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Ok, let me entirely change this request for knowledge, as it's whole other problem.
Got the weber on, started the car up, splutters at first and then dies.
Second start up,the revs go up to 2500rpm.
At this point, I don't have the throttlecable linked up and the idle speed screw is backed off so it's not touching the throttle.
I've disengaged the electric choke at this point as well.
So, how should I progress with checking.
I suspect an air leak around the manifold,plates and carb base. Anyone got any surefire tips and techniques for getting that spot on?
Anything else it could be? There's a lot of smoke accompanying the engine going wild.
Thanka for all your help.
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Last Edit: Aug 21, 2017 19:29:23 GMT by rhymeface
Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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Aug 21, 2017 19:29:57 GMT
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Bumped as the situation has changed.
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Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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fad
Posted a lot
Posts: 1,781
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Air leak for sure. Do the wd40 test.
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Was hoping it wouldn't be as this is the second time I've tried to install it.
Assuming it's not the carb itself leaking, any tips on getting it completely sealed? I figured last time I just didn't let the gasket sealer set for long enough.
Between the carb and manifold are two adapter plates and the original ptc heater element, so I guess I've added 4 additional points of potential failure.
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Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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Aug 22, 2017 10:50:31 GMT
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Follow up to this - when I pull the throttle plate by hand and look down the peimary barrel, the fuel is coming out of the accelerator pump jet in a trickle rather than a mist - that's not right,right?
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Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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fad
Posted a lot
Posts: 1,781
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Aug 22, 2017 14:26:16 GMT
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Yeah thats normal, squirts in rather than sprays.
Have you set the carb to default settings on the idle mix screw (usually 2 and a half turns out) - not idle speed but the mixture screw?
Are you just using liquid gasket?
All faces clean and smooth before bolting up?
No ports left open?
Timing set properly?
Any pics of your install?
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Last Edit: Aug 22, 2017 14:26:38 GMT by fad
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Aug 22, 2017 16:24:07 GMT
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That's good to hear on the jet front - I just this minute read a thread on another board saying the same thing. Idle Mix screw on the base corner under the choke? Yes, set that to 2 turns. Worth the extra 1/2 turn? Permatex Aviation Form-A-Gasket is what I'm using - www.permatex.com/products/gasketing/gasket-sealants/permatex-aviation-form-a-gasket-no-3-sealant-liquid/ - if this isn't right or good enough, do recommend something. All the faces were clean and smooth when I did the set up on Sunday - spent a fair while scrubbing the form-a-gasket off of the adapter plates and heater, cut new gaskets from some gasket paper I ordered and then scrubbed the face of the manifold and bottom of the carb before reinstalling. The only thing I can think might be an issue now I think about is that the front two bolt holes on the manifold go through the manifold - so you have to apply a bolt down through the carb, adapters, heater and then the manifold itself and secure with a nut underneath the manifold. The read holes just terminate in the body of the manifold. I wonder if those front bolts might be presenting a leak. None of the ports are open - there's only the fuel unions and vacuum port on the carb, and then the vacuum port on the manifold (which has been capped off). Timing - this is one thing I haven't done and purely as I don't have a timing light handy. I take it this is as vital as not having a vacuum leak. Can you explain why that is? I see a lot of articles saying get the ignition timing right but explaining why. Here's a pic of the carb from the front at the moment - depends on what angles you need. Let us know and I'll try and snap them.
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Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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fad
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Posts: 1,781
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Aug 22, 2017 19:19:41 GMT
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Briefly... If timing is incorrect, you are sparking at the wrong time so no amount of tuning carbs will make it run right, you will either not have time for fuel to burn before the exhaust valves open (run rich) or burn all the fuel too early or even start burning before your intake valves close (manifold detonations or pinking). It will run like a dog until its set. Set the static timing at the very least (gives you a starting benchmark), there will be a YouTube video for your engine somewhere, you don't need a timing strobe to do that.
Where are you based?
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Aug 22, 2017 21:30:25 GMT
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Falmouth. Thanks, man. I'm going to get on it (as well as check the build of the carb).
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Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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Update to this.
So, I totally didn't notice that the throttle plate was held slightly open because it couldn't move past the high idle arm. Only realised that on taking the whole carb apart. That might resolve at issue, perhaps, as it would have been holding the throttle valves open more than they should.
Need to get a screw extractor for the distributor as the screws are shredded but am almost there setting static timing.
I checked out the sparkplugs while cranking the engine to tdc - all are completely black on top.
Got everything spotlessly clean - a good soak in dettol helps, I find - so ready for install #3.
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Last Edit: Aug 25, 2017 8:27:17 GMT by rhymeface
Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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fad
Posted a lot
Posts: 1,781
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Aug 25, 2017 12:10:09 GMT
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Keep in mind the most important thing to do:
Learn! There's no mistakes, only lessons.
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Aug 28, 2017 16:27:19 GMT
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Right, so I refitted the carb and it ran pretty much the same.
Just out of interest to see what difference the ignition timing made,I retarded it and it brought the revs down to abouy 1200rpm from 2500rpm. I take it, that's not a fix, right?
At the very leadt, it allowed me to locate the leak at the back of the carb as the lower revs made the change in idle more noticeable.
Lot of smoke though..
Additional: Had the car running about 1500rpm for a couple of minutes. Switched it off and it kept turning over before letting out a load of smoke from the engine and an audible hiss.
Might be time to get a professional involved.
