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Braden

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That looks like the stock 4 into 2  510 exhaust manifold which is basically a cast iron header. So when the L20B was installed it was just bolted up to it. All L18 engines used the same or similar 4 into 2 exhaust. Only L20B that used it was the '74 610. All other L20Bs used a 4 into 1 log exhaust manifold.

 

You have a '69 so probably have the individual air pump tubes in the top of each exhaust pipe where it exits the head. They may be cut and crimped or plugged or welded.

 

IMAG7406.jpg

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  • 1 year later...

Here's mine. It's the stock manifold L18 manifold and the stock 2-1 pipe and then after the merge I built it with 2.25" stainless tubing.  I used a Vibrant resonator, I think 9" in length, and then a Magnaflow 4x9 offset muffler.

 

Sorry, I'm not good at making videos; not sure where that double pan thing came from.

 

 

Before I got the tailpipe done...

7NLrpC7.jpg

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V5o9o8x.jpg

 

This is the one you want on the left. 1 & 4 and 2&3 together. Some later ones just dumped into the center but had the two outlets. Keeping adjacent cylinders from firing into each other.

 

 

I have an L16 exhaust manifold on my L20B connected to a 'modified' 240sx down pipe grafted to the resonator under the floor. The Y pipe join is about 33" from the exhaust valves, like a long tube header. The pipe back has an expander to a new 2" muffler from a yard sale and a 45 degree down outlet.

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  • 1 year later...
On 8/7/2016 at 7:43 AM, KamakSun said:

Hi all,

 

510 expert  Ron told me to post a pic of my L20B manifold hoping that someone could identify it.

 

Please let me know what you think it is.

 

Respectfully,

 

Brian

 

B87D7A60-80BB-423F-A7B8-5E62D6548099_zps

 

 

 

 

 

 

It looks just like mine. I've lost track of what I pulled it from, but it's one of the true 4-into-2 ones with no air injector pipes. 

M9nr9Ky.jpg

xIN5Sru.jpg

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 The earliest use I know of, of an L20B, was in the '74 610. That might be from one... maybe.  They didn't have the air injection pumps. All other L20Bs starting in '75 were the co joined intake/exhaust manifolds. Not even close to looking like that one.

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  • 7 months later...
19 minutes ago, edekalil said:

Ok, I have to remove the old studs from a L16 exhaust manifold that connect to the down pipe. Any suggestions on how to go about it with out having to drill them out.

 

Heat and PB blaster?  If they are as rusted as mine were they will probably break when trying to remove them and you will have to drill them out regardless.  

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Just snap them off and remove the exhaust manifold. Take to someone with a torch. If there are nubs heat around to yellow hot and vice grips will easily turn them out. If snapped off flush you can only drill them for an easy out, then heat with a torch and turn them out. Did this with my L16 manifold and they screech but turn easily. I can't imaging doing this on the vehicle. I replaced the studs with SS and extra long brass? or bronze nuts. They looked kind of yellow? Several years later I took off for a wide band and they were pristine.

 

You can see where the heat was applied...

otASYRV.jpg

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On 8/7/2016 at 4:40 PM, datzenmike said:

I think the later L18 ones were the ones to avoid. Anyway, top one... avoid. Bottom is better

 

http://i138.photobucket.com/albums/q251/datzenmike/L%20Z%20Heads%20and%20Motors/standardand4intotwoexhaust001.jpg

I had one of each of these around. Found out the preferred one has a hole in one pipe which a welder friend said he could brass it closed plus the studs at the down pipe connection are in bad shape. The other was in better shape with no hole. So I gave it to him to get the studs out. We'll see how it goes. I'll stop by and pass your info on about getting them out using your advice Mike. Thanks so hopefully somehow I'll have the exhaust leak fixed and go from there.

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9 hours ago, banzai510(hainz) said:

Mine all sheared off and I had a guy do mine and a spare manifold in case this happens again im ready to swap it out

I'll have to see if I can locate one or Three in my area to take care of my other cars.

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  • 5 months later...

Big thanks to @Brandon S who I basically copied with my exhaust setup on my cam'd, bored, dual mikuni'd L20b in my 521. 

 

Because of my torsion bars I had to do 2" from the downpipe past the torsion bars and then 2.25" from there all the way back.  I used a vibrant resonator and a magnaflow muffler and  I think all in it cost me $800 or so.  Couple hundred for the muffler and resonator and $600 for the exhaust to be built.  

