1972 Dodge Demon 340 restoration

[CFD244]

My charcoal canister plan was to use the replaceable filter element (WIX 42998) both outside and top and bottom inside adding the wire mesh between the filters and the charcoal. Once the filter arrived I confirmed it also would fit inside the canister and order two more. I then cut the top and bottom stainless mesh filters including the small one for the center raised boss.
I fit checked then assembled the top filters into the cleaned canister using a bit of 3M spray adhesive to hold in place. Then the same process with the bottom. I then added the charcoal having previously measured the amount required (approximately 2 lbs.- basically full minus a bit). Finally I replaced the bottom using a thin bead of black RTV as an adhesive and sealant.
A side note the PCV valve is removable which being careful with 54 year old plastic I did. Be careful with the spring and metal cup the could fly away. The thin rubber diaphragm was dirty but intact. I cleaned everything and reinstalled the parts.
So that’s it. No drama but thought it was worth documenting.

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Nice job

 

[oldkimmer]

Awesome car and awesome work u r doing. Kim

 

[RustyRatRod]

Nice job on the charcoal canister! Most people would chunk it. Lots don't realize it can actually pick up a few MPG.

 

[Duster Garage]

I went through the same process with my 71 Duster in 2001. Very rewarding and enjoyable time. Best of luck. I look forward to your future posts.

 

[JDMopar]

Back to the pistons, if you haven't ordered and committed yet. KD243's are good pistons, but I have started paying more attention to the modern ring pack like Icon pistons use since my last engine assembly. That motor (273) had pistons with the 1/16 #1 &2 rings. It had significantly less drag than the last motor I assembled with KB pistons with the older/thicker rings. Talk to your machinist and see what he says.

 

[Whyjay]

Back to the pistons, if you haven't ordered and committed yet. KD243's are good pistons, but I have started paying more attention to the modern ring pack like Icon pistons use since my last engine assembly. That motor (273) had pistons with the 1/16 #1 &2 rings. It had significantly less drag than the last motor I assembled with KB pistons with the older/thicker rings. Talk to your machinist and see what he says.

I definitely want to discuss piston options. I’ve read through many forum discussions about options. I know the machinist doesn’t like going much more than 9.5 CR even at this elevation. The engine ran fine but seemed down on power for a 340. I’ll attribute that to the 318 heads.

 

[mpgmike]

The last engine I built I decided to use the upgrade chrome rings. They are supposed to last about 80% longer than the Moly rings, but take longer to break in. I'll never do that again, the "take longer to break in" part was quite excessive -- like 3k miles! With about 7k miles on it now, they are seated well.

 

[nckennyb]

Looks like you're doing a great job. I used to have a Top Banana 1972 Demon 340 so I like seeing one really get fixed right. I have the Silvolite replacement pistons in my current 340 and they've been doing great since 1996. Economical too.

 

[Renegade]

Great work!

 

[Whyjay]

Thanks for all the comments I do appreciate them.
While I struggle with the grill repairs I’ll share a bit about the transmission and recent discoveries. Last week when I sent the engine and heads to the machinists via a friend there was discussion about balancing the rotating assembly and that I would need to send along the harmonic balancer and flex plate. My friend assumed the balance weight would be in the flex plate like more modern engines instead of on the torque converter.
Years ago I had purchased a rebuilt balancer from The Damper Dr. so I just needed to dig it out of storage. Easy enough. But I didn’t recall seeing the balance weight on the torque converter when I had unbolted the transmission from the engine. Hum, I quick inspection confirmed that there wasn’t a balance weight! That explained the slight vibration I assumed was driveshaft and worn out engine and transmission mounts. The solution was to buy a B&M 340 cast crank specific flex plate. Way more beef than I need but it solves the problem.

 

[Whyjay]

So while on the transmission subject does anyone have opinions regarding the present torque converter behind a mild build 340? I’ve identified it as a Hughes 24-25.

 

[tom999w]

I went through the same process with my 71 Duster in 2001. Very rewarding and enjoyable time. Best of luck. I look forward to your future posts.

With the charcoal canister? That's strange, my '71 Demon never had a charcoal canister.

 

[tom999w]

Nice job on the charcoal canister! Most people would chunk it. Lots don't realize it can actually pick up a few MPG.

Most also don't realize that some states require the complete emissions/charcoal system to be operational in order to be street legal too..
No charcoal canister = failed inspection.

 

[CFD244]

With the charcoal canister? That's strange, my '71 Demon never had a charcoal canister.

In 71, they used the ECS tank. Charcoal canisters didn't show up until 1972.

 

[Three40]

Great Car! FE5 Red with the white stripes, top and interior really set that car off. Love it. Keep us updated.

 

[tom999w]

I'm just noticing from the pictures, it looks like before you moved you lived in an large-sized house, and then after you moved you lived in a jumbo-sized house. I'm just not grasping why a filthy rich guy is messing with A-bodies, and not Rolls Royces, 300 foot yachts, and Lear jets..

 

[dr dodge]

I'm just noticing from the pictures, it looks like before you moved you lived in an large-sized house, and then after you moved you lived in a jumbo-sized house. I'm just not grasping why a filthy rich guy is messing with A-bodies, and not Rolls Royces, 300 foot yachts, and Lear jets..

