Hi guys,
My 1997 motorhome w/ 460 has an exhaust leak where the rightside manifold bolts up to the front pipe...right at the flange. Haven't taken a close look yet, but was wondering if Ford used a donut ring or paper gasket at this connection point??? Or, does the front pipe simply bolt up to the manifold, metal to metal?
Thanks for your thoughts.

Peter

 

This is a CUp and Cone connection. There is no gasket. It is supposed to seal along the tapered surfaces.

The 460 generate4s a lot of heat and this can weaken the exhaust pipe just after the flange. The pipe will wrinkle which tilts the cup and cone and then the seal is broken.

I have had this happen twice to me while towing. A weak spot in the 460. A shop quoted me about $80 to cut off the wrinkled flange and weld a new one in place. I stupidly took it to the dealer who replaced the whole Y pipe, $600, yeow.

I have read that a good low restriction exhaust will fix this issue.

Good Luck,

Jim Henderson

 

Thanks for the insight Jim. I just got in from having a good look at the design. I see what you mean by "cup-n-cone" attachment. I guess I'll try to loosen up the attaching nuts (currently soaking in PB Blaster) and attempt to re-seat the cup-n-cone. With crossed fingers, hoping to be successful. I'll keep in mind your repair results and checkout the new welded flange.

Peter

 

Peter, I own a 1995 F53; The "Y" pipe that Ford used on the motorhomes is very well designed and very heavy. The muffler is another story. It's very restrictive. If your F53 has the original muffler, do yourself and your MH a favor and replace it. Then re-seat the "Y" pipe on the manifold. Every thing else in the exhaust system is free flowing. There is no catalytic converter on 94-97 F53s. The first piece after the "Y" pipe is a resonator. If you really want to put a permanent fix on you exhaust system, contribute to Gale Banks retirement fund and he'll send you a complete Power Pack System. The you can wave at the V10s when you out pull them in the Rockies.

Richard

 

Hi Richard,
I know what you mean about the Banks Retirement Fund. I've looked into the Power Pac System and have considered it, but still trying to justify the dollars. Also looked at Doug Thorley ceramic headers which appear to be a decent alternative with a good price.
Currently, I'm stock from manifolds to tailpipe. When the time comes, I'll look at Magnaflow muffler for replacement, have one on my 454 Suburban and like it. Manifolds look surprisingly good for their age, all bolts are in place and no leaks.
This has been a Florida M/H since birth and now lives in Massachusetts, so I'll be watching closley for corrosion and such due to the amount of road salt tossed around here in winter.

Peter

 

LT46, sence you got to pull it apart to fix it & you'll probably need to go to a muffler shop anyways, check with them & see if they have any diesel pickup take offs laying around.
Lot of young guys getting these diesel pickups & changing out the exhaust system for a larger system & just leaving the old stock stainless system behind.
The stock exhaust system on a F350 7.3 Super Duty has 3 1/2" pipe & muffler out to the tail pipe & all stainless so no worries about corrosion.
Just have a 2 1/2" to 3 1/2" adapter made & hook on at the Y pipe & go from there.

When you take a 460 engine & put it into a motorhome, unless it is like say under 20' long, that engine should be considered under severe duty conditions at most all times when running. Yours being EFI removes a lot of the high exhaust heat issues that those engines will see just trying to move the unit because of the computer controling things.
Those heads on the 88 & up engines are dsigned a little different from the old carbed model engines & have less problems getting the high heat out & into the muffler system. This is why its important for having a good flowing exhaust system, to get that heat out.
If you have back presure, which would cause heat to stay longer around the valve & valve seat areas & then if something should happen to the computer & it start leaning out the engine, those valves & their seats are dommed.

I have a 88 36' M/H with a carbed 460 & have to date spent around $5,000.00 so far tryin to keep from burning up the valve seats in those heads.
Heads have been off 3 times to install different valve seats that maybe could do the job. Right now it has carbide seats & Inconal exhaust valves & doing right well, but only time will tell if they will hold up.

