Cam Chain Tensioner Mystery...

[rossiz]

@ Diseazd:

first thing i did was to set tdc comp before taking anything apart. timing mark on pulley pinned to 0 degrees, cam lobes off the rockers, kept it there the whole time. so when i took out the pump it was already set to receive the dizzy shaft tang correctly. just slid it right back in after timing the shaft - piece of cake.

so i got her back together, all buttoned up, filled w/fluids, checked that everything was put back together and torqued up.

fired her up and am quite pleased with the results. i'm guessing the old cam chain was stretched, because there's a huge difference in the way she runs & revs. up at around 4,500 she just sings and pulls like crazy. even sounds different, more growly than before. took her out for a test spin and wow, very nice - responsive and i must admit the sound of the motor led me down a rather childish path - all done on a closed course... :laugh:

[olzed]

Nice result.

[Captain Obvious]

Excellent. Glad you got it back together and that the tensioner didn't take out any other parts when it snapped.

when i replaced the head, the chain was super tight - so much so that i had to lever the cam sprocket on with a big wrench. it seemed too tight to me, but everything i read stated "zero slack" and that's what it was. the first startup turned over verrrry slowly for a few revolutions, then something clicked and the engine spun free and started. i figured the tensioner was clicking into position or seating itself after being displaced.

Your tensioner clicked into position all right. Into position at the bottom of the front cover that is!!

Impossible to go back at this time, but I wonder what happened. You think you didn't get the tensioner plunger into position correctly at the very beginning? My guess is that it slipped out and was wedged on an angle from the very beginning and that's why you had such a hard time getting the cam chain on. And it went from there.

I liked your shot holding the distributor drive shaft from the top. I did the same thing when I was changing my oil pump and didn't want to mess with the timing. Looked like this:

[rossiz]

yes cap'n, i believe you are right - it was out of the housing and at an angle, i'm guessing the "click" was when the head sheared off the plunger and the pieces fell down into the bottom. the two things that blow my mind are that the pieces never made any trouble with all the other moving parts in the immediate vicinity, and that the engine ran for 600+ miles with no tensioner whatsoever without skipping a tooth. i'll call it a great deal of luck!!

the other side benefit from this whole exercise is that i've now rebuilt most of the engine - all that's left is the block

[rcb280z]

rossiz, you were able to "wiggle" the oil pan free but was there a struggle re-installing? What did you use for gasket and sealant?

[rossiz]

the pan wiggled out quite easily, went back in with no drama. i bought the gasket from msa - they had two versions, i bought the more expensive one which they told me is a bit thicker... it's a green gasket material - neither cork nor rubber, installed with no sealant. seems to work just fine (no leaks yet!)

[Namerow]

Nice write-up and pix. Thanks for taking the time (during and after). It's good to see that the cautions about 'jack-up-the-engine-and-remove-the-oil-pickup' were unnecessary. I'm curious to hear more details about two components of the work that you say much about (and which have earned commentary in write-ups by others):

1. What tool(s) and procedures did you use to loosen harmonic balancer securing bolt? Degree-of-difficulty rating? Did you just put the car in gear rely on wheel chocks to keep the crank stationary, or did you remove the starter and wedge the flywheel ring gear?

2. Any drama in loosening the 3 long bolts that secure the water pump & timing cover (esp. the skinny 10mm bolt located at the 11:00 position on the pump body)? Tips/techniques... or did they all give up without a fight?

[rcb280z]

very cool, I forgot about the competition oil pan gasket from MSA.

[Captain Obvious]

the two things that blow my mind are that the pieces never made any trouble with all the other moving parts in the immediate vicinity, and that the engine ran for 600+ miles with no tensioner whatsoever without skipping a tooth.

Agreed... It's simply astounding that you didn't jump a tooth or run a chunky bit through the chain.

Murphy must have been off doing something else. You might want to watch your back.

[Virto]

2. Any drama in loosening the 3 long bolts that secure the water pump & timing cover (esp. the skinny 10mm bolt located at the 11:00 position on the pump body)? Tips/techniques... or did they all give up without a fight?

Those water pump bolts are notorious for rusting and breaking. Soak them for days with a combo of ATF/Acetone and you might get lucky. I only broke one when I did my water pump.

[rossiz]

1. What tool(s) and procedures did you use to loosen harmonic balancer securing bolt? Degree-of-difficulty rating? Did you just put the car in gear rely on wheel chocks to keep the crank stationary, or did you remove the starter and wedge the flywheel ring gear?

thanks for the kind words - always fun to give back a little, especially with all the help this forum has given me. no special tools - i took off the oil pan first, then simply wedged a block of wood between the crank and the side of the block and used an 18" breaker bar to loosen the pulley bolt. it gave in pretty easily, no drama. getting the pully off was a pain, primarily because the two threaded holes for the puller were filled with crud and i couldn't get them clean enough to get the puller bolts in, so i made a Rube Goldberg by putting nuts and large washers on 3 bolts and wrapping the whole mess in bailing wire to grab the outside of the pulley (i guess it would properly be called the "pullee" in this case). fortunately it wasn't suck on too bad and came off with little fuss.

2. Any drama in loosening the 3 long bolts that secure the water pump & timing cover (esp. the skinny 10mm bolt located at the 11:00 position on the pump body)? Tips/techniques... or did they all give up without a fight?

HA!! drama for sure. i had already broken one of the long bolts when replacing the water pump and had drilled & re-tapped it all the way through the timing cover a while back (i left the water pump on the timing cover for this whole exercise - why create a leak, eh?) and fortunately none of the other long bolts broke. i did replace them all and chased all the threads clean with a tap. the heater hose connector bolt to the timing cover broke and had to be drilled out, i replaced both of those with some leftover manifold studs i had laying around.

[Zed Head]

You got a lot done in a short time. Impressive. I like the bailing wire puller trick, I did similar with an adjustable pipe clamp on a two jaw puller, to break a bearing loose and pull it. I think I took a picture for the record just because it looked so bad.

Found it...