Exhaust manifold nut problem--need ideas

[chrysler1941]

I borrowed an Induction heater for stud removal. Fantastic tool. Heats only applied, They are expensive,

Here is a video for those unfamiliar. 

 

[Sam Buchanan]

Yep, that is a nice tool.

 

I resorted to lower tech....a stud extractor picked up at Autozone. That thing worked great for pulling the long studs and the stubs sticking out of the intake manifold. Got the studs turning with a long breaker bar and finished them up with the ratchet. Now in the process of tapping the stud hole I drilled out and then the block will be ready for installation. Next job is the block-off plate for the exhaust manifold and modding the intake manifold.

 

Edited October 3, 2019 by Sam Buchanan

[rallyace]

I would go for the full stud kit. It includes the washers and the nuts with the taper machined on one end.  A touch expensive but when I did my engine I felt it was worth the money. Studs alone will run you about $3 each at NAPA or the hardware store.

[Sam Buchanan]

The P15 is now back on the road and is as quiet as a new 1948! With the windows down I can't hear the engine above 40 mph.

 

Total expenditure was less than $50 which included new gaskets, five new studs, a 3/8" drill/tap, the stud extractor, a tube of anti-seize, four bolts for the heat riser and all new nuts. The block-off plate for the heat riser came from my scrap box.

 

Ten hours of labor working on a neat old car.......priceless.   

Edited October 6, 2019 by Sam Buchanan

[Mike36]

On 10/2/2019 at 6:27 PM, TodFitch said:

 

Those are not highly stressed parts, the manifold stud nuts being brass and all. Worse comes to worse a stainless bolt from your local hardware store cut to length with some fine threads cut on it (I assume you have a set of dies) will work. At least that will work if you can find a bolt with a long enough unthreaded shank.

Good luck with that. 20 years in a machine shop taught me that will not work. Dies are for cleaning up an existing thread. With no existing thread, the die will dive around on the bolt shank and cut an irregular substandard thread.

[Sam Buchanan]

The five studs I needed were sourced from the local NAPA store. They only had 3/8" studs with coarse threads on both ends but they worked nicely to secure the manifolds to the crankcase. A wire brush was all that was needed to clean up the threads on the original studs that remained in place.

[chrysler1941]

2 hours ago, Mike36 said:

Good luck with that. 20 years in a machine shop taught me that will not work. Dies are for cleaning up an existing thread. With no existing thread, the die will dive around on the bolt shank and cut an irregular substandard thread.

Yes, also I'm no expert in metals but mixing 3 metals should be avoided. Stainless bolts and nuts are weak and can strip. And pain in the butt to drill out.

[NickPickToo]

On 10/2/2019 at 4:43 PM, Sam Buchanan said:

 

I'm going a different direction with the heat riser situation. The exhaust manifold will get a blockoff plate that is bolted to the manifold, and the intake will be trimmed to allow clearance for the blockoff plate bolt heads. I don't want to ever have to deal with a blown gasket between manifolds and I'm not worried about losing the preheat. I will make new steel washers where two manifold ears are secured by hte same nut.

So does that mean that the heat riser can be deleted without big issues?  I ask because I am modifying my exhaust manifold to a dual exhaust with the rusty hope kit and I would like to delete the riser if I can get away with it.  If the exhaust is warming the intake manifold anyway, what purpose of the riser?

[Sam Buchanan]

8 minutes ago, NickPickToo said:

So does that mean that the heat riser can be deleted without big issues?  I ask because I am modifying my exhaust manifold to a dual exhaust with the rusty hope kit and I would like to delete the riser if I can get away with it.  If the exhaust is warming the intake manifold anyway, what purpose of the riser?

 

Nick, my car seems to be happy without a functional heat riser. However, I don't know if this is of consequence in a colder clime such as Michigan. I'm sure more experienced members will chime in with opinions.

[NickPickToo]

6 minutes ago, Sam Buchanan said:

 

Nick, my car seems to be happy without a functional heat riser. However, I don't know if this is of consequence in a colder clime such as Michigan. I'm sure more experienced members will chime in with opinions.

Thanks,  My dad is not much help, he was a diesel mechanic and keeps asking where the glow plugs are and then laughs.  We did read that the exhaust helps heat the intake manifold which can get cold due to pressure changes, but if you just open up the riser then you have heat all the time so I'm not sure what you loose if you delete it.  

