My thanks goes out to you all for your many posts - I have learned a lot from this forum. I have a 1990 300e that was running pretty good but decided to replace the cylinder head and change the gaskets to solve some oil burning & leaking issues. This is the first time attempting something of this scope, but after researching job online & with haynes in hand, undertook project. Took necessary parts off & with assistance from brother, carefully put rebuilt head onto fresh gasket after a couple trial runs - went on fine & then torqued in head bolts to spec.
Then I attempted to use 27mm socket to turn to TDC, but the crankshaft will only turn 90 degrees - a quarter turn - also will only turn CC to original starting point. The camshaft is not even in so pistons can't be hitting valves. Thought that though I was careful suspending the timing chain it had somehow got bound up - tried maneuvering it while turning crankshaft back & forth - of course even being careful I ended up cracking timing chain guide. So I proceed to take off everything needed to remove lower timing chain cover to check possible bind/replace guides. Finally reach that stage & find chain is not jammed. Took off broken guides & chain is now hanging loose - not even on sprocket to cause a problem. The crankshaft will still not rotate more than 1/4 turn - spark plugs are not even in so it is not a compression issue - its like hitting a wall after a quarter turn. The car was in park, but also tried to turn while in N. I am baffled what could be causing this - does anyone have any ideas? Much thanks in advance.
Not sure I can help but I can promise to ask questions! Did you reuse the original head or a different one? You said "replace the head" but also "rebuilt" so I'm not sure. Are you totally certain there was nothing in the bores other than the pistons when you reassembled? Unfortunately I would remove the head and spin the crank over without the head on to see if it still has the obstruction. This might cost you a head gasket but going further without knowing what the cause is would risk much more.
Vehicle: 91 300E, 92 400E, 96 S420, 97 V10 Ford E350 to tow them home from time to time.
Location: Boston, Ma
Posts: 3,530
If the timing chain moved while you were removing the head the tensioner spring may have popped all the way out. Don't know what problems this might cause. This happened when I did mine, but I stopped and fixed it. The spring only goes one way and must be disassembled, pushed all the way through and then re-installed. It is very easy and quick but you'll need a large allen wrench to get to it. 17 or 27 mm.
I removed the timing chain tensioner & suspended the chain with zip tie. still thought that could be a problem so took off the lower timing chain cover with all that entails - chain was not an issue. took tuttebenne's advice and removed new head (a rebuilt - not original but identical as i initially wanted a fast turn around & the price was close to having mine rebuilt.) once the head bolts were loose i tried turning crankshaft (nut back on but not pulley/harmonic balancer)- the crankshaft turns fine but makes enough contact with the head that it raises it .5mm and you can here just a little noise. took it all the way off & compared it with original - they seem identical. the new gasket (victor r)seems a little thinner as it is not swelled with fluid like original. somehow it is either the new head or gasket not giving any clearance. i can see little scuff marks on rebuilt cylinder bottom - not valves but near - were it would appear piston contact was being made. i can switch out this rebuilt head with another but by comparing it to original, I can't see how it will make a difference. could my mistake be the victor r gasket?
thanks for your input - will ship this back tomorrow & exchange for another. you're right -there is absolutely no room to be shaved - the clearances are minute. hopefully the victor reinz gasket is not part of the problem
the camshaft & rockers where not even installed yet so the valves were all closed - rotating it without chain installed to make sure it operated smoothly & to verify TDC before the cam etc.. was installed.
the gasket set is victor reinz from pelican parts. it is really weird because upon taking it off & comparing with original head & measuring clearance to valves, it appears identical. i placed the original head & gasket back onto block to verify problem & crankshaft turns fine. it seems that microns of difference between gaskets/heads is causing contact & when the rebuilt head is torqued down that contact prohibits turning
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