My 1971 521

[wayno]

The one on the right in Mikes photo is still better than most headers, but the one on the left is the one I was talking about.

I have had a header on my work truck since the mid 90s, the last 2 headers I used were/are made of a thicker metal, the last one I replaced didn't leak, but would not fit the chassis I used.

All the headers before them last couple ones I used/am using leaked within 3 years, I would fix them and they made it 2/3 more years and were then replace with another new one, they all leaked in the middle where the 4 tubes come together, I had to cut them just past the tubes, weld them back together on the inside, then weld it back together where I cut it apart, then reinstall it.

They also make noise, the one I have now sounds like an exhaust leak at lower RPMs but it has no leak, it is annoying sometimes.

The best exhaust manifold is the pre smog L16 version on the left in the photo.

[d.p]

4 to 1 minus the emissions/air pump crap.   Nothing special.

[d.p]

Cam someone recommend a car/truck cover?  Need something to cover this bitch with when it sits for a while.  

[mrbigtanker]

2 hours ago, d.p said:

Cam someone recommend a car/truck cover?  Need something to cover this bitch with when it sits for a while.  

California car cover

 

I have one for my truck.

 

[d.p]

Which one did you order?  

 

I see small car 157 x 65 x 47H ...would that work?

 

 

[mainer311]

Build a garage. You’re welcome.

[d.p]

24 minutes ago, mainer311 said:

Build a garage. You’re welcome.

 

I got one mfer.  Just not big enough to fit 3 cars. 

[mrbigtanker]

4 hours ago, d.p said:

Which one did you order?  

 

I see small car 157 x 65 x 47H ...would that work?

 

 

Call them they made a custom one for me. Fits like a glove.

[Steve240z]

Ray

Do have any pictures with the cover on the truck?

Thanks

[mrbigtanker]

9 hours ago, Steve240z said:

Ray

Do have any pictures with the cover on the truck?

Thanks

some where is my thread. i will try to post one tonight.

[mrbigtanker]

https://www.calcarcover.com/CoverDesigner/ChooseCover

 

Its been a while but I put 73 Nissan 620. Same thing though. This link should get you there.

[d.p]

On 8/29/2018 at 8:07 AM, mrbigtanker said:

https://www.calcarcover.com/CoverDesigner/ChooseCover

 

Its been a while but I put 73 Nissan 620. Same thing though. This link should get you there.

 

Ok so they didn't make you one custom to a 521, you just ordered one from them for a 73 620 which works just fine?  

[datzenmike]

If you have the stock engine or another L16 you probably have the right cast exhaust. The air pump tubes can easily enough be removed, but if you do.. take them right out not cut them off and fold them. Those pipes go in almost to the valve so removing them is a good idea.You can put pipe plugs in the holes or just weld them up. You will still need the twin onto one down pipe to connect to your exhaust.

[mrbigtanker]

15 hours ago, d.p said:

 

Ok so they didn't make you one custom to a 521, you just ordered one from them for a 73 620 which works just fine?  

Yes it’s been so long I could not remember 

[mainer311]

22 hours ago, datzenmike said:

If you have the stock engine or another L16 you probably have the right cast exhaust. The air pump tubes can easily enough be removed, but if you do.. take them right out not cut them off and fold them. Those pipes go in almost to the valve so removing them is a good idea.You can put pipe plugs in the holes or just weld them up. You will still need the twin onto one down pipe to connect to your exhaust.

 

FYI, the thread size for the plugs is M14x1.5, which also happens to be a common thread size of oil drain plugs. I put aluminum washers under the heads and then cranked down on them pretty good.

[d.p]

On 9/1/2018 at 8:48 AM, mainer311 said:

 

FYI, the thread size for the plugs is M14x1.5, which also happens to be a common thread size of oil drain plugs. I put aluminum washers under the heads and then cranked down on them pretty good.

 

I tried to back those nuts out and the sides of them collapsed.  They are so far gone at this point. 

 

I would love to remove them but not looking to battle those 4 nuts in frustration...especially with the manifold still on the truck. 

Edited September 2, 2018 by d.p

[datzenmike]

They are soft to begin with or the millions of heat cycles soften them. Just twist them out anyway. The tube inside continues almost the length of the port and it's worth getting it out.. The threads in the manifold will still be good. Then get pipe plugs or allen wrench plugs...

 

 

No, I don't remember the size. I think it's a metric pipe plug. Cut the pipe off short so you can get a proper socket on them and they should come out. Try running the engine to heat the manifold. Take the fitting to a hardware store and match it to something.

 

 

[d.p]

Mainer said they are M14x1.5 and I think datsungatherer said the same thing.  Trust me I would like to get them out but at this point it will turn into a multiple day job and its just too fucking hot and humid to mess with them now.   

[mainer311]

The reason they’re not tapered threads is because the nut bottoms out when the bubble flare compresses on the inside of the manifold.

 

Mine didn’t come out easy either. I hit them with a MAP gas torch first.

[d.p]

1 hour ago, mainer311 said:

The reason they’re not tapered threads is because the nut bottoms out when the bubble flare compresses on the inside of the manifold.

 

Mine didn’t come out easy either. I hit them with a MAP gas torch first.

 

Did they collapse as well?  You do it off or on the truck?  My problem is my manifold to exhaust bolts are rusted to hell so even if I wanted to take the manifold off I would have to fight those bolts as well.  

[mainer311]

None of it was easy. I snipped the tubing out first, that way I could get a 6-point socket down onto the nuts. Once they were all loosened, I knew I could get them out, so at that point I pulled the whole manifold.

 

I had the same problem as you: the studs holding the exhaust down pipe on were all rusted, so the reason to pull the whole manifold for me was to fix that. I got lucky and 2/3 of the studs came out. I managed to get the 3rd one out with a lot of heat. 

 

While it was out, I finished plugging the manifold, and then sprayed it with high-temp paint.

Edited September 2, 2018 by mainer311

[d.p]

I saw this stuck nut tool on instagram, its like a crescent with a point inside it, so you crank it down on the stuck nut and it splits the nut in half.  Think that would work on those exhaust manifold bolts?

 

https://cratecrowd.com/collections/all/products/splitter

 

And I stripped and painted my tail light surrounds black.  Also discovered how fragile the inside of the lights are, especially the white plastic dividers between the brake and reverse lights.  Did the headlight surrounds come with black accents on these trucks?  I see some NOS ones with the black squares painted black but don't see it all on any trucks today. 

 

And my throttle seems to stick, weird cause I have the return spring on it but its either lost its ability to spring back or something is sticking.  

 

Edited September 12, 2018 by d.p

[datzenmike]

Clean the head threads and replace the studs with stainless steel. They aren't as strong but are stronger than rusted ones snapping off. Use a little anti seize on the nut ends.

 

If Nissan didn't paint the surrounds black.... they should have. It looks great.

 

I think I lined my light housings with aluminum foil to reflect as much light as possible.

[mainer311]

You can fill in the accents with Testors model enamel and let it dry while laying flat. The accents are supposed to look like a continuation of the center grill. Paint 'em up!

Edited September 12, 2018 by mainer311

[d.p]

Yeah looks like it: