Post Head Job L16 unkown sound.

[Entrymax]

Recently completed a head job on this motor. Started right up, got it hot and finished adjusting the valves. .012 exhaust and .010 intake. 

 

I'm not to keen on what a good running L16 should sound like, and theres a slight noise I'm unsure about.

 

Thanks for the input.

 

[wayno]

Did you use a cam chain holder when you removed the head?

Are you sure you didn't lose the cam chain tensioner?

[datzenmike]

Good one wayno. I was going to say reduce the valve clearance 3 thou.

[Entrymax]

Well. I used a wrench with rags ziptied around it jammed between the chain and bungee cord holding the chain up with the hood. I'll pull the valve cover and take a look. 

 

Is there any way of pinpointing if the tensioner is still there or not?

[metalmonkey47]

Take a flashlight and look. Or grab the chain and see if there's any slack. 

[wayno]

Oh my, it's not easy for me to tell you what to look for, I just know that if the chain was not kept tight 100 percent of the time, then you likely have lost the tensioner, and you should not start or run the engine anymore, as you now have a oil leak.

I don't know what you did or how you did it, so I cannot tell you for sure what has happened, but if the tensioner has come out of its hole, then the timing chain cover is going to have to be removed, and everything is going to have to be found and put back where it belongs.

Others might be able to tell you what to look for down that hole, but the mere fact that it started makes me think that if it is out of its hole, it must have went somewhere where when you started it, it didn't start destroying things.

Maybe everything is fine, I don't know.

[Entrymax]

Hmm, I honestly don't even know how much slack is too much slack. :/ 

 

I checked inside and there isn't anything out of the ordinary.

 

Currently going through the motor trying to find anything loose.

 

[wayno]

Did you let the chain get loose at any time while removing and replacing the head?

Did the cam gear go back on the cam easy?

Everything looks good down the hole, but I have never looked down there to know, as I always use the chain holder to keep the tensioner in position.

If at any time you let the chain get loose, and then have to dig it out of that hole, then you likely lost the tensioner.

Have you ever done a head replacement on one of these engines in the past?

[wayno]

This is what it looks like down there.

See the block of metal in the center of the photo that has 2 bolts holding it in, see the black triangular shaped piece pressing against the chain, if the chain gets loose, the spring inside the block will push out the tensioner.

 

[Entrymax]

This was my first time doing a head replacement. Ever. 

 

I did my darndest to keep the chain tight the whole time the head was off and on. Never dropped. It was quite hard getting the chain back on the sprocket and had to move the cam slightly to get the sprocket back on.

 

Planning right now on pulling the timing cover. Even if I don't know that its on or off, I would rather be sure its there. 

 

Is it possible to pull the timing cover without pulling the motor? Only by removing the radiator assembly?

 

If its of any help, im running Valv. VR1 10-30. Lighter than required.

[wayno]

You cannot likely get it out and back in without loosening the bolts on the oilpan and dropping it a quarter inch, you don't have to remove it, just lower it a quarter inch.

You will also have to remove the harmonic balancer, which can be difficult sometimes.

I wish I were closer, it is hard to tell from a video what the sound is, and where it was coming from, I just don't know.

When you put the head back on, did you use all the same bolts in the same holes?

One of the holes that holds the thermostat housing on goes into that hole the cam chain is in, if the bolt is to long, it can hit the cam chain, that would also make a lot of noise.

Did you see the photos I posted just before your reply?

[Entrymax]

A friend recommended using one of those extendable peep mirrors to push against the tensioner to see if it's there. Running to the local gas station.

 

And yes, I did see your photos. 

 

The bolt wasn't hitting the chain.

 

I really appreciate the help. Really do wish there was a datsun guy locally to have second opinion. Thank you.

 

I did use the same bolts in the same holes.

[datzenmike]

 

.

 

Looks fine to me. Can see the crank worm gear and chain sprocket. You wouldn't be able to if the tensioner were out.

