Catalytic converter

[xboxrox]

catalytic converter replacement plan (not a California CARB version) 1986 Power Ram50

Drivability & History:

Truck has a worsening trend toward poor gas mileage, intermittent miss, acceleration lag,tendency to run hot up steep grades, lack of power, rough idle AND has had adjustments for ignition timing, RPM setting and new parts for Mikuni carburetor, distributor ignition module, spark plugs, plug wires, coil, PCV valve, both engine coolant sensors, O2 sensor, oil pressure sensor, new muffler, new cylinder head, air, oil, crankcase filters new, etc... Hawaii roads are mostly 25MPH stop & go driving which leads to a plugged catalytic converter... There are freeways on Oahu where the truck can be driven long enough & fast enough to heat up the catalytic converter to burn off the crud that collects inside a converter...

Reference:

https://mechanicbase.com/engine/bad-...rter-symptoms/

Photo of exhaust manifold catalytic converter canister taken when replacing O2 sensor:



PARTS:
Exhaust Manifold to Catalytic converter inlet Gasket MB687020
Catalytic converter outlet to exhaust piping Gasket ???
Catalytic converter as shown in photos below (OEM Catalytic converters are obsolete & not available)




WORK STEPS:

1) Accumulate parts
2) Remove piped catalytic converter
3) Clean out old catalytic converter canister & remnant from inside the exhaust manifold (truck will use only one catalytic converter)
4) If needed target old catalytic converter on workbench & reuse it's piping ends onto new converter if new converter is not an exact fit...
5) Test drive with X'd fingers...


comments, suggestions, bashes..? cheaper ways of DIY..?

[FMS88]

If the upper converter is plugged, does it necessarily follow that the lower one is plugged too? (Others in the community may be able to answer this question.) If only the upper cat may be plugged, why not remove it, give it your proposed treatment, then see if the problems persists? If so, then get the lower cat and install it. Dividing the repair into two parts would require little duplicate effort, but also save purchasing the lower cat if found replacement isn't needed.

Also, I have MD100652 as the P/N for the lower cat. A few Mitsubishi parts warehouses list it (but that doesn't mean they actually have it) for around $350 plus shipping. The P/Ns for the upper cat are MD084434 / MD167726. Lists for $275.

[xboxrox]

FMS your point is well taken & I will break the work into II parts as you suggest, great idea TYVM... Monday I will phone Jason @ MPC in Texas using your part #s for availability...

[xboxrox]

UPDATE: Phoned REAL TRUCK 866-904-2650 for availability & shipping price to Hawaii for Magnaflow Direct Fit FED catalytic converter MAG-23238 ~ item is not stocked but they will contact Magnaflow Monday to see if the item is available ~ their lowest shipping cost to Hawaii is $140.00 (ouch)

REAL TRUCK: https://realtruck.com/p/magnaflow-di...e/ram-50/1986/



Item no longer available...

[xboxrox]

If the upper converter is plugged, does it necessarily follow that the lower one is plugged too? (Others in the community may be able to answer this question.) If only the upper cat may be plugged, why not remove it, give it your proposed treatment, then see if the problems persists? If so, then get the lower cat and install it. Dividing the repair into two parts would require little duplicate effort, but also save purchasing the lower cat if found replacement isn't needed.

Also, I have MD100652 as the P/N for the lower cat. A few Mitsubishi parts warehouses list it (but that doesn't mean they actually have it) for around $350 plus shipping. The P/Ns for the upper cat are MD084434 / MD167726. Lists for $275.

TODAY'S PROGRESS

FMS thanks for this info ~ it was too late to phone mainland Mitsubishi dealers today by the time I got finished with other phone calls to O'Reilly's, Carquest, E-Trailer, Magnaflow Co. etc...( must check availability of these Mitsubishi Part #s you provided...)

