I have reported on my EFI conversion of the Mopar 440 in this thread: https://moparforums.com/forums/f62/440-efi-15187/

Now I will report on the installation of a GM 4L60e behind this 440.

I decided on the GM 4L60e because of the following factors:
1) It has a 3:1 1st. This makes the car more aggressive off the line;
2) It has a deep overdrive 4th (0.7 :1);
3) it has Torque Convertor (TC) lockup.
4) It was available in South Africa.

I actually wanted the mechanically controlled 4L60 and not the electronically controlled 4L60e but only the latter was available here - used.

Being a used transmission imported from the US, I did not want to chance it by installing it as is, so I also imported "Monster in a box" upgrade kit (from Monster Transmissions) to overhaul the transmission with. They claimed that it will improve the known weaknesses of the 4L60e. Well, so far its holding out 4600km later.

To mate the transmission to the engine, I used an adapator kit from Wilcap.

The 4L60e requires an electronic control module and since my engine is already running on Megasquirt-2 , I decided to use the "Megasquirt developed" GPIO box running the Extra Firmware: Transmission Control.

The elegance of this solution is that MS-2 supports a CAN-bus, and so does the GPIO, thus, for the RPM and throttle position, it was not necessary to bring those inputs directly to GPIO as these are obtained over the CAN-bus.

With hindsight, I'm really glad that I was "forced" to go the electronic control route as now I'm able to program shift patterns EXACTLY the way I want the transmission to behave utilising the immense torque of this engine.

* I have it shifting up at about 1600rpm (no need to go higher) for throttle position up to 20%. This translates to swift acceleration without attracting attention. Below 1500rpm, 20% throttle is very close to full throttle in terms of manifold pressure;
* It locks the TC Clutch at about 30mph (in 3rd);
* It shifts to 4th with TC remaining locked at 45mph;
* It will not downshift unless throttle is opened more than 65%. Below 2000rpm 65% throttle is pretty much full throttle anyway. Again this allows me to use the torque without waking the city with a down shift.
* Depending on speed etc, it may down shift from 4th directly to 2nd or from 3rd directly to 1st.

Having converted from a 727 to the 4L60e, I had to change my speedometer from mechanical to electronic as well and I used a VDO speedo to do this with.

On the open road the car now does 2100rpm at 75mph and returns 16.5mpg @ 64mph (distance checked with garmin 276c GPS). I believe that 17.5mpg might be possible as I had a leaking fuel cap with the above instance.

Questions most welcome!

 

VERY VERY interesting. On my car, which is not yet back together and running, I "ended up" buying a new HP computer and harness. "Not" the whole system, I already had a used Commander 950. But I continue to be interested in MS and what they and users are doing. Thanks very much for the write up

 

First, is the 440 bottom end stock? The Interceptor III had the 8.2 compression ratio pistons, and 280 hp net. They also had either a 2.88 or a 3.07 differential gear. That would mean that the overdrive is too steep, and you will have better high speed performance with 3rd gear than with 4th gear. You could try compensating for that by reducing further the gear ratio (do not know if alternative ratios are availabe with that differential, I do not think you have the Mopar 8.75).


Furthermore, while the 3:1 first gear will help you off the line, at some point you will pay the price for a wider gap between either 1st and 2nd, or 2nd to 3rd.


The other issue that I see is the robustness of that transmission, especially if you upgrade the engine. GM engines typically made fairly low hp and torque (even if they advertised large numbers) and a well built 440 can and will tear up GM transmissions. It is hard to beat a Torquflite in robustness and low cost (at least in the USA). If you really want 4 gears, best way may be the Gear Vendor OD which will allow you to keep the Torquflite, but you will still need to change your rear end ratio if you want to have all 4 ratios as performance ratios. What you really want to have is a top gear hitting 5000 rpm between 145 and 155 mph.


What size tires do you have? I think originally you had 185/70R15.

 

I believe the bottom end is stock with 8.2:1 CR. The engine has the letters "HP" stamped near the engine no which I believe mean the cam is slightly more awake than the worst smog detuned version. To me the cam feels like a standard broad range cam. I've had it up to 6000rpm once - just to know if it could and it pulled strong all the way up there. The way I drive it now RARELY sees more than 2000rpm. I do not believe that the overdrive is too steep. There is not a hill in my area that this car can not climb in 4th with the abundance of torque it has. This, considering that I live and drive at 4500' above sea level where barometric pressure is 85kpa. (Typical engine performance is down by 15-20%)

My car has the 3.07 diff ratio. I had no designs on top speed or even in gear acceleration. I wanted to optimise and maximise utilisation of the engine's torque. I'm putting my hope in the "Monster in a box" upgrade from Monster Transmissions which the transmission has been rebuilt with - having read that the 4L60 has certain known weaknesses.

