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joebarthlow

Replacing heat shield on exhaust manifold

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Later model sheet metal version. bottom two hole have rusted out, leaving the top two securing it. It rattles.

 

Seems pretty easy. four bolts. What could possibly go wrong? first one won't budge. I didn't push it as to not bust it. Second one turned about 1/4 turn then promptly snapped off. third one won't budge. Fourth one turn about 1/4 turn then stops (see the second one for possible conclusion). I now have one bolt holding it on.

 

Questions from a novice BMW wrencher:

 

Q1. Will the earlier, thicker, aluminum heat shield fit OK on the later M10 and what I believe is a stock exhaust manifold? 

 

Q2. Looks like I'll need to remove the exhaust manifold to extract the broken bolt(s). Is it as simple as it looks? Disconnect at the header and unbolt the manifold from the block? 

 

Q3. Is it worth it to extract and retap or just find a replacement manifold?

 

Q4. I don't need to pull the motor, do I?

 

Q5. besides penetrating oil on the existing bolts, any other tricks to remove the three remaining bolts without busting them?

 

 

 

 

Edited by joebarthlow

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this is another option, if you're willing to ditch the metal one.

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http://www.rogerstii.com/bmw-2002-320i-318i-exhaust-manifold-gasket-heat-shield/

 

one trick to remove the bolts is to work them back and forth, not just in the out direction.

 

order new copper plated nuts for the manifold and the downpipe

 

new studs might be a good idea too.

 

use red loc-tite in the cleaned stud holes.

 

having an AFR bung welded onto the downpipe is a fun tangent to take while it is out.

you could put a plug in it, if you are not ready to install the sensor yet.

 

check the rubber bits in the exhaust bracket that attaches to the transmission.

they get gooey when they've been oily.

 

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The E21 style heat shield works better and will not rattle.
You will need to remove the exhaust manifold to do the job.
Usually this also entails replacing some or all of the exhaust manifold studs and bolts. If the manifold has never been removed, some of the studs will need replacing anyway.


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The main reason for the 2002 style heat shield (whether the aluminum or sheet metal one) is to provide a source of warm air for the air intake (the summer/winter box at the "snorkel" on the radiator support).  The E21/E30 shield doesn't do that.   When set to "winter" it directs warm air into the factory air cleaner to prevent carburetor icing.  The thermostatic spring in the summer/winter box gradually cuts off the warm air flow as the engine warms up.  Of course if you replaced the factory air cleaner with the little foam cleaner atop your Weber, it's a moot point.  

 

AFAIK the aluminum and steel heat shields use the same bolt pattern, and yes, you'll have to remove the manifold to drill out those horizontal bolts.  If you're successful, replace 'em with stainless steel bolts liberally coated with an anti-seize compound.

 

cheers

mike

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16 hours ago, mike said:

The main reason for the 2002 style heat shield (whether the aluminum or sheet metal one) is to provide a source of warm air for the air intake (the summer/winter box at the "snorkel" on the radiator support).  The E21/E30 shield doesn't do that.   When set to "winter" it directs warm air into the factory air cleaner to prevent carburetor icing.  The thermostatic spring in the summer/winter box gradually cuts off the warm air flow as the engine warms up.  Of course if you replaced the factory air cleaner with the little foam cleaner atop your Weber, it's a moot point.  

 

AFAIK the aluminum and steel heat shields use the same bolt pattern, and yes, you'll have to remove the manifold to drill out those horizontal bolts.  If you're successful, replace 'em with stainless steel bolts liberally coated with an anti-seize compound.

 

cheers

mike

 

 

the e21 shield looks like a good option. I presume it's what '76mintgrün'02 posted above. my plug wired don't tough the shield either. I'm running a weber with a weber air filter, so no snorkel. thanks for the info

Edited by joebarthlow

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Q2: I applaud your optimism but exhaust work rarely goes as planned unless you had it all off recently. If its been on there a while prepare yourself for a few obstacles.

