Jump to content
Crashtd420

A 521 in Massachusetts

Recommended Posts

And on to the next issue I found....

Started feeling some vibration while driving... sure enough the center u-joint on the drive shaft is loose.....

I'll have to get that out and replace it....

  • Like 1

Share this post


Link to post
2 hours ago, Crashtd420 said:

I also put the restrictor with a .040 hole in and I can still see oil coming from the spray bar.... so I'll see how it behaves now...

 

Back to an ac question...

The one thing I noticed is a slight rpm drop when the compressor turns on.... only about 150-200 rpm...

I believe that's normal but I'm wondering is there a way to combat that other then just turning the idle up a little?? 

Current I turned it up to 800 rpm....

Older EFI systems use a idle air control circuit, which controls this. For a carbureted system, there is such a thing as an idle up solenoid. Common on 80's carb's engines. They mount near the carb and actuate on the throttle linkage.

 

Try this - https://www.google.com/search?ei=CpRlXc_zCsLysQXHv5fIDw&q=chevrolet+idle+up+solenoid&oq=chevrolet+idle+up+sol&gs_l=psy-ab.3.0.33i22i29i30l6.343382.348047..349472...0.2..0.253.2466.0j20j1......0....1..gws-wiz.......0i71j0i131j0j0i67j0i22i30.cn2TrY89njU

  • Like 3

Share this post


Link to post

Is there room in your brain for newly acquired knowledge, or every time you learn something new do you forget something else like your way home? 

Edited by wayno
  • Like 2

Share this post


Link to post
1 minute ago, wayno said:

Is there room in your brain for newly acquired knowledge, or every time you learn something new do you forget something? 

I only forget the useless stuff....

I think 🤔

  • Like 2

Share this post


Link to post

I wasn't talking to you.

1 minute ago, Crashtd420 said:

I only forget the useless stuff....

I think 🤔

 

  • Like 1

Share this post


Link to post
3 minutes ago, Crashtd420 said:

I only forget the useless stuff....

I think 🤔

Just wait until you get older!!!

 

 

2 minutes ago, wayno said:

I wasn't talking to you.

 

I can remember the part number for the fog lights on the Taurus SHO I had back in the 90's, but I can't remember the haircut appointment I missed last week.

  • Like 1
  • Haha 1

Share this post


Link to post

 

33 minutes ago, wayno said:

I wasn't talking to you.

 

Well that makes more sense...

  • Like 1

Share this post


Link to post
49 minutes ago, Stoffregen Motorsports said:

Older EFI systems use a idle air control circuit, which controls this. For a carbureted system, there is such a thing as an idle up solenoid. Common on 80's carb's engines. They mount near the carb and actuate on the throttle linkage.

 

Try this - https://www.google.com/search?ei=CpRlXc_zCsLysQXHv5fIDw&q=chevrolet+idle+up+solenoid&oq=chevrolet+idle+up+sol&gs_l=psy-ab.3.0.33i22i29i30l6.343382.348047..349472...0.2..0.253.2466.0j20j1......0....1..gws-wiz.......0i71j0i131j0j0i67j0i22i30.cn2TrY89njU

I'll look into that further.... at least I have an idea what I'm looking for ...thanks...

  • Like 1

Share this post


Link to post

The guy I bought a SD25 engine from had one of them idle up solenoids on the engine for when it was cold outside as diesel engines need a little help when it is cold outside, but he had it wired to a switch, you would likely need it wired to only work when the AC was on and under load, not sure how that would work.

  • Like 1

Share this post


Link to post
Just now, wayno said:

The guy I bought a SD25 engine from had one of them idle up solenoids on the engine for when it was cold outside as diesel engines need a little help when it is cold outside, but he had it wired to a switch, you would likely need it wired to only work when the AC was on and under load, not sure how that would work.

 

Looks pretty easy to wire.... when the under dash unit turns on it sends a signal to the compressor to activate the clutch.... i just need a relay to power the idle up solenoid and I can use that trigger to the compressor to trigger the relay when the ac turns on.....

Trick is gonna be figuring out how to mount one on a Weber side draft....

  • Like 1

Share this post


Link to post

The carb has an arm for the throttle on the front and back.... technically I guess that would be left and right.... 

 

20190827-170536.jpg

 

Either way the Front has alot going on but I think the back will work....

 

20190827-170543.jpg

 

I have some other hardware for the carb so I can look at that also and see what I can figure out.... 

  • Like 1

Share this post


Link to post

This is what that guy I bought the engine from made.

010.jpg

 

011.jpg

 

I will post again in a little while on what I would do.

  • Like 3

Share this post


Link to post

OK, this is what I would do, but I have the parts needed to do it because I have parted out several Datsun/Nissan 720 diesel trucks.

Here is a diesel gas pedal( icon-lol.gif ) and idle adjustment cable, the cable mounts just under my dash on my 521KC turbodiesel.

014.jpg

 

Here is the cable mounted on the dash behind/under the diesel tach.

016.jpg

 

015.jpg

 

Here is the lower mount that is connected to the diesel emergency brake assembly.

012.jpg

 

013.jpg

 

Now I realize that this is stuff you don't have, but you could make most everything you need with a choke cable and some welding, I do have an extra diesel pedal, but the idle adjustment cable is expensive, I bought one from Nissan once, never again.

I made this post to give you ideas mostly, I have done this kind of stuff several times over the years, all my 520/521 trucks have 720 gas pedals and e-brake assemblies.

