exhaust manifold

[Megunticook]

I got my replacement "heat stove" last week, went to remove the two hex cap screws securing the center part of the exhaust manifold (the stove is secured with those screws), and need some advice.

I've been hitting these with PB Blaster daily for the last week. After wire brushing the loose rust off, I tried getting a 6-pt 7/16 box wrench on the first one and it's not a tight fit--seems like enough material has rusted off over the years that the cap is smaller. A 3/8 wouldn't fit.

I've rounded the corners very slightly, despite my best efforts, but it's not totally buggered yet. What's my next move? It looks like the head is maybe fused to the exhause manifold--you cannot see any seam at all where they meet.

Strangely, I took the short screw out of the front pipe (the one on the inside) and it came out with absolutely no problem.

Any suggestions? The only torch I have is propane and I don't have a welder.

I also noticed a chunk missing out of the very top front corner of the other manifold--the threads of the stud are explosed along one side. I haven't notice any exhaust leaks, but I'm a little concerned. Where can I get a replacement manifold? Is there an aftermarket manufacturer? Would dealers still have these? My understanding is that it would have to be pre-94.

[Delray Dude]

if your socket is made by "craftsman" or other lifetime tool company - try hammering on a 12 pt 3/8 socket and getting a big extension...

I usually use a floor-jack handle slipped over the end of the socket (a fence pipe or anything like it) and try to break it loose.

If it does....yee-haw.

if it breaks...well get out the drill.

I'd assume any exhaust manifold would work from atleast 87 back - i'm sure some newer ones will too.

[ramitupurs84]

I orginally thought get extensions out and a nice breaker bar. Well if he does break it, then he will have a worse problem. I would assume the threads are just one piece of rust metal at this point. I wonder how a good a easy out would be if you sheered it off in the block you will have bigger problems. I think theres a trick out there and someone just needs to post it lol!

[76D100]

do you "need" the heat stove? Is there no way you can rip the old one off and get the new one over top? if you do break that bolt off (i think its a exhaust manifold bolt) then you will have a much bigger problem.

hit it with the torch untill it wont get any hotter and try again.

this is why i would be/ am scared to attempt to get some headers for the truck... i dont want to pull my heads off right yet.

[Megunticook]

do you "need" the heat stove? Is there no way you can rip the old one off and get the new one over top?

A mechanic pulled the old one years back and it never was properly hooked up to the air cleaner before that...so I don't "need" it.

But I can't stand that cold rainy day stumbling/stalling issue that I'm pretty sure is ice in the carb throat, and the heat stove is supposed to prevent that.

And eventually that manifold gasket is going to need to be replaced anyway.

I could just leave well enough alone for now. I spent about half an hour fussing with it last night, I may spend another hour of gentle persuasion. Patience and calm, deliberate actions seem to be the key to not making the situation worse. I'll keep hitting it with the PB Blaster daily and when I get some time I'll see what I can do with it. I'm thinking maybe I can break the bond between the hex head and the manifold by tapping it with a hammer and maybe some gentle chiseling at the point where the seam "should" be (It all looks like one piece of metal now).

I'm wondering if one possible tactic could be to dremel slot across the top of the head and get a beefy screwdriver in there...if it turns out I can't get a bite with a 6-point socket or wrench.

A 1/8 or 3/16 reverse threaded drill bit might also be worth considering...

What I can't figure is why that other bolt came right out with virtually no effort, but the two center ones look like they've been sitting on the deck of the Titanic at the bottom of the ocean for fifty years...

[ramitupurs84]

After I started torquing down the fastners on my shaft for the roller tip rockers and I sheered a bolt..3 people later running vacums and etc it was out.

If he heats it up does it change the composition making it easier to break or twist off?

[acton mike]

it might be easiest to take the manifold off the engine and grind the heads off the rusted/seized and rounded off cap screws; then drill and tap to accept new fasters

If you do not feel comfortable or have the equipment for drilling and tapping then an automotive machine shop will do it relatively inexpensively

Sometimes, if you drill a pilot hole, after grinding off the heads of the cap screws and then using larger bits, make the hole bigger, at some point in the process the remains of the old bolt will become freed up and you can back it out

then you chase the threads with a tap and install new stainless fasteners

patience is the key to this process

beer does not help

[bherder]

Ya know Meg .... Before ya bust everything to shit and REALLY cause yourself a headache .....

Last time I checked (Which was a while ago) NAPA, or most other parts stores have/could get a 'universal' kinda' choke stove. It was/is basically what you got now, but is held onto the exhaust manifold with hose clamps. Not 'stock' but works.

I've had my share of removing/destroying exhaust bolts/studs.... When they've been on there a loooong time, they can be real MF's to remove.
Last time was on a 351 FURD. All it took was the ONE bolt/stud to turn your day into a giant pile of crap. Anyway, the bolt was all rusted out and snapped right off. I was LUCKY enough that it snapped off at the surface of the head... In other words, the hole in the manifold was my 'drill-guide', it was in a 'good' spot, and all it cost me was a Thermo-Nuclear-Ultra-Titanium-Diamond bit. 1/4" bit at ACE Hardware, $20.00... It drilled through the broken bolt like a hot knife through butter... A regular HS bit couldn't touch it.... Re-tapped the hole, and all was OK....

