Headers info please

[Dodgefran]

Hello,

I am having a DeSoto 228 long block (25") engine rebuilt. I've been reading about improving the performance with exhaust headers. Langdon's Stovebolt have a stainless steel header that they fab up with .085" thick pipes. Is that a bit thin for the heat? Do any of you have this setup?

My other option could be to take my original exhaust manifold and add another flange opening to it. It all ready has a chunk off the corner of the 4 bolt flange so it has to be repaired anyway.

What is the longevity of these options, and who do you trust doing this work? Thanks for your help.

[blucarsdn]

Many people insist that headers and/or split manifolds greatly improve the performance of an engine... In reality headers are meant to be ran as open exhaust, on race engines... Split manifolds with un-chambered mufflers (glass packs) give a person lots of bragging rights, however, they do little for the actual performance of the engine.

In reality headers and/or split manifolds tend to make an engine run rich because the heat riser has been eliminated. If a person takes the time to read the actual spec's on headers, the fine print will clearly state..."not intended for use on vehicles operated in cold winter temp's".

I have had many people tell me through the years that they found out that their fuel mileage decreased with headers/split manifolds, of course the reason for the loss of mileage was their heavy foot on the throttle, so they could hear the 'sweet sound' of the exhaust.

[greg g]

contact forum member Moose.

[BeBop138]

Hello,

I am having a DeSoto 228 long block (25") engine rebuilt. I've been reading about improving the performance with exhaust headers. Langdon's Stovebolt have a stainless steel header that they fab up with .085" thick pipes. Is that a bit thin for the heat? Do any of you have this setup?

My other option could be to take my original exhaust manifold and add another flange opening to it. It all ready has a chunk off the corner of the 4 bolt flange so it has to be repaired anyway.

What is the longevity of these options, and who do you trust doing this work? Thanks for your help.

Ask the local speed shops in your area---I am sure they could steer you to somebody who could split the exhaust. The best combo is to mill the head--more carbs--dual exhaust. If you got a lot of miles on the engine you may want to think about a rebuild before doing the mods---hopping up a tired engine reduces the life of the engine. Just doing the exhaust makes it sound cool but not a big improvement in HP---overdrive with good rear gearing is another option with any engine mods.......Lee

[mrwrstory]

Headers or a split manifold, as previously stated, do little for performance on an old and/or nearly stock engine. However, headers are cool both for looks and for sound. As long as you are looking at the cost of a repair, I'd say go for the headers and enjoy showin then off. .085 wall thickness is plenty generous and better than most.

[dezeldoc]

Many people insist that headers and/or split manifolds greatly improve the performance of an engine... In reality headers are meant to be ran as open exhaust, on race engines... Split manifolds with un-chambered mufflers (glass packs) give a person lots of bragging rights, however, they do little for the actual performance of the engine.

In reality headers and/or split manifolds tend to make an engine run rich because the heat riser has been eliminated. If a person takes the time to read the actual spec's on headers, the fine print will clearly state..."not intended for use on vehicles operated in cold winter temp's".

I have had many people tell me through the years that they found out that their fuel mileage decreased with headers/split manifolds, of course the reason for the loss of mileage was their heavy foot on the throttle, so they could hear the 'sweet sound' of the exhaust.

Nothing in your post is correct,except for the heavy foot. Headers will improve the exhaust flow and eliminate back pressure therefore making more hp. Splitting will do the same just not as much as headers. It takes more that just headers to make the motor work right, as was stated mill the head to raise the compression, bigger carb (multiple or bigger single) headers and if you want to go big do the cam. You would be surprised at the extra amount of hp they get. By upping the hp/torque the motor does not need to work as hard to make it move or keep its momentum, in essence giving better mileage as long as you are not in the throttle hard all the time. the crossover is just for easier warm ups in cold weather and most will work fine without it or it can be done with a water plate under the carb if necessary.

Edited April 29, 2012 by dezeldoc

[austinsailor]

I have a set of Langdon's headers and they are plenty thick. They are also excellent quality, I'm not sure how he can come out ok on his price with what he's put into them. they are quite a buy.

I have not assembled my motor yet, so I can't comment on performance.But the solution to the rich/heat issue is to get a water heated intake. They are around, I have two Edmonds versions. One is a dual single barel carb model and one is a dual 2bbl version.

The other things you should do is mill the head somewhere in the .050 to .100 range as already suggested ($40 at my machine shop) and send your cam to Edgy for a regrind. ($125).

