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It might be cracked. Not from the trans guy but from heat cycles.
Broken rear exhaust manifold bolt
- Thread starter Jjbiskup
- Start date
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Did he replace the broken stud, or is the vehicle limping along with one of 'em missing?
Does this vehicle use the usual "donut" gasket between manifold and pipe? They don't last long if not properly tightened.
Machine shop to have it planed flat and smooth. This can be done on a milling machine (expensive) or on a gigantic, glorified "belt sander" (less expensive, not as nice of a finish.)
That's IF the manifold isn't already cracked, and IF you use the manifold-spreaders before you loosen the bolts.
www.amazon.com/Lisle-13000-Manifold-Spreader-Chevrolet/dp/B0009OR94W/ref=sr_1_1?crid=1FR0UQ7CI4PIGsprefix=exhaust+manifold+spreader%2Caps%2C138&sr=8-1
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You'd need two of these. They stay in place the entire time, from before the manifold-to-cylinder head bolts are loosened, until the bolts are torqued.
Without the spreaders, the manifold warps so that the ends twist toward the middle, and then you can't get the bolts through the manifold and lined-up with the holes in the head. This is so common that there was a time when GM cast a reinforcement bar into the manifold to prevent warpage in that direction...but they didn't do that on these vehicles.
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If you buy a "new" manifold from Dorman, or some other aftermarket supplier, you can expect to need to have it planed flat and smooth at the machine shop, and you may need to do some "porting" of casting flaws in addition. Here's an iron booger inside a Dorman BBC manifold.
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Pretty sure its not cracked, its missing a bolt. Ill get some pictures tomorrow.
he drilled out the broken stud and put a piece of allthread with a nut on either side of the flanges.
Yeah im pretty sure the donuts are shot too. Should i just go ahead and put shorty headers on or would that require egr modifications (or delete)?
In general, "allthread" is the shiitiest, weakest steel on Earth.
Kinda tells me he used "allthread" because he drilled off-center and screwed-up the female threads in the manifold, so he couldn't put a new stud in place.
When that was me, I used long bolts, rather than allthread and a nut on both ends. The bolt is much better steel than "allthread".
This is a TBI, not a Vortec...right?
TBI doesn't need anything special to keep the EGR functional. Vortec does. TBI might need AIR fittings, though. My '88 K1500 5.7L has an AIR pump, with fittings on both shorty headers to supply air to the exhaust stream. If you have an AIR pump, you'll need headers with AIR fittings. Otherwise, no.
Be sure to clean-out all the remains of the donuts. It's no fun. I burnt-up a pair of donuts on my Edelbrock Tubular Exhaust System (TES) (Shorty headers) because the "stainless steel" headers had mild-steel flanges, and the flanges rusted to death. I had to install new flanges along with the new donuts.
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The bolts I had on hand are too long, so there's some larger nuts being used as spacers.
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If you're lucky, you can get vice grips on it after the manifold has been removed. Heat and quench with penetrating oil, wiggle, repeat ad nauseum.
Correct it is a 94 305 tbi. So for the shorty headers they should just bolt on and its done? No o2 sensors or anything right? Im pretty sure the 02 sensors are both in the Y pipe. If thats the case i might just do that.
Ive heard that the spark plugs are harder to remove with long tube headers. Would that be the same case with the shorty headers?
Also yes he drilled out the stud in the flange along with its threads. Would i be able to weld a new stud in there. Im pretty sure its cast iron but just wondering if anybody has done it.
Also if i run long tube headers my check engine light would come on correct? Unless i build a whole custom exhaust for the long tubes to include 02 sensor ports.
Do you have more than one O2 sensor? My '88 uses one in the left-side manifold/header.
If yours are in the Y-pipe, then header selection becomes easier. If you don't have AIR, header selection is even easier.
Headers generally make spark-plug access, and plug-wire clearance more difficult. Be careful. (I got lucky that way--my plug access is better than stock!) Maybe need heat-shielding on one or more plug wires. They sell fabric sleeves for exactly that purpose.
If yours are in the Y-pipe, then header selection becomes easier. If you don't have AIR, header selection is even easier.
Headers generally make spark-plug access, and plug-wire clearance more difficult. Be careful. (I got lucky that way--my plug access is better than stock!) Maybe need heat-shielding on one or more plug wires. They sell fabric sleeves for exactly that purpose.
So would shorty headers be better as a drop in fit? I know long tubes give you more hp but require a whole custom exhaust and o2 attachments ontop of that.
i dont really care for the hp factors. Just want my truck to look good sound good and be reliable.
Also if i do decide to do a true dual exhaust have you had any luck with using high flow cats, or o2 sensor spacers after a cat delete?
How
Many
O2
Sensors
Does
Your
Truck
Have
?
Where
Are
They?
Many
O2
Sensors
Does
Your
Truck
Have
?
Where
Are
They?
