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Just bought a 521


mainer311

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be sure to mark your torsion bars brackets b4 you reindex them i did that and i turned them 1 or 2 splines and then readjusted the bolts to gt the stance i wanted. i know that you can use a saturn alternator but may have to bypass the voltage regulator wiring i think cuz the saturn alternator is internally regulated

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What is the best 60A alternator retrofit for the 521? And by that I mean, closest to a direct drop-in? I'll be honest, every time I search, it seems like only 510 and 620 swaps are documented. 

 

Saturn internally regulated one?? IDK I just went with a re-pop'd one and called it a day.   Also 510/620 (some years) both had L16s same as your truck so what works for them should work for you as well. 

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Good to have a recovery tank. See what will fit, go to,junkyard. Got mine at my from an old Volvo and mounted it next to rad.

 

I just bought a small universal one on Amazon for less than $10. 

 

I was sitting in traffic last night and my temp gauge went way up...almost to the red line. I don't have a temp gauge to verify, but after a minute or two it went back down about half way. I'm thinking the thermostat got stuck or opened late. The PO just installed a brand new aluminum radiator, new hoses, and a new 180 degree thermostat. It got me thinking about the fluids in this truck, since I haven't checked any of them yet.

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Thats whats great about these trucks, uncovering all the weird shit POs did or didn't do over the past 45+ years of existence.

 

Anyways the 521 temp gauge always a mystery to me.  Like there is the break in the line but where should the needle be pointing most of the time?  Is there a given range that is consider OK?  

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I just bought a small universal one on Amazon for less than $10.

 

I was sitting in traffic last night and my temp gauge went way up...almost to the red line. I don't have a temp gauge to verify, but after a minute or two it went back down about half way. I'm thinking the thermostat got stuck or opened late. The PO just installed a brand new aluminum radiator, new hoses, and a new 180 degree thermostat. It got me thinking about the fluids in this truck, since I haven't checked any of them yet.

...good to have a mech. Temp gauge makes a difference when u see numbers.
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I just bought a small universal one on Amazon for less than $10. 

 

I was sitting in traffic last night and my temp gauge went way up...almost to the red line. I don't have a temp gauge to verify, but after a minute or two it went back down about half way. I'm thinking the thermostat got stuck or opened late. The PO just installed a brand new aluminum radiator, new hoses, and a new 180 degree thermostat. It got me thinking about the fluids in this truck, since I haven't checked any of them yet.

 

Yea, the thing about the thermostats in the early L blocks is that they need a hole in them on the outer edge as the thermostat housing does not have a bypass, so if a new thermostat was put in without a hole drilled in it then you will get wildly fluctuating coolant temperatures, one day it will just overheat and eventually you will blow the head gasket from it getting hot all the time.

The L20b engines came with a thermostat housing bypass, so they don't need the hole drilled in the bypass.

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The idea of the hole/bypass is that it lets the hot coolant out of the head into the lower thermostat housing, then this hot coolant opens the thermostat.

Without the hole or bypass the coolant inside the head gets super heated and warms the thermostat housing coolant eventually, when it finally does open the gauge shows real high and then cools down pretty fast as the coolant that was in the radiator(almost cold) enters the block/head, the thermostat closes some as cool water gets to it, it then cools the block and eventually the thermostat closes and the cycle is started again.

Some have no issues, while others like me have lost the head gasket, I figured it out and put a lower thermostat housing on it with the bypass and have never had an issue since.

Normally with the hole/bypass the coolant gets up to temp and then the thermostat opens and then finds a happy place half open and just stays there and keeps the coolant temp steady.

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I’ll add it to my short term list. I have a 160 t-stat in my roadster and it takes a long time to warm up, but it’s a different setup. Heck, sometimes in the late fall, I don’t think the t-stat ever opens.

 

Were the fan clutches ever a problem with the 521/L16? The roadster guys usually remove it and bolt the fan directly to the water pump shaft.

 

Carpartsmanual doesn’t show a clutch anywhere, so I’m assuming these trucks never had one. One less thing to worry about.

 

On an unrelated topic, I went to put the new exhaust on the wife’s car tonight and found that the cat pipe had the flange broken clean off of it. So now it’s looking like a manifold-back exhaust. I hate cars sometimes.

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Yesterday I had some time after work to take a look at the thermostat. Promptly broke one of the bolts off...just like everyone else. I had a pretty good amount of stud left to grab onto, and tried putting some heat to it (which doesn’t really work with water-filled aluminum), and managed to get it out. Whew! The PO had a brand new 180 degree t-stat and gasket so I went nuts with a 1/8th drill bit and reinstalled.

 

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:lol: You only needed one hole, the idea is to let just enough of the warm/hot coolant out of the head to get to the thermostat to open it.

You may have drilled to many holes, it might take a while to warm up now, I really don't know how that will work, maybe it will be like having a real bypass as that bypass hose is actually quite large also.

Let us know how it works, pay attention to how fast the temp gauge needle rises, is it slower to rise than it was before?

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