What are these dudes called and how do I adjust them correctly?
Posted by Special-Arm6302@reddit | projectcar | View on Reddit | 21 comments
So I was doing a routine check on this car, a Nissan sunny from 1988 with the 1.6 slx engine, and I noticed it was leaking a bit of oil from the right bolt on the picture. So I checked and the bolt was very loose so I thought that I would just adjust it and go on with my day but then my idle got all messed up? It died within seconds and it hasn't done that before.
Are these screws connected to my carburetor somehow, I don't see how and I have tried to look at an exploded view (I think it's called that) but I'm still lost.
I then tried to go by the sound of the engine and loosened the nut again and the idle did get better, it didn't die, but when I tried taking it for a spin it felt much weaker and it was suddenly struggling to drive. It was doing fine before I touched that nut... If only you could time travel and tell yourself to not touch it
JackTheBehemothKillr@reddit
Those are acorn nuts. You screw em down till you can't anymore.
If you have a leak its the gasket underneath em
sprolololoo@reddit
Nissan E-engine. Those are just nuts that hold down the valve cover. Funfact: over-reving the engine kicks the rocker shaft loose and it rattles like hell
Special-Arm6302@reddit (OP)
Thanks! Yeah it make alot of sense that they're just for the cover. I'm trying to learn how to adjust the idle since it keeps dying. It feels like I need to adjust the air to fuel ratio but I can only see that I have an idle adjust screw. Do you or some one else here have any tips? It's my first time adjusting a carburetor so I might ask some dumb questions heh
sprolololoo@reddit
You adjust the afr from the back of the carb, near the base. there's a rod that holds the mixture screw in a fixed position, you propably need to bend it. it's right between the carb and intake manifold.
Special-Arm6302@reddit (OP)
I see, I just needed to adjust the idle screw it turned out, so now it runs fine. It was surprisingly easy to fix once you used your braincells so that was nice atleast, thanks for the help! :D
wdhutch3@reddit
Those look like valve cov and r retaining bolts that do not need adjusting to me.
Special-Arm6302@reddit (OP)
What I noticed was that the bolt seemed to be leaking oil because it was so wet around it, so when I felt it was very loose I wanted to tighten it and then it started idling weird. I can’t see what correlation these bolts have to the fuel or air since the carburetor is in the back of the engine
everyoneisatitman@reddit
There are seals under those nuts that get rotted out. Replace them and then adjust the carb due to increased crankcase vacuum. The air that is getting into the engine goes through the pvc valve and goes into intake creating a lean condtion.
Special-Arm6302@reddit (OP)
That seems logic, I tightened the nuts now and adjusted the carburetor and now it works fine. Thanks for the help!
mooreb0313@reddit
Shouldn't the valve cover be under slight vacuum such that oil shouldn't be forced out through that bolt? Maybe also a pcv or blow-by issue?
mostlywhitemiata@reddit
In an ideal PCV situation, likely but if the intake is not pulling air from the crankcase then it is naturally under positive pressure due to piston ring blowby
Special-Arm6302@reddit (OP)
I'll check the pcv, might be the issue. Thanks!
mooreb0313@reddit
To be fair, I think the other comments about air fuel mixture make a lot of sense. I'm battling an issue with crankcase pressure on my son's car so I'm kinda looking at everything through that lense. Easiest way to check is see if you have vacuum or pressure coming through the oil cap. Yank it off, start the car, see if air is coming out or going into the valve covers through the cap opening.
Special-Arm6302@reddit (OP)
I'll do that, no problem, thanks! :D
cannibeesurfrnd@reddit
That in a Pulsar? Or Sentra/Stanza?
Special-Arm6302@reddit (OP)
Yeah it is, I think the called the sunny pulsar on the us market?
PulsarGTI@reddit
B12/N13 judging by the mounts
Klo187@reddit
Those are just acorn nuts to hold the valve cover on.
pitchingataint@reddit
They are engine nipples. You twist them until your engine moans.
Aleutian_Solution@reddit
Those are for the valve cover. If they’re leaking then the seal on the bottom is likely worn out. If you tightened them down it’s possible you bumped a vacuum line for your carb and now it’s running poorly
Halictus@reddit
It probably had a vacuum leak through the valve cover gasket that you fixed by tightening it. If the idle mixture on the carb has been adjusted to compensate for the leak, it would run very rich once the leak is removed.