Replacing exhaust heat shields

#1

My next project will be replacing the exhaust heat shields. They have almost disintegrated (I hope this doesn’t indicate another problem such as a very lean mixture). This morning I tried to remove the exhaust manifold. I was suprised how easy the studs and bolts came out, with two exceptions. Two studs remain in place, the bolts came off very easily. I’m thinking that if I was able to get all the studs out, there should be sufficient flex in the exhaust system for me to slide out the old head shields and gaskets and slide the new ones in.

I’ve a bit reluctant to try and use vise grips to remove the remaining studs because given my relative lack of experience I am likely to screw it up. I picture myself damaging the threads on the studs and not being about to get them out (I do have replacement studs and bolts).

Do I need to remove the bolts holding the more distal portion of the manifold from the exhaust pipes? This would seem to allow for easier manipulation of the manifold, but may be more work than is necessary.

Thanks!

Andy

#2

Andy, your post is confusing. I mean beyond using med school words like “distal”. Don’t remove your studs, remove your manifolds. And if you do need to remove a stud, put two nuts on it and work one against the other.

To replace the exhaust manifold gasket, which is your heatshield, remove the nuts on the studs that fasten the exhaust manifold to the head. The studs are not supposed to come out, but if they do, it’s not a crisis.

Then remove the nuts that fasten the manifolds to the downtube. Remove the manifold, clean all the surfaces a bit, and then put in new gaskets everywhere. Yes, at the downtube too.

All the nuts in this effort are nonstandard. They’re made of copper or something that looks like copper. Always try to use new fasteners if you can.

The downtube nuts can be tricky. They have a habit of loosening up, and you’re likely to find non-standard size nuts there which gets confusing when you’re trying to put a socket on a nut that you can’t see. They’re supposed to be 14mm IIRC, but my car had a smorgasboard of nuts. Downtube nuts have a habit of loosening up so try to use new nuts and give them a bit of extra torque.

#3

Ranger wrote:

[quote]Andy, your post is confusing. I mean beyond using med school words like “distal”. Don’t remove your studs, remove your manifolds. And if you do need to remove a stud, put two nuts on it and work one against the other.
[/quote]

I’m so used to using terms like “distal” I don’t even give a second thought any more. Most of the guys who are on the Lemons team are also physicians so it tends to be the way we talk about engines anyway!

The studs came out with the nuts, with two exceptions. I do have a fresh set of studs and nuts that I bought when I got the heatshield/gaskets. What I didn’t get were the gaskets for the manifold/downtube connection. I guess I need to get a set of those too. How critical are the heatshields. Would it be ok to run a couple of track days without them? I’m running short on time and I’d hate to have the car non-functioning for my first HPDE.

I wasn’t sure if I had to remove the whole manifold or if there was enough flex in the system to get done what I needed. Should I put anti-seize on all the nuts? I’ve been so used to putting locktite on everything, but I read somewhere that exhaust nuts were different.

Thanks for all the help!

Andy

#4

I would go ahead and remove the exhaust from the exhaust manifold. I would also purchase new nuts and gaskets for that. I would put anti-sieze on any bolt/stud that involves the exhaust system. The nuts used are actually a lock nut in that the end of the nut is oval sized and they are technically one time use nuts, so you might want to order a bunch while you are at it.

#5

Understood distal. I just did this and I left the manifold connected to the exhaust. If you don’t have any leaks from the manifold to downtube, no reason to break it apart. You should have plenty of room to move it over to the side and hang it with a piece of wire (coat hanger).
Ed

#6

King Tut wrote:

Is there a type of anti-sieze that can tolerate prolonged exhaust temps?

OP: If, per edavidson, you can pull the manifolds away from the head while leaving the downtube fastened, that would be the easier way to do it.

The heatshield protects the plug wires. You could probably survive a DE without them, but you might want to fasten a piece of sheet aluminum or something underneath the plug wires.

#7

Ranger wrote:

[quote]
OP: If, per edavidson, you can pull the manifolds away from the head while leaving the downtube fastened, that would be the easier way to do it.

The heatshield protects the plug wires. You could probably survive a DE without them, but you might want to fasten a piece of sheet aluminum or something underneath the plug wires.[/quote]

I spent two hours this morning trying to get access to the nuts on the underside of manifold. A couple are easy the rest seem to be impossible to get either a socket or a wrench on with enough room to actually turn the wrench. I’m sure this is probably much easier than I am making it, but I’m buggered if I can figure it out.

If I can’t get it done I will probably do what you suggest and put some aluminium foil between the manifold and the plug leads.

#8

It’s all in the tools. The link below is to a gearless 3/8th ratchet. It’s my favorite tool. It’s not only small but because it’s gearless you get a lot of socket turning for whatever room you have to move it’s handle.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=98750

Another thing to try is a “wobbly” socket extension. The don’t give you as much angle as a U-joint, but some wobblies are nice and short and that might work too.

Those nuts are 12mm. Have you tried a 1/4" socket set to get to it?

Take heart, what you’re doing is easy with the right tools. Head down to Harbor Freight or Northern Tools with your credit card and buy everything that catches your eye. It’ll all get used soon enough. It’s a lot better to waste $30 on a tool that you never use, then to spend hours in frustration beating your head against a hot afternoon wall.

#9

The right tools are the key! I used a combination of a u-joint and a wobble extension and was able to get off all but two of the nuts. I did manage to round off a couple of nuts but I was able to get them off with my handy dandy Sears nut removing kit (currently my favourite tool as I am great at rounding heads). I went to Lowes and picked up a 3" wobble extension which I think will help me get to the last two. That will have to wait until the end of next week when I have time again.

I was changing the oil at the same time and I found it easier to access the underside nuts with the oil cooler lines and oil filter removed.

Thanks for all your help!

Andy

#10

I can’t recall exactly what I used when I did this last. To my sorrow the truth is that I’ve done it so many times in the last 14months that my brain is on autopilot now for much of it.

That being said, I think that the 3" wobbly extension will get the outboard nuts, but not the inboard pair that are nearest the downtubes. 3" might be too long of an extension. I think that I used the 3/8th stubby with no extension to get those. The head of the stubby is small enough it can fit most anywhere.

#11

I used a stubby open end wrench for the tough-to-get-to ones.
Ed

#12

edavidson wrote:

[quote]I used a stubby open end wrench for the tough-to-get-to ones.
Ed[/quote]

I’ve been reluctant to use anything other than a ratchet because I’m awesome at rounding off the nuts. I’ve only got two more to do and hopefully I won’t have to do them again!

#13

A couple yrs ago I read a study re. “penetrants”. As in “I can’t get this nut off, so I’ll spray some of this stuff on it and see if it loosens up”. The stuff that did the best in the study, better then all of the marketed products by a significant margin, was a 50-50 mixture of acetone and ATF.