Edited April 29, 2012 by austinsailor

[1941Rick]

Just to add to the thread....I have hopped up my 218 in steps.....shaved 040 from the head = no noticable difference, Offy twin manifold next = noticable difference, then Red's Headers and Walker cherry bombs = noticable difference again. The only problem I have encountered is a rich running engine. That is my next challenge.

With the addition of headers the car has a lot more bottom end torq. Most likley from the fact it has better intake and exhaust flow. ( and the sound also helps )

[Rusty O'Toole]

If you are not doing anything else to the engine headers are a waste of money.

If you are doing a hop up, all the parts have to match and work together.

A mild hop up or stock engine, would do well with a stock exhaust manifold, just have a larger exhaust made up if you need a new exhaust.1/2" larger diameter than stock. In other words if your old one is 1 1/2" get one 2" diameter.

Next step is to split the manifold and run dual exhaust pipes all the way to the back of the car.

Final stage would be headers and dual exhaust. This would be if you had a completely hopped up engine with dual or triple carbs, hot cam, aluminum head, and shaved flywheel.

It's all according to what you want to do.

[Socal48]

Rusty Hope has a simple solution, bottom of this page.....

http://www.rustyhope.com/intakesexhausts.html

[Daliant.]

The problem with putting headers on any carburated inline engine is the loss of heat to the intake manifold, the intake has to be hot for the fuel droplets to atomize properly and burn completely. Running a hot water plate bolted under the intake will help some and will probably be fine if the car is just a summer driver.

[Don Coatney]

The problem with putting headers on any carburated inline engine is the loss of heat to the intake manifold, the intake has to be hot for the fuel droplets to atomize properly and burn completely. Running a hot water plate bolted under the intake will help some and will probably be fine if the car is just a summer driver.

Couple of things I dont understand and you may be able to explain. First off I have a split stock manifold on my engine with the heat riser plate welded in such a position as to allow heat to the intake manifold 100% of the time (as pictured below) and my engine runs great.

What I dont understand is how running engine coolant water through the intake manifold jackets helps anything? Exhaust mainfold temperatures will exceed 500 degrees almost as soon as the engine is running. Engine coolant water will rarely reach 200 degrees and this will not happen until the engine comes up to temperature. Factory manifolds use a temperature sensitive spring to regulate the ammount of hot exhaust gasses that find there way to the heat transfer section of the intake manifold. So I must ask at what temperature do the fuel droplets properly atomize? If the fuel droplets do or do not properly atamize what are the results?

[greg g]

Hmmm, I always thought that according to old Dan Bernoulli the atomizatioin process that which is a colloid suspension of fine solid particles or liquid droplets in a gas is done within the carburetor. That the manifold's job was to transport this colloid suspension to the valves via the vacuum created when the piston for that cylinder travels through the intake stroke, the enriched mist reacting very briefly to its transfer assembly. The job of the heat riser is to warm the intake in cold weather to keep the suspension of air and fuel droplets from reforming into liquid prior to entering the cylinder.

It doesn't take very long for under hood temps to reach a warm enough temp to take the need for the heat riser out of the equation. With that in mind its a wonder how all these hot rods and street rods can run at all with no hoods, headers, zoomies and especially with v8's very minimal intake warming...

Edited April 30, 2012 by greg g

[hkestes41]

If you are not doing anything else to the engine headers are a waste of money.

Is that scientifically or dyno proven or just an opinion?

Nearly all automobiles are equipped with an exhaust system designed to decrease noise levels, and transport the exhaust gases to the rear of the vehicle. Unfortunately, due to production cost considerations most exhaust systems are not optimized for maximum horsepower, torque, miles per gallon, or performance acoustics. Exhaust manifolds are built to the lowest possible price, sacrificing the flow of exhaust gases from the engine. Due to the firing order of each combustion chamber, the exhaust exits the exhaust ports at different intervals that can create back pressure if not properly tuned by altering each header runner length or seperating adjacent firing cylinders. Stock manifolds join the cylinders together in such a sort distance it is not possible to properly size each runner for optimal performance, isolate adjacent firing cylinders or smoothly transition the bends. These factors contribute to reductions in exhaust velocity, thereby robbing your vehicle's performance potential.

Headers isolate adjacent firing cylinders, smooth the transition of each pipe to equalize funner length and direct pressure waves away from the combustion chamber. All this translate into less back pressure and increased exhaust velocity, which increases power and extends miles per gallon. Headers typically offer larger piping diameters than OEM manifolds. The larger diameter offers benefits even to a completely stock engine (because car makers are generally too conservative with exhaust pipe diameters) and even larger gains to modified engines, whose stock exhaust pipe diameter is severely limiting power gains of the cumulative effect of the upgrades. Overall, headers give your vehicle improvements in horsepower, torque, and miles per gallon.

