Jump to content
silroc

wondered why fan/belts weren't turning

Recommended Posts

Dug into it and found the big bolt holding the lower pulley was loose as was the pulley itself.

Doesn't look good - the woodruff key was sheared over and worn down, the pully ID looks messed up and its' slot.

The crankshaft key slot looks bad too. Otherwise the crankshaft has some marks on it, but looks like the pulley was the softer metal.

So... how bad is the news?

Do I look for a replacement pulley (stock or aftermarket?) Or get this one machined if that's possible.

Does anyone have info for a replacement woodruff key (dimensions, availability)?

 

JevZsmP.jpg

 

 

 

n3lae5T.jpg

 

 

While I'm at it, was considering new radiator with electric fans, in which case I'd want to remove the upper fan and "TEM-COUPLING" unit.

Is there anyway to remove that TEM-COUPLING part or do I have to install a new water pump that doesn't have one?

 

Thanks much

 

 

 

  • Like 1

Share this post


Link to post

Definitely the pulley must be replaced. Unfortunately the crank slot is damaged enough that it may not support the woodruf key and this will happen again. Was the crank bolt loose? This may have been the cause. Someone may have had this apart and failed to get it torqued properly. Well nothing to loose here. Put together and make sure the bolt is torqued to 120ft.lbs. That alone should hold it.

 

Only way to remove the clutch on the water pump is to cut it off.  Do NOT cut too close to the press on pulley. Slice the aluminum parts with a cut off disc. You'll do best if you break off smaller parts. It's difficult to do without slicing the pulley. Avoid doing that. Expose the bearing...

F7SRxLX.jpg

 

uIbQLzV.jpg

 

Here you can stop or carefully slit the steel races and keep going. Stay at least 1/8" away from the pulley directly behind it. It's pressed onto the same shaft

  • Like 1

Share this post


Link to post

Yeah the bolt was loose.

Do you know if the pulley and keys are available anywhere?

I poked around on the internet some without luck so far.

woodruff key = Nissan #00926-51600

Pulley = Nissan #12304-B9800 or 12303-U6000

 

Btw, I'm now retired so have started on my 620 project. I wanted to get this problem fixed first so I can run the engine some.

I'll be posting progress pic's as I go. Not sure how much people want to see. Seems with this website everyone has been there, done that.

 

Thanks for the help as always.

 

  • Like 1

Share this post


Link to post

The crank damage looks bad, but what have you got to loose? Try installing the new key and pulley, and use red loctite on the crank pulley bolt before you torque it down. The damage is already done.

 

It is possible to have that repaired, but it may not be worth it.

  • Like 1

Share this post


Link to post
54 minutes ago, Stoffregen Motorsports said:

The crank damage looks bad, but what have you got to loose? Try installing the new key and pulley, and use red loctite on the crank pulley bolt before you torque it down. The damage is already done.

 

It is possible to have that repaired, but it may not be worth it.

I’d err on the safe side and use green loctite. It is designed as an adhesive/retainer. I’ve used it to hold spun bearing races in skid steers and similar applications with great success. Apply it to the key, the keyway and all around the crank snout. Assemble and torque then leave it to cure for a day or so. 

Only caveat, she isn’t coming apart again without some serious heat applied liberally.  

Edited by Ben_upde
  • Like 2

Share this post


Link to post

As long as you can remove it at a later date. Torque to 90-116 ft lbs. It ain't coming off.

  • Like 1

Share this post


Link to post

Buy 2 of the woodruff keys and pulleys so if it fails again you will have them when you rebuild your engine and replace the crank.

  • Like 1

Share this post


Link to post

Might not have a choice if he wants to drive it.

Share this post


Link to post

I put the new pulley on - without a key but with the recommended locktite and torque - holding so far so good.

 

 

 

Y2YYLps.jpg

 

 

 

Before I put it all back together I cleaned up the engine compartment. I applied an Everbrite satin to give it a little shine.

 

TYOtgX1.jpg?1

 

 

I only ran it for about 15 minutes to warm it up for a compression check. That turned out good with about 163-165 psi on all four cylinders.

However, a couple things from that little run time; First, it sucked down a gallon of gas sitting there idling for 10 minutes! Is that do be expected?

Seems like the exhaust fumes are heavy - not white, blue, or black, just noxious!

Secondly, I pulled out the brand new set of plugs to take a look and found #1, #2 coated dry black. Again, this after only 15 minutes of run time.

