340 Intake Manifold Heat Shield

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Peini

Peini

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Hi guys,
I need some recommendations on how to remove the heat shield of my stock cast iron intake manifold. I searched the forum and found an explanation on using a chisel under the head of the stem and then unscrew with pliers since the stems have something like a thread.

Unfortunately this did not work for me so I cut a small groove and used a screwdriver -> did not work either.
I do not want to grind down the heads since I would like to keep the stems.

Thx in advance!
Best
Chris
 
Try using the chisel on both sides of the rivet,until it lifts up... then use vise grips to turn the rivet out. They have splines that will turn out.
I used a cut off wheel , made a cut to simulate a screwdriver slot., then got my large screwdriver and turned them out. very easily came out.
Both suggestions have worked for me on two diffrent intakes.
On the intake I used a chisel on,. I tapped a new thread into each rivet hole, and lock-tited a new hardened screw into the hole to keep it from vibrating loose..
Hope this helps, sometimes those rivets are a pain.
HotRod20
 
HotRod20 said:
Try using the chisel on both sides of the rivet,until it lifts up... then use vise grips to turn the rivet out. They have splines that will turn out.
I used a cut off wheel , made a cut to simulate a screwdriver slot., then got my large screwdriver and turned them out. very easily came out.
Both suggestions have worked for me on two diffrent intakes.
On the intake I used a chisel on,. I tapped a new thread into each rivet hole, and lock-tited a new hardened screw into the hole to keep it from vibrating loose..
Hope this helps, sometimes those rivets are a pain.
HotRod20
Click to expand...

Thanks a lot, the thing with the screwdriver did not work yet. I will try with the chisel on both sides.
Just one more question: Do the rivets have any kind of thread on them?
Thx.
Chris
 
The rivet will screw out with some vice grips. You will see why when you get it out.
 
Yes the rivets are made with cutting splines to self thread and twist back out when removing.You will see when you get them out.
HotRod20
 
Sometimes you can get a pair of vice grips on them and turn them out. Another option its to use a cut off wheel and cut a flat slot in then use a screwdriver.
Dont be surprised to find a substance similar to tar under the plate or worse a solid block of concrete hard carbon.
 
Peini said:
Thank you all for your help. I will let you know how it worked.
Thx
Chris
Click to expand...
They look like this.

rivet.jpg
 
Finally managed to get at least one rivet out in one piece. I had to crush the head of the second one, there was no way to get it out in one piece.
The substance under the heat shield was as mentioned by MoparMike: solid as a rock ;-)

I will drill out the rest of the second rivet. Do you suggest to use a new rivet or should i cut a thread and use bolts?
I would like to sandblast the whole intake but use nutshell to be on the safe side. Have you guys done that and any hints? With this i also hope to clean out the hard carbon from the heat crossover because this one is almost blocked.
Thanks a lot for your help!!!

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You can leave that heat shield off. The newer '90 318 roller engines don't use them, they are designed without and work just fine.

Then you are not creating that cavity to boil your engine oil from the crossover exhaust.

Plenty of people block off the crossover with the proper gasket too. Not a problem if not driving your classic in the extreme cold.

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We used to block off the crossover with aluminum foil jammed in the hole. It worked well.
I would leave the plate off or get the correct rivits to reinstall. If you do thread and use bolts be sure to lock tite them.
 
All great advice, personal choice whether to reinstall the heat shield or not.
I drilled out the broken rivets in one of my intakes, drilled out the screw stubs,re tapped the holes, then installed new threaded bolts (coarse or fine thread,screw or hex head your choice) with Loc Tite. Done.
HotRod20
 
Many thanks to all of you for your advice. I will reinstall the heat shield with screws and Loctite.

One last question: Heater and bypass nipple are stuck is if they were welded to the intake. It is insane, even heating everything up with my torch does not change a thing. So i was thinking of welding a nut to each nipple and try loosen it with the impact wrench. Any better way to solve this problem?

Thanks a lot once more!
 
Take a new hack saw blade, attach it to a trimmed down paint mixing stick, use duct tape or whatever.. and saw the bypass nipple down the ID center. Once it is through you can split the nipple off the threads.

YES it is time consuming but, it does work and you save your intake threads without galling them up. Otherwise, you would need to re tap a new thread if you
extract that old nipple and pull the threads out with it.. Heater nipple may have to be re tapped if you muscle it out. Or cut it flush at the hole. and drill out remaining stub. Or die grind the ID out again. You still may end up re tapping the hole.
HR20
 
Why remove the heat shield in the first place? The nipples, cut it off and leave about 1/16 " or more. I then cut the nipple down through the center until I knew that I was close to the threads. Then I took a small chisel and started tapping the edge of the cut I made, until it separates the nipple from the manifold or caves it in. I had it out in 5 minutes.
 
Last edited:
Finally...thanks to your hints I was able to remove also the bypass nipple.
Unfortunately I cut a little to deep and hurt the thread on the intake but with some sealing on the new nipple it will work.

CRUZE 418 said:
Why remove the heat shield in the first place?
Click to expand...
I thought a small part the of the manifold gasket fell under the shield so I wanted to be sure nothing is underneath that does not belong there.

Thanks everybody and merry christmas!

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It's part of the learning curve. That's why I use a cut off wheel and get close to the manifold . Less nipple to saw and easier to judge the depth of your cut. You got it out, it will be fine.
 
I like to just take the meat out and try tapping the nipple to see if it starts to collapse. Once it bends/moves no more sawing. You should be fine with some sealer
 
It had been awhile since I last did this, I couldn't remember what I used to cut the nipple down the middle. I used a die grinder with a carbide diamond pattern bit. What ever it takes, more than one way to do it.
 
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