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thetwood

Failed CO emissions - all controls removed - where to start?

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The curved side goes with the chain's curve.  Straight side on the straight side of the chain.

timing chain.jpg

You want to drive it down until it hits the lower chain sprocket, red arrow.  You'll feel it "click" into place when it pushes the tensioner in, yellow circle.

image.png

Edited by siteunseen

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7 minutes ago, Pilgrim said:

OK, it downloaded in Chrome. Firefox blocked it. Thanks for the nudge.

The only dimension noted is the length. It would help to have a dimension for the top width, the distance to where the block narrows, and the width after it narrows.

Not complaining, just trying to make sure our online friends have the info they need.

I can do that!  Quick beer first, this makes my head hurt just thinking about this little job. LOL

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Well Mr T Wood I hope when you print it out the measurements will be true and you can lay it down on a piece of wood, draw it out and then cut it out.

Let me know if I can be of anymore help. Cliff

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I just remembered my first time doing this, nervously I will add. :love:

I used a long screwdriver turned upside down.  The handle fit perfect and held the tensioner back then my nightmare began.  I couldn't get the damn screwdriver out!  Finally got a good hold of the flat blade with some vise grips and pulled like a mother.  Then I did my Happy Dance. :beer:

Edited by siteunseen

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Thanks very much for helping with more measurements.

And I hear you - if you managed to do that with a screwdriver, I bow to you, and to both your mechanical prowess and considerable good luck!!  😎

Edited by Pilgrim
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I made the one from the down load plans. That being said I would hesitate to go too deep into this. Back to orig problem failed HC, so I assume rich setting. easiest thing to try 1st is to confirm AT THE ECU the resistance values vs. Temps on the temp sensor. A little bit too much resistance there and you end up with a rich run. Next Start switch enrichment, again it should not be there AT THE ECU when key is not on "Start". Lastly AFM air temp sensor, again AT THE ECU. Since it has the stock ECU might as well make sure those parts are sending it good info. I just seems like its going to be hard to know what is working without a way to monitor the exhaust gases with any changes made.

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1 hour ago, Dave WM said:

I made the one from the down load plans. 

The one I scanned? If it worked I'm happy. I wasn't sure the true size would come out on a printed piece of paper. Thanks

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1 hour ago, siteunseen said:

The one I scanned? If it worked I'm happy. I wasn't sure the true size would come out on a printed piece of paper. Thanks

honeslty cant recall, but it did have dimenions, and I did have to adjust printer setup.

time chain tool.jpg

Edited by Dave WM
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it was a little oversized (I may have just cut it a bit larger when cutting the wood) had to sand it in spots, not a big deal.

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Injectors are off to be flow tested, so type/flow can be nailed down. Not sure what the full turn time will be, but expecting a few weeks with shipping in each direction.

I'm a bit nervous about pulling the camshaft after the warnings. I don't mind digging into things, but would prefer to not need to pull the fan, etc. I have the time to do this as I'm waiting for the injectors, but sounds like it may make sense to test other things first. But do appreciate all the help with the tension retainer. I'm going to go ahead and cut one out now to have and test. 

Per @Dave WM, I'll read up on how to test the ECU and temp sensor. Also still working on tracking down some parts to go back closer to original like the charcoal canister.

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Given the work involved in dealing with the cam, I'd probably leave it in place, take care of the rest of the things you've identified and see how it runs. 

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If you had a good dial caliper you could just measure to determine cam lift. Might be some math here but somebody on the forum can probably help fill in the blanks. There is probably a simple way to determine duration, maybe a dial indicator and a home made degree wheel. That way you wouldn't have to pull the cam gear. Then match it up to the closest Schneider cam specs. Should get you really close

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You should be able to very easily measure the base circle to at least determine if it's a stock grind or not. No calculations, no degree wheel.

If it measures out to a stock base circle, you're done. If not, we can talk about that later?

Don't pull that cam gear off now. Absolutely not. Way far down on the list of things that might get done. Or not.

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Going by my '77 and what I did as far as removing everything like your sons car, my honest opinion would be go back to a '78 fuel pressure regulator with that fuel rail.  Unless you injectors are some fuel hogs it should run fine with the OE style FPR.  I ran into that same dilemma when I did mine but after tons of reading I found the '78 one inlet style was sufficient.  Maybe the previous owner read something I missed but I doubt it.

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19 hours ago, Captain Obvious said:

You should be able to very easily measure the base circle to at least determine if it's a stock grind or not. No calculations, no degree wheel.

If it measures out to a stock base circle, you're done. If not, we can talk about that later?

Don't pull that cam gear off now. Absolutely not. Way far down on the list of things that might get done. Or not.

I'm new enough to all of this that I'm not sure what exactly I'm supposed to measure here. Advice on where to read/learn more so I know what I'm doing?

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1 hour ago, siteunseen said:

Going by my '77 and what I did as far as removing everything like your sons car, my honest opinion would be go back to a '78 fuel pressure regulator with that fuel rail.  Unless you injectors are some fuel hogs it should run fine with the OE style FPR.  I ran into that same dilemma when I did mine but after tons of reading I found the '78 one inlet style was sufficient.  Maybe the previous owner read something I missed but I doubt it.

I was looking at the OE FPR and have a question. With the fuel rail that I have it doesn't look much like the pictures in the EFI book. It's basically tank > fuel filter > Rail (injectors) > return > FPR > back into tank. Maybe not too much different than stock rail, but less loops and such. If I get a stock FPR, do I just put it on the return line after it's gone through the aftermarket rail?

 

78FuelCircuit.PNG

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You need a decent set of these

image.png

Then measure one of the valve lobes across the bottom width. Not from the peak to the round end but from one side to the other. That should be the base circle measurement

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3 minutes ago, Patcon said:

You need a decent set of these

image.png

Then measure one of the valve lobes across the bottom width. Not from the peak to the round end but from one side to the other. That should be the base circle measurement

Got it. Know I have those, just need to figure out where it put them in my garage... Thanks. Appreciate the help.

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That fpr no matter where it is regulates the fuel pressure. My 77 had in on both sides return on bottom vacuum nipple on top. With mine and your straight shot fuel rails comes in the front closer to the radiator. Then the fpr takes that incoming fuel and regulates it (same psi) for the whole rail. It will take what you need and dump the excess through the return. That's the cool thing about those aluminum rails, they constantly flow fresh "cool fuel". No fuel overheating causing the hot restart problem a lot of folks experience.

So to answer your original question, the 78 fpr has an incoming fuel nipple that regulates the psi. And a vacuum nipple on top. Rockauto.com had one for $75 when  I did mine.

DSC_0662rw1ks.jpg

Edited by siteunseen

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1 hour ago, Zed Head said:

Here's more goodness from atlanticz's ancient page.  Looks like 33.3 mm is the typical Nissan base circle diameter.  You can measure that without removing anything except the valve cover.

http://www.atlanticz.ca/zclub/techtips/valvetrain/index.html

Ahhh pictures...much better! Thanks Zed

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