Phoncon Results today:

O'Reilly's has Magnaflow 334104 CARB cat $229.00 + $10.00 shipping
Magnaflow Co. says their direct fit FED cat MAG23238 is no longer available (rep said their CARB & FED cats are same..!?!)
Walker website states that a CARB cat should last longer than FED with it's better outer coatings & better (more?) chemicals inside
CarQuest has Walker FED cat 15051 $121.99 Free Shipping
MPC MB687020 Gasket exh manf to exh piping is available (no answer yet on rear gasket...) OEM cats obsolete & not in stock nationwide
MEGAZIP website shows part #s for the bolts springs etc to connect piping to exh manifold (not checked yet)
Pacesetter direct fit FED cat listed as no longer available at Summit Racing and other sites as well; will phone PaceSetter Co.
E-Trailer says Magnaflow Direct Fit FED cat MAG23238 is no longer available

Looks like cutting & welding the SS409 piping of a new cat will be required to install either the O'Reilly's CARB cat or the CarQuest FED cat ~ IF the original piping on my truck can be reused after removing the old cat... IF so, then maybe mgr Chad at Five-O-Motors will allow me to work with his one employee that knows a little about welding ~ providing their weld machine & equipment is operational & capable of using the proper welding wire for SS409 exhaust piping BLAH BLAH ah HECK..!?!
To conserve energy and time & most likely have a sat fix; will measure the O.D. of my truck's exh pipe then order the rear cat and hope all goes well removing all the bad & installing a new rear cat (exh manf will not have a cat unless MD167726 is available; will phone MPC again...)

QUESTIONS

Has anyone ever removed the upper catalytic converter case from the exhaust manifold..? Any help with this is much appreciated & does anyone know if the exhaust manifold with rear cat attached can be removed from the truck in one big piece..?

My engine is still using plenty oil even after installing a new cylinder head ~ oil ruins catalytic converters ~ maybe there is a way to help piston rings seal (soak Marvel Mystery Oil into the cylinders..?) The cylinder head & oil pan need removal to access rings, right (?) Wow a rebuilt short block in my future..? Shipping to Hawaii..!?! The CARB cats are built to last 5 years or 50,000 miles while the EPA & FED cats for 25,000 miles... RockAuto has a 1986 MM DEC brand CARB cat for $1,679.00! Will phone DEC see if they are still in business, prices and if they might sell me the parts only for DIY welding...

Phoned Jeff @ DEC and he referred me to ebay store BIG RED AUTO PARTS (a Calif dealer that sells DEC products) contacted Big Red through their ebay store & their Facebook page; they acknowledged receipt of my mssg and will get back to me soon...

[xboxrox]

UPDATE: ebay store BIG RED AUTOMOTIVE sells an EPA/FED rear catalytic converter link here:https://www.ebay.com/str/bigredautoparts

PART# CR2421

I sent them an email asking if they would ship the cat to Hawaii because their ebay store says no shipping outside the 48 states... Google search has results that say DEC bought PaceSetter Co.

[FMS88]

My engine is still using plenty oil even after installing a new cylinder head ~ oil ruins catalytic converters ~ maybe there is a way to help piston rings seal (soak Marvel Mystery Oil into the cylinders..?)

How much oil is it using? Is it as bad as (or worse than) before the head replacement? Does it blow blue smoke all the time, or on start ups and mostly when accelerating from a stop? If it's a serious issue, best to address before worrying about the catalytic converter.

If the consumption is excessive, do a compression test and maybe a leak down test if the compression test results are concerning. If it passes these tests, the rings aren't the issue. Maybe they used low quality valve stem seals on the new head. Bad seals won't affect compression readings, but they will increase oil consumption.

Regarding your questions about the manifold and converters removal, I don't know for a fact, but it looks like there's room to remove everything together. To separate them, use plenty of WD40 and an impact driver. Hopefully they're available at Five 0 Motors.

If you do disassemble the manifold and cats, why not give the lower cat the same "treatment" as the upper cat? It would save the cost of a new lower cat. Or alternatively, why not get a set of Pacesetter headers which are about as costly as the lower cat? Both options aren't EPA compliant, but neither is treating the upper and replacing only the lower converter.

