Hey padres, upon inspecting under my hood, looking for my exhaust leak, I discovered a few manifold bolts which have been decappitated. Could this leak be leading to my hard and extremely rich starting? And how hard are these suckers to get off to put on new gaskets and get out the old studs? Mainly on the passenger side. Do I gotta rip half the motor apart to get em out? Thanks, Mike

Just got my new Weld rims today....look f*ing awesome.

 

That's factory
Doesn't mean it's right.
Remove all the bolts you can, slip over headless ones.
Remove the headless ones, replace with wrecking yard obtained manifold bolts.
Works fine.
Use Manifold gaskets, new.

 

They're not that hard. I pulled the passenger side (the hard side) and put a gasket on in a few hours time. The driver side is easier.

Oh, and there aren't any gaskets on there from the factory but you can put aftermarket gaskets on.

Also, that shouldn't cause a hard start. The exhaust leak will affect the oxygen sensor, but since a cold start is considered "Open Loop", the ECM isn't even looking at the oxygen sensor. I suggest you hook up a fuel pressure gauge and see if the system holds rest pressure.

 

Anyone have to drill out the bolts? If so what did you
use to get in there?

RBob.

Who has bolts broken off flush w/the head.

 

On my 1985 example, this is the way it came.
Really.
Stupid as it sounds.
And no exhaust gaskets, as the engine left the factory.
Once the headless bolt is accessable, put a vise grip on it, twists/comes right out. Mine were really that easy.
When I went to the yard, to get another set of manifolds, I removed all the the proper bolts from several wrecking yard engines.
My exhaust manifolds I went to look for (to replace my original cracked manifolds), I found on the ground, already removed from a car.
$20 later, I was out.
The bolts are 10mm heads.
It's the exhaust pipe bolts (15mm) ya soak for several days.
The engine manifold bolts? Spray often and then drive. Heating of the lubricant on the bolts may assist in easier removal.
But you will see some underhood smoke, which disappears, shortly.

 

The problem is that the bolts are broken flush/recessed
in the head. I used another bolt and inserted it into the
manifold hole to gauge the depth.

On the pass side there is very little room. I really do not
want to pull the head. I'll put a 3.4L crate motor in before
I do that (g).

RBob.

 

Soak them for a few days before attempting to remove.

 

I agree with Brian about soaking them for a few days before working on 'em. When you wake up in the morning, spray them. When you wake up to go to the bathroom at 2:00am, go outside, and spray them (with penetrant, of course).

I also agree with ked on using vise grips. I've come across broken exhaust manifold bolts from three different 2.8 motors; mine, the http://www.geocities.com/tomp_3rdgen swap motor, and the spare set of heads in the basement. With the bolts that weren't snapped flush with the head, I removed them with some liquid wrench, which only sat for about a minute, and a pair of vise grips.

I think the majority of these broken bolts break because the head snaps off. I also think, because of the ease of the vice-grips, that when a manifold bolt is hard to remove, it's because the head or shank has rusted to the manifold- NOT because the threads have rusted to the head. Try a reverse-direction drill bit, maybe the old bolts will unscrew themselves from the head. (NOT the same as an easy-out.) If nobody locally carries them (remember you're drilling a STRONG 10.9 bolt), http://www.eastwoodcompany.com has a few for sale.

Don't re-use old exhaust manifold bolts! Score new ones! Remember that these bolts are metric, you can't use standard ones. The bolts should have "10.9" (metric equiv of grade 8) stamped on the top. Dammit; I thought I had the specs on this site... shoot, they're gone. (I guess the message was too old.) I'm 99% sure that they're x70mm and x40mm lengths. Can't remember the width or the thread pitch... oh, wait, no, M10...... yeah, that's gotta be it! That looks familar. (The brain is working!) M10x70mm and M10x40mm. See if the local Pep Boys has those.

Home Depot has no metric 10.9 bolts... neither does Lowe's, or the local hardware store- I checked Pep Boys last, and sure enough, they had 'em. Bring an old bolt with you just to make sure. I dragged my selection out of their "open" hardware bins; problem is, the jerks didn't organize their bins, so the bolts were all over the frickin' place. Took me a good hour to locate enough. The pre-packaged ones are easier to find but cost more. Slather them up with a TON of anti-seize.

While you've got the manifold off, remove the donut between the manifold and y-pipe. See the sharp transition between bore size inside the donut? Take a metal file to that ridge, and smooth out the inside of the donut. You'll feel an extra kick when you take the car for a drive.

 

Oh, the thread pitch on the M10 is 1.50 ...

 

I found the bolt sizes from another one of your posts (TomP).

To prevent future problems the sizes are:

M8 1.25 x 40 mm short bolt

M8 1.25 x 70 mm long bolt

An yep, PepBoys has 'em, 49 & 99 cents each. With 10.9
stamped on the head.

Thanks,

RBob.

Oh, and while you are there get some flat washers for
under the bolt heads!

 

Thanks for reposting that info; sorry about botching the thread pitch from "memory". Don't forget the tube of anti-seize!