I was hoping this could be a thread about all the little quirks the 4.X engines had over the years. I'll start off with what I know.
EXHAUST MANIFOLDS 82-85 4.1 eldorado, deville, seville, and fleetwood had cast iron manifolds (cross-over) 86 4.1 deville and fleetwood manifolds are tubular stainless steel, and different than all other years (cross-over) 86 4.1 seville are tubular stainless steel (cross-under) 86 4.1 eldorado are tubular stainless steel (cross-under) 87 4.1 rear seville, and eldorado manifold is tubular stainless steel (cross-under) 87-88 4.1 front seville, and eldorado is tubular stainless steel (cross-under) 87-88 4.1/4.5 rear deville, fleetwood are tubular stainless steel (cross-over) 87-88 4.1/4.5 front deville, fleetwood are tubular stainless steel (cross-over) 87-88 4.1 allante are tubular stainless steel (cross-over) 88-89 4.1/4.5 front deville, fleetwood are tubular stainless steel (cross-over) 88 4.5 rear eldorado, and seville is tubular stainless steel (cross-under) 89-90 4.5 front eldorado, and seville is cast iron (cross-under) 89 4.5 rear eldorado, and seville is cast iron (cross-under) 89-93 4.5/4.9 rear devile, fleetwood are cast iron (cross-over) 89-90 4.5 front deville, fleetwood are cast iron (cross-over) 90-95 4.5/4.9 rear eldorado, seville, allante and also 4.9 rear 94-95 deville are cast iron (cross-under) 90-95 4.5/4.9 front eldorado, seville, allante and also 4.9 front 94-95 deville are cast iron (cross-under) 91-93 4.9 front deville, fleetwood are cast iron (cross-over)
I think that is it! As far as I know all the manifolds will bolt to all the different displacemets 4.1, 4.5, 4.9 please correct anything thats wrong. Here are some pics of the stainless steel manifolds. I belive they are from a late 80's 4.5. They have a smaller diameter exit port(where the exhaust hooks up), and there is definately some room for flow improvement. The worst area is right inside the main exit port. Lots of jagged edges sticking out.
[This message has been edited by collinwestphal (edited 11-08-2004).]
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01:06 PM
PFF
System Bot
Master Tuner Akimoto Member
Posts: 2267 From: South Florida,USA Registered: Jul 2003
Here is a problem that I ran into lately for the first time after doing several 4.9 installs ,there are some manual flywheels that is made either in Tiawan or Mexico that if used with a 4X engine will cause the flywheel to jam against the oilpan and damage your clutch assembly.The reason is these are a little thicker than the original and has to be machined down or spaced with the little spacer from the automatic flexplate ..............just thought I would add this to the mix.
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01:35 PM
collinwestphal Member
Posts: 698 From: Waukesha, WI, USA Registered: Jun 2003
the rwd HT4100 manifolds will fit and work. the right one sweeps back at an angle while the left one dumps straight down. In my swap I used 2 left manifolds on my 88.
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07:39 PM
collinwestphal Member
Posts: 698 From: Waukesha, WI, USA Registered: Jun 2003
The maniflods pictured above weigh 5 lbs for the front, and 6 lbs for the rear (with the main exhaust port) Now all we need are weights of the cast iron ones!!
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09:08 PM
Dec 2nd, 2004
collinwestphal Member
Posts: 698 From: Waukesha, WI, USA Registered: Jun 2003
anyone have the weights of the cast iron manifolds?
Let me get home and I can weigh the 91 Eldo cross under manifolds and post pic's too.
OK I got home, these weigh 4lb's each. They are the front from a 91 Eldo.
------------------ 4.9 Caddy in Garage! Car in Driveway! ACK! **************************************** http://home.cfl.rr.com/fierose Central Florida Fieros http://www.centralfloridafieros.org Proud Member and founder of the DOWN SOUTH SUNNY WINTER PICK ON SNOW PEOPLE COALITION!
[This message has been edited by Kento (edited 12-02-2004).]
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04:47 PM
rockcrawl Member
Posts: 2528 From: Lehigh Valley, PA Registered: Jul 2000
no difference between stick or auto. I am almost certain the stainless ones are lighter than the cross-over cast iron ones. I am not certain about the cross-under cast iron ones. I find it hard to believe that they only weigh 4 lbs, but they are smaller, so I guess they could be.
The stainless ones are 5&6 lbs, I would guess the cast iron ones are 10 lbs each or so. Not much savings, but some. The stainless ones can crack over time, which I don't think the cast ones have a problem with. The stainless will let more heat into the engine bay too probably.
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02:31 AM
collinwestphal Member
Posts: 698 From: Waukesha, WI, USA Registered: Jun 2003
I forgot to add, if you go stick, you have 2 choices.
1. Extend the cross-over pipe to fit around the shift linkage on the transmission (easy) 2. Use the cross-under manifolds, and go under the tranny/engine
Both should work stock with the auto.
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02:33 AM
86fieroEarl Member
Posts: 2203 From: Orlando, FL Registered: Jun 2002
I forgot to add, if you go stick, you have 2 choices.
1. Extend the cross-over pipe to fit around the shift linkage on the transmission (easy) 2. Use the cross-under manifolds, and go under the tranny/engine
Both should work stock with the auto.
