The exhaust gasket on my 1988 Formula is blowing - and yes, it's on the forward (firewall) side. So I've looked at some of the essential reference posts on the subject - like Jetman's guide at https://www.fiero.nl/forum/Forum2/HTML/065384.html , and various others.

I haven't yet been able to remove the cat and get a good look at how the manifold is fixed. Visibility isn't great, and the heatshields and other stuff are in the way. But I have read the warnings about how difficult it is to undo the bolts, and the risks of snapping them, and I'm trying to prepare all the parts before I start.

Now here's the question that's confusing me: bolts or studs? Are the manifolds fixed to the cylinder head with bolts, or with nuts on to studs? I've read references to Rodney Dickman's set of replacement studs (but they're no longer available). And the Fiero Store lists both a "correct GM style" Exhaust Manifold Stud Kit (p/n #88100) of 12 studs and nuts, and an "Exhaust Manifold Bolt" (p/n #69843). So what is there at the moment, and what should I be ordering as a contingency replacement? Am I right to assume that the OEM installation is with 12 bolts, but that people prefer to replace these with studs and bolts when they have the opportunity?

And at the risk of straying into another topic, does anyone have views or experience on using the stock Felpro replacement gaskets which come as a pair (three joined together for each side) , versus the suggested alternative - which I think I saw on this forum - of VW 'Beetle' gaskets. The FelPro ones are expensive to order for UK delivery, whereas the VW ones are easily found and very cheap over here! So unless anyone advises strongly against them, I'm thinking of using the VW ones...

br1anstorm

GM used bolts as stock fasteners with (IIRC) the exception of two on the back side to hold the shield on, those were studded bolts. A small trouble mirror is invaluable to help see what is on the firewall side. I got an "el-cheapo" trouble mirror on an telescoping gimbal mount, perfect for getting into those tight areas.

The advantage of studs is that you can easily remove stubborn nuts later with a cold chissil and a sharp blow with a hammer, split the nut, it comes right off. I will confess that I did use a standard hardened bolt under my alternator bracket, was being lazy, didn't want to loosen it.

Your call on the VW gaskets, if they're inexpensive for you that may be a very good option.

Thank you for the compliment, it's gratifying to know that I can pass along my experiences.

Research all available on this.. when you do not need the car,, the nite before soak soak the bolts itis difficult to soak the lower bolt..you can fasten a retainer to hold the pennetrant ,,curved plastic clued to flange which holds fluid in a small pool that will seep into threads,hopefully some of the bolts have been removed by a previousowner (sure!) chck them easy just a firm pull to see if the bolt will loosen.. you want a perfect angle pull so there is no angled stress on bolts,try them after an evening soak see if a few of them will come loose..it will be great if all come loose easily it means you have led a pure life and soon your life will be blessed broken bolt should be carefully center punched,and drilled with a top quality small bit first to assure center hole , I broke 3 on the front one is still welded in place ,ifyou use a eazy out of any sort drill largest hole possible,,easy outs break easily ,,ifyou break more than 2 bolts on the front unless easy to get to.. you will have to remove head
P Bblaster or liquid wrench is best.
when you break a bolt you can drill a hole all the way thru the bolt and spray penetrant to end of bolt ,, some bolts are so stuborn you can thread the broken bolt,not easy better to remove head.
the V W gaskets ?? I am going to use them
what ever gaskets you use if you install new valve seals use fel pro seals...any fel pro gasket would be great or a GM
the stud kits are the way to go ..if there is a Saturn dealer near you they have an exhaust stud that is perfect for the Fiero ,, these are metric so you should be able to find a suitable stud or bolt in england..you can use regular harden steel bolts just put heat resistant coating on to resist rust and corrosion.. the single best modification you can make to a fiero 2.8 V6 is to port the exhaust manifold !!cut the excess weld away and cut down the staintless steel pipe that sticks up blocking exhaust flow the,,makeport smooth just like the first exhaust port you will understand when you see this ,,then weld outside flange so pipe does not leak... the Y pipe needs to be opened up and the obstruction cut away

[This message has been edited by uhlanstan (edited 08-29-2008).]

Thanks to both jetman and uhlanstan - for the advice and the warnings! First task for me then is to get one of those inspection mirrors...

Meanwhile my search for info has turned up a couple of really useful articles on the NIFE website at http://www.fierofocus.com/ . Jetman, looks like you were almost right about the manifolds being held with bolts but with a couple of special studs on one side. In Ron Dittmer's article he says

"Always replace all bolts with new ones when replacing the gaskets. Manifold bolt selection is critical. Considering both manifolds, you will need nine bolts, GM part number 11509843, and three bolt/studs, GM part number 373928. If you buy "off the shelf" bolts, the "hardness" code number on the head of the bolts should be a minimum of 9.8 like the factory originals, as a lower number is a softer material which will encourage bolt stretching, eventually breaking or loosening the bolt over time. It is also easier to twist off a softer metal head during installation, as well as breaking a stubborn bolt during disassembly. A lower rated bolt also rusts more aggressively. Standard stainless bolts are extremely soft, a poor choice. The "Y" pipe bolts can be purchased at a hardware store, with the same rules applied."

So there are nine bolts, and three bolt/studs. I've googled, and looked on GM parts websites, for those specific numbers with no success. I wonder if the part numbers have changed? Anyone out there who can provide the current (or alternative) part numbers?

I will recommend that when you reassemble that you use anti-seize lubricant on each stud. I do recommend going with the studs instead of the bolts. If you ever have to take it apart again you'll be thankful for both items. I have used both the VW individual gaskets and the GM three in a row. They both work fine. With the VW ones the studs are preferable and easier to work with.

Be careful on the GM type gaskets. The gaskets for the lower HP 2.8s (ie Blazer version) will fit , but the openings for the exhaust gases are smaller and would need to be trimmed to port size.

On the GM gaskets pay attention to the orientation of the old gasket and make sure you use the new gasket with the same orientation.

I used hardened bolts to replace the stock ones, but, on my new engine I'm using stainless studs and nuts. Enough of the rust

Arn

Definitely use studs instead of bolts. they offer twice the chance of a successful removal next time. Anti-Seize is also a good idea, but it will smoke awhile the fist time the car is restarted as the moisture burns off.

I was lucky enough to get all my factory bolts out without breaking. I used a thread restorer on the bolts and the holes. Then, I liberally applied anti-sieze before reinstalling.

The reason for my choice was i wanted stock. I like the bolt-studs for mounting the heat shields.

[This message has been edited by sjmaye (edited 08-31-2008).]