The Forward Look Network
The Forward Look Network
Search | Statistics | User Listing Forums | Chat | eBay | Calendars | Albums | Skins | Language
You are logged in as a guest. ( logon | register )

1958 Desoto 361 exhaust manifold valve
Jump to page : 1
Now viewing page 1 [50 messages per page]
View previous thread :: View next thread
   Forward Look Technical Discussions -> The Exhaust Pipe - Modification & PerformanceMessage format
 
DieselJeep
Posted 2016-10-18 11:26 PM (#523780)
Subject: 1958 Desoto 361 exhaust manifold valve



Regular

Posts: 79
252525
Hello all.

On the 361 in my '58 Fireflight, the passenger side exhaust manifold seems to have some sort of weighted or sprung valve in it? I am only recently a 1958 Desoto owner once again, and I am uncertain of what or if anything might be missing from it. What is it's intended function? If an actual valve that may choke the exhaust(if non functioning as intended), is there a way I can make sure it stays open fully untill headers and a new exhaust?

If there is one one the left(drv) side, I missed it.

I tried several site searches before asking, but no go.

Thank you in advance.



Edited by DieselJeep 2016-10-18 11:27 PM
Top of the page Bottom of the page
Viper Guy
Posted 2016-10-18 11:54 PM (#523786 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Elite Veteran

Posts: 950
5001001001001002525
Location: Branson, MO
That unit you are referring to is called a heat riser. It stays closed when the engine is cold and opens as the engine warms up. Works like the choke on the carburetor from the heat sink on the intake manifold. The "spring" senses the heat and expands as it heats to allow the valve to open. More often than not, the valve "freezes" up and it stays open all the time and most folks don't even realize it. It is supposed to be lubed periodically to keep functioning. There is only one and it is on the passenger side of the car. If you want to make sure it stays open as you say above, you can use wire to keep it open once you open it manually and disconnect the spring when the engine is cold. Ooops, I forgot to mention that the intention is to aid in engine warm-up.



Edited by Viper Guy 2016-10-19 1:08 AM
Top of the page Bottom of the page
DieselJeep
Posted 2016-10-20 3:01 PM (#523917 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Regular

Posts: 79
252525
It is free, and probably operating correctly in my car. Just got it started today.
Thanks for the help. I have a lot to learn, and remember.

Top of the page Bottom of the page
Rodger
Posted 2016-10-23 11:53 PM (#524189 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve


Expert

Posts: 1506
1000500
Location: Colo Spgs
Hola

Where did you learn that a set of headers is going to help you with a better performance with a 1958 car ?



Rodger & Gabby
Colo Spgs
Top of the page Bottom of the page
DieselJeep
Posted 2016-10-25 11:32 PM (#524407 - in reply to #524189)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Regular

Posts: 79
252525


Any header will make more power if sized correctly than a log manifold.

I really can't see a 361 CID big block with 10-1 compression exhaling it's deepest possible through 10 feet of 1 1/2 exhaust pipe with about half dozen crushed bends per side. It's all the original pipe. Talk about restrictive. Let alone the pulses banging into and cancelling each other in that log(designed for cost).

I have the calculations around here somewhere, but pretty sure 2 1/2 mandrel bend dual exhaust with a true crossover pipe will make more power, and not cool the exhaust pulses too much.


And if I hear that ignorant, unscientific term "backpressure" one more time, I will vomit.

Top of the page Bottom of the page
Rodger
Posted 2016-10-28 2:25 PM (#524644 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve


Expert

Posts: 1506
1000500
Location: Colo Spgs
Hola

With a set of Dual 2 1/2" Pipes --- what Engine RPM's or High-Way Indicated Vehicle Speed are needed to over come a "Lazy Air Flow" of the exhaust system ?



Rodger & Gabby
COS
Top of the page Bottom of the page
DieselJeep
Posted 2016-10-28 7:51 PM (#524649 - in reply to #524644)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Regular

Posts: 79
252525

Rodger - 2016-10-28 2:25 PM Hola With a set of Dual 2 1/2" Pipes --- what Engine RPM's or High-Way Indicated Vehicle Speed are needed to over come a "Lazy Air Flow" of the exhaust system ? Rodger & Gabby COS


I am not sure I understand what you are asking.

Exhaust primary(on header) and actual exhaust pipe diameter is calculated by engine CFM requirements, at what RPM. The calculations are out there, if ya google.

