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[ericjd]

Hi Phillip,

  Thank you for the website and the info. I had  already read SOME of the info at : http://www.miata.net/garage/crankshaft.html   before you you sent it to me. However, I went back there again and read it more. My crankshaft has the Big Nose which  is one that is supposed to be OK. However, The manufacturer date of my 91 capri is 08/1990 which I believe is supposed to be the bad one.

[ericjd]

Hey Rocketman, Yeah I just re-read the info at  http://www.miata.net/garage/crankshaft.html  again. Maybe my keyway is worn then. If so that may be the problem. I guess I'll have to take the timing cover off again and check the timing belt gear for wobble.
   I did not get a chance to get outside in the rain today to do anything on the car (vacuum leak) or anything. It would be temporary until I got the part.
   I'm in Watertown NY 30 miles from the Canadian border.
   I did see the following excerpt from that website which I will definitely try before I have to buy and replace the engine.

THERE IS A LOCTITE REPAIR
 I will mention that there are successful repairs involving shims, new keys, welding and the like. Probably the best repair is a Loctite fix that has been developed with the direct assistance of Loctite engineers.

[Phillip]

How have you determined that you have a big nose crank? The article applies to the Miata but only some of the info applies to us. Identifying the crank by the slots in the pulley is not accurate info for us. According to the info provided my 91 would be a long/big nose crank and it wasn’t. RM is correct if it wobbled at all at some point then the crank is damaged, worn on the outer circumference of the nose and in the key way. There is a fix method explained in the article but that is a temporary fix. I would do it then source another latter made motor. My opinion only.

[ericjd]

Thanks again Phillip and Rocketman,

  I want to be certain that I am properly checking the crankshaft for this defect before I determine it to be bad. Sooo if I take off the timing belt cover again and look at the timing belt gear on the crankshaft while the engine is running and it is wobbling then that means the crankshaft is bad. Correct ? Let me know. Thanks

   If so, does anybody want to buy a good used engine for parts. Only 98,000 miles. Everything is very good except the crankshaft.

[ericjd]

Rocketman,

   Today I took the pulleys off the crankshaft so I could see the timing belt gear on the crankshaft while the car ran. I could see absolutely no wobble at all in the timing belt gear on the crankshaft. However, I did call the ford dealership service dept that replaced the key for me and they said yes the keyway was a little wore when they replaced the key with a new one. So is there no hope for that engine without a complete tear down with replacement of the crankshaft, or will the timing belt gear stay put on the crankshaft now while I try to adjust the timing belt a notch one way or the other ?

[Gostlrs]

Actually no, my 280 had same problem but much worse. the pulley cracked in half and the hole was really elongated. what i did was get some of the "steel" crap that comes in the small tube. you basically kneed it and it gets really hot then you fill in the hole where the key goes and put the key back in. within minutes it starts to harden. while you are putting it un wet your fingers and you can smooth it out. i put the pulley on then off to ensure a good fit. let it harder 1 day, then put it back together and worked like a champ. not sure how long it will work. but a hell of a good fix for temp.

[ericjd]

There was mention of using loctite to do the same thing in the link that explained this crankshaft problem. My question about using something like that is this: How do you line up the timing belt gear, the key, and the key way properly if the key way is wore. There is gonna be some play there. Or doesnt it matter if does not line up in its original spot because once it is hardened you can adjust the timing to its new spot.

[Gostlrs]

mine was only worn on the one side. the other was perfect. loctite would not work. the heat would break it down. steel would withstand the heat. hell i even used it to do some body work on the 280. it sets nice. use wet fingers to smooth it out while its setting or a putty knife. i have over 500 miles on mine so far

[Phillip]

The only real way would to be to determine Absolute TDC and figure a way to translate that that to the cams. You can get the TDC determination by using a dial indicator and extension rods to tell when the #1 piston hits its’ top travel. Remember there will be a neutral time where the crank travels over its TDC rotation and it starts to pull the piston down. With a V8 there are degree wheels you can buy to determine the amount of travel you have before the piston starts down its used to dial in a crank/cam combo but I’m not that versed in the I4 to know if you could use that to help with your problem, 2 cams don’t equal one, I’m more of a BB Ford Aficionado than a I4 one.
There isn’t an excuse for cubes! Ever see a BB Mustang launch from the line? Its’ really impressive!

[ericjd]

I was planning on getting top dead center by putting an antenna (round end down) into the # 1 cylinder head through the spark plug hole and turning the crank until the piston is visually at TDC. Is this accurate enough ?
   Also the timing marks on the valve cam sprockets do not stay lined up with the timing mark on the timing cover on the engine unless you hold them there with a wrench. When you let go of them with the wrench the valve springs pull, turning the cam timing marks off . Should I hold them in place while I install the belt or would the timing be more accurate if I let the valve springs pull the cam to where it settles making the timing marks slighty off ?

[Rocketman]

You need to hold the cams into place. Everything needs to be pretty exact when you set the timing.

That is a good check for TDC but I dont think its possible to discern a 5-10* variance on the timing cog visually.

Vacuum leak fixed?

[ericjd]

Nope vacuum leak not fixed yet. I am just waiting for the part to get here.

   Thanks for that info rocketman. Before I attempt to get the timing set right I need to know which of the following spots to set the TDC  on the piston at while the cam marks are right on. Should the #1 piston be: (A) just reaching the top (B) Somewhere in the flat spot before it actually starts going back down OR (C) At the top just as it starts to go down.

[Phillip]

One more thing turn the engine over once or twice without the plugs in it before you put it all the covers on to make sure all the slack in the belt was tensioned out. You could have a little slack not accounted for that shows up latter and fouls the whole process. This will even out the belt and show you the true alignment.

[ericjd]

Thank you Sir Phillip, will do. One more thing though. Check my last post above. Should I have the piston at A, B, or C.

[Phillip]

TDC would be at the mid point of where the crank makes the transition between its' upward movement and its' downward movement so none of the above apply. It is an absolute point in the rotation of the crank, i.e. 0*.