I did number 1 way on my stick 4.9, If I could start over again I would do the under the engine and tranny way, That crosover sucks being there period..... But it is easy to just extend the crossover to fit around the shift linkage.
------------------
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08:40 AM
Kento Member
Posts: 4218 From: Beautifull Winston Salem NC Registered: Jun 2003
Here is a problem that I ran into lately for the first time after doing several 4.9 installs ,there are some manual flywheels that is made either in Tiawan or Mexico that if used with a 4X engine will cause the flywheel to jam against the oilpan and damage your clutch assembly.The reason is these are a little thicker than the original and has to be machined down or spaced with the little spacer from the automatic flexplate ..............just thought I would add this to the mix.
I ran into this same problem with my 88' coup. A few whacks on the pan edge with a rubber mallet solved it.
------------------ Don Hites 88 GT 88 Coupe 4.9 V8
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04:45 PM
2-tone Member
Posts: 592 From: Winchester, KY Registered: Jan 2002
Is there anyone 'currently' running the TH-125 w/ the 3.33 gearing and the 2095 stall TC...?? What are your thoughts on using this tranny behind a stock 4.9L..?? I am going to switch to the 5speed later, but want to get it back on the road for now...
You wanted the weight of the DeVIlle exhaust manifolds? Mine weigh 18.2 lbs with the studs. Is heat the best way to remove them? I have soaked them with pb blaster for two weeks to no avail.
TIA
[This message has been edited by geobass (edited 12-23-2004).]
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06:41 PM
watts Member
Posts: 3256 From: Coaldale, AB, Canada Registered: Aug 2001
Just for motivation... look at the above... then this: That's the same manifolds (with crossover of course) after they just came back from being ceramic coated.
As for getting those studs out - try Lloyds Moovit, then apply heat, and crank 'em out with a pair of nuts locked together.
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09:01 PM
jeffndebrus Member
Posts: 2772 From: Jacksonville, Fl- usa Registered: Aug 2001
Just for motivation... look at the above... then this: That's the same manifolds (with crossover of course) after they just came back from being ceramic coated.
As for getting those studs out - try Lloyds Moovit, then apply heat, and crank 'em out with a pair of nuts locked together.
Oh Wow--that's purdy!!
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10:57 PM
Dec 24th, 2004
collinwestphal Member
Posts: 698 From: Waukesha, WI, USA Registered: Jun 2003
my 88 izusu 4.9 has no crossover. it has true duels.
Your exhaust would be improved by a crossover pipe. Crossover pipes dampen noise and increase horse power/torque. They were discovered sometime in the 60's if I remember right. They are an improvement over stock duals.
Here are some discussions/information on H and X style crossovers.
ust now much power are we talking about? This is one of those "it depends" things. Every combination sees different gains, but in testing, the power increase range runs from 5-20 HP at wide-open throttle (with corresponding increases in torque output).
Whenever you can reduce the load on an internal combustion engine, you are likely going to see performance and efficiency benefits. The difference between an H and X crossover is a smoother path for the exhaust gas to follow. Exhaust gas, like a liquid, will follow a path with the least amount of resistance. An H crossover has a path with two sharp 90-degree angles that are close together. An X crossover has a path with a much more gradual bend to allow the exhaust gases to continue their path back out to the ends of the tailpipes, rather then turning sideways for a short distance, then turn again to head out the tailpipes. Smooth flow with high velocity means more power by use of scavenging. Using an exhaust system with too large of piping diameter work against scavenging in the same way that running an exhaust with too small of tubing chokes the motor and forces it to work harder to expel the exhaust gases.
for those of you who really push your motor hard, you can strengthen your transmission brackets. I was bending the rear tranny bracket under heavy load. I decided to go with rodneys poly mounts, and some reinforced stock brackets.
This was my first real time using a MIG welder, and I think it turned out pretty good. They are MUCH stronger than before. I didn't need to do the front one, but I figured it was worth it for the peace of mind. This gave me some practice welding before I start welding my intake up. I'm scared to burn through it.
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07:05 PM
Jan 11th, 2005
collinwestphal Member
Posts: 698 From: Waukesha, WI, USA Registered: Jun 2003
To settle the exhaust manifold bit for once and all, I just took off my 4.9 deville manifolds, and compared them to the stainless ones.
The rear cast iron manifold is MUCH better. The volume inside must be an extra 50% over the stainless one. The exit hole, is also HUGE on the cast iron one. probably 40-50% bigger than the stainless hole.
The rear cast iron manifold is also roomier. I'd guess 25% more volume than the stainless one.
When I took my cast iron manifolds off, there were no gaskets???? I have never removed them before. I thought for sure there would be gaskets. How can it seal?
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09:07 PM
86fieroEarl Member
Posts: 2203 From: Orlando, FL Registered: Jun 2002
When I took my cast iron manifolds off, there were no gaskets???? I have never removed them before. I thought for sure there would be gaskets. How can it seal?
It is called a Surface Seal, if I remember correctly. Notice how much space is around them, as long as the surface is clean and flat, it will seal just fine because there is so much area. They do not have a gasket and will not have them from the factory.
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09:39 PM
PFF
System Bot
Jan 27th, 2005
NotAFieroAnyLonger Member
Posts: 4413 From: 75762/Texas/USA Registered: Dec 2003
theres room under there..?? Are talking about under the cradle..?? 
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