There are very built, race oriented, but much smaller CID V8's than a 361 that would need larger than 2.5" per side. Or even a turbo'd 4 cyl might need bigger. An engine is an air pump. That's all.  Air easier in, easier out, and equalize the power made between all cylinders, it will make more power overall. Airflow also hates 90* angles, and changing directions. That log manifold is as restrictive as it gets for flow.

If I was willing to put different heads on, bore it out(or stroke), change cams(and possibly valvetrain), modify the intake to actually flow, and equalize the flow(MAN that factory intake is AWFUL), or even modify a modern mopar bigblock intake to fit these earlier engines, bigger carb, ect., I bet it would be easy to make 350+ HP, or even 400HP from a 361(or whatever the end result cubes were). But it would be a barely streetable, rumpity, rough motor.

This is a rough list, and I am not a mopar expert...YET. Others here would know what you could and cannot do(at least easily, or what has been done already, or what is possible) to these, and other mopar engines.

And, I am not willing to heavily modify a 361 that is a low milage survivor, and runs like a top, to pick up as much power as possible. Exhaust system will do all I want. And 300 HP is a fair amount of power already, esp by today's standards.



Edited by DieselJeep 2016-10-28 8:07 PM
Top of the page Bottom of the page
DieselJeep
Posted 2016-10-30 3:04 AM (#524760 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Regular

Posts: 79
252525
Been doing personal research, inspired by an old school vintage 2x4 mopar intake on Ebay right now.

My bad, I said wrong. Seems ya can buy all kinds of intakes for the short deck mopar big block motors.

Be careful of exhaust headers you buy. These earlier small valve heads might have a much different exhaust port bolt pattern than the later heads. I am still learning about mopar big blocks.

If I can't find any with the right bolt pattern, I will make some flanges, and weld my own headers.



Top of the page Bottom of the page
1960fury
Posted 2016-10-30 9:08 AM (#524780 - in reply to #524760)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Expert

Posts: 4469
200020001001001001002525
Location: northern germany
DieselJeep - 2016-10-30 3:04 AM


Be careful of exhaust headers you buy. These earlier small valve heads might have a much different exhaust port bolt pattern than the later heads. I am still learning about mopar big blocks.

If I can't find any with the right bolt pattern, I will make some flanges, and weld my own headers.



no, they all use the same bolt pattern (a correlation between valve size and ex. bolt pattern?). so that is not the problem, however, in order to run headers in a 58 desoto you must fabricate your own.
unlike what you posted in another thread, the mopar big block is the easiest engine to work with and to upgrade, these engines are bullet proof that eagerly respond to performance mods and parts are cheap and easy to find, as it was THE muscle car engine of the 60s. not without a reason these were built from 1958 to 1978+ (blocks still reproduced aluminum&iron).
Top of the page Bottom of the page
DieselJeep
Posted 2016-10-30 9:23 AM (#524781 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Regular

Posts: 79
252525

It wasn't an intentional correlation. Doing research, I would have sworn I saw a "lazy w" style diagonal exhaust bolt pattern on the early "B" heads, not the straight across of the later heads. I admit, it was 3 AM, and I was in for the night, and too lazy to walk back out to the garage. All bolts in a straight line, at least for certain on my '58 361. And I certainly have a lot to learn about mopar parts, engines, ect.

Do you mean what I said earlier in this thread about intakes, ect?



Edited by DieselJeep 2016-10-30 9:26 AM
Top of the page Bottom of the page
1960fury
Posted 2016-10-30 10:01 AM (#524786 - in reply to #524781)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Expert

Posts: 4469
200020001001001001002525
Location: northern germany
no, in your initial post here on fl net. the first generation of bb ex manifolds are very restrictive and heavy pieces and i do not deny the benefits of headers, but run em with a heat riser.
Top of the page Bottom of the page
58coupe
Posted 2016-10-30 10:06 AM (#524788 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Elite Veteran

Posts: 1198
1000100252525
Location: Alaska
Hey Sid, I have never seen or heard of headers run with a heat riser. I'm curious, have you got pictures. That is one of the problems with headers on the street, it takes longer to warm up the engine.
Top of the page Bottom of the page
1960fury
Posted 2016-10-30 11:35 AM (#524799 - in reply to #524788)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Expert

Posts: 4469
200020001001001001002525
Location: northern germany
58coupe - 2016-10-30 10:06 AM

Hey Sid, I have never seen or heard of headers run with a heat riser. I'm curious, have you got pictures. That is one of the problems with headers on the street, it takes longer to warm up the engine.


i run headers with heat riser, if it wasn't possible i wouldn't run headers as the disadvantages would almost outweigh the benefits. i run a 2.5" (bb) chevy heat riser (its a separate piece that you can sandwich between header and pipe without problems) but header manufacturers offer heat risers for their products for about 10 years now. the chevy heat riser works perfect and is 1/2" bigger than the stock heat riser, all i had to do was change the orientation of the counterweight as the collector is not in a vertical position.

