exaust problems

[73dreambronco]

Im putting a new exaust on my 73 and ive added hedmen headers in place of the old manifold, is there anyone that sells a full system for a single 3" pipe. my collecters are 2 1/2" any help will be appreciated

73dreambronco

 

[bluesman17]

why dont you want the dual pipes?

 

[73dreambronco]

why dont you want the dual pipes?

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Why do they make a kit for the dual pipes, and if so who offers this and how much?

thanks

 

[S_bolt19]

just go to a reliable muffler shop, not Midas or Parts America or one of those parts stores that have garages in them. Most of your locally owned shops are pretty good about it. For that matter talk to someone with a muscle car and find out where he had the exhaust done and go to that shop. Shouldn't cost you more than about $250-300 for true dual exhaust. Put a set on turbo mufflers on it and you will have a nice sound and a good breathing engine. I dont think I would go with a 3" pipe though, are you running something that is putting out more than 300 hp? You can over pipe your exhaust just like you can under pipe it too. With true dual and a 289/302 you shouldn't have to go any bigger than a 2-2.25" pipe. If you have too much pipe, your engine won't have the back pressure to give you all the horse power the engine could be producing, just like a 1" pipe would constrict the hp output.

 

[Broncoholics]

I run a single 3" exhaust pipe with one flowmaster. Its loud but it works. Since I run a 205 t-case the dual exhaust couldn't run over or around it and I didn't want to go under. So I did a Y pipe - see below photo. Both exhaust tubes off the manifolds are 2.25" and enter into 1ea. 3" pipe to exit. Anything smaller than 3" will cause overheating. Or at least from what my buddy said at the exhaust shop. I still have some overheating problems. Could this be the problem I have? Not sure until I try 3.5" or 4"...

 

[S_bolt19]

Well considering that the original exhaust size is 2-2.25", I dont buy the overheating information your buddy gave you. A Y-pipe is what was original in there in the first place. For overheating, I dont think the size of your exhaust will directly cause that. I dont know for sure, but I find it difficult to relate cooling problems to exhaust plumbing unless your manifolds are cracked.

Does your fan shroud have cracks in it? What about getting a new thermostat or a bigger fan or one with more blades. I have been real lucky because I have never had mine run hotter than 190 on a blazing hot day....Blazing here in Colorado is about 95-100...A couple of years ago, my fan shroud cracked at the mounting screws and it fell into the fan. I ended up replacing the fan with one from Checkers that I think has 7 blades on it and my running temp dropped from average 180-185 to a steady 175 all the time. Summer, winter, altitude, non altitude...whenever. It would probably do even better if I put a new shroud on too...lol.

But the point of my ramblings is that I dont think your overheating problem comes from the size of your exhaust. There could be a number of reasons you are overheating. The ones that I might look at first in order are the schroud, fan, thermostat, radiator fluid, water pump, radiator, heater core. I would guess the problem is somewhere there. Flush the system and start there.

 

[bluesman17]

Do you have a straight six or v-8? i should have asked that before

 

[Broncoholics]

Yeah, myfan shround does have some air gaps I should fill. Jeff's Bronco Parts sells a fan shroud for Broncos with body lifts. Took a few modification cuts so the fan would clear. It helped but not enough.

The exhaust manifold does have a crack or leak as it makes a ticking sound. Its done this for years. I've tried new gaskets with no luck. I wouldn't see why this could cause the motor to heat up? Tell me more.

 

[Orangecrush]

Yeah, myfan shround does have some air gaps I should fill.  Jeff's Bronco Parts sells a fan shroud for Broncos with body lifts. Took a few modification cuts so the fan would clear. It helped but not enough.The exhaust manifold does have a crack or leak as it makes a ticking sound.  Its done this for years. I've tried new gaskets with no luck.  I wouldn't see why this could cause the motor to heat up? Tell me more.

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Have you checked your spark and/or valve timing? ******** would obviously heat things up.

As for exhaust, 3" exhaust will flow about 100% more air than 2.5". Unless there's a restriction of some type, the exhaust itself shouldn't hold heat in the engine/water. Quick check would be to check manifold vacuum and see if it's too low and/or drops steadily at one rpm. I doubt it though.

Mine's getting a little hotter than it was up until I monkied with the spark timing (while dicking with that whole bad carburetor issue that I'd just as soon forget about). I am sure that if I advance the timing a little more, it will cool off slightly. After that, I'd get myself a 7-blade fan from Summit.

 

[Broncoholics]

Just ran out to my Bronco. It only has a 5 blade fan! I always thought it was a 6 blade! Better put the beer down! I bet a 6 or 7 would work pro. I'll let you know...

 

[S_bolt19]

Definatly get yourself a 7 blade fan. That will help a ton. I forgot all about timing. THAT will help emmensly. Be sure to take into consideration what altitude you live at. Seeings how you are in WA state, I would assume that you probably arent more than 2-3 thousand feet above sea level. Use that as your bench mark. If I remember right, timing on both the 289 and 302 is 6 degrees below TDC. Like I said I dont remember if it is BTDC or ATDC, either way, if you are at 3000 feet altitude set it at 9 degrees A or B TDC. Here in Colo. I used to have mine set at 12 degrees (that was before EFI Conversion /emoticons/[email protected] 2x" width="20" height="20" /> ) and mine ran like a champ every day. When I headed to the hills (9-10k) I would bump the timing up.

But glad Crush brought that up...that could be your problem too.

As for the ticks you said, is it coming from the cylinder on the pass side, back of the engine, right above the starter? If it is, every older Ford engine I have run across has had that same problem as some point in time. Both of my EBs had that problem, so does my 66 'stang as well as my dad's 'stang. I have heard that tick on 289s, 302s, 351s, 360s on up. I have been told that it is an oil lubrication problem that Ford had on the older heads. Whether it is true or not, your guess is as good as mine is but like I said, all the older Ford engines I have run across seem to have that same problem.

 

[Orangecrush]

My 351 "ticks" too....at the back of the left (passenger side) bank. I has fresh cam and lifters; so, that's not it. Either exhaust or a noisy valve. Either way, it seems to run very strong.

 

[Broncoholics]

I figure its a crack in the exhaust manifold or its leaking around a bolt due to a possible crack in the head. Could be why its over heating as well. With a stethiscope I can hear the tick right at the manifold (passengerside) on the bottom but can't quite find it exactly.

It never had the tick until I took off the heads to replace a cracked piston. At first I thought it was a gasket so I got a new one. No dice. Had a friend at the exhaust shop play with it and he thinks its a warped or cracked manifold. Good time for headers eh?

You are right, timing could be the issue of overheating. Works great at sea level but I'm driving fast on pavement. When I hit the mountains it heats up but now I'm climbing hills slow in low range.

I'll try a 7 blade and bring a timing light on my next trip.