I've got two sets of wheels for the car. Around town I use 245/45/18s and for longer trips I use the standard 15"rims with 205/70/15 tyres (for the sake of being able to store a punctured wheel in the spare tray under the car)

 

You can try to find out which cam the engine has by pulling the valve cover and measure gross lift. If you measure 0.450" or so, you have the HP cam.


The OD being too steep applies for high speed, i.e., over 100 when the aerodynamic drag really starts kicking in. At low speeds, I am sure you can climb hills, but then again at low speeds you do not need OD that much anyway.


If you do not push the car hard, and since you have the low compression ratio, your transmission may live for a while. But with a 10:1 compression ratio your car will really start running like a top-line performance car. And will need premium gas!


Your 15" wheels have about 4% lower rolling radius, so they will likely be a bit better suited for high rpm. Curious, do you see any change in handling and hard cornering between the two tire sizes?


How did you do the EFI? Do you have throttle body injection, or do you have individual injectors?


How is the cooling? Even 383's in Jensens are known to have issues in hot weather, especially with the AC on. I think the Interceptor III had louvers on the hood which helps under hood (bonnet?) ventilation, but still, the engine is stuffed up in there.

 

You mention premium gas. The highest octane we get here is 95. We also have 93. I find that the car pings on 93. Sure I could retard the timing but on 95 it does not ping.

It cruises easily in 4th at 113mph but I don't do this regularly - could land me in jail.

I dont explore the car's limits so I can not really tell you if the 245/45's corners better than the 205/70's, but surely they HAVE to?

For more info on the EFI conversion, please refer to this thread: https://moparforums.com/forums/f62/440-efi-15187/

Cooling: Cooling has been the least of my worries. We've had temperatures up to 100degF and I can drive the car in bumper-bumper traffic with AC on full.
BUT
I did have an issue where I would get home, stop in the garage with temp where it should be, switch off, and a minute or so later she would start boiling and dumping coolant. I believe this was caused by those narrow slits in the head gaskets allowing VERY little coolant to pass from the block into head leaving hot spots. Having fitted new head gaskets where I've opened those slits to max, this problem is now gone.

My car has the louvres but I'm having a new hood made (GRP) without louvres but with a scoop to get cool air to the air filter, for the sake of higher intake air density (and hence a more efficient engine).

 

Have you tried 93 since the head gasket mod ??

 

Yep. Pings all the merrier! Until this engine started pinging on me, I would not have believed that a low compression engine could actually ping but this has brought me to new insights.

 

We have 93 octane here too, and high compression 440's are fairly happy with it. In high elevations here in the US, the highest octane is often 91. But there are two ways to define octane number, and do not know which one they use over there. But since you are also in high elevation, I would expect that 95 would be more than fine for a 10:1 engine.


It may be possible that somebody replaced the pistons and you now have high compression ratio. Since you pulled the heads, you should be able to tell. The high compression pistons reach all the way to the block, The low compression pistons allow a significant clearance, I think about 2 mm (easy to calculate).


The low compression engine should run fine with lowest octane, 86 or 87.


The wider tires will not necessarily improve handling. The very low profile tires demand very small camber angles under cornering. Older cars are designed to allow some camber under hard cornering because the higher profile was less sensitive to it. Also, your new tires raise the car off the ground a bit.


I have never heard of restrictive head gaskets before on 440s. But I have heard of Interceptors with cooling issues in hot climates. Too much engine on a tight engine compartment. May be the modern electric cooling fans are better than what they had back in the day.

 

Apparently those restrictive head gaskets aimed to increase the head temp with a view to reduce emissions.

The fans in my car are the original ones and they do a fine job. IMHO its the last thing that needs upgrading - IF everything else is working as it should.

 

I looked at the thread with the EFI. If you indeed have the original low compression ratio, then you either have too much carbon build up, or your timing is over advanced. Or may be a combination. At what operating conditions did you have knock? WOT, or low speed light acceleration?


I had the opposite problem on a 440 I am tuning. I have a relatively large cam (but still a street cam), and high compression ratio. In my search for proper timing, I could not get the engine to knock, and I ended up over-advancing. At least part of my problem was too lean fueling, so lean that was not even getting into the knock range. But at low rpm low load accelration, I could occasionally hear a bit of piniging. I have now made it much richer (and is much faster), and have heard knock under certain speed ranges. My other 440 (with probably the HP cam) has a very distinct knock range on the spark timing.


On your hood upgrade ... Hotter intake air will actually give you better gas mileage, but obviously colder air will improve performance.

 

Both heads and pistons were clean when I did the head gasket replacement. It was clear to me that the engine had been overhauled and actually ran extremely little since the rebuild. So, no carbon issues.

