor mat...4500 bucks for such a shameless work, not to mention those 4 shims on one of the head bolts,lol). Also chain has a lot of free play, about 0.5'' wich is disqualifying it imo.
how many degrees is it off when you line the two up. i do not know enough about degreeing (sp) a cam. jim
Can you explain what we are looking at? I know it is the timing chain and gears, but for those of us new to engine diagnostics( Me):grin: , could we get a lesson on what is wrong?
Hmm... I've got to go back to what is the timing set at?? Could the thing be installed one tooth off, and then the distributor cranked around till it's timed close enough to run? I counted the top teeth that I could see, estimated 60 teeth (sounds like too many), that would make a tooth off be 6 degrees off. I would think that you could be that far off and make it up with the distributor?? wouldn't leave much adjustment but it might work and might be what they did.
Hehe i guess you are right,i hope its that way:TU: .I have found couple funny things made to that Nailhead.I wonder when valves meets pistons ,at 2 tooths off or at 3? And yes,key should facing down but on camshaft not on crank...
Has the block been line bored??????? when that is done it moves the crank closer to the cam, causing slack in the timing chain..... The reason I never line bore a block.....:Brow: :Brow:
Doc i have no idea if that has been done, nothin about it on invoices,there is new cam,pistons,lifters all bearings 0.01 oversize,i have found even invoice for balancing and block cleaning.... Could you tell me how much there should be from crank bearing sit to deck or just nominal block hight? Thanks.
Not right off the top of my head, but if the block hasnt been messed with the timing chain will be as tight as a fiddle string when you install a new set.... if there is any slack at all , it probably has been line bored at sometime in its life....
I will just check the block hight and post it so maybe you can say if it's allright or have been grounded. Thanks for your input so far.:beer
Well, I checked through the procedure that was listed in the service manual. Chances are whoever put that engine together used an old chain that was already stretched, or was cross-eyed or drunk. I've seen some idiots do whatever it takes to get the sprocket on, and where ever it lines up is where it stays. Another thing could be that he was trying to "degree" the cam, and misread the wheel. Either way, the car probably ran like a toilet. Good luck with the rebuild, hope you don't find anything else stupid that could potentially cost a lot of money!
In looking at your picture, it looks like it may be correct. But you do have to rotate the crankshaft about one more tooth to the left (counter-clockwise) until the mark on the crank sprocket is straight up, and the mark on the cam sprocket is straight down. The marks that need to be aligned are: The round dot on the tooth of the crank sprocket, The round dot between the teeth on the cam sprocket. Maybe you are using other marks? It's common to have some slack in a timing chain. A new chain may have 1/4", a used one may have 1/2". I just put a 401 together. The Cloyes chain fit a little loose, so I tried a Melling chain I had...it fit's tighter. Your results may vary!
Walt,indeed there is a mark on crank sprocket tooth but it rather looks like some accident punch for me.If you look closer at the pic you can see ''o'' mark on the sprocket not on tooth, and watching manual they show that mark for timing,not the on on tooth.I ll make better pic of sprockets and will post em after i get back home. o No: P.S.In manual its even typed : ''o'' mark BTW anyone of you knows Mesa Machine shop?are they good in rebuilding engines, especially Nailheads or should i start to collect new parts and do it myself?
