Exhaust manifold gasket replacement, detailed with pictures. (Page 1/6)
jetman JUL 25, 08:05 PM
Exhaust manifold gaskets, lengthy, detailed with pictures at the end.

It was exhaust manifold gasket replacement time on my 86 V-6, manual 4-speed, non air Fiero. Oh yeah, everybody’s favorite task but this time I tried to think ahead (read prepared) and be smart about this. I’ll go through and describe how I went about this and include as many specifics as I possibly can for you. I performed the project in stages over several days, breaking down the job into several smaller, more manageable tasks.

Started to spray down the “PB blaster” well ahead of the job including the Y-pipe bolts. I changed gaskets many years ago, remembering that I reused several studs and bolts, not a good thing as I have learned after the fact. I have a temporary straight pipe in place of the catalytic converter, so I knew that there was room to work. If you have a cat, consider removing it for the job. My back up plan included a drill, EZ-outs and etc for snapped studs.

Just to see what I was going up against before I actually do the job, I took my 13MM 6-point, swivel head socket wrench and tightened up all of the bolts, yes, I tightened all of them. I had heard that this works to break them loose, figuring that the old gasket could still be compressed. I did have a couple of stubborn ones so I kept working them with a tap hammer back and forth, trying to use the vibration / shock value of the hammer to break them loose. I figured that this was the hardest part of the job so I took my time with this, at my leisure, a couple at a time, when I was afforded the time.

I was able to loosen all of the manifold bolts so I went ahead and ordered Rodney Dickman’s stud kit, Rodney’s phone is (262) 835-9575 and the Felpro gaskets. Felpro part number MS 93045, 173 (2.8) engine exhaust manifold set. I already had some car ramps, safety glasses, trouble light and an assortment of 13MM wrenches, sockets in 6-point, light bulbs for trouble light, shop towels, rubber disposable gloves. I worked over a big piece of carpet for comfort but I bet that cardboard would work just fine. Permatex brand hand cleaner, item number 01013, is my best friend for cleaning up my mitts afterwards!

My favorite tools used are the ¼-inch drive socket wrench, great for tight spots and studs, long 13MM box wrenches, long 3/8-inch swivel head socket wrench, deep well 13MM sockets in 6-point. I wished that I had purchased a “stubby” short 3/8-inch swivel head socket wrench for those tight spots. You may wish to make that investment, sure would have been nice to have on hand. Another tool for your consideration is an “S-bend” 13MM wrench, it was great for the manifold bolt behind the air conditioning bracket on my other car.

Disconnect the battery, be safe, use wheel chocks, jack stands or ramps and please wear those safety glasses especially under the car.

Started with the trunk side manifold, removing the Y-pipe heat shields and manifold was straightforward. Used a Dremel high speed tool and ported the manifold, there really is allot of restriction due to GM’s manufacturing process.

From past experience, while porting, always wear safety glasses, junk clothes, work outside if possible and most importantly wear gloves. Those metal slivers will get everywhere if you’re not careful. You will cut your porting job time down by purchasing a new bit, $10 bucks well spent. Dremel part number 9903 tungsten carbide cutter. Heed my warning about those metal slivers, take all precautions, they’re nasty, toss your clothes and gloves in the trash afterwards.

I prepped the manifold and mating surface with a sanding block, lightly, just enough to have a clean surface and gave it a coat of Permatex copper spray a gasket, item number 80697. I used just a slight touch of Permatex lock-tight, thread locker, item number 24206, on the studs only and replaced the truck side manifold. I’ll be honest, I’m not sure if the lock-tight is the best choice, you decide for yourself. I didn’t want the studs backing out while I still wanted the option of removal in the future if needed.

The alternator heat shield cover was in the way of the new stud so I used a bolt instead, with Permatex anti-seize, item number 81343. I’m lazy, could have removed the cover, maybe I’ll do that this weekend. I needed new bolts at the Y-pipe and I used anti-seize on those two. Y-pipe hex head cap screw size is Grade-8, M8 x 1.25 pitch and 50 MM long. “Needa” part number 005260 hex head cap screw, Qty: 2, available at the auto parts store. That took care of the truck side manifold.