So, point of the whole story is, If you're afraid of breaking something (Especially something on the HOT exhaust side) you probably will. When you have 35+ year-old manifolds, the more you can leave them alone, the better...

So far as brand-new cast iron manifolds, YES you can buy new ones. Dorman makes them. Driver-side are easy to find... Passenger-side can be found but with a bit more difficulty. Google.
You ARE going to pay for them.... $400-500 for both sides new....

As Delray says, hope and PRAY you can beat a socket on and break the bolt loose.... If it comes loose, you just won the Lotto ... If not... You're in for a lot more work that you planned on.....

[76D100]

Ok guys....

Heating up the bolt real hot makes it expand a little bit and can aid in braking the seal with the surrounding material. Heating up the surrounding area will make the material expand on the bolt making it tighter.

Ether way at that point theres a good chance of breaking it anyway.

THEN

When you get in to the world of heli coils/ drilling out you need to be perfectly perpendicular to the work material. If your not the bolt wont sit right and you will have problems. Also taping new holes then inserting heli coils isn't always easy not to mention doing it in the side of an engine in a truck...

How cold does it get there? the only time i had real problems with my truck is around -30 and colder.

Titanic... good one!

Consider the locations of the bolts, oil spillage/ seepage... Mabe they were taken off before and had the paint damaged letting corrosion in... lots of reasons.

[bherder]

beer does not help

????????????

Since when did/does beer not help anything?

If anything, beer will make you realize... 'Ya know ... Maybe I just ought to try this tomorrow...' And then just have another beer....

Sounds like a 'win-win' all the way around to me.......


:D :D :D

[Megunticook]

it might be easiest to take the manifold off the engine and grind the heads off the rusted/seized and rounded off cap screws; then drill and tap to accept new fasters

Hmmm...I'm not picturing how the manifold is going to come off unless all the fasteners are out...

Sometimes, if you drill a pilot hole, after grinding off the heads of the cap screws and then using larger bits, make the hole bigger, at some point in the process the remains of the old bolt will become freed up and you can back it out

You're talking about drilling it with reverse-thread bits, right? I've had some success with that technique in similar situations.
install new stainless fasteners
Amen to that...I was thinking you don't need a grade 5 or 8 fastener in this particular application, my only concern with stainless is from what I understand it doesn't have the strength of a hardened steel.

I have been using stainless a lot whenever I replace stuff, with plenty of anti-seize paste.

beer does not help
You're right...better go straight to the bourbon...

[Megunticook]

Ya know Meg .... Before ya bust everything to shit and REALLY cause yourself a headache .....

Last time I checked (Which was a while ago) NAPA, or most other parts stores have/could get a 'universal' kinda' choke stove. It was/is basically what you got now, but is held onto the exhaust manifold with hose clamps. Not 'stock' but works.
Another option I guess...thanks for the tip.
When you have 35+ year-old manifolds, the more you can leave them alone, the better...
Good point. I presume these were removed when I had the motor rebuilt in '96, right after I bought the rig. Developed a nasty leak on the passenger side about 5 years back, had a guy replace the gasket, so that one was off again. But this driver side has been on for 12 years anyway. What I don't get is why that other capscrew came out with hardly a whimper, while these center ones act like they're welded to the manifold...

I think I'll keep picking away at it when I get a little time, but walk away as soon as I hear myself starting to cuss...

So far as brand-new cast iron manifolds, YES you can buy new ones. Dorman makes them. Driver-side are easy to find... Passenger-side can be found but with a bit more difficulty. Google.
You ARE going to pay for them.... $400-500 for both sides new....I wasn't having much luck with Google, although I just did a quick 10 minute search. NAPA has them for big blocks, well over $200 a piece. I'll checkout the Dorman website and see if they have part numbers...

[Megunticook]

The closest thing I found over at Dorman was this:
https://www.dormanproducts.com/cgi-bin/vm91corp30r/classdtl.p?clt=hwrap1&sid=0x00aaa65a&tid=17143&rid=0x00310c17
https://www.dormanproducts.com/images/items/hwrap1/5013748.jpg
https://www.dormanproducts.com/images/items/hwrap1/5013749-kit.jpg
My truck is not listed on the application chart--closest thing is a '79 W150. It looks like it does fit some cars back through '77.

It should bolt on though, right? Is it just missing the heater riser valve? It also says something about a smog pump, which my truck never had...is that why there's no heat riser?

I found these on sale for $100 each (over half off), if someone can confirm that they fit I may just grab a couple...

[B-300]

The bottom one is for the right side of a car that uses a vacumm control to operate a seperate heat riser valve... This is why the gasket and longer bolts are shown in the picture.
The valve is the called the EFE valve if I recall correctly. (evaporative fuel emission?)
I have seen air injection manifolds used on those without it from the factory... They have a cover in place of the AIR tube,
I didn't know manifolds had become so scarce that they cost $400.
As mentioned stainless isn't as strong as grade 5 fasteners.
With liquid rust out there I can only add one thing to general maintence: Make sure all fasteners will turn and use anti-seize on all of them.