Like I said before, I prefer running higher octane than having to retard.

Why do you say that hotter air will improve gas mileage?

 

It sucks that they rebuilt the engine and did not upgrade the pistons.


Retarding the timing COULD also improve fuel economy and performance if you are too far advanced. Especially in low compression engines, where you may exceed the optimum before spark knock.


But the hot air is the counter-intuitive one ... At part load, there is a lot of manifold vacuum due to the closed throttle. This is the largest fuel economy loss of spark ignition engines, compared to say a diesel. In your case with a BIG engine on a little car, this is even more the case. This is called "pumping loss". During the intake stroke, the piston fights the low pressure (you have atmospheric pressure in the crankcase). But it is necessary, because the only way to cut on the fueling rate to reduce load is reduce the air density. SI engines need a constant A/F ratio. (in diesels, you cut fueling rate and they do not need to be throttled, and that is the main reason they are more efficient, especially at part load).


Again, this is the same reason why, say a 383 will get better mileage than a 440, if all else is equal. Same if you run a 4.11 as opposed to a 3.23 rear. You drive the car with the throttle closed.


Hot intake air has lower density, so you need less vacuum (or higher absolute manifold pressure) for the same load. Or, another way to see it, for the same steady state speed, the throttle is a bit more open. That means, the piston has to fight less vacuum in the intake stroke, and therefore less pumping losses.


This is the principle reason you get better gas mileage in the summer (the other is shorter warm up times and warmer oil, but even in long distance driving summer mpg is better). You should also get better mpg in high elevations, especially in your case with the EFI.


Obviously, at WOT, there is no vacuum and no pumping losses, and you are trying to maximize power and mpg is irrelevant.

 

Hear! Hear! It so happens that my '72 was also rebuilt and it has high compression pistons - I'm told by PO.

Will soon pull that engine - also to open the had gasket ports - and will then confirm the pistons.

 

You should be able to tell from the performance point of view. When the Jensen III came out with the smog 440 and 3.07, the older 383 cars and 2.88 were faster in all speed ranges. If your 74 has 8.2, and your 72 has 10.0:1, then regardless of EFI or transmission upgrades, the 72 should be substantially faster.


If you take the 74 engine out, you may also put a step up or two on the cam. Modern cams exploit further the large lifter diameter, and we now have some large lift/low duration cams. I have one on my Imperial (you can find my thread, "440 build for Imperial" or something, where I am trying to tune the engine by taking shortcuts (I am cheap), and also by using a principally wrong type of carburetor (I am still stuck in the mid 20th centrury!).


Also, if these headers are complete nightmare, you could consider putting back the manifolds. The Chrysler maifolds were actually fairly good, and unless you are trying to build a 500 hp monster, the benefit may be marginal.

 

It so happens they are actually quite good. Normally after market headers create all kinds of secondary issues but with the TNT made ones, it seems quite OK actually!

 

Happy to hear that the MS-2 and GPIO and all are working out for you...
The MS-2 has so much to offer. But I'm sure it took quit some time to get the programming done. But it is sure nice to tweak things the way you want them.
Sounds like Jensen is moving rite along....

 

Bob, I can not tell you what a nice car its turning into! With all that torque now coming into play, the car accelerates effortlessly, employing low, low rpms, but deceivingly quickly.

I will not claim that the MS-2 tuning is easy, I've been playing with MS-2 since '06 - and I'm still learning. But the "reward factor" is sky high!

The cherry on the cake is the most acceptable fuel consumption on the open road. I'll be doing a 2000 mile trip with it in mid Feb and can not wait for it!

I'll be doing a Youtube video soon of me driving it....

 

That will be very cool to watch !!!!!!!
Phil.. One more question... What does that cars weight now? if you know?
Anyway, Great job. You have done a great job... I have followed much of your build on other sites when I run into it. Hand down a great job you have been doing with this project....

Hat tipped

 

Thank you Bob! Sincerely appreciated.

Wikipedia puts the weight at 3500lbs but I don't believe that. I recon its closer to 3900lbs as per its registration.

 

Interceptors weighed about 3900 lbs with the 383, and about 4000 lbs with the 440. They were not exactly light feathered cars, but I think this is more of a positive attribute. They were known for very good ride (by Euro standards) plus good handling. They also had a very nice interior. They were very expensive, substantially more expensive than an Imperial or a Cadillac. With the 383 they typically had a high 15 second 1/4 mile and almost 140 top speed. They offered a Six Pack version (440) that was good for high 14's and 145 mph. The Series III with the smog 440 were slower, but obiviously they have potential.


How do I know all that? I have a book on the interceptor road tests ...