78_lilhustler

What I ended up having to do was get a fan for a later 70’s or early 80’s model 720 or d21 whatever they are called the Nissan Oem part number is as follows: 21060-N8560 the 8 blade fan that ran in these late 70’s 620’s w ac are basically impossible to find. You’d have to get lucky in a junk yard looking at 720’s and 200sx’s of the late 70’s and early 80’s from what I understand. the fan of the part number above is 7 blade but has the 5.25 in (133.5 or 134.5 ish mm) bolt pattern and will have the proper offset to clear the pulleys.it’s only a bit wider inoveall diameter if I rennet correctly. Like a few mm’s. It is possible that it may not exactly fit the stock shroud. I am currently not running a shroud since it melted but the fan definitely fits and will probably be your only real option for replacement. They seem to be much more avaible online eBay etc. Hope that helps.

Sorry for late updates on the progress here all, trying to work on this in between my 10 and 12 hr shifts as a sous chef in Philadelphia. Needless to say I don’t get but a few hours after and or before work to get at this. so this morning did a lot of looking around, adapter plates and studs in the intake for mounting the carb were definitely loose. So as I’m sure you all are aware, it’s not easy getting a wrench or socket down between the carb and everything else to tighten the nuts. I decided if I’m going in might as well remove the carb get proper tightening on the studs and clean the carb. i also investigated the vacuum brake booster lines and the line leading to the auto trans. Brake booster lines are solid and still the stock ones. The vacuum lines leading to the trans that datzenmike mentioned are steel but had a fitting from the manifold to the steel line to the trans cover in a rubber sheath. The rubber looked ok prob original and hard to move up but it exposed the connection which is a flanged steel tube leading to another steel tube to the trans. Looked as hard as I could for any damage and could not find any there. this is about as far as I could get this morning before work. I have some Puc for reference but need time to upload and post. so in summary all other vacuum line look good, definitely needed to get carb set tighter on intake, also going to clean carb while off for good measure. when I get done with my shift here I will start on the carb clean. I’ll keep you updated.

Oh yeah jet I’m sorry.

The idle adjust has always been set all the way in since I got it. Opening it up just ramps the idle too high.

This should have taken place just over a year ago after I had the truck for about 6-8 months a cylinder lost compression and I took it to a very professional engine shop, one that rebuilds any thing from small boat engines to full on detroits. Owner very knowledgeable about old Datsun/Nissan engines. Couldn’t believe I had this truck in such good condition. Anyway he checked over everything replaced the timing chain and I would think went through the valves then.

It is definitely worth looking in to. I did pull the idle set screw out to check it to see if it was gunked up but it was clean. The way it behaves it does seem like the idle circuit is not working properly

No it had been installed by someone else and since it ran fine and due to my previous inexperience with Weber carbs I did not notice. The flaps still open when warm so not sure how thralls works? I did notice however as I started going through all the electrical in the engine bay and finding both that lead for what I assume is the choke and the lead for the old anti dieseling solenoid taped up and tucked away.

Right didn’t really think the AC had any connection to this issue was just noting that stock ac and auto has proven to have specific parts and specific issues I hadn’t previously considered as a whole. thanks again

Thanks for the response datzenmike. I will begin checking this list of of possible issues first thing tomorrow morning starting w the adapter plate. Good chance it is loose. I feel both the break line booster and or the line to the trans are hood possibility too have not really been looking in that direction yet.

Yes the flap is closed when cold. Definitely opens up when warm. i will time the engine w the auto trans in gear but have not been able to get it set since it cuts out as soon as it’s warm enough to go set timing. The auto trans and factory AC combo for this year definitely has many curveballs I hadn’t considered as compared to manual non ac vehicle etc. thanks for the advice!

Hello all, I have a 1978 Datsun 620 with an L 20 B that is a factory AC and automatic truck I have a weber DGAV 32/36 carb installed that is only about two years old. This truck was running and idling fine previously with this setup but now it will start and idle fine for a few mins then just die when warmed up. I can get it to start right back up but it then dies shortly after as if the key was turned off. If I leave it sit to get cold it will fire right up idle til warm then die again. the Weber dgav 32/36 does not have a cut off solenoid or anti dieseling solenoid and I did not have any electric choke connected previously and it was fine. the only big change to anything was recently I had a battery catch fire which melted some wiring and few vacuum lines. I replaced all the batter wires, lugs, new ngk spark wires, replaced any melted or questionable wiring with proper gauge wires, all vacuum lines have been checked and replaced as necessary. I don’t think vacuum is it because there should be no advance at idle and that’s the only port to the carb. plus it starts fine and does not need to be throttles to maintain idle. Any one have any ideas or have this problem? Do you think it’s the carb? Possibly damaged circuitry?

Understood datzenmike. After more research it seems that fans from 240z models of similar years have the same bolt diameter as the clutch on my engine. Is there a reason these will not work with my set up? Such as clearances, my shroud is also gone so I could work around that and find a shroud solution later.

Hello all, Battery recently caught fire in my 1978 620 and melted the fan blade and shroud. It is a factory AC vehicle so it came with an 8 blade fan which I have had difficulty locating. I have been told that 80-83 200sx and possibly 720’s of that time ran the same fan or possibly same dimensions. Searching on line does give results that look similar as far as fitting the clutch but are always 7 blade fans. I have reached out to some of the sellers for diameter dimensions to get a better idea of a possible fit. Does anyone have any other experience with this issue? Is there a “good enough” fit? Is is possible to replace the clutch that will fit a more readily available fan blade? Id rather not have to do an electric fan conversion if I can be avoided. Everything else is in working order just need a fan blade replacement. Any feedback, guesses, anecdotes, complaints, and general knowledge is appreciated.