[Delray Dude]

Follow up on B 300's notes:



I'm running my 87 cast manifolds (with the air tube) (untill i header the truck) on a '70 318 block and heads. They work fine - if you use these on the non air heads it's no problem - heck I left the openings on the air tubes open (since there is no hole on the heads for that). Only prblem I found was with the small exhaust ports on the 70 heads - I had to use the steel shim gasket for the 70 exhaust to seal due to the lack of the provision where the air gets into the head - but no bid deal.

I suspect that if you go to any local yard you'll have your choice of manifolds any 318 or 360 from the 70's to the 80's will work and chances are you'll find one in great shape for a few bucks.

(heck I took mine off - parts washed them good - and sprayed them down with break-clean and painted them with high temp paint - looked better than new and the paint is still mostly there and in good shape.

[Megunticook]

I suspect that if you go to any local yard you'll have your choice of manifolds any 318 or 360 from the 70's to the 80's will work and chances are you'll find one in great shape for a few bucks. Ain't none that old in these parts--I've called quite a few yards and they all said "good luck."

Anybody have a source for stainless exhaust manifold fasteners? I see that the hex cap screws on the inside of the outer arms measure 2 1/8". Closest thing I've found is 2" and 2 1/4". I've read that you do not want to go long on these because it can damage your heads (?).

How about the special conical-shaped washers? Anybody have a source on those in stainless? Or just regular steel?

The more I think about this, the more reluctant I am to force the issue on removing those frozen bolts...at least for now. I may be able to figure out another way to mount that heat shield. But I'll give it a few more tries. Been adding the PB Blaster daily...

[acton mike]

while it may seem like a big PITA, I humbly submit the best way to deal with this wee problem is to take th manifold off the car and work on it on the bench.

You can mount it up in a drill press if you have to or take it to a machine shop

From bitter experience stemming from buggering up the intake manifold in the 3.0 V6 in my son's voyageur by trying to tap and drill to install new studs for the thermostat water box - I highly advise taking it off

I ended up taking the intake off and having a machine/welding shop repair the mess I made -

It would have been less costly and a more efficient use of time to have done that in the first place

[Megunticook]

the best way to deal with this wee problem is to take th manifold off the car and work on it on the bench.

Hmmm...but how I do that with the fasteners still on there? You mean grind the heads off of those two center bolts, pull the manifold, then work on extracting the decapitated shanks from the heads?

I've got a 6-point 7/16 socket that should be arriving any day (my only 7/16 is a 12-point), I'll give it a shot with that. I wasn't able to do much with my 6-point box wrench on those center screws, but a socket may be easier.

I probably should wait until I have an exhaust leak and need to pull the 'fold before attempting it, just because of the huge amount of time it could potentially devour. If I can just get those two center capscrews out of the middle arm so I can get my heat stove installed, I'll call it good.

I noticed the mechanic who replaced the gasket on the pass. side a few years back for some reason replaced the studs and nuts on the outer fasteners with capscrews. Same difference, or is there a reason Chrysler designed them with the studs and nuts?

I took a hand at loosening some of those, too, and by the looks of things I'd say her didn't bother to put anti-seize on the threads. Would've taken him 20 seconds of extra time--every time I work on my rig I'm reminded of why I don't take it to shops anymore...

[Delray Dude]

Ain't none that old in these parts--I've called quite a few yards and they all said "good luck."



Humm... I see them here in the yards most of the time - but then again - when you are in need thats when you can't find them....

But if you are in need - I can yank one at the yard if I see it - I think they are about 15 to 20 bucks - or when I do do the headers - I'll have a set sitting around collecting dust and rust....

The more I think about this, the more reluctant I am to force the issue on removing those frozen bolts...at least for now. I may be able to figure out another way to mount that heat shield. But I'll give it a few more tries. Been adding the PB Blaster daily...

Yeah...i don't blame ya - but PB Blaster is our friend.....

[B-300]

The ends have studs as they go into the cooling passes and can get rusted in or leak, also they provide a way to hold the manifold and gasket on the production line.

[Megunticook]

Just for kicks took a crack at those 2 center bolts on the driver side manifold, where the heat stove bolts on...and wouldn't you know it I got 'em both out. Tapped the socket on nice and tight, then cracked them loose by turning them clockwise a tad.

Finally...after all that fussing.

So is it OK to replace those bolts with stainless, with plenty of antiseize? I realize they're not as strong as hardened steel, but if they don't rust then there shouldn't be a problem getting them out down the road, right?

[bherder]

I'd have NO prob with replacing them with stainless.... It's just nuts and bolts ... Not like they're going INto anything....

[acton mike]

another trick to get the recalcitrant bolts off would be to use a metric size impact socket and drive on with a hammer and then with a johnson bar see if it will release.

The metric size might be just small and tight enough that it will give enough grip

[swami2806]

Invest in a Crapsman Bolt-Out set. I think Irving makes a set too. They are basically inverted Easy-Outs that work on nuts and bolts. They look like normal sockets from the outside.