Nylon-toothed timing gear.

[6thGenImperial]

back to your question... the intake manifold is the same as a carb 318. The gasket that the TB sits on there at the intake manifold is a common vacuum leaker and a new one should be a regular maintenance replacement item if you're keeping it EFI. They won't run if they lose much vacuum.
Special to the Imperial were engines, transmissions, rear axles, and ancillary components. This page from the brochure shows how they were given special attention and used thicker body panels http://imperialclub.org/Yr/1981/Brochure/81brochure2Jmd.jpg
They screwed down the body parts like the engineers wanted them, no doubt they are the best build quality FMJ cars (except for the doomed EFI, of course). I presume the engines were selected for the best balanced crank assemblies and should be duly stamped by the engine block number, likewise for the other large components.

Umm, again, not looking to tangle, but this isn't like any 318 carb intake I've ever seen. There's no choke well for the carb. In fact, the EGR is on the passenger side where the choke well normally is. It shows sharp machined edges at the throat, resembling the later TBI intakes, but the bolt pattern is different. One bolt is offset, and it's larger than the 318 BBD carb base. I'm making an adapter to use a larger 2V carb so as to not drill the intake, nor change it. The P.O. set it on fire and damage the EFI harness and fuel control boar, so I am going carb. Will post pics soon.

 

[FredMcJoe]

I stand corrected, I thought they saved a few bucks and used the carb version. Motor Trend backs up the story that the components for the Imps were sorted for closest spec in their 10/80 issue.. http://imperialclub.org/Articles/81MotorTrend/Page1-reg.jpg

 

[6thGenImperial]

Check these.

 

[6thGenImperial]

So basically I used the base plate gasket as a template for the bolt pattern to secure the adapter to the manifold, and the holes are already there for the carb. Snug fit with that particular carb, which is what Mopar used on 360-400's. That way I don't drill any holes in the manifold, don't have to change the manifold (at this point), and have more carb, but not 4V size.

 

[FredMcJoe]

ya, that's unique to the EFI for sure. See? I need to buy one to know what I'm talking about! I have an eye on a certain green EFI Imp that someday shall be mine maybe.
That must be the TB spacer gasket that is a must change thing in the last pic. A carb makes them a real car.

 

[6thGenImperial]

Sounds like good enough reason to me. The fellow who had this one was all about getting the EFI fixed, and I get that, but I'm not concerned with car shows. Maybe later, so I'm open to restoring the EFI, but right now it's better to have it drivable.

 

[FredMcJoe]

Have you read thru the factory carb conversion kit manual? 1981-1983 Imperial Carburetor Retrofit Manual

I think u can keep all the computer stuff working, the MPG function in particular, with a fuel flow retrofit.

 

[FredMcJoe]

more factory conversion kit pics 1981-1983 Imperial Carburetor Retrofit Pictures

 

[FredMcJoe]

I wish the imperialclub site would locate Dick Benjamin's page so that we could find it... this is THE page for those stupid EFI systems, Dick was the guy who did the most to devise fixes for the EFI Imp people. Information rich webpage: 1981-1983 Imperial Repair Tips

 

[6thGenImperial]

I have looked at it here and there. Am sure I will consult it more as I go.

 

[6thGenImperial]

Well that tears it. I just went thru the FSM and every pic showed that stinking nylon gear! ARRRGGGHHH!!!

 

[FredMcJoe]

Well that tears it. I just went thru the FSM and every pic showed that stinking nylon gear! ARRRGGGHHH!!!

Plastic Happens

 

[BudW]

I have listened to two identical engines, one running plastic gear and other roller chain/metal gear.

The plastic gear (when new) is quite a bit quieter. As parts wear, the noise difference is not much.


The reason I heard from a factory rep, back in the day, was plastic gear setups are cheaper to make, are quieter and last longer than dual roller chain setups.
I disagree with the "last longer" aspect, but the first two make sense.

I haven’t seen any metal timing gears wear to the point the engine can jump time, though. I’ve seen a lot of plastic gears worn down to nuttin’ and have jumped time.

I recommend for ANYONE building a Chrysler small block or changing the timing chain on one, to install the timing chain tensioner setup and you can thank me later for it.

Now to find a setup like that for a big block . . .
BudW

 

[FredMcJoe]

now there ya go. Those EFI Imps are timing sensitive, especially. A tensioner would keep the slop out. The nylon coated sets were planned obsolescence. Engines were thought to be toast after 100k and all parts are engineered down to that amount of life expectancy. I got 126k out of my 72 Newport before it let loose.

 

[Aspen500]

That tensioner is the boss. Put one in my '96 Dakota when replacing the chain and no more idle rattle. It rattled at 49,000 miles when I bought the truck and rattled at 150,000, only worse. Couldn't take the noise anymore. The 3.9L engines were notorious for chain rattle, right from new. That's why they added the tensioner in '97 but it retrofits into any 3.9/5.2/5.9L and of course, 318, 340 and 360 back to the begining of time. Probably would fit a 273 also. Not sure about the poly 318 though.

 

[BudW]

A 100% chance it will fit the 273’s.
I’m 99.44% sure it would fit the Poly’s, and a decent chance it may work on the Gen 1 Hemi’s as well.
I hadn’t seen any in such a long time – I just can’t recall.

The small block and Gen 1 Hemi’s share a lot of parts - much like the Gen 2 Hemi shares a lot of parts with the big block.
You can even bolt a Gen 3 Hemi transmission onto the back of a Gen 1 Hemi block (But getting it work will take a whole lot more work).

BudW

 

[6thGenImperial]

Recently received a new double roller set. Will install soon as I get over a freakish episode where I developed DVT's in both legs simultaneously (I never do anything half-way). Anyway, after over a month being sidelined, my hands are as clean as they were at birth. Looking forward to getting back into things, but I am not adding the tensioner. The chain Mopar used with that tensioner is more civil (factory steel for MPI, chain link edges are smooth), meaning, if I use one with this set, it'll chew that sucker up in no time.