[xboxrox]

How much oil is it using? Is it as bad as (or worse than) before the head replacement? Does it blow blue smoke all the time, or on start ups and mostly when accelerating from a stop? If it's a serious issue, best to address before worrying about the catalytic converter.

If the consumption is excessive, do a compression test and maybe a leak down test if the compression test results are concerning. If it passes these tests, the rings aren't the issue. Maybe they used low quality valve stem seals on the new head. Bad seals won't affect compression readings, but they will increase oil consumption.

Regarding your questions about the manifold and converters removal, I don't know for a fact, but it looks like there's room to remove everything together. To separate them, use plenty of WD40 and an impact driver. Hopefully they're available at Five 0 Motors.

If you do disassemble the manifold and cats, why not give the lower cat the same "treatment" as the upper cat? It would save the cost of a new lower cat. Or alternatively, why not get a set of Pacesetter headers which are about as costly as the lower cat? Both options aren't EPA compliant, but neither is treating the upper and replacing only the lower converter.

The Saga Continues to Evolve

FMS88 I have never measured oil used per miles driven but the oil used is about the same as before & after the new cylinder head install ~ just seems that every or every other gas fill that it needs at least 1/2 to one quart of oil ~ I put gas in the truck whenever it is 1/4 full and am not sure how much mileage it gets per gallon of gas ~ 5 years ago when we shipped the truck to Hawaii the best it ever got was 22 MPG ~ but, new tires caused a drop in MPG to about 18 to 20 ~ replacing the O2 sensor made a world of difference in smooth idle, no more miss & gray colored tailpipe BUT that only lasted two days ~ since taking the truck (1/26/23) on the H3 fwy for a 26 mile mission @ 60 MPH, it used half a tank of gas per the gauge WOW BAD WORSE EVER YET and I noticed going up the steep 3000 ft elevation the engine coolant temp gauge got up to 3/4 to 7/8 scale almost reaching the red mark ~ so, gas mileage is poop; the engine runs very warm on a steep grade; loss of power could not get over the Koolau Mtns in 4th gear as usual but had to use 3rd gear, and there is often a big lag of power now, as tho no fuel is getting to the engine but then after a moment it slowly picks up and goes (using a very slow gradual press on the accelerator usually prevents this nagging new miss) ~ my gut is telling me after seeing the front catalytic converter full of crud blocking the honeycombs that a fix is needed to the exhaust cats, at least ~

I hear you about damage to cats 'n should fix those problems before install of a new cat (truck had a recent history of coolant out the tailpipe & an O2 sensor that was toast and perhaps 35 years old..!? and, a history of burning some oil) all of which ruins cats ~

With regard to putting this California version truck back to legal C.A.R.B. smog standards you're right, it ain't gonna happen on my watch; it would cost too much and I doubt it will be shipped to Calif, but you never know ? anyway, since Hawaii only requires an EPA/FED style cat and since I have not yet checked MitsubishiPartsCentral about availability of that front case style cat inside the exhaust manifold; the plan is shaping up (if Big Red Auto supplies the rear FED cat) to install a new rear cat into the exhaust piping ~ hopefully a FED cat there might last near the 25,000 miles before getting plugged or rusting off and it should help prevent nasty exhaust smells ~

The direct fit Big Red cat is $300.00 free shipping to mainland

If Big Red Auto will not supply their cat then I will be forced to buy a cat from my local O'Reilly's which has C.A.R.B. cats for the truck but it would require me to cut weld fabricate the old piping onto the O'Reilly's cat priced @ $229.00 + $10.00 shipping ~

Heck, I still need to measure the O.D. of the exhaust piping; it must be either 2" or 2.25" as that is the size cats everyone sells; RockAuto lists the manifold to piping gasket size as 2.25"

At least Big Red Auto might be a source for folks needing a catalytic converter for these trucks..?

Do you think any California SMOG inspector or SMOG station is savvy enough to check the front cat being missing inside the exhaust manifold..? I think not but they sure as heck would look for the CARB # on the rear cat, yeah..?