There are multiple articles out there that discuss the science (some say black magic) of exhaust manifold/header design. A little research is all that is needed.

I'm not sure where the dump is located on your stock manifold but lets consider the worst case and say it is all the way to the rear of the manifold as some are. That would mean that the distance the exhaust from #1 travels is roughly 20 inches or so longer than that of #6 before reaching the down pipe. Also consider your firing order of 1,5,3,6,2,4 is there a chance that the exhaust charge of number #1 could be nearing then end of the manifold as #5 is trying to evacuate the exhaust gas from the cylinder? Same issue for #2 and #6. With headers splitting 1,2,3 and 4,5,6 and the fact that the exhaust gas flow is in individual pipes for much longer before joining into a single pipe the possibility of interference from a previously fired cylinder is greatly reduced.

However, you are the only one who can determine if the cost is worth it.

The problem with putting headers on any carburated inline engine is the loss of heat to the intake manifold, the intake has to be hot for the fuel droplets to atomize properly and burn completely. Running a hot water plate bolted under the intake will help some and will probably be fine if the car is just a summer driver.

I am running cast iron headers on my 230 and drive it year round, in fact I have driven it when it was cold enough that I was scraping the inside of the windshield to be able to see (heater doesn't work). Ran just fine.

Edited May 1, 2012 by hkestes41

[dezeldoc]

If you will look most of the cars today run tube type exhaust "headers" from the factory. Not the greatest quality but much better than the cast logs of past.

[mrwrstory]

I think you guys are overstudying the issue. If you try to rationalize your decision based on ROI, then you better forget it! If it costs a few bucks to have something a little different and you can afford it,....it sure is fun. Our old cars, as a whole, don't make any sense from an economic standpoint anyway. ....take your pick!

[Rusty O'Toole]

"If you are not doing anything else to the engine headers are a waste of money."

"Is that scientifically or dyno proven or just an opinion?"

The engineers who designed your car were not stupid. The various parts were designed to work together for the best combination of performance, economy, reliable service in all conditions, and first cost.

Tests have proven there is little to gain by changing just one thing. In other words, there is no magic carburetor or ignition that is going to double your power and mileage, no magic pill you can put in the gas tank.

Possibly the closest thing to a magic potion would be milling the head for more compression. And, the engineers were perfectly aware that raising compression improves mileage and power. But they were restricted by the octane of the gas available at the time. When better gas became available they made higher compression engines.

To get back to the header question. Yes, a free exhaust is necessary for best performance. But what if the stock exhaust already flows enough for the engine? What if the valves, camshaft, carburetor and air filter are also restricting the engine? What good would it do to put on headers if the engine can't use them?

This is why I say headers should be part of a total package including attention to carburetor and intake, camshaft, compression, and possibly valves and ports.

I also pointed out that a free exhaust can be had at low cost, in fact no cost if you need a new exhaust pipe anyway, just by having the exhaust made 1/2" larger than stock.

This did not come out of my foggy little noodle either. It came from Chrysler's engineers. They made a package for the slant six called the Super Six that included an exhaust system 1/2" larger than stock, along with a special intake manifold and 2 barrel carburetor and recurved distributor. These 3 simple mods were good for an extra 10HP or a 10% gain on a 100HP engine.

Edited April 30, 2012 by Rusty O'Toole

[Daliant.]

Couple of things I dont understand and you may be able to explain. First off I have a split stock manifold on my engine with the heat riser plate welded in such a position as to allow heat to the intake manifold 100% of the time (as pictured below) and my engine runs great.

Your engine runs well because the heat from the exhaust manifold is vaporizing the fuel/air charge in the intake manifold, this helps the fuel/air mixture burn completely. Manifold heat also keeps the carb from icing up on cool humid days.

What I dont understand is how running engine coolant water through the intake manifold jackets helps anything? Exhaust mainfold temperatures will exceed 500 degrees almost as soon as the engine is running. Engine coolant water will rarely reach 200 degrees and this will not happen until the engine comes up to temperature. Factory manifolds use a temperature sensitive spring to regulate the ammount of hot exhaust gasses that find there way to the heat transfer section of the intake manifold. So I must ask at what temperature do the fuel droplets properly atomize?

