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Weber 32/36 install, exhaust re-gasket, de-smog


c4ck4

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Its been a while since I posted, almost a year since I bought my 620, and progress has been slow.  I drove the truck for a few months but then started having issues with the brakes, and it started running really rough so I parked it for a while and eventually got back to it.

 

I had vacuum leaks, exhaust leaks, and it just needed some going over.  The plan is to have it to be my daily driver soon.

 

I'm now in the middle of a weber install, de-smog, and exhaust manifold re-gasket and switch.  Currently the manifolds are off and I'm figuring out how to run all the new vacuum lines and cap some of the smog stuff (most of it was deactivated or not running when I bought the truck anyway).

 

My main hangup at the moment is trying to remove a sheared off stud.  There was some sort of fault/corrosion in the stud shaft itself and there was only a tiny bit of metal still connecting the two halves of it.  I removed the thermostat cover piece and distributor to get better access, but still wasn't able to drill it centered and after going up several sizes the hole is way off center.  I dremeled it out and drilled some more, its not quite round though and I might have to increase the size a bit and retap in a larger size, I've never tried a helicoil, maybe that's what's best in this situation.
 

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Showing the tiny bit of bolt that was still attached

 

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The broken off stud

 

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location of stud, not my head just a pic I found

 

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After some drilling

 

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Is there supposed to be that much oil in the distributor attachment spot?

 

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Looks like somebody stuck some jb weld in the EGR

 

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Here are a few shots of the old and new exhaust manifolds.  I'm still trying to figure out if I can use my old intake with this new exhaust manifold since they wouldn't be bolted together in this configuration.

th_IMG_20140829_153109240.jpg

Intake, bolt together style

 

th_IMG_20140901_121603984.jpg

old and new exhaust manifolds

 

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welded shut holes

 

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drilled out tubes

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IMG_20140829_152950886.jpg

 

Perhaps JB but they can clog up by themselves. You can plug it or remove it but what ever you do keep the PCV valve in operation.

 

IMG_20140831_124229665.jpg

 

Looks pretty gummed up,maybe not enough oil changes. That's how the distributor gets oiled so not to worry. The dizzy has an O ring seal and the gasket seals it in.

 

You could use this manifold BUT that bottom plat had better not fail and leak or you'll have a hell of a time figuring out what's wrong. I wouldn't use it. If you have ever been near a carburetor backfire ... think of a shotgun blast. The cover might blow off. Run a '78-'80 L20B intake it has larger runners than the L16/18 and doesn't have that cover to the exhaust on it. OR run the L16 intake as it only has the PCV valve and no EGR manifold bolted to it.

 

IMG_20140901_121603984.jpg

 

Left is a '75-'77 L20B intake. These years they were bolted together and used exhaust heat to warm the intake. Trouble was it warmed too well. Earlier and later exhausts used engine coolant in the intake runners. It warmed when the air was cold and removed radiated heat from the nearby exhaust. This kept the intake air at a more constant temperature and the engine was easier to drive, easier to tune, gave better mileage and lower pollution.

 

 

IMG_20140831_143113041.jpg

 

The trick here is to center punch exactly in the middle and keep checking until well started. Once you have a small pilot hole work up in size until almost into the threads. The larger the hole the less metal holding on and the larger the easy out you can use without snapping it off.  Next time....

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IMG_20140829_152950886.jpg

 

Perhaps JB but they can clog up by themselves. Besides it's way easier to simply pull the hose off to disable the EGR. You can plug it or remove it, but what ever you do keep the PCV valve in operation.

 

IMG_20140831_124229665.jpg

 

Looks pretty gummed up,maybe not enough oil changes. That's how the distributor gets oiled so not to worry. The dizzy has an O ring seal and the gasket seals it in.

 

You could use this manifold BUT that bottom plat had better not fail and leak or you'll have a hell of a time figuring out what's wrong. I wouldn't use it. If you have ever been near a carburetor backfire ... think of a shotgun blast. The cover might blow off. Run a '78-'80 L20B intake it has larger runners than the L16/18 and doesn't have that cover to the exhaust on it. OR run the L16 intake as it only has the PCV valve and no EGR manifold bolted to it.

 

IMG_20140901_121603984.jpg

 

Left is a '75-'77 L20B intake. These years they were bolted together and used exhaust heat to warm the intake. Trouble was it warmed too well. Earlier and later exhausts used engine coolant in the intake runners. It warmed when the air was cold and removed radiated heat from the nearby exhaust. This kept the intake air at a more constant temperature and the engine was easier to drive, easier to tune, gave better mileage and lower pollution.

 

 

IMG_20140831_143113041.jpg

 

The trick here is to center punch exactly in the middle and keep checking until well started. Once you have a small pilot hole work up in size until almost into the threads. The larger the hole the less metal holding on and the larger the easy out you can use without snapping it off.  Next time....

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Thanks Hainz, I did watch part of that video already, but I skipped around.  Thanks for the link to the complete thing, I kept jumping back and forth on the youtube videos.
 
Datzenmike, the exhaust I was planning on using is the one on the right, I think its an L16 manifold?  As far as the intake, you're saying I COULD use the one that I have but I'd want to seal up the exhaust port really well?  I have a U67 head btw, so I don't seem to have any coolant channels coming out of the head near any of the ports.
 
Sadly, I did center punch as good as I could, of course the surface is never flat so it was probably off a bit.  The hole appeared centered, but as I went up in size it drifted further and further off center.  I reamed it pretty hard and destroyed a few dremel bits, at that point the hole was tapered, bigger at the opening than deeper in.
 