High exhaust heat & getting it out of that engine any way you can what you need to be thinking right now or else the engine will suffer soon or later.
Neil

 

C-Leigh Racing wrote;
"LT46, sence you got to pull it apart to fix it & you'll probably need to go to a muffler shop anyways, check with them & see if they have any diesel pickup take offs laying around.
Lot of young guys getting these diesel pickups & changing out the exhaust system for a larger system & just leaving the old stock stainless system behind.
The stock exhaust system on a F350 7.3 Super Duty has 3 1/2" pipe & muffler out to the tail pipe & all stainless so no worries about corrosion.
Just have a 2 1/2" to 3 1/2" adapter made & hook on at the Y pipe & go from there."

Thanks Neil, excellent idea! I'll 1st try to re-seat the pipe but if that fails (I'm expecting it will) my next stop will be to a muffler shop for a work around.

Peter

 

Something else you might could try, pull the Y pipe completely off, out of the way & check the manifold & see if its cracked in that area or burned out & caused a hole that the flange cant seal. More than likely though the Y pipe is at an angle such that when you tighten up the nuts it cant seal like its suppose to.
If its just not sealing, might could get a torch & heat the flange lip of the Y pipe red hot & then tighten up the nuts real quick & make it seal that way.

You may even end up like they do the chebys & have a short piece of pipe inside the manifold & Y pipe for extra sealing effort, like a little nipple of sorts.
Neil

 

UPDATE

Disconnected the pipe/manifold flange and can see exactly what Jim had reported. A crease/wrinkle in the forward half of the Y pipe and the subsequent out-of-round tube. Manifold end looks perfect. The gap is the thickness of a matchbook cover, ever so thin, but what a racket it makes.
Gonna try a bandaid fix for the short term and will probably drop the Y pipe at the end of camping season and have a new flange welded on. Checked with Ford and they want $800+ for the Y pipe. YIKES...are they NUTS????
Bandaid fix will include a thin layer of Permatex Hi Temp (Red) gasket goop along the flared out forward edge of the Y pipe and then sealing over the top of that with some exhaust putty. I know, I know....it'll never hold and simply blow out....but it'll make me feel good for 30 seconds or so
The real fix will come at the end of camping season.
Thanks guys!!!!

Peter

 

Man!, go ahead & pull that Y completely off & see if you can hammer it back in shape. Better yet get the muffler shop to form you a new end & weld it back onto the Y.
Your doing a lot of hard to get at work under there & that permatex aint even comming close to a bandaid fix, be blowed out & gone before you ever leave the driveway.

Think about this, that carbonmonoxide from the exhaust leaks going to find its way inside that camper, & you know what that does. Seal it up even if you got to get some stove cement & blob around the opening.
Neil

 

C-Leigh,
You're 100% correct but I've got a time line to deal with. Leaving Friday for weekend get away. So, bandaid it'll be for the time being. Have lived with this nuisance all season, so what's another 30 or so days?
The way I figure it, next time I drop this pipe it'll be a breeze. Ya know, looking at the pipe, it very well may be able to be hammered out. Heat and hammer-n-dolly will probably do just fine. Will attempt this 1st and if I bung it up, new welded flange will be the final fix.

Peter

 

Probably too early to claim complete success, but so far (fingers crossed) I've silenced the exhaust leak. At idle anyways, haven't hit the road yet
I did manage to better reseat the pipe to mainifold by moving the pipe a bit using a wooden wedge here and a tap of the hammer here. Seemed to button up much more flush to one another. The bead of Permatex hi temp goop seems to be holding but only time and a good hot run down the highway will be the true test. A camping we must go, so with fingers crossed, I'm loading the MH fridge with adult beverages. I'll tip a few to all who've offerred their insight. Thanks again and I'll report back after the weekend.

Peter

 

Final Update;
Put 300 miles on the MH and my repair has held, complete success! I believe the fix had more to do with repositioning the front pipe than using the Permatex Hi temp goop. As I said earlier, I got the front pipe to come forward a bit which allowed the mating surfaces to line up much better than they had been before. The goop filled the mini gap at the front and hasn't disintegrated. I'm happy that the tick tick tick is gone and enjoyed the adult beverages I tipped in honor of all those that have offered insight.

Peter