  • Like 3

Share this post


Link to post

I would be cautious of mounting the solenoid on the carb, having it actuate the linkage. With a cable throttle, the slack in the cable when the solenoid is actuated, could cause the cable to get hung up or fall out somewhere.

 

Mounting it on the pedal is probably a smarter, safer idea.

 

Wire it so that it cycles with the compressor. And I would isolate it with a relay too.

  • Like 1

Share this post


Link to post

I don't know if you could do use a idle solenoid on the pedal as it would have to pull on the cable, there isn't a lot of room down there, that is why a manual choke type cable is so nice, it can be adjusted while you are driving or sitting in the driveway without getting out if your seat.

I see a tang just under the fuel line, could that be used?

  • Like 2

Share this post


Link to post

I don't recommend doing this but if you were to take the oil sender out of the block and start the engine you won't believe how much oil will come out in the time it takes to get out and look. The mains are well oiled, believe me and at low speeds it isn't making hardly any hp to stress anything. At idle just what ever it takes to spin the crank at 700.

 

This is why car makers don't put numbers on the gauges or they are on a 15 second damper like the gas tank. Gas tanks vary from sloshing and people don't need or want to see it jumping all over. It confuses them. "why do I have a full tank when I stop but half full when I take off??? For oil pressure all they need is a low pressure light... no light... no worries.... good to go. If you run a gauge be prepared for some whack numbers. Sudden stops or hard turns can show zero pressure for a couple of seconds that the dampened red light does not.

 

My gauge shows from 63 to 70  (oil pump is shimmed) when driving and 30- 35 hot idle. (shim has no effect on low pressure only the high limit) Maybe it's really less, maybe more? than this, who knows? But it's a visual and is constant, so if there is an odd change then I'm alerted that something 'might' be wrong and I would check a few things. A red light won't do that till almost too late.

  • Like 1

Share this post


Link to post

The idle up solenoids mounted on Chevy V8s are used with cable throttle. Hmmmm, the linkage must be passive to a certain extent. Then again, it won't take much movement to get the idle up a couple hundred rpms.

 

Food for thought.

  • Like 1

Share this post


Link to post

I have a cable throttle on my diesel engines, that adapter mounted solenoid just pushed the throttle shaft far enough to up the idle a couple hundred rpms, since the cable is attached to a bell crank the cable never got loose enough to concern me, but I am not the one that made all that, I like the choke cable type setup the factory installed in the diesel 720s, so I didn't use it.

  • Like 1

Share this post


Link to post

Solenoids are usually fairly weak...doesn't seem like one is going to overcome those throttle return springs anyways.  What carb make/model is it?

  • Like 1

Share this post


Link to post

This solenoid was made specifically for pushing against a throttle spring, but I you make a solid point. I suppose it would be worth the $59 investment to find out.

 

Cable throttles are cool, but it wouldn't be able to cycle with the compressor, meaning your idle would be high the whole time the lever is pulled.

 

One caveat is that the idle up may lag a bit with a mechanical solenoid. Maybe a vacuum solenoid would be a better idea. Create a momentary vacuum leak to idle up, just like an IAC valve on EFI. https://www.amazon.com/Universal-Conditioner-SW-9001C-Solenoid/dp/B003R43J2C/ref=asc_df_B003R43J2C/?tag=hyprod-20&linkCode=df0&hvadid=316708741155&hvpos=1o5&hvnetw=g&hvrand=3492883928222282780&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032419&hvtargid=pla-630961705620&psc=1

 

  • Like 1

Share this post


Link to post

Does this Lynk manifold have any kind of balance tube? I don't think they come with any such provision. A balance port (or tube) will allow for a vacuum leak (like PCV or this idle solenoid we're talking about) without creating an erratic idle.

 

On my Austin Healey, I drilled across the carb flange before to create an internal balance port. It required an extra long drill bit to get through the flange, and then I plugged the hole with an NPT plug. You could also weld the hole shut.

 

See the rusty pipe plug?

20190218_154504_zpsx3ejpoqd.jpg

 

Not a great shot, but whatever.

20190218_154450_zpsj4kld4ov.jpg

 

 

 

 

  • Like 1

Share this post


Link to post
8 hours ago, wayno said:

Is there room in your brain for newly acquired knowledge, or every time you learn something new do you forget something else like your way home? 

Wayne, I also used to be a chef, so if you want any advice on how to roast a perfect chicken or throw together an apple galette, I can help with that too. 👍

  • Like 1

Share this post


Link to post

All good food for thought..... thanks...

To answer a few questions....

 

Stroffgren No the lynx does not have any sort of balancing tube.... but I like your idea about cross drilling it.... I have been wanting to plumb a Pcv valve in eventually..... I'll look at those vacuum valve to.... I assume you need a vacuum controlled solenoid too....

 

ThisisMatt ....

That's a 40 dcoe weber.... I have that spring setup because I dont have the spring that goes on the pedal..... 

  • Like 2

Share this post


Link to post

No, I don't think you'd need another solenoid. I think you could plumb the vacuum solenoid to the intake and then to open atmosphere on the other port. When the compressor cycles, the vacuum solenoid opens, creating a vacuum leak, and raising the idle. Maybe you could wire in some sort of RPM actuated switch, or TPS so the vacuum solenoid does not operate anywhere but at idle. There are generic TPS on the market these days, for when guys want modern electronically controlled transmissions behind their carbureted engines.

 

You would be the only guy on the planet with A/C on an L4, a single Weber side draft and an idle up solenoid. Lead the pack!!!

  • Like 1
  • Thanks 1

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.