I really appreciate your estimate that the manifold & cat could come out as one piece, not sure the difficulty of removing those two spring covered bolts holding exh manf to pipe, hmmm...

Life is Good
Aloha ~ George

[FMS88]

Okay. If oil consumption is the same as before I'm less concerned. Looks like you're getting up to 1000mi per quart which isn't great but not terrible. I think the converter can handle that for quite a while.

Getting the manifold and converters out and apart may be challenging due to rusted bolts and nuts. Hit them with multiple applications of WD40, heat and vibration from a hammer or impact wrench to loosen them. Once they're separated, see if you can tell if the lower, rear converter is plugged. It may not be which will save you time and money spent to replace it.

[xboxrox]

You really wanna put me to work & not spend much money doing it too FMS..! I may just take the truck to Five O Motors they are open today ~ maybe O'Reilly's has gaskets..? I have a food butane torch & new can of PB blaster...

Found another supplier of the DEC Pacesetter direct-fit FED catalytic converter ~ they FB mssg'd me they have it but must phone them for shipping to Hawaii price ~ search for 1986 MM: https://www.sfxperformance.com/


I roughly estimate the truck burns 1 qt of oil somewhere between 500 & 800 miles..? A guesstimate...

[xboxrox]

Feb 1st Update:

There are no OEM Mitsubishi catalytic converters for our trucks on the planet; per the Costa Mesa, CA Mitsubishi parts dept...
Big Red & SPX are not answering phone calls or ebay & FB messages..!

[FMS88]

Not surprising that there are no OEM converters. Why not take it to a muffler shop to see what they would do? If you can learn from them what part they’d use, how they’d install it and their charges, it might help your decision process.

[SubGothius]

Just as well no OEM cats are available anymore, as those likely would have been the older pellet type of cat. Current aftermarket cats are (nearly?) all the honeycomb type, which used to be sold as a "free flowing" aftermarket upgrade by Magnaflow/etc.

Also, the only difference between "direct-fit" vs. an equivalent "universal" cat of the same size/spec for the same vehicle application is that direct-fit come with mounting flanges already attached, whereas universal need to have flanges welded on at the proper overall length to swap in for the stock cat, or can just be welded into the exhaust piping directly, sans flanges.

[xboxrox]

Good Points Sub & FMS

Some good news today ---> SFX Performance https://www.sfxperformance.com/ finally contacted me by Facebook messenger ---> they were shut down by the big freeze ice snow storm that hit their Texas location the other day ---> they will ask the cat manf factory (DEC..?) to use the lowest priced method of shipping to Hawaii if we do buy their rear cat ---> SFX is only a distributor & so is ebay's BIG RED but big red has not replied to my messages..!

If I can get some exh gaskets from O'Reilly's then I would like to try using the lift at Five O Motors and some heat, PB blaster & rattle gun to loosen the exh manf to pipe fasteners and the rear flange joint fasteners too ---> then sometime, try removing the rear cat assy for inspection and access to the front canister cat IOT remove it from the exh manf...

Eventually, am hoping this thread might provide catalytic converter solid info & source of supply ---> possibly get the truck running normal again which could/would help members with similar engine issues...

[xboxrox]

Was able to reach & loosen the 4 rear cat bolts in a dry run for removing the cats this week ~ I think the front cat container is bolted to the exhaust manifold; if so, plan is to remove it due to it being plugged ~ once it's removed reassemble & test the rear cat & exhaust system for back pressure ~ a failed back pressure test will require replacing the rear cat...

[xboxrox]

Whew..! Glad the site is back up & running ~ Thanks Marty

Inspected the exhaust system again and decided to purchase the rear cat as a result of seeing how bad the front cat is plugged (the truck was burning coolant with cracks in the cylinder head for a couple months before A miss & bog got really bad...) Removed the exhaust manifold heat shield to expose the five bolts holding the front catalytic canister case onto the manifold ~ it might be possible to remove both cats out the bottom w/o having to remove the exhaust manifold (?)

