Could I get opinions on my exhaust manifold? (1 Viewer)

[chaka]

Okay, So I was able to get my intake/exhaust manifolds out today, and was going to get them milled. Upon inspecting them I did find some hairline cracks. Can you all take a look at the pics and tell me if it is worth having them milled or should i just get a new set of manifolds?

the cracks are in the center of the first picture and the 2nd picture is a close up of the first....

Many thanks for your expert opinions... before i go waste money on getting them milled if should actually be looking for a new set....



By the way, for those trying to take the manifolds off for the first time this is how I did it.
1. Remove all bolts holding the manifolds to the block.
2. Remove the 2 14mm bolts holding the cooler to the block.
3. Remove everything as a Unit
4. After unit is out, remove the cooler and J-pipe from the intake manifold iwth a plumbers wrench.

I hope that if someone else has a similar problem the above steps might help....

 

[Degnol]

Are you sure those are not just casting marks? Can you grind them off?

 

[chaka]

I am not really sure... just thought that maybe other people had better ideas than i did. i know it is hard to judge from the pics... but they appear to be cracks and not just casting marks...

 

[Degnol]

I think a machine shop can magnaflux them to see if they are really cracks, or maybe even use something more low tech. I have seen marks like that on the cast aluminum intakes before. Are they raised at all?

Ed

 

[Pin_Head]

Even if they are cracks, they are bupkus. They aren't leaking significantly.

 

[chaka]

Just got back from the local auto shop, the guy took one look and said "time to get a new one", but all of you say they don't look too bad. He said they will continue to get worse and worse. So should I get them milled? or just get a new set...

 

[CRZRJames]

You could keep your intake manifold if it is in good shape and get a header. If you decide to get a new exhaust manifold, you will need to get a matched set of intake and exhaust as they are milled at the factory to have the same flange thickness. cruiserparts.net can probably hook you up.

James

 

[Pin_Head]

I don't know that I have ever seen a used manifold that didn't have something that looked like what you show in your picture. There is no carbon around it, so it isn't leaking. If it bothers you, you can braze them or get a new manifold.

 

[chaka]

it doesn't bother me, I just want to do what's best and easiest to get this thing back up and running for the spring. It has to pass emissions and I am installing a new exhaust system for that (muffler was rusted through).

That being said, what is the worst thing that could happen if I left the current set up in?

if i get them milled is it smart to replace all bolts (connecting intake and exhaust) and wire brush the threads in the block?

 

[F-junker]

Chaka,
I recenlty had my intake and manifold milled and was really torqued to find that I had a leak due to the fact that the manifolds were not milled to a uniform thickness.
My exhaust manifold is slightly thicker at the mounting flange than on the intake, thus the intake sucked and whistled. Bummer!
I went through too many hoops IMO to keep the damn manifold ie, needed header pipe flange (PITA to find, finally mud guy in BC sent me one God Bless him!), planing, pulled flapper out, all new teh gaskets and welded the holes shut.

Bottom line I sould have ditched the manifold!! however I was far from complete too. BTW, shouldn't your truck be emissions exempt being historic?

If you do keep the manny (they are nice and quiet) definitely buy new bolts (they stretch) and have a good machine shop do the plane trying to keep the thickness at the mounting points even. Also buy two gaskets to insure a leak free seal. Good luck and if you do in fact need another manifold drp me a line line I'm in MD and have an extra.

 

[chaka]

F-Junker,

When I called the DMV about being exempt from emissions, they told me that I was not exempt, however I would only be tested at the 1974 levels (whatever that means). The manifold isn't the reason for the emissions issue, a rusted out muffler was. And when trying to remove the exhaust pipe, one of the studs sheared off. so to get the stud out, had to remove the manifold. Thought to myself "as long as I have the manifold out I should mill it"; now i have cracks so I am thinking "maybe I should replace it"....

so that is a short story long.

so my option is get the current one (with small cracks) milled and maybe blasted, replace all the bolts and hardware....

or buy a new set...

Does anyone see any problem in using a minorly cracked (see pictures) manifold?


And F-Junker... do you have both intake and exhaust? or just exhaust?

 

[Degnol]

If PinHead would run it, so would I.

Ed

 

[chaka]

okay,
so how do i go about choosing a machine shop? I will ask the local cruisers but what are good questions to ask to make sure they know what they are doing?

 

[IDave]

I don't think it's rocket science, although obviously it could be messed up. If you line up and bolt down so the outer surfaces where they mate are flat, then it should be easy for a machine shop to flatten if necessary.

I have two sets of manifolds that were not factory mates, on two different trucks, one gasket (or set of gaskets in the case of the F135) per setup, and no leaks. Header leaks are much more common and hard to deal with than manifold leaks.

But you may not even need to have them milled. That has nothing to do with cracks. If the surfaces that mate with the head are good (not corroded) they will likely go on fine with one gasket.

If those are really cracks in the exhaust manifold(and I'm on the side of those who doubt that they are through and through), then I think they could easily be brazed.

 

[grant5127]

the condition of the heat riser and through shaft is another deciding factor........

 

[F-junker]

I agree on that heat riser issue, mine was fine but I removed it anyway. It's a highly overated device. Chaka, I do have both manifolds. I would go ahead and use what you have if you don't want headers. I'll be happy to give them both to you for 50 bucks BUT, they might not be any beter than what you have.

Again as I mentioned above I wish I would have put a header on to start with however the main reason I did not was the noise factor. The noise can really be over come with a good muffler though. many folks like loud mufflers, I don't, I've got loud motorcycles and grew up with loud glasspacks and such. I want a quiet ride with this truck, after all it's a tin can to start with. adding loud tires, and no top, makes loud exhaust another reason to not like driving it.

If your gonna keep that anchor...Take that stuff to the machine shop after you break the two loose from each other... plane em' braze em' slap them back on.

Nice to see some semi-local folks here, are you a member of Capital Cruisers? I've thought about joining but the meetings are a bit out of my way. The guys on the CC site here could tell you the best place to get that stuff planed up in DC probably. As for the club, I still may join for some trail riding though. Good Luck with your truck. Ken

 

[outdoork9lady]

I went new

I went new and ceramic headers. Done, FINI, something I do not have to mess with for another 30years (<- wishful thinking?) One less thing to worry about that affects a whole bunch of other stuff.

 

[chaka]

Okay... I believe this to be the final update. After removing the manifold, and deciding to get them milled, I thought "I should try to get the stud out first. bad idea. welding didn't work (probably operator error), and then bolt extractor broke off (definitely operator error) and when I was trying to use a punch to rotate it out, the entire Flange broke... see pics. Needless to say, an expensive day for me....

SO...... anybody got a 74 intake/exhaust manifold combo for sale, or maybe just the exhaust manifold...?

 

[chaka]

PM'ed you F-Junker

 

[Hobbs]

Look at the bright side, ya' got the stud out !