[NickPickToo]

On 10/3/2019 at 1:11 PM, chrysler1941 said:

I borrowed an Induction heater for stud removal. Fantastic tool. Heats only applied, They are expensive,

Here is a video for those unfamiliar. 

 

I have a friend who's dad converted an old electric floor buffer into a hand pushed zamboni for his backyard rink using induction heating, but this is pretty cool too.

[NickPickToo]

There are a lot of comments on heat risers out on HAMB.  Opinions are various and good reasons to keep or delete so I'm not going to sweat it too much.

[Sam Buchanan]

2 hours ago, NickPickToo said:

Thanks,  My dad is not much help, he was a diesel mechanic and keeps asking where the glow plugs are and then laughs.  We did read that the exhaust helps heat the intake manifold which can get cold due to pressure changes, but if you just open up the riser then you have heat all the time so I'm not sure what you loose if you delete it.  

 

I may have misunderstood your question. I have a blockoff plate on the exhaust manifold that prevents hot air from entering the plenum in the intake manifold. Rereading your post makes me wonder if you are referring to deleting the heat riser flap and leaving the intake exposed to hot air all the time. I suspect our engines are tuned so mildly that whether or not there is hot air in the plenum doesn't impact power output very much. But it probably has an impact on driveability under extreme conditions.

[NickPick'sCrew]

I'm veering off a bit on this thread, but wondering if anyone has experimented with a heating element in the intake manifold.  We have seen exhaust and water heating discussed on the forum but both require the engine to be running to provide any heat.  My tractor has an on-demand heating element (its really just a simplified glow plug) in the intake that I can cycle for up to 10 seconds on very cold days to warm the air prior that will be going into the cylinders prior to starting.  My tractor is a diesel, but I believe its gasser twin has a similar feature.  Has anyone run across this setup on these intakes.  Perhaps our friends in Alaska?  It's doesn't seem to be as cold as it use to be in Michigan when I was younger, but we certainly have our share of cold days.

 

Sam, we will end up blocking out the heat riser as well.  placing the whole for the second exhaust track under the heat riser ends up changing the dynamics of the flow anyway.  I also gave in and got Nicholas a duel intake that while it mounts to the exhaust similar to stock, it doesn't have ports to allow flow deeper into the intake manifold anyway.

[Sam Buchanan]

18 minutes ago, NickPick'sCrew said:

Sam, we will end up blocking out the heat riser as well.  placing the whole for the second exhaust track under the heat riser ends up changing the dynamics of the flow anyway.  I also gave in and got Nicholas a duel intake that while it mounts to the exhaust similar to stock, it doesn't have ports to allow flow deeper into the intake manifold anyway.

 You will probably be fine, the engine may just need a little more time to warm up the intake for smooth throttle response on cold days.

[Dodgeb4ya]

Some of the last carbureted cars (early 80's ) used a electric heater grid plate under the carb for better warm up emission control.

[Merle Coggins]

The intake heater on your diesel engine serves a completely different purpose than the heat riser on the car. On the diesel it preheats the incoming air for better starting in cold weather. The heat riser in the gas engine helps warm the carb to prevent icing in cool damp weather. Without it you may only notice problems around this time of the year shortly after startup. But with a little extra warm up time it would become a moot point. Whatever you do, don’t leave it open all the time. That extra heat with a hot engine over heat the carb and cause other issues. 

[Richard A]

FWIIW:  On the Chrysler 8's they recommend brass nuts on those manifold studs.  Not sure about the 6's, but might not hurt to confirm.

[Dodgeb4ya]

That's true on the 323 chrysler 8's.

On the sixes not so other than the 4 brass 3/8" thick exh manifold expansion/ contraction washers.

[Loren]

I just removed the manifold studs on my 25 inch block.

Most studs are "thru hole," where they go into the water jacket. Of course I broke some and they had a characteristic way of breaking.

Every one that broke turned at least one full turn and sometimes two. That tells me they corroded on the ends and broke when the corroded part got tight in the hole.