 

[Whyjay]

5

Ha ha good one thanks for noticing. IDK about filthy rich more like just filthy dirty especially after disassembling the 8 3/4. I almost forgot how nasty old gear oil is. Waiting for the Dr. Diff shim kit for the cone style sure grip.
Yeah we were looking for a place on 5 acres to get out of the city just happened that we ended up where we are but still had to build the barn for all the mopar “horses”.
This particular A body was our sons high school car. We sold it, it suffered through 5 owners before I found it and bought it back 20 years later. Thus all the effort and expense.
I really didn’t want to go full restoration. Been there before with my 71 Charger R/T Six Pack car. So I knew all about mission creep. Oh well it’s kept me busy throughout winter and spring.
I need to post some updates. Plus While I’ve been putzing around prepping various parts the body is getting some FE5 color!

 

[Whyjay]

I’m way behind posting progress! After the charcoal canister I moved on to the grill. At some point in its life somebody with a heavy hand tried to release the hood catch by pulling on the plastic grill. So a piece was missing when we gather car back. I purchased a parts grill with the intent of harvesting the missing section and grafting into the original grill. So that’s exactly what I did. I did use some thin ABS as doubler material at the splice joints and used black ABS plumbers glue as the adhesive.

 

[Whyjay]

I just took my time and tried to stay focused on repair -actually several repairs as I broke one mounting tab while handling the grill. It took several attempts before I was satisfied with my “bodywork”. Then the tedious parts of masking and painting. I used a light argent silver paint for the main areas there was some remaining evidence on the original grill. The grill horizontal bars received black SEM satin trim paint. Basically the process was mask- apply silver paint- remove masking - mask what was just painted -apply black paint. I’m satisfied with the end result but am concerned regarding the durability of 54 year old ABS plastic. I may still buy the reproduction grill instead.

 

[autoxcuda]

Moving along thought I’d share what’s going on with the 340. After doing a leak down test, with excellent readings- all eight cylinders less than 10% leak down, I was confident I could just clean it up, pull the pan to scrape off the generously applied orange RTV, check the oil pump pickup for debris and put it back together a prep for paint. That was the cheap me thinking.
After removing the original exhaust manifolds my suspicions grew. How come the exhaust ports weren’t matching the manifolds? Removed a valve cover and yup, someone had replaced the J heads with later model 318 heads. Ugh. With the heads removed I verified the cylinders were .030 over and had stock appearing replacement pistons (four valve reliefs and down in the hole approximately.060) plus tha couple cylinders had scrape marks like a pin clip had come loose.
So now the engine is at the machine shop. Hope it’ll clean up at .040 over. Piston pick is TBD but I’m considering a lighter weight ICON. Any thoughts appreciated.
The cam is an old comp cams 268H. To my eye it and the lifters looked fine. I’ll wait for the machinists opinion.

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I’d just buy a cast crank balanced SCAT stroker kit with 9.3-9.5 to 1 compression. Won’t need to: turn crank, resize rods for new rod bolts, balance.

Something like that XE 268 cam or tad more but I would call Bullet Cams for something to to work with your cast iron exhaust manifolds. Stroker soak up cam some.

Put in 2.02 valves in your J-heads, just clean up casting flash.

The added torque and power makes the car so much more fun to drive. The pistons and rods are so much lighter than stock it revs like your stock 340.

 

[Whyjay]

I’d just buy a cast crank balanced SCAT stroker kit with 9.3-9.5 to 1 compression. Won’t need to: turn crank, resize rods for new rod bolts, balance.

Something like that XE 268 cam or tad more but I would call Bullet Cams for something to to work with your cast iron exhaust manifolds. Stroker soak up cam some.

Put in 2.02 valves in your J-heads, just clean up casting flash.

The added torque and power makes the car so much more fun to drive. The pistons and rods are so much lighter than stock it revs like your stock 340.

Thanks for the thoughts. I was really considering a stroker kit but backed away. Once done this car will probably be another “drive to local car shows” victim. A stroker would be a waste. I need to find one with bodywork done and in primer, someone’s stalled project. Then I could have some fun.

 

[Whyjay]

Meanwhile I’m starting to see red. FE5 red!

 

[autoxcuda]

Thanks for the thoughts. I was really considering a stroker kit but backed away. Once done this car will probably be another “drive to local car shows” victim. A stroker would be a waste. I need to find one with bodywork done and in primer, someone’s stalled project. Then I could have some fun.

I don’t think it costs a heck of a lot more. Makes those drives to cruise-in’s more fun streetlight to streetlight.

 

[autoxcuda]

I just took my time and tried to stay focused on repair -actually several repairs as I broke one mounting tab while handling the grill. It took several attempts before I was satisfied with my “bodywork”. Then the tedious parts of masking and painting. I used a light argent silver paint for the main areas there was some remaining evidence on the original grill. The grill horizontal bars received black SEM satin trim paint. Basically the process was mask- apply silver paint- remove masking - mask what was just painted -apply black paint. I’m satisfied with the end result but am concerned regarding the durability of 54 year old ABS plastic. I may still buy the reproduction grill instead.

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Stick with your original one. Fits well and paint will match your headlight bezels.