Today I attacked it some more with a better drill bit.  I wish I'd had some scrap aluminum or something around, but the hardest thing I could find was a scrap of black walnut.  I drilled a guide hole in the wooden block and lined it up over the messed up bolt and hole.  I filled the hole with WD40 for cutting fluid and went to town on it.  The problem was that the drill was grabbing a lot harder on one side (duh) and so it kept seizing and eventually wore the guide hole oblong.  Even so I got all of the old stud out and was able to retap the hole oversized, but it was unfortunately slightly crooked because of the soft guide block, so the stud is now at a slight angle.
 
I wanted to use a solid threaded insert (EZ Lock style) to keep all the bolts the same size, but the tap size for the insert was getting pretty big, and the water jacket where the thermostat housing attaches is pretty close to the hole and I didn't want to risk busting through.

 

1.jpg

Guide block setup

 

3.jpg

Shiney new threads

 

2.jpg

The stud at an angle :(

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Datzenmike, the exhaust I was planning on using is the one on the right, I think its an L16 manifold?  As far as the intake, you're saying I COULD use the one that I have but I'd want to seal up the exhaust port really well?  I have a U67 head btw, so I don't seem to have any coolant channels coming out of the head near any of the ports.

 

 

Yes the right one is a much better choice. The U67 head can very easily be converted to run coolant into the intake runners. This is a much better set up than the stock U67 head had. Just drill two 3/8" holes by placing the correct gasket on the head. The two holes are already there for a guide.

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I bought a matching flange from mklotz, and Eagle Adam gave me an old Y pipe, but it's in poor shape, I think I'll just show them and say "make this".

 

I'm not sure where I'm going to find and intake yet though. Craigslist and classifieds on here doesn't seem to have much.

 

I like the idea of converting to coolant run intake like datzenmike said. Thanks for suggesting, I had no idea you could do that.

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Intake?

for what Yoiu can make your work.

I gave Ted about 4 L16 intakes. But since you have a L20 head the L16 intake poerts need to be enlarged to match better.

 

I don't understand much about the specifics of how the intake pre-heating functions.   So I can run my current intake as is without pre-heating from either being bolted to a matching exhaust manifold or without coolant lines in the intake?

 

Is the pre-heating more a matter of efficiency than basic functionality? That is its not necessary at all?

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The largest port L20B intake that does not bolt to the exhaust like yours is the '78-'80 car or truck. It has coolant in the runners and all you need to do is drill two 3/8" holes in your U67 head to make it functional. You will need the '78-'80 water pipe that connects it back into the lower rad return so it circulates.

 

Coolant in the intake helps keep the intake air temperature in a narrow range. In winter it warms the air and this helps the fuel evaporate better. In the summer it absorbs radiant heat from the close by exhaust manifold.

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I do like the idea of running an intake with coolant in it for the reasons you mentioned earlier:

 

This kept the intake air at a more constant temperature and the engine was easier to drive, easier to tune, gave better mileage and lower pollution.

 

Just so I'm clear on my options here though, If I don't have and can't find one of those intakes and need to get the truck running soon for other reasons (which I do need to) then I can just run what I've got?  Downsides are crankiness when cold, worse mileage, and maybe less consistent performance?

 

Like this:

testfit.jpg

 

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I always sit on the sought after stuffs, like early intake and exhaust manifolds, 6" Con rods, and 521 clocks. I have two heads, four intakes two weber 32/36s,  an oddball L16 block with oil cooler lugs, an extra 521 hood, 200mm clutch and collar, 200 mm flywheel, three EI dizzies, an extra 280Zx oil cooler adapter and cooler... I'm sure there's more I'm hoarding. This guy just seemed like he needed the part.

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Thanks for the thought hainz, $25 still seems totally fair for an intake to me though.  I paid $30 I think for my exhaust mani.

 

And thanks for offering from your secret stash laotsu, it'll go to good use.  More updates to come after I get everything together.

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So I got the L16 intake from laotsu (thanks) and after a trip I'm ready to keep working on it.

 

The U67 head can very easily be converted to run coolant into the intake runners. This is a much better set up than the stock U67 head had. Just drill two 3/8" holes by placing the correct gasket on the head. The two holes are already there for a guide.

 

Can I drill these holes while the head is still in place?  I'm worried about lots of chips getting into the water jacket, tips?

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Can I drill these holes while the head is still in place?  I'm worried about lots of chips getting into the water jacket, tips?

 

Yes.... just use a shop vac to suck up the shavings as you drill. One can also flush the cooling system after the fact.

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I got the holes drilled out, I followed the advice of hainz in an old thread that suggested to drill them out only to 1/4".  When attaching the coolant line to the intake, does it T into the line coming from below the thermostat housing, or does it replace that line?

 

I got a plug for one of the two holes in the new intake, but I'm not sure which to use for PCV and which to plug, one is a straight shot and the other is a right angle, would one be preferable to the other?

Finally, I tried to adjust my valve lash, but didn't have a flat enough wrench that fit the lower nut, its pretty narrow under the spring retainer wires, is there a specialty tool for servicing those?  I mean everybody has to set their valves, what's typical procedure for that?


 

Coolant holes drilled at 1/4"

1-1.jpg
 
 
What is this line for and do I tee into it with the coolant line coming off the L16 intake?
2-1.jpg
 
Is one of these more preferable than the other?
3-1.jpg
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2-1.jpg

 

What is this line for and do I tee into it with the coolant line coming off the L16 intake?

That is the thermostat by pass hose. Yes, it should be also connected to the intake hose. You need a T fitting.

 

You also need your distributor vacuum advance connected as well.

 

 

Is one of these more preferable than the other?

3-1.jpg

I would say #1. The block vent hose comes from the back of the engine and faces forward. #2 would make too sharp a bend.

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