 

With the motor HOT adjust the valves. If you set them hot then try reducing the lash 2-3 thou to quiet them.

[wayno]

.

 

Looks fine to me. Can see the crank worm gear and chain sprocket. You wouldn't be able to if the tensioner were out.

 

With the motor HOT adjust the valves. If you set them hot then try reducing the lash 2-3 thou to quiet them.

 

I was wondering if the tensioner could fall into the oilpan if it fell out, but I cannot recall if there is enough room for it to get by the lower chain gear.

How loose would the chain be if there was no tensioner?

It would not be that loose in my opinion, because the tensioner only moves out a little bit, we are not talking about an inch of slop here.

He said it was tough getting the cam gear back onto the cam, so that makes me think it likely is alright, but I don't want to actually say that, as I am not there to verify it.

[Entrymax]

Is this the tensioner? 

 

 

Unsure.

[Datsunrider71]

Is this the tensioner?

 

 

Unsure.

You should take off the From cover and see what's sup in there papa.

[wayno]

OK, what I would try is this, since you know where the tensioner is supposed to be, I would use a longer piece of metal(2 foot long), and bend the tip of it(1/2 to 3/4") at a 90 degree angle, then I would stick it down the hole to where the tensioner is supposed to be, I would then press on the tensioner and see if you can feel it push in and then come back out as you release pressure, before doing this, I would turn the engine by hand(1 inch) to loosen that side of the chain, if it pops out a little, maybe you can see the tensioner block.

If all this fails, then you will need to remove the timing chain cover, but I would loose the camera, use your little mirror and a good flashlight, and focus on just figuring out if the tensioner is in position.

That video has noise, but I could not tell what type of noise it was.

[hobbes_the_cat]

I think it's highly unlikely that the tentioner completely fell out. On my L20b in the garage I let the tentioner slip on purpose just to see exactly what it would do. The shaft was too long to allow the unit to come out completely with the chain in the way, it just gets stuck. Maybe it could fall out completely if the tentioner pad was very worn though...

[datzenmike]

It's easy to say pull the front off and see but the reality is half a days work.. and it might be fine... and you may cause an oil leak. Should be easy enough to see if it's in or out.

 

The shoe tends to move upward with chain travel and you can't see down to the crank sprocket. The vid shows the crank sprocket and worm gear clearly looking down between the slack and the tension sides of the chain... so I think it's fine.

 

Having said this the tensioner would have a hard time getting down between the body that holds it and the chain and lower sprocket. There is also very little room for it to get out betwen the body and the slack side chain guide. Just look at the picures of proper placement. Traditionally when someone has fucked this up they complainthat "I can't get my chain back on the cam sprocket after doing a HG change!! Help!!!" This is because the tensioner is out of place and the chain can't move back to give ANY slack.

[Stoffregen Motorsports]

and why is cutting the spring a bad idea?

[KlassicMotion]

You said you set the valves to .010 and .012.  Was that cold or hot?  Those are the hot specs.  Setting the valves cold, they should be .008 intake and .010 hot.

[Entrymax]

Well the tensioner is still there!

 

 

Time to get all OCD about finding loose bolts and getting the valves set perfectly.

 

Now i'm back to step 1 of finding noises.

 

Yes Klassic, I set them hot. I'm about to set them cold.

 

I appreciate the input! Thank you.

[KlassicMotion]

I don't remember if someone else already asked this, but did you mark a cog on the sprocket with the matching link on the timing chain when you removed it, to make sure the chain went back on in the same position?

[KlassicMotion]

You should pick one of these up for your next head gasket job.  I did, and I just used it this last week to do my gasket swap.  It worked great.... I think.  I'm still putting everything back together!!  But everything seems to be in good order.  I should know for sure tonight.

 

http://community.ratsun.net/topic/56314-if-you-own-a-datsun-you-should-also-own-one-of-these/

[datzenmike]

 

This is what tends to happen when it pops out. Can't go down and can't go up except between the guids and the chain. If it was out woul wouldn't have hot the chain back on.