The next day, I backed up on the ramps, removed the bolts, working from both the bottom and top on the firewall side manifold. The Dremmel earned its keep in a big way, I did have to cut one of the Y-pipe bolts off, man alive, what a handy little tool. I had forgot that I did have to use a bolt and a nut on the Y-pipe to manifold connection years ago. The size is grade-8, M8 x 1.25 pitch nuts, “Needa” part number 001220 hex nut, Qty: 10, matching washers and the 50MM long grade-8, M8 hex head cap screw, again using anti-seize.

After my porting and inspection of the manifold, I installed the upper studs, got the manifold up there first and then installed the lower studs. There may be a tight clearance issue with a cooling tube that is in the lower passenger side area of the manifold, you may opt for a grade-8 bolt there, however, I thought that I had enough room for future manifold removal with the stud. After the manifold was installed, I reinstalled the curved heat shield with three more nuts, anti-seize also. I have not used the big recall shield between my manifold and block in many years, only using the Felpro gaskets.

For grins and giggles, I picked up a can of Dupli-Color high heat 1200F spray-paint. The Dupli-Color item number is DH1602, black. I used that on my heat shields. I know that this is just a daily driver, just wanted to make it look cared for. Hey nothing fancy here, just degreasing prep and I sprayed away. Sprayed the deflector shields, air cleaner and cooling tubes also to make it all match in black.

The gaskets have been manufactured as one piece (per side) with three ports of which has extra material running between the ports. I chose to install the gaskets with this extra material towards the bottom half of the manifold as to not interfere with the spark plugs. I mention this because I overlooked this little aspect on my other Fiero, changing plugs is a bit more challenging.

The most important aspect of this job, in my mind, was not to try to tackle it all in one afternoon and plan ahead. Several parts of this task were done on different days and evenings. I was still able to use the car between the different stages of work. If I had snapped a bolt, I would have stopped, drilled it out, then moved forward again. Same thing if I had a cracked manifold, I had shops lined up to do the welding work in a pinch if needed.

I cannot say that this is a complete description of everything that you may encounter when you tackle this job. You may need more or less, your job may go smooth or it may not. I have done this job three times now, suffered through two nightmares, this time things went fairly well. I have carefully documented the specifics as well as I could, hopefully with this information, your gasket job will go well.

I have a couple of after thoughts for you. Perhaps I could have taken the manifolds to a machine shop to have them sanded down true and flat.
I really should have painted the manifolds also while I was at it, just didn’t think of it at the time.

I wrote this procedure up not for the green in my ratings bar, although it would be very much appreciated, but mostly for all of my PFF friends throughout the world. This is a most dreaded job, perhaps I have helped make it go better for you, if so, please email me sometime and let me know, ok?

Ok now for some pictures! I saved these for the end of the post just in case someone wanted to print the top half out with all the part numbers and information.

Exhaust manifold porting, before

and after the porting.

Exhaust manifold gaskets blown out on all four corners. Those bolts were easiest to remove, matter of fact, I believe that some had started to back out resulting in the blown gaskets.

The kitchen table at the last stage, gee no wonder why I’m still single.

Firewall side manifold. You are on your back on the ground under the car with your feet out the rear of the Fiero. You are looking up the cylinder head that I have sprayed with the copper spray a gasket to prepare the surface.

The same orientation as above, this last photo shows the manifold in place. The curved heat shield was put over this.

Whew, took almost as long to write this up as it did to do the job!
It's all worth it if it helps someone out someday.


Silver 86 SE 2M6 4-speed, with
"check wallet light"

FieroGTdude JUL 25, 08:53 PM
Nice write-up! + for you.
smartaxel JUL 25, 09:14 PM

Just like me..workin parts on the kitchen table!!