 

Magnaflow muffler (#14335) 

Vibrant resonator (#1790)

 

 

 

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  • 1 month later...

Ok, I need some opinions on a very controversial topic. I'm thinking about straight piping my 1979 210 and need to know if its a good idea. Some people say it'll destroy my valves some say it wont, what's the move? My AI4- with cat already has a rusted-ish exhaust system and the exhaust already smells cause old car shit. Would it be worth getting rid of the cat and muffler? 

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The only real question is will you want to put up with the raspy popping exhaust sound. You may say 'sure no problem' now, but it gets old very fast. Police won't like it, neighbors won't like it and a fine will cost more than replacing it properly. I wouldn't dump the exhaust where the catalytic converter is either. Run new pipe back to the rear axle at least. Exhausts are rusty, they all are. If you don't have leaks and holes I say leave it alone till it really makes economic sense to replace it.

 

Then:

I would run some kind of 'turbo' muffler that absorbs the snapping sounds and mellows it a bit. It will have low restriction and sound absorbing packing. Don't get any 'muffler' that you can see through end to end. Seems like the quietest mufflers are $30 but the least quiet are 4 times this. Noise and belief that noise is power... sells, go figure. Keep the stock pipe size, and what I did was use an expander coupling to increase the pipe size and fit a muffler with a larger inlet pipe. I think it was 1 7/8" up to 2 1/8 but a 1/4" increase. The muffler was a never used $29 generic I got for $5 at a yard sale. Physically it was larger than the stock one. Why spend more? The outlet was a 45 degree bend down to keep the hot exhaust off the axle. I don't have a converter but I do have a resonator up front, I left that. Muffler, clamps, expander was maybe $20. Nice low frequency rumble at idle and not really much louder when driving.

 

Will it melt your valves???? The short answer is no. Reducing your resistance to flow (back pressure) can upset your fuel mixtures in the cylinder. It might run richer or leaner, may add power in some places and take away in others but not by a lot. You can 'read' you spark plugs to be safe. If it really matters you can increase the carburetor jet sizes.

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23 hours ago, JacobBieg said:

Ok, I need some opinions on a very controversial topic. I'm thinking about straight piping my 1979 210 and need to know if its a good idea. Some people say it'll destroy my valves some say it wont, what's the move? My AI4- with cat already has a rusted-ish exhaust system and the exhaust already smells cause old car shit. Would it be worth getting rid of the cat and muffler? 

No. Not worth it. Too loud. Fire hazard. Snapping, popping gets old. Too loud. Muffler in exhaust makes more power (backpressure). Too loud. Do you like your neighbors? How about your ear drums?

 

Build a car so you won't get sick of it. That's the only recipe for a long life with that car. If you hate it, you won't drive it and it will sit and then rot and become worthless.

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On 11/15/2021 at 1:41 PM, Stoffregen Motorsports said:

No. Not worth it. Too loud. Fire hazard. Snapping, popping gets old. Too loud. Muffler in exhaust makes more power (backpressure). Too loud. Do you like your neighbors? How about your ear drums?

 

Build a car so you won't get sick of it. That's the only recipe for a long life with that car. If you hate it, you won't drive it and it will sit and then rot and become worthless.

Ok, I wasn't sure how loud it would be due to it only being 60hp but if the backpressure is needed in that engine than ill just consider redoing the exhaust as is, thanks

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Back pressure is just resistance to flow caused by the stock pipe diameter, length, bends, cat and muffler. The engine is adjusted to run, pushing against this factory 'back pressure'. If you remove some or almost all the resistance, the 'tune' can be affected and it may loose some of it's torque at lower speeds. It can be mostly adjusted out by tuning and making adjustments.

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On 11/17/2021 at 11:16 PM, datzenmike said:

Back pressure is just resistance to flow caused by the stock pipe diameter, length, bends, cat and muffler. The engine is adjusted to run, pushing against this factory 'back pressure'. If you remove some or almost all the resistance, the 'tune' can be affected and it may loose some of it's torque at lower speeds. It can be mostly adjusted out by tuning and making adjustments.

Soo like whats the move? I dont have to much money, so like what would i have to do in order to tune it for lower backpressure

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