Hi all

First post on this forum.

I hope to soon own a "Jensen Interceptor Series 3" (http://en.wikipedia.org/wiki/Jensen_Interceptor). This car will be fitted with a low compression (8:1) Chrysler 440 with dual carbs.

It is my intention to optimise the engine's performance as follows:

1) Convert the engine to fuel injection. This will be done using an Edelbrock 7144 EFI manifold with Megasquirt 2 ECU firing two EDIS-8 coil packs directly for wasted spark ignition. I'm very familiar with the Megasquirt side of things now having done many Rover V8s and Jaguar V12s.

2) Upgrade the compression ratio to around 10:1

I would like to start a thread on how I can cost-effectively increase the compression ratio on the 440 and what other upgrades I should do while the engine is open. Please guide me as to where I should post this question.

TIA
mopwit

 

Welcome!

When you say "fitted with" so you mean that you are swapping in a 440 with an 8:1 compression ratio?

A couple things you can go is to have the heads shaved and the intaked fitted accordingly then. That will bump up the compression. Different pistons will too.

A lot of what you should put in for performance depends heavily on what you plan for the car. Is it s street driver only? Street and strip? Strip only?

 

welcome to the forum
have you looked at the Holley HP or Domintor EFI they are self learing

 

Need a lot more info ! The Jensen is a heavy car special consideration need to be made during the rebuild..
Compression It may have had either a 383 or 440 depending on year.. ?/ KeithBlack pistons are good for a street motor would require a rebore of the cylinders
Gear ratio- intended use ?
Cam ?
I'm assuming it is an automatic 727 converter type ?
Head type ?
What type of gas ?
and so on !!!!

 

Welcome to the forum.. In an all out race engine we use the FAST system for our Hemi....

 

The car will have an 8:1 440 engine when I get it. Jensen did this to meet emissions regulations of the era. This is the engine the cars were manufactured with.

I would be reluctant to shave heads as that is such an irreversible process. Even so can shaving the heads increase the CR that much from 8:1 up to 10:1?

I intend for the car to be mainly a street driver, but I really want to bring out "the best" from the engine without going "over the top".

 

Going with another EFI management system will again be a huge learning curve. Having gone through this learning curve with Megasquirt (MS), I don't want to do so again. And for the money, you can not do better. The MS can even batch fire low impedance injectors no sweat. I'm running 6 LoZ injectors per output (it has 2 outputs) on my Jag V12s without current limit resistors!

 

It WILL be a 440. I will not purchase the 383, simply because I want the BIGGEST V8 available to me!

Why will a rebore be required? Ar the KB pistons oversize?

It has a Torqueflite 3sp auto. I MIGHT later on do a manual conversion but for now I will stay with the auto. It will be street use only.

Your advice please? I want all the torque she can give from idle to 5000 rpm. I do not intend revving the living daylights out of her but I want smooth raw torque, as much as is possible from idle to 5000 with most of it coming in from idle to 3000rpm.

Affirmative. I'm not sure about the "727" bit though.

There are different types? What should I look for?

We have lead free gas labelled "93" and "95". Megasquirt allows me to tune the ignition advance map for this fuel but I add a switch to it which will then select a different (retarded) fuel map in the event that I can not get 95 but only 93.

I also live at about 4500' AMSL where barometric pressure is 85kpa but I do drive to lower lying areas from time to time.

Thanks for all the replies guys!! It feels like I'm in good hands

 

To get that type of compression change you must change the pistons and have a machine shop re bore the cylinders for a proper fit ! You might luck out ?? depending on mileage to replace the pistons without re boring, you would still need to hone the cylinders. DO NOT COUNT ON IT..
BB only came with a 727 trans. at 4500 ft 10/1 compression would be fine.
The low dollar way ? IF you want you could machine .030- .040 off the cyl heads and another .030-.040 off the block..for a compression boost. IT WOULD then require custom fitting the intake manifold also would need to check piston to valve interference

 

Machining the heads may net you .5 more compression. You'll need to change the pistons and probably bore the cylinders to get a 10:1 compression.

Since you don't plan on going higher than 5000 RPM, make sure that you match your intake, cam and headers. Otherwise each item will help to make power in different RPM ranges and not all at the same time. I think either Comp Cams or Crane Cams has a program on their website that allows you to input your motor with how you are building it and how you plan on using it and it then tells you want cams you should be looking at. Another option is to call their tech line and ask them what they recommend.

 

Thanks, you are confirming my thoughts that I would really have to change the pistons. Any suggestions as to which pistons in particular? This would pretty much boil down to a complete rebuild as I might as well then replace all bearings and seals. This is why a cam change (if justifiable) would also be opportune.

1) Are these engines prone to cam and lifter wear? (Like the Rover V8s are)
2) Where could I look for an engine rebuild manual?
3) Is there a web site somewhere where a rebuild of the 440 is shown in detail?
4) Where is a good place (price vs quality) to buy parts for this engine?

I'm a firm believer in not re-inventing the wheel and would be keen to learn anything and everything anyone is willing to share with me.

 

Welcome aboard.

 

Just thought I should update this thread.

I have now implemented the Megasquirt-2 but for now it is controlling ignition only.

The Crank damper was converted to a 36-1 trigger wheel by cutting slots into the circumference like this:


The coil packs were mounted like this:


And the enigne now looks like this: