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rcb280z

Tackling 2 leaks, rad and front main

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After installing my new end links I decided it was time to pull the aluminum radiator, drop it off to be repaired, and replace a leaking front main. The rad shop showed me where the leaks were and said it has to be epoxied. I've never heard of this before. I'm used to having the older style copper/brass units. Anyway, they  are working on it now.

I removed the crank damper and could clearly see where the leak was at the main seal. The whole front portion of the engine is pretty grungy from leaking for a long time. I did clean it up a little. The front main seal came out super easy! Cleaned the matting surface and installed a new seal. Was definitely tighter than the old one. Put the crank damper back on and torqued the bolt to 105 ft lbs.

There is one thing that is now bothering me, of course after the fact. The woodruff key was cocked at an angle (in the crankshaft) when I removed the damper. I was able to remove it fairly easy. And could put in place fairly easy with a magnet and my finger. So I looked at my "How to rebuild your Datsun" book and I see they had to remove it with a screw driver and mallet. Should I be concerned about mine being loser? It's a poor pic but I think you can make out the woodruff key is sitting cocked. Let me know what you guys think.

woodruff.jpg

Edited by rcb280z

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27 minutes ago, siteunseen said:

Won't the damper slide over that and hold it in place?

That's what it did. My concern is with how "loose" it is in the crankshaft slot. I can slide it back and forth fairly easy. I don't feel any side to side movement. I was just concerned when I read how Tom Monroe said to remove the woodruff key. But if you guys think I'm concerned for no reason, let me know.

Edited by rcb280z

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The Woodruf key, I if  Iam not mistaken has a bit of a "BOAT SHAPE" to it. It appears at the angle you have it at there is a possibility it will not hold the balancer in place. I would give it another try. The ease of removal was because of the presence of oil. That key should have the flat side outwards but the flat surface should be as parallel as possible to the shaft or at least that is what I would aim for to ensure it doesn't undo itself. Give it another try for everyone's sake! If it comes off your radiator repair would be pointless!

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58 minutes ago, esmit208 said:

"BOAT SHAPE"

Right. So maybe there is a reason for that rounded side of the key.(?) Just in case of movement, if it moves a little it will still seat? I tried again. I think the same thing happened but can't be 100% sure. Its locking in place, just not sitting in the crankshaft slot like I think it should be.

I looked at the How to rebuild your Datsun book again and see Tom tapping the key into place will a piece of wood and a mallet. I did NOT have to do that. There was no noticeable damage to the key slot in the crankshaft that I could see. Looked normal. So I'm not sure what to think. 

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Okay, it just dawned on me that it's been sitting like that for many years. The pic I posted was what it looked like after I pulled the crank pulley this morning. The last time the pulley was off was in 1995 when I had to replace it with a good used one after it separated. It probably happened then and has been that way since.

Edited by rcb280z
corrected when the crank pulley was off

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Seems like the rounded bottom allows the key to be tilted towards what is being slid over it. Once the part is in place the key would sit level.

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 Cliff's got it right. The key is installed tilted just enough to allow the h-balancer to slide onto it easily. The key will rotate as the h-balancer is slid over the key. I think I'd use a dab of blue tread locker on the key but in reality the key can't come out once it's been installed. 

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Well guys it's a good thing I decided to take it back apart. As you can tell in the pics I have parts to order :facepalm:Oil slinger looks bent.  What a bummer!

today.jpg

today2.jpg

today3.jpg

Edited by rcb280z

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I . the key is available at any Nissan dealer for like $3, Tell them its for a 300zx

2. A new alum radiator(3 row) is like $125 delivered to you house, cheap insurance, a bad epoxy job will result is a head gasket job(or worst), not worth the risk.

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I’ve always lubed mine when I put it in so it can pivot easily. It’s not going anywhere.

What year is your car? I may have an extra balancer I would sell you. 

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Bummer. That's what happens when you torque the crank pulley nut down without having the key and damper all situated correctly before applying mucho force.

The key is supposed to be able to rock in the slot and find it's proper "happy" location. But if you get it rocket too far before you start fitting parts together, it's possible to rock it backwards and get it cockked into a position where the force is normal (perpendicular) to the install direction, and as you found... You can crack the brittle damper.

So I got a question.... Where is the chunk(s) of cast iron that snapped off the back of the damper? Is that stuff inside your front cover now?

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Yeah Capt, I thought everything was lined up, for what I could see. Not sure how / what to do different with the new one. Kinda worried.

14 minutes ago, Captain Obvious said:

The key is supposed to be able to rock in the slot

I believe this is what gave me the trouble, too much movement. Even Tom Monroe in his how to rebuild your Datsun states you have to tap it in place for the key to seat into the keyway. I could pull mine out with a magnet, thats how loose it was.

I should have stopped and pulled the damper back off when it started to get tight while bolting it in place. But I didn't and it cost me a perfectly fine damper.

The cast piece that broke was still connected. When I pulled the damper back off to look at things it was attached but ready to break off. It just took the flick of a finger to break it the rest of the way. 

I admit that it was all my fault. I should paid better attention to what I was doing and really don't understand why I didn't. One of those, woulda, shoulda, coulda moments. I ASSumed it was going on ok and that's that.

I've got a new balancer, oil slinger, woodruff key, and front seal coming. Everything is OE except for the balancer.  

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Well I know it won't make you feel that much better, but you're not the first one to do this. A local buddy of mine did the exact same thing to his pulley. Glad you didn't lose the chunk behind the front cover. That would have just added insult to injury.

I've messed with lots of keys of various designs working on machinery in addition to cars. Most of them are snug (tight) enough that they don't fall out with gravity, or a magnet, but that's not always the case. I'm not sure a new key will be any tighter, but you'll find out when you get your replacement.

So, to help make sure if doesn't happen again... First, put the pulley on with NO key, just to get a feel for how it goes on. You should be able to feel and hear it clank against the hard stop shoulder on the crank. Pinching the slinger and all that... I've heard some of the pulleys are so tight that you have to use the center bolt to actually jack the damper into place, and I'm not sure how I feel about that.

Get a feel for how it SHOULD go on, and then make sure the key slips gracefully into the slot inside the damper. If the key won't go into the slot on the ID of the damper, then it'll rock out of position when you try to put the pulley into place. Just take it easy and remember, you're not the first!  :)

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CO, thanks for the words of encouragement.

Yeah, I'm going about it differently, that's for sure. Will post when I get the parts in and installed.

Edited by rcb280z

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Decided to clean it up a little while I await the parts. Starting to look better.

I can actually see my oil pump now.

cleaning.jpg

Edited by rcb280z
  • Like 1

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I had a similar problem with my cummins when I replaced the injection pump, the key tends to move (pushed back) when the sprocket is inserted, the solution was using some retaining fluid (locktite) let it dry a bit and install sprocket, worked like a charm.

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 I'd go with blue Loctite. Someone may need to remove the key in the future. Out of curiosity, does the key way look OK?

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I did think that yesterday but I've owned this car since 1985, the harmonic balancer was off twice and the same key went back in. The last time the balancer was off was in 1995. Replaced it with a used one because it was separating. Been on there ever since, with the same key.

Edited by rcb280z

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