Edited by 1960fury 2016-10-30 3:49 PM
Top of the page Bottom of the page
DieselJeep
Posted 2016-10-30 1:51 PM (#524808 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Regular

Posts: 79
252525
I agree, I would love to see a pic of your heat riser, if ya can share...
Top of the page Bottom of the page
1960fury
Posted 2016-10-30 3:43 PM (#524811 - in reply to #524808)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Expert

Posts: 4469
200020001001001001002525
Location: northern germany
i think i posted it before. having trouble uploading pictures as my pc for some reason does not accept my cellphone anymore. will try.

meanwhile, this might help.

Edited by 1960fury 2016-10-30 3:48 PM




(hedmanheatriser.jpg)



Attachments
----------------
Attachments hedmanheatriser.jpg (14KB - 34 downloads)
Top of the page Bottom of the page
58coupe
Posted 2016-10-31 10:08 AM (#524868 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Elite Veteran

Posts: 1198
1000100252525
Location: Alaska
Thanks Sid, I must have forgotten you have that set up. (sometimers disease)
Top of the page Bottom of the page
Chrispy
Posted 2016-12-19 2:39 PM (#529188 - in reply to #524649)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Extreme Veteran

Posts: 508
500
Location: Colorado Springs, Colorado
DieselJeep - 2016-10-28 5:51 PM

Rodger - 2016-10-28 2:25 PM Hola With a set of Dual 2 1/2" Pipes --- what Engine RPM's or High-Way Indicated Vehicle Speed are needed to over come a "Lazy Air Flow" of the exhaust system ? Rodger & Gabby COS


I am not sure I understand what you are asking.

Exhaust primary(on header) and actual exhaust pipe diameter is calculated by engine CFM requirements, at what RPM. The calculations are out there, if ya google.

There are very built, race oriented, but much smaller CID V8's than a 361 that would need larger than 2.5" per side. Or even a turbo'd 4 cyl might need bigger. An engine is an air pump. That's all.  Air easier in, easier out, and equalize the power made between all cylinders, it will make more power overall. Airflow also hates 90* angles, and changing directions. That log manifold is as restrictive as it gets for flow.

If I was willing to put different heads on, bore it out(or stroke), change cams(and possibly valvetrain), modify the intake to actually flow, and equalize the flow(MAN that factory intake is AWFUL), or even modify a modern mopar bigblock intake to fit these earlier engines, bigger carb, ect., I bet it would be easy to make 350+ HP, or even 400HP from a 361(or whatever the end result cubes were). But it would be a barely streetable, rumpity, rough motor.

This is a rough list, and I am not a mopar expert...YET. Others here would know what you could and cannot do(at least easily, or what has been done already, or what is possible) to these, and other mopar engines.

And, I am not willing to heavily modify a 361 that is a low milage survivor, and runs like a top, to pick up as much power as possible. Exhaust system will do all I want. And 300 HP is a fair amount of power already, esp by today's standards.



Later "B" motor intakes bolt right up. No need to mod, just acquire a nice aluminum intake.

https://www.summitracing.com/parts/edl-2186/overview/make/dodge

https://www.summitracing.com/parts/edl-7186/overview/make/dodge
Top of the page Bottom of the page
DieselJeep
Posted 2017-01-07 11:34 AM (#530692 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Regular

Posts: 79
252525
TY for the pic, Fury!

TY Chrispy!

I learned that as I was doing mopar homework. Thrilled to learn brand new performance goodies can be bought, bolted on, and easily removed from my 361!

Top of the page Bottom of the page
Chrispy
Posted 2017-01-11 2:21 PM (#531099 - in reply to #523780)
Subject: Re: 1958 Desoto 361 exhaust manifold valve



Extreme Veteran

Posts: 508
500
Location: Colorado Springs, Colorado
Hughes is a great shop for b/RB stuff too if you are hunting for parts.... :D

http://www.hughesengines.com/Index/index.php

Edited by Chrispy 2017-01-11 2:22 PM
Top of the page Bottom of the page
Jump to page : 1
Now viewing page 1 [50 messages per page]
Jump to forum :
Search this forum
Printer friendly version
E-mail a link to this thread

Search for anything on eBay!

(Delete all cookies set by this site)