Itinerant Air-Cooled

Installed some new step studs; three all together. I have one stud (outside rear on right bank) that is half covered/ won't line up on the right bank. I've got another set of manifolds, so not worried about McGuyvering these. That metal is hard! I've using round bastard files, and a cobalt drill bit and have made very little progress. Any suggestions?

I'm surprised it's so far off to be honest....there wasn't that much metal when I drilled the tap hole, and you'd think the original hole would have guided the bit straight.

My other thought is to take out the stud that is lining up (not a step stud IIRC), install the manifold, then reinstall the stud with the hopes that everything lines up once it's all nestled in place.

My guess is if you remove the other stud you will still be off. But, it is a low risk proposition.

A bit late for the suggestion of having the manifold bolted in place and using it as your guide to drill the hole for tapping.

drober23 wrote: ↑

Sat Jul 08, 2017 6:35 pm

My guess is if you remove the other stud you will still be off. But, it is a low risk proposition.

A bit late for the suggestion of having the manifold bolted in place and using it as your guide to drill the hole for tapping.

Oops.

Are these F-pipes? I took all my bolt holes up a size using a drill press and some Milwaukee drill bits. I also needed to bend them a little with a floor jack to fit. Any chance that the studs are in the right place but your manifold has twisted a little?

Not Troll, but I think they are. Pretty sure he has the '75-'78 style manifold/u-tube/heat exchanger setup.

My biggest concern is that I used red Loctite put the studs in. Will make it a wee bit difficult to take them out. Order some ez loc inserts the other day. Plan is to heat up the offending stud and hopefully the red Loctite will break free and then I will use the manifold as a guide to drill a new hole for the easy lock insert . Will let you know how it goes

the pipes warp with use. It is common with exhaust manifolds where the ends move towards each other over time. The usual fix is build a spreader tool of some kind, heat the manifold to expand it until it fits then when it cools file the flanges parallel with either a large belt sander or a big mill file. A spreader could be a couple pieces of all thread with a nut at one end filed curved so it doesn't slide off the manifold, and a special threaded portion in between that moves the pieces of all thread apart. Then heat the area one wants to bend with a torch. Don't melt the brazing on the flanges.

The other solution if they are close is to drill out the holes a little. This is less preferred but quicker. The step thread area has a pocket behind it so there isn't as much bite there as one might think.

Mark (BusDaddy elsewhere) suggested heating the pipe with a torch or Mapp gas and using a scissors jack to spread the tubes a little. Be careful to not break the flanges free or crack the welds. Check the tops for flatness afterwards.

I used a dash of everyone's suggestions....including my own. :) Yes, the exhaust manifolds were drilled out (that was two weekends ago), and as SGKent suggested, used my scissor jack to stretch the manifold just a wee bit. I also removed the (properly oriented) stud (with no red loc-tite), managed to get the exhaust manifold on, and the stud threaded back in.

However, the stud that was slightly askance, was askanced inward enough that I did not have enough clearance to get a socket on to tighten down the nut. . tightened it a fair amount with a open end wrench and channel locks. Fired it up, and, dang it, exhaust leak. So I said to my self, "Self, how are we going to get this torqued down to spec's?" Had a bunch of random sockets left by the PO of the house, found a 1/2 inch 12 point, ground it down skinny like, but couldn't get it to fit right, and it scuffed up the top edge of the nut. So went back to the socket pile, found a 6 point, ground it down, and although I had clearance, did not want to clear over the buggered top edge of the nut. So I said fark it, lined it up, and tapped it on with a ball pein hammer, and low and behold got it torqued down to the right specs. Still have an exhaust leak though.

I know there are folks out there that are cringing at this, but remember, both of these heads are toast, not even good for cores (broken exhaust stud boss on one, insert in spark plug hole that has a death grip on the spark plug on the other). Engine cost me $250 and it runs awesome other than the exhaust leaks, and I've put 20k on it (and who knows how many miles on the death grip plug). Part of this is just to see how far I can take it before I have to finally replace the heads....the other part is I wanted to at least get it through a couple of camping trips this season (maybe next your too?).

Cheers,
Mike

did you heat the copper rings to 900 F temp to soften first as described by Richard Atwell? http://www.ratwell.com/technical/Exhaust.html

sgkent wrote: ↑

Wed Jul 19, 2017 5:16 pm

did you heat the copper rings to 900 F temp to soften first as described by Richard Atwell? http://www.ratwell.com/technical/Exhaust.html

I confess that I did not. I Did not expect perfection, but it is leaking more than I thought it would. As it probably took me all told about 10-12 hours to McGyver everything back together....and I know I need new heads anyways...really not keen on taking it all back apart. I do have 3 more functional studs, however, it does leak more (at least the right bank...left bank that is missing a stud actually sounds a bit quieter). Goal is to take it on a couple of short (500 miles round trip) camping trips this year...and maybe get one more season out of it (I only put maybe 1500 miles a year).

So the exhaust is more soundly attached..but the exhaust leaks a little more...hoping after everything takes a bit of a set, and after I re-torque everything, she may get a bit quieter.

During my first visit with Colin last year when we fought the carbs and the distributor he easily ascertained that I had not done the heat treat of the copper rings as I had multiple exhaust leaks, worse I never even replaced the originals. In this case he somehow used the leak to help dial in the engine... of course he did . Once he left, since the engine was still not in the bus, I precariously balanced the engine off of my solid bottom stand, removed the old exhaust ovals, and followed the Ratwell procedure with my new ones, made an amazing difference with regards to ability to seal.

As I am learning (the hard way of course), shortcuts are just that, short term time savers. long term work creators. Last night I rebuilt a squealing wiper assembly, per Collin's procedure (partly), slapped it in and behold wipers that were cleaning my lights. After rereading the procedure and looking in Bentley I now know that there is a method to ensure that the wiper parks in the right place. Pulled out the wiper assembly set it per Bentley (+ or - 5 deg. to the motor axis) and reinstalled, all should be great, not a chance. Turned out that the arm had to be exactly opposite of where Bentley indicated, read that section three times to make sure I wasn't missing anything. After the third install finally have excellent, quiet working wipers...

Moral of the story... not sure.

Do your cylinder heads have the "air injection ports" accessed from above with their M10x1.0 plugs in place? It will sound like an exhaust leak that gets slightly quieter when you close the deck lid hatch. I've been bitten by those before……

Robbie

TrollFromDownBelow wrote: ↑

Wed Jul 19, 2017 6:41 pm

it is leaking more than I thought it would.

So, after the scissor jack spread, did you re-bastard file the pipe ends parallel?

Yes, we want and can achieve a leak-free exhaust.
Colin

Amskeptic wrote: ↑

Sat Jul 22, 2017 9:38 am

TrollFromDownBelow wrote: ↑

Wed Jul 19, 2017 6:41 pm

it is leaking more than I thought it would.

So, after the scissor jack spread, did you re-bastard file the pipe ends parallel?

Yes, we want and can achieve a leak-free exhaust.
Colin

I filed before, but not after spreading. It's bugging me enough, that yes, I will take the right manifold off, if...and that is a big if... I can extract the 9MM step stud that I put in with red loc tite. If not, it will most likely accelerate getting new heads. Regardless, it is going to make the 300 mile round trip camping trip this weekend the way it is. I need a solid half day to tinker with it, won't have that until after next weekend.

the studs should not come out when you remove it. Only the nuts need to come off. Why you are missing a stud I don't quite understand. Enjoy your trip. you can use a piece of fuel line to listen for where the exhaust leak actually is before you start pulling things off.