Maybe some connection with the poor gas mileage and these two cylinders? What would cause only two cylinders to be this way?

 

 

LoyxB2C.jpg

Share this post


Link to post

I imagine a gallon is just an exaggeration.

 

#3 and #4 are lean and #1 and #2 are rich. Did it even run???? Did the engine shake while idling??? Can you take the air filter off and post a picture of the intake where the brake booster hose joins it???

 

Firing order looks right.

 

 

 

Looks like the heater hose from the back of the head is looped and connected to the return at the lower rad hose??? This is only a good idea if you can somehow plug it so there is no flow through it. The heater has a shut off valve when not being used. This is a lot of hot water that is being sent right back into the engine with out being cooled by the rad or the heater.

Share this post


Link to post

At idle it should run a minute or 2 w/o any gas going to it after one pulls the fuel line

 

float level not right

ck the valve lash but since you had good comp numbers most likely it’s good 

make sure intake ,carb tight

Edited by banzai510(hainz)

Share this post


Link to post

You guys are quick on the help!

I ran the fuel line into a little 1 gallon gas can (I don't know what's in the tank), and it definitely used that up. 

This is my first L20, but have listened to quite a few motors in my time. To me it sounds like it runs OK. What I would expect for an old truck 4-banger.

I guess a little shake initially, but smoothed out after a minute. Rev'd it up towards the end, seemed fine.

Nothing slips by you Mike - I did that with the heater hose just temporarily. Good tip tho - guess I could just clamp the hose to stop the flow next time.

Here are a couple of pics as you asked for

 

pbYfYRa.jpg

 

 

TnaOdm0.jpg

Share this post


Link to post

I was hoping to find the brake booster hose loose and leaking air into the 3 and 4 runner. This would make the mixture lean. Can you inspect for looseness or cracks in those hoses. Check the top intake mounting bolts are snug.

 

LoyxB2C.jpg

 

3 and 4 should look more like 1 and 2.

 

Just to satisfy my curiosity, could you pull plug #3 and #4 wire off separately, put and old plug in the end and lay on a grounded surface. Crank the engine with the starter and see if there is a spark?

 

Share this post


Link to post

I did a little experiment with all the plugs hooked up at the same time so I could compare the sparks.

814uVg8.jpg

 

Here is the video of the cranking (in the dark).

https://imgur.com/V8TrdTb

https://i.imgur.com/V8TrdTb.mp4

 

Newbie to Imagur too, don't know why the video link doesn't work like the pic's.

 

Kind of hard to tell if all the sparks are equal. They all seem to spark brighter/dimmer sometimes. But at least they are all firing.

 

Haven't checked the manifold bolts yet.

 

When installing the new pulley, I eye-balled the crank slot and made a mark so I could line up the pulley slot with it. I think its pretty close - I'd say within a 1/32. I figured these engines aren't all that precise!

 

Share this post


Link to post

I would strongly recommend against running the engine without a crank key.

 

I understand your situation, but it's a failure waiting to happen.

Share this post


Link to post

Thanks for the advice. Coming from someone with your experience, I take it to heart.

 

  • Like 1

Share this post


Link to post

I've honestly never installed a crank pulley (non-damper) without a crank key, but I have seen what happens to them when the bolt comes loose. Pulleys get welded to crank snouts, or get wallowed out by being loose. I've even seen crank snouts snap off.

 

If you used a sleeve retainer where the pulley slides onto the crank, it may allow it to stay put long term, but therein lies the problem...you'll never get it off.

 

Definitely keep us posted. I'd love to hear how this holds up.

Share this post


Link to post

Really nice job on setting up a properly grounded set up for testing spark. Most everyone including myself jury rigs some kind of half assed hope it is grounded kind of setup that may show the spark or has some kind of defect in the circuit. I feel a little smarter after witnessing this. Thanks!

Share this post


Link to post

I had the same crank pulley situation with a 91 prelude. Crank key gone. damage to the crank, damage to the damper/ pulley, no damper/ pulley to be had anywhere after hours of searching online so I just decided to just put it back together.

 

I wish I'd seen this tread before you (OP) had put yours back together without a woodruff. I would have told you to go to your local ACE hardware bolt bin and get a new key to install. Mine local one had actal woodruff keys but the prelude needed a square one so I picked one up cut it in half, installed pulley and bolt with blue locktite. In hindsight, I should have used the locktite on the key as well.

Put it back together and fired it up and it seems to be holding

  • Like 1

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.