I'm just a mechanic not a scientist so I couldn't tell you at what temperature fuel droplets properly atomize, actually vaporize would be a better term for what we are talking about here.

If the fuel droplets do or do not properly atamize what are the results?

Adding a water jacket under an intake manifold which is no longer heated by the stock exhaust manifold (like when a header is added) will help keep the carb from icing up once the engine itself comes up to temperature, unfortunately it wont do squat until the engine warms up so for the first ten minutes or so the engine will probably run a little on the rich side until it warms up. It wont be a cure-all but it will help.

If an engine is sucking in a bunch of unatomized fuel the plugs will foul, the combustion chambers will build up with carbon and any unburnt fuel will wash oil off the cylinder walls and end up in the crankcase none of which is good.

ooo

Edited May 1, 2012 by Daliant.

[Daliant.]

With that in mind its a wonder how all these hot rods and street rods can run at all with no hoods, headers, zoomies and especially with v8's very minimal intake warming...

Most V8's have a exhaust passage that runs through the intake manifold under the carburator to heat the air/fuel mix.

Some performance manifolds dont have this feature and they dont do to good in the cold. They tend to foul plugs with alot of unburnt fuel.

Edited May 1, 2012 by Daliant.

[T120]

I think you guys are overstudying the issue. If you try to rationalize your decision based on ROI, then you better forget it! If it costs a few bucks to have something a little different and you can afford it,....it sure is fun. Our old cars, as a whole, don't make any sense from an economic standpoint anyway. ....take your pick!

I have to agree with your take on the subject... (ROI)

[martybose]

I think it depends on your definition of ROI. If you use the strictly financial definition, then engine mods are ridiculous. But if your definition of ROI includes a fun factor, things are very different.

Nothing can financially make sense for my engine, which has Edmunds head and intake manifolds, dual Carter-Weber carbs, cast iron headers into true duals, a mild cam, increased compression via forged pistons and an HEI ignition system, but the smile it puts on my face every time I fire it up is priceless!

Marty

[blucarsdn]

For the first ten years of my automotive life I tried my best, following the lead of the best motor heads of the time, to turn a 'pigs ear engine into a silk purse'..

I got paid on Friday and was broke by Wednesday.. I generally had one of the badest, fastest cars in Eastern Idaho, however, I also had some very unreliable, temperamental cars.

One day I woke up with the realization that rather than try to build up an engine into something it was not intended to be, why not just switch to a larger engine.. I put a 270 CID GMC into my '38 Chevy, added a Mallory ignition and went out an blew everyone off the road, full race Merc's, etc..

I was king of the road until a guy got smart and dropped an Olds Rocket into his Ford... My racing days were numbered so I sold the '38.

My general rule is if it ain't broke, don't fix it... If you want to go faster, buy a bigger engine.... There is no substitute for cubic inches when it comes to power.

My '39 Plym conv is perfect example of my train of thought... It goes like a rocket ship, yet is very civilized, safe at any speed and will cruise at 70/75 on the highway hour after hour.

I am currently building a '49 Olds 88, which will also be a resto-mod with a '72 Olds 403 V8.

My '48 Dodge has a '48 Chrysler Spitfire in it... A very nice compromise..

[Andydodge]

Marty........re your engine.......where did the forged pistons come from?..........sounds like a nice combo.........is your engine the red one?.........andyd

[martybose]

Marty........re your engine.......where did the forged pistons come from?..........sounds like a nice combo.........is your engine the red one?.........andyd

Andy,

Nope, my engine is dark brown! In my case, we started with a ring catalog, looking for a modern ring set in a bore size that would clean up a worn-out .060" over 230. We found a metric ring set for a Toyota that worked out to a .072" overbore. Then I took one of the .060" over OEM pistons and sent it, along with a set of the new rings to Venolia, who made a sweet forged piston with a Toyota-sized set of ring lands. We then bored the block using a honing plate to Venolia's recommended size. So far so good!

Marty

[dezeldoc]

Andy,

Nope, my engine is dark brown! In my case, we started with a ring catalog, looking for a modern ring set in a bore size that would clean up a worn-out .060" over 230. We found a metric ring set for a Toyota that worked out to a .072" overbore. Then I took one of the .060" over OEM pistons and sent it, along with a set of the new rings to Venolia, who made a sweet forged piston with a Toyota-sized set of ring lands. We then bored the block using a honing plate to Venolia's recommended size. So far so good!

Marty

Hmmm Big dollar forged pistons= big shot of nitrous!!