One could prevent that from happening again (if you care, as it is unlikely you'll be the one to overhaul it next time) by not screwing the studs all the way in. I ruled out shortening them or removing some of the threads as they plated and if you do that they will corrode quicker. My plan is to run a tap down each hole and carefully measure the depth with a caliper, writing down the measurement. Then when I install the studs I will "glue" them in with ARP Thread Sealant screwing them in only so far as the depth of the hole plus one thread.

I used the Summit Racing online catalog to find the studs I needed. ARP doesn't make the size I needed but Dorman does. In boxes of ten, studs are 79 cents each. At that price I bought two boxes! ARP 12 point nuts and flat washers to finish things off. I am not bothering with brass nuts for this engine as I have Langdon's cast iron headers and I am making my own intake manifold. The split exhaust manifold should not be as troublesome as a full length one.

It's my humble opinion that studs should not be reused unless you know their entire history. On a race car you keep log so you know how many times they've been loosened and tightened and you know they've always been torqued correctly. On a passenger car you know none of this.

 

[Sniper]

On 11/12/2019 at 12:14 AM, Loren said:

I just removed the manifold studs on my 25 inch block.

Most studs are "thru hole," where they go into the water jacket. Of course I broke some and they had a characteristic way of breaking.

Every one that broke turned at least one full turn and sometimes two. That tells me they corroded on the ends and broke when the corroded part got tight in the hole.

One could prevent that from happening again (if you care, as it is unlikely you'll be the one to overhaul it next time) by not screwing the studs all the way in. I ruled out shortening them or removing some of the threads as they plated and if you do that they will corrode quicker. My plan is to run a tap down each hole and carefully measure the depth with a caliper, writing down the measurement. Then when I install the studs I will "glue" them in with ARP Thread Sealant screwing them in only so far as the depth of the hole plus one thread.

I used the Summit Racing online catalog to find the studs I needed. ARP doesn't make the size I needed but Dorman does. In boxes of ten, studs are 79 cents each. At that price I bought two boxes! ARP 12 point nuts and flat washers to finish things off. I am not bothering with brass nuts for this engine as I have Langdon's cast iron headers and I am making my own intake manifold. The split exhaust manifold should not be as troublesome as a full length one.

It's my humble opinion that studs should not be reused unless you know their entire history. On a race car you keep log so you know how many times they've been loosened and tightened and you know they've always been torqued correctly. On a passenger car you know none of this.

 

 

I am going to go to a set of Landon's manifolds as well, do you recall the specifications of the studs you used?  I'd like to have them on hand before I start.

[Loren]

I got my studs from Summitracing.com but I am sure NAPA has them on hand. The Dorman box says 675-070  QTY:10 DBL END STUD 

They were as I said 79 cents each!

When you talk to Tom Landon ask him about an intake manifold as well. In projects like this I go for the path of least resistance and I've almost talked myself into his dual carb 2x2 manifold. He takes an Offenhauser Chevy 216 manifold and cuts the flanges off and welds on the correct ones for the Chrysler. The carburetors are 2 barrel Weber/Motorcraft with progressive linkage. He supplies the 1 to 2 barrel adaptors fit them to the manifold. I am thinking the whole ball of wax would be about $1,000. Old Edmunds or Ellis manifolds have been going for $600 and up on eBay so this is not a bad deal at all. Besides you knew it's going to work as this guy knows what he's doing. 

[Sniper]

In line for a Thickstun dual 1bbl intake.  It looks like it's a better design that the Offy stuff.  Thanks for the info.  Any idea on the long studs?

[Loren]

I love the shape of the Thickstun manifold for a Plymouth! I wish he made them for the Chrysler 25 inch block that would be epic!

How long do you figure you'll have to wait for it? Oh and who do you call?

 

A visit to NAPA with the part number I gave you will put them on the page with the long studs I am sure.

The Dorman studs are nothing special just available and cheap. At that price you can change them each time you take the manifold off.

Just be sure not to screw them in any farther than you have to. On my engine I figure I'll take an average thread depth then make a gauge to prevent the ends from rusting.

Too many threads in the water jacket and the ends mushroom with rust and when you go to take them out they snap off. I hate when that happens!

 

The next time I call Tom I'll ask him about the Thickstun Chevy 216 Manifold. I am sure he will have an opinion.

[Sniper]

supposed to be another batch in "late January".  One Ebay, user name eastcheam842

 

I have a set of his finned sidecovers enroute as we speak.