I removed mine last week. The 3 nuts at the manifold to downpipe would not break loose. Even after days of liberal application of penetrating oil.

Ended up having to drop the manifold and downpipe still connected together out the bottom, have to raise the car for that.

6 of 8 cylinder head studs threaded out of the head. this leaves them stuck on the manifold and you have to get the nuts off them somehow. Penetrating oil, vise grips and a good box end wrench dealt with 5 of the 6. The last one had to be cut in half to get it out.

So now I have to replace/ install new mount studs in the head and either get my manifold repaired or replaced (found a big crack)

If you get it all off don't skimp, buy new studs as required and all new hi temp nuts. Use copious amounts of ANTI SIEZE.

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I used Kroil penetrating oil and a cam operated stud remover to get most of the studs out of the head with the manifold removed. Of course some studs also came out like bolts when the bolt head was twisted. Recommend that you Spray the heck out of every fastener each day, 3 days before work.

Best penetrating oil is 50/50 mix of Dextron ATF and acetone.
This stuff is Very FLAMAMBLE. Only mix up what you are going to use and don’t leave it laying around.


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On 5/14/2019 at 11:56 PM, joebarthlow said:

Later model sheet metal version. bottom two hole have rusted out, leaving the top two securing it. It rattles.

 

When you say "sheet metal version" assuming is not the cast protective cover, which was installed on 49 state models

Regardless if it is metal or cast version recommend you use part # 07119915057. I had similar issue and these type bolts fixed rattling issue for me

238369983_ScreenShot2019-05-16at5_38_25PM.png.ba1e7284fc8ce8fd267f14a889f08078.png1126118111_ScreenShot2019-05-16at5_38_38PM.png.5428f5b6316ce8bf2eb7ea7348ab9abb.png

 

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5 hours ago, Buckeye said:

 

When you say "sheet metal version" assuming is not the cast protective cover, which was installed on 49 state models

Regardless if it is metal or cast version recommend you use part # 07119915057. I had similar issue and these type bolts fixed rattling issue for me

 

 

 

I believe BMW moved to the lighter sheet metal shields in '74. I have the older cast one to install, but that e21 option looks easy and more simple. I'll keep an eye open for the later/correct version, but they are no longer made. the challenge, now, will be removing the exhaust manifold and replacing the studs.

 

thanks for your input!

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4 hours ago, joebarthlow said:

 

I believe BMW moved to the lighter sheet metal shields in '74. I have the older cast one to install, but that e21 option looks easy and more simple. I'll keep an eye open for the later/correct version, but they are no longer made. the challenge, now, will be removing the exhaust manifold and replacing the studs.

 

thanks for your input!

 

As Buckeye said, Joe, cast aluminum heat shields returned with the 1976 49-state versions, here on my ‘76.

 

Best regards,

 

Steve

 

1DD50554-7891-4176-AF2D-F1718914B668.jpeg

02B8267B-78B3-4E7E-984C-9F67AE35C810.jpeg

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EBE7DDAD-B2F7-4578-B46C-AF87187C1439.jpeg

223EDC1F-9547-4F28-9D0C-9D01732E9DC5.jpeg

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What did the e21 do about emissions (in the US) if they didn’t have the thermal reactor, thus allowing the combined gasket heat shield?

 

Did all of that disappear again with the advent of CIS fuel injection?

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The one final option is heat...plenty of it...like from oxy-acetylene ….and if you have any stud left a good vice grip. Barring that you are in for a long day.

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16 hours ago, Conserv said:

 

As Buckeye said, Joe, cast aluminum heat shields returned with the 1976 49-state versions, here on my ‘76.

 

Best regards,

 

Steve

 

1DD50554-7891-4176-AF2D-F1718914B668.jpeg

 

 

 

that's what I just acquired. Looks good, I'll go that route, thanks, Steve!

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