Cool write-up. I always hoped I'd never have to do it, but my 87 sounds like a sewing machine.. I"ll be doing the same soon also. Good to have this writeup!

jetman JUL 27, 11:39 PM
I recieved a bunch of questions through PM and email so I'd post some answers for everyone.

The first answer is for the wise guy! Ok, I'm a bit portly but I was able to slide under the car on standard car ramps, the oil pan didn't get wiped clean on my shirt, thanks.

I neglected to mention that I used an "el-cheepo" 5MM 6-point socket to install Rodney Dickman's studs. The studs have a 6-point "star" pattern. If, heaven forbid, I ever have to remove the studs then I will find a "star" pattern socket.

I tightened the studs down to where a shoulder is on the stud, about 5/8ths of an inch. I tightened down to where there was resistance, then backed the stud out by a half a turn and let the thread locker set up.

The starter was not in the way of the installation, the wire harness was persuaded out of the way temporarily. The temporary straight pipe was a minor pain to reach around but not impossible. Remove your cat, you'll have allot more room.

This was a good question. "How does the car run now?" Quiet, no ticky, ticky, tick! The idle is bit lower now and the ECM drops the idle down to 950 rpm at stop lights much faster than it did before.

Another question. Horsepower improvement from the porting job? I'm not sure but it sure sounds healthy. I will judge it and get post my thoughts.

Thanks for the emails everyone, and especially for the kind words about my write up.
Tm,,,edit for spelling

Silver 86 SE 2M6 4-speed, with
"check wallet light"

[This message has been edited by jetman (edited 07-27-2005).]

sublime922 JUL 28, 01:14 AM
good write up, ill probly refer to it when i do my gaskets in a week or so, even thought ive done them before, extra ideas dont hurt.

i did notice that the new gaskets, the metal ring on the inside of the port, one side is flat, the other has a rounded edge. im not sure which edge should be facing the head and which should be facing the manifold... i think the rounded side should face the head, giving it a smoother transition into the manifold, but i might be wrong...

any ideas on this?

Jake_Dragon DEC 21, 07:18 AM
You posted a link, Im going to bump it up to put it in my favorites.
Dodgerunner DEC 21, 08:40 AM
Thanks. My front one is ticking. Hope it is just gasket also and not cracked. This will be a great help when I do mine.
F-I-E-R-O JUL 16, 10:47 AM
I need to replace mine, but I'm still trying to work up the courage to do it. If this were a straight forward replacement like something I'd face in my '77 Camaro which would allow me to practically get into the engine bay while working on it I'd have no reservations. It's 10:47 am and I need to make a choice- do I try to do this today or do I wait until I have two days off in a row...
wanobi JUL 16, 02:11 PM

Originally posted by F-I-E-R-O:

I need to replace mine, but I'm still trying to work up the courage to do it. If this were a straight forward replacement like something I'd face in my '77 Camaro which would allow me to practically get into the engine bay while working on it I'd have no reservations. It's 10:47 am and I need to make a choice- do I try to do this today or do I wait until I have two days off in a row...

Wait til you have 2 days off in a row. Nothing ever goes straight forward for me.
jetman JUL 16, 06:12 PM

Originally posted by wanobi:
Wait til you have 2 days off in a row. Nothing ever goes straight forward for me.

Yes, this is sensible.
Start preparing the area by cleaning the engine, spraying PB blaster, gathering up the tools such as 13MM wrenches, car ramps, safety glasses and etc. Try to have your back up plan in place, drill and bits just in case od the worst or someone who can weld a nut to the shaft of a snapped bolt. Some of the heat shields need to be removed, Y-pipe bolts, start spraying those down. The idea is to have much of the pleminary (sp?) work done in advance so when the "big" day comes you'll have a smoother time of it.
Good luck.

edit,,,, still trying to spell

[This message has been edited by jetman (edited 07-16-2006).]