Buying the rear FED catalytic converter assembly from https://www.sfxperformance.com/

[FMS88]

Not sure if the upper cat can be removed from below. Take off the two lower heat shields first then give it a try. If you do have to remove the manifold, you can re-use the head-to-manifold gasket.

[xboxrox]

Received the new rear cat today and Wed, Thur or Fri next week will do the install

[xboxrox]

(The FRONT & REAR catalytic converter assy came out from the top; the exhaust manifold did not need to be removed...)
Removed FRONT catalytic canister which was melted & plugged inside the exhaust manifold attachment ~ the REAR cat was OK & reused it ~ also discovered a vacuum hose split and not attached to it's barb under the carburetor ~ the truck now runs normal; no miss, no bog..! Photos 'n more details soon
Thanks to those who gave me helpful advice ;^)

[FMS88]

Good to see all went well. How difficult was it to separate the upper cat from the manifold? I’m very curious to see what it looked like and how you unplugged the upper cat.

[xboxrox]

Good to see all went well. How difficult was it to separate the upper cat from the manifold? I’m very curious to see what it looked like and how you unplugged the upper cat.

We used an air driven impact gun on low setting with 12mm socket to break loose the five front cat case to exhaust manifold bolts...

Wife helped a lot ~ she used a long blunt nose chisel & small hammer to knock out the melted honeycomb material & she crawled under the truck to hold the rear cat while I bolted the front cat casting onto the exhaust manifold ~ she really was helpful..!

FMS88 your advice to do this before purchasing the rear cat was spot on (our existing rear cat was alright) & would have saved us $350.00 BUT we will keep the Pacesetter cat as we plan to keep the truck ~ we would have used the new rear Pacesetter cat except it required drilling larger holes to slip onto the spring bolt shafts & it does not come with the bracket to mount the original heat shield metal ~ also, the "V" shaped gaskets they provided were too small I.D. to fit over the pipe end of their cat ~ so, we had to reuse the original formed "V" shaped gasket... and, their cat inlet pipe is a little smaller I.D. than our existing cat (see photo) who knows if it might increase or decrease power... Hope photos answers your ??

[FMS88]

Thanks for your post and pictures. Now I know how the honeycomb was fixed inside the cast iron casing. The surrounding mesh makes sense plus I bet it made removing the honeycomb easier.

Too bad you couldn't use the new cat, but then by not needing it, you saved a lot of time and effort to make it fit correctly. Nice work on your part and your wife's!

[xboxrox]

Thanks for your post and pictures. Now I know how the honeycomb was fixed inside the cast iron casing. The surrounding mesh makes sense plus I bet it made removing the honeycomb easier.

Too bad you couldn't use the new cat, but then by not needing it, you saved a lot of time and effort to make it fit correctly. Nice work on your part and your wife's!

Thanks for all the Kudos :^)

IMHO that mesh was the only way any exhaust gas was able to pass through the system ~ the photos don't really show that the entire honeycomb was plugged or melted...

In a 1/2 mile distance WOT test drive to a fwy exit the "before" speed reached was 55MPH and the "after" speed reached was 75+MPH ~ altogether, no real butt-oh-meter increase in horsepower but just a smooth running keep up with traffic daily driver...

Aloha & Mahalo
George

P.S. Other reasons for not installing the new rear cat (yet) include time constraints at Five-O-Motors shop 9am to 6pm; we checked in at 12 noon got on the lift and finished at 4:30pm, customers must stop work & begin cleanup at 5pm... Also, they are not well equipped with drills or drill bits... Some other day we can prep the new rear cat and procure a proper size gasket for it's connection to the spring bolted joint...

P.P.S. Assuming our truck's exhaust system was the stock Mitsubishi (?) I guess in 1986 the Japanese were not required to place a C.A.R.B. number on the rear cat as there are no markings on it... This is a California model truck shipped from Nagoya to Portland then trucked to California ~ the bill of lading military purchase orders showed 7 of these trucks bought by the China Lake Naval Weapons Station near Ridgecrest, Ca.

https://en.wikipedia.org/wiki/Naval_...ion_China_Lake