Timing Chain Gear Misalignment

[pamotorman]

the thrust plates that go with a needle bearing for the cam are .031 thick so just use a extra one behind the cam gear. you can machine .005 off of the back of the gear to get the .025 you need. someone could have machined the block where the back of the gear runs. made a special tool to do that if the area was worn and then shimmed for the correct alignment

[Wolfplace]

the thrust plates that go with a needle bearing for the cam are .031 thick so just use a extra one behind the cam gear. you can machine .005 off of the back of the gear to get the .025 you need. someone could have machined the block where the back of the gear runs. made a special tool to do that if the area was worn and then shimmed for the correct alignment

If this is a flat tappet cam that is not the best idea
You want the lobes to the rear not in the middle of the lifter bores or it will not rotate the lifters correctly so I would suggest not pulling the cam forward

[snub]

^ Wolfplace, did you or could you have a look at the first picture I posted showing the position of the cam lobe? If you think the lobes are o.k. where they are I will just machine the back of the crank gear and be done with it. If need be, I will try to get a better picture. Thanks!

[Wolfplace]

Hard to tell in the picture but it appears the first one is closer to correct
The second looks like it was taken at more of an angle to the bore. Is the lobe in the center in the second picture or still set to the rear?

[snub]

The first picture is the lobe sitting with the cam gear in its normal position. For the second picture I moved the cam gear ahead .025" to simulate what would happen if I used an .025" shim behind the gear. It appears to be close to center in this position.

[Wolfplace]

Just going with your pictures I would say leave it alone & machine the crank gear

[machinedave]

You could lay a straight edge across the timing chain gasket surfaces and place a .002" feeler gauge on the cam thrust surface to see if the thrust face has been machined down before.

[snub]

^ machinedave. what a coincidence you posted this about the same time I was doing it. I finally remembered that all the block surfaces on the front of the engine are on the same plane. And I found out this block has never been messed with. I took a picture for future reference ( for me and anyone else that might need this info).
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[snub]

I just chuck the gear in a lathe and use a carbide tipped bit, they seem to cut pretty easy, it's not as hard as you think, rub a file on it and you will see.

You are absolutely correct, they are not that hard. I built a mandrel to hold the gear in the chuck as it wouldn't sit right in my 3 jaw and I had fears of damaging the teeth. I also bought a new carbide insert from a reputable source. And I built a sacrificial washer with a chamfer to match the one in the gear so that the bit wouldn't be chattering over the 9 keyways. Worked like a charm. Most of my machining is with aluminum so I was apprehensive at first, but glad I got it done.

Some pics :
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[wyrmrider]

nice work

[user-9613590]

Being a Jap (Toyota) engine fan these problems are just... incredible!
How a one of the world's biggest car manufacturers could produce such a crap!
OK, it's all about cost and so,do not change the production line unless it's absolutely necessary.Hell,it's made engines last 40 years so it must be good!
Years ago I did head job of Cad 500.First I wondered have I set up my seat cutter wrong since the cut was offset.. After checking I come to conclusion that the original seats were cut offset..
Then the biggest car manufacturer in the world and their best,most expensive model.. Same crap as the cheapest Chevy.
The -66 Cad 429 I did was a better ;materials felt good and overall the feel that there was a try to make a good engine.
So the bean counters ruin everything the engineers create.Read :CHEAP! CHEAP! Could you save just a few cents in design? In fact you HAVE to save few cents! Then the saving get down the line and production. Of course you can cut the machine time! Speed up the line !

Rant off;take the next beer

[racinnut15xm]

Just want to book mark this so i can check mine this winter. Timing was moving 12 degrees and by running the cam stop/bolt in the water pump in we got it down to 4 degrees and said we can live with that for now.

[tenxal]

Before gettin' too carried away with machin' stuff:
-Install the intake manifold
-Drop the distributor in
Then check the timing gear/crank gear alignment.

Have seen more than a few 'corrected' this way.

[racinnut15xm]

We machined the back of the crank gear on mine, as mentioned the crank chamfer was not letting it slide all the way back. It was forward a good ways(i dont remember how much now)

[Wolfplace]

We machined the back of the crank gear on mine, as mentioned the crank chamfer was not letting it slide all the way back. It was forward a good ways(i dont remember how much now)

Excellent,,
This is a real bad deal if not fixed & you would not believe the number of people that smack the gear on until they feel it bottom & never look.
If not against the shoulder instead bottoming in the radius it will eventually break the snout off the crank.
Gear chamfer puts a real nice stress riser in the crank radius,, damper eventually leaves with crank nose,,,,,,,,,,,,
Alignment becomes the least of the worries