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Last Edit: Aug 28, 2017 16:51:38 GMT by rhymeface
Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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fad
Posted a lot
Posts: 1,781
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Aug 28, 2017 20:09:16 GMT
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OK so the dip in revs is normal for changing timing. But you *need* to set static timing properly for your engine.
The hiss... That is indicative of a vac leak.
What colour was the smoke?
Have you done a compression test?
Did the engine run normally before the carb swap?
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Aug 28, 2017 22:07:14 GMT
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Did a compression test - results came out good across all four cylinders.
The engine ran OK but there was a leak on the old carb that was patched up and played up occasionally - more in winter.
I guess I need to reseat the carb a fourth time.
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Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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fad
Posted a lot
Posts: 1,781
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Just reread your post... So it runs on after knocking the ignition off? Hmm.
Don't get professionals involved yet, whatever it is will be fixable. We just gotta work out what is wrong! lol!
So. Let's start at 101. Get the timing static timed. This vid is for a vw bug but you get the idea, find one specifically for your engine:
Next. Find that hiss!
After that... Make sure everything is connected, electrically and mechanically.
Take a few close ups of the carb from all angles so that other eyes can see what you can. Its easy to miss things!
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Aug 29, 2017 15:55:37 GMT
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Ah, I did see that - so the principal is pretty much the same, right? Just a matter of getting that spark at TDC? Or at whatever degrees BTDC is best for that carb? I found a guide here that I've been referring to a lot: community.ratsun.net/topic/6117-weber-tuning-guide/Figured being Datsun engines, it's only a small step away from my Nissan (1.6 E16S engine in case you can find a specific video - I couldn't myself). In that guide, it says this, Not sure how that would translate to static timing set-up. And yeah, I read that the term for what I saw after turning the engine off is "running on" but the hiss came at the end of that - like pretty savage plume of grey-ish smoke and a loud hiss before spluttering out. Concerning stuff to the uninitiated. I REALLY appreciate this comment, fella. I'm so up for fixing this but don't want to be so stubborn that I bite off more than I can chew. Also, this is the daily driver, so I'm without wheels until this gets sorted. Onwards! I think I might have found the source of the leak going on this post: www.nissanforums.com/b11-b12-kn13-82-90-chassis/69762-weber-carb.html#post682553I did notice the two holes - you can see them in the photo below - even have liquid in them (that's pre-clean btw - not the state I'd have the plate when I'm trying to mount it), I guess if that's pumping coolant into the new gaskets, that might be an issue? But then it wasn't for the old gasket and Hitachi carb, would it be for the Weber? Food for thought.
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Last Edit: Aug 29, 2017 15:56:05 GMT by rhymeface
Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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fad
Posted a lot
Posts: 1,781
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Aug 29, 2017 19:33:49 GMT
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Drunk. Reply tomorroe
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Aug 29, 2017 19:39:53 GMT
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Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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fad
Posted a lot
Posts: 1,781
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Ah, I did see that - so the principal is pretty much the same, right? Just a matter of getting that spark at TDC? Or at whatever degrees BTDC is best for that carb? I found a guide here that I've been referring to a lot: community.ratsun.net/topic/6117-weber-tuning-guide/Figured being Datsun engines, it's only a small step away from my Nissan (1.6 E16S engine in case you can find a specific video - I couldn't myself). In that guide, it says this, Not sure how that would translate to static timing set-up. And yeah, I read that the term for what I saw after turning the engine off is "running on" but the hiss came at the end of that - like pretty savage plume of grey-ish smoke and a loud hiss before spluttering out. Concerning stuff to the uninitiated. I REALLY appreciate this comment, fella. I'm so up for fixing this but don't want to be so stubborn that I bite off more than I can chew. Also, this is the daily driver, so I'm without wheels until this gets sorted. Onwards! I think I might have found the source of the leak going on this post: www.nissanforums.com/b11-b12-kn13-82-90-chassis/69762-weber-carb.html#post682553I did notice the two holes - you can see them in the photo below - even have liquid in them (that's pre-clean btw - not the state I'd have the plate when I'm trying to mount it), I guess if that's pumping coolant into the new gaskets, that might be an issue? But then it wasn't for the old gasket and Hitachi carb, would it be for the Weber? Food for thought. Setting static time in principle is always the same. You just need to know what BTDC you need for your engine (ignore timing tweaks for carb change for now). Your hiss might be coolant? That there is a manifold preheat system I reckon. Weber carb likely has no channels for it. Plug it for sure mate, I would almost certainly think that is the source of your issue.
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One month down the line and I'm still no further forward.
Blocked the coolant ports.
Set the static timing. Found a site about Datsuns that suggested setting the timing to +7 BTDC, so took that as a baseline.
Actually took off the intake manifold as it was easier to sit down with it,the carb and the adapter plates and make sure everything was mounted properly.
Started it up - it seemed to work - idle sat at about 1400rpm. Went to go get some other bits and bobs. Came back and it did what it was doing before - straight up to 2500rpm. Made sure the choke plates were open as well.
I checked for vacuum leaks all around the base of the car and the manifold ports - no audible change in the engine sound.
I wondering if it is the carb itself that isn't right somehow.
As this is my daily driver, I need to make a decision about it with Autumn rolling in. There's a weber specialist not far from me. Wonder if I can get them to come over and give it a look.
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Nissan N13 owner | Mechanical neonate since 2016 (Give me all the info)
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