Upgrade 2.4 with MFI
 

I have so many questions but figured I would start with some basic questions and see where this would lead me. I have a good running stock 2.4T motor with the original MFI. I would like to retain this motor as it is numbers matching to my car and definitely want to retain the MFI. However I want more power from a budget of $10-$15k. I plan to do much of the work myself. It is a 4R case. I would like to hear ideas for what you would consider for your build. I have read Bruce Anderson's upgrade to a 2.7 which seems pretty straightforward. In addition to ideas for the motor, I would like ideas for the MFI as well. In the end I want something within my budget that will be reliable and durable and retains some originality to the car (at least the case and MFI). Oh and I already plan to run a secondary oil cooler up in the front fender. All input is welcome and appreciated!

So are you saying you are not going to machine the case? IMO, that will limit your choices.

You need to make some choices ..
- Whether you want to retain the ‘T’ spec pump or get it modified
- Whether you want to Port the heads or retain standard
- Wether you want to Port the stacks
- Whether you want to change camshafts

I think it’s possible to build a high compression T engine which uses E cams without modifying the MFI pump, retaining cast iron cylinders. I think you have to be careful pushing up the compression using standard T cams as they dynamic compression gets too high.

No issues machining the case - just want to retain the original case (assuming it is in good shape once I tear the motor down and have it inspected).

I did expect to modify my existing T pump and stacks. I assume I need to wait to determine the rest of the build until I decide the specs for the modifications - although I would like to start with going thru the MFI system first (I have heard that Pacific and MFI Werks are good). I need to understand more about what do do with the heads and cams based on how it all comes together for the build, but was at least thinking dual plug.

your budget will ultimately limit what you can do. Good bang for the buck upgrade might be to do the following build to 2.5 long stroke.
don't split case to avoid machining costs.

Upgrade cylinders to slip in 87.5 nickies at 9.5 to 1 compression cost 5K
Upgrade cams to S or mod S with reconditioned rockers cost 1.5K
Have heads redone with ports opened up depending on what's needed (valves etc) Cost 1K to 2K
Have throttle bodies modified to larger port size and bore stacks Cost 2.6K
Have MFI pump modified to match engine cost 2K
All the other misc stuff you will need or want to replace cost 1k to 2K

These changes would probably get you around 200HP

If you spit the case figure a additional cost to:
Mag and polish crank, rebuild rods, oil bypass mod, inserts for case, likely needed case machine work etc
This can be several thousand depending on case condition.

additional case machining to go 2.7: add bore and deck spigots and shuffle pin, can save some on P&C by re-plating 2.7 cyl and running JE or CP pistons.

HP now 210 to 230. but now looking at 15 to 20K


I was in the same place good running 2.4T. Missed shift bent valves. I ended up with the following:
2.4S P&C 8.5 to 1 comp (got new set for trade from racer that decided to go with 2.2S for more compression)
purchased set of E cams and had them reground stock and rockers rebuilt new shafts
case machined: inserts, oil bypass, line hone, deck and bore spigot holes, rods rebuilt polished and balanced. heads surfaced new guides and valves, ports opened slightly to match gaskets. Crank magged polished and balanced. upgrade oil pump to SC, upgrade idlers to later wide style, hydraulic tensioners. All new bearings, clevites for rods, chains, ramps gears etc
Stacks matched to gasket but let to stock size.
I was able to tune the pump to work with above combination by using wide band o2.
Engine runs very well and dyno results on Dynojet were 145HP and 146T at the wheels. This would be about 170HP at the crank. Cost of parts and machine work was around 13K not counting the P&C. I did rebuild myself so no cost. I port matched MFI stacks and tuned my self so no cost there either. Still an expensive engine to build up in the end.

john

thanks, John - this is definitely starting to get my wheels turning. Some options to consider for sure. i guess i need to assess the condition of the bottom end if I am not splitting this case. the motor ran very strong before i pulled it.

Are you retaining the motor for originality or because you like it? If for originality consider finding a second engine to swap in, they can be had for less than your budget and might not require any modification to provide more power and torque.

I don't know how it compares to a 66mm stroke engine, or if it has some kind of light flywheel, but my 78 SC engine revs like a turbine- delightful.

Dan

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Fair question - it is a little of both. I want it for originality and just don't have the space to store a motor anywhere, but also because I am trying to stick somewhat with the vintage of the car - these MAG motors are lighter and IMHO compliment these lighter longhoods well. It is also important to me to keep the MFI - again, somewhat for matching to the vintage of the car (and it is sad but you rarely see these with MFI anymore). I also have an SC and 993, so I already get to experience the 3.0 and 3.6 (which are both superb motors), so when I jump in my '72, I want to keep that experience different from those others.

Need to add an s to your user name!

Well done, I would like to add a 66mm car to my garage. Need a bigger garage first.

haha right :) lucky to have what i have in the garage - although i may sell the 993. i have maxed out my tiny 2 car garage with a lift - but it is crammed in there. my '72 is in pieces and many are in my house since i dont have space in the garage!

Looks like John kind of summed it up.

I would like to add, from reading your responses, that IMO, the big question to answer is what sort of character are you looking for from your motor?

Do you want a high strung, high revving, screamer? Or a torquey cruiser? Or something in between.

Remember, all the components you chose must be able work together in harmony for your build to be successful.

If if was me, I would build a 2,8 or 2,9 with 9.5 CR, 36mm ports and S or mod S cams. :D If money was no object, 10.5 to 1 CR with dual plugs. :D

All good suggestions. 9.5 CR with Mod S cams is an AWESOME motor. Down side is the MFI is matched to the cam and can be very tricky to get mixture right. Also, T cams will not machine down to S or mod S...you will need new cams.

Chris
73 e with above mods

Gordon, to answer your question I guess it would be something in between.

This has been really helpful - i wish money wasn't an object :) given my budget, i think i have some ideas for a decent build and should suit the car well with power to weight for street use. i am stripping the car down a bit to lose weight.

Re-mapping the space cam is a must for the aggressive cams and engines from 3.2L to 3.8L. With re-mapping you can still use the governor spring adjustments for Idle, Mid and Hi rpm. Makes it less work to get the mixture right. Of course a Dyno is your best friend.

Myflat6. Thanks for starting this, I am in th exact same position and also in so cal so maybe we can compare notes My 72 is getting trans and lsd next week then suspension after that , I am expect I will have to wait to recover befor any motor upgrades but I have been having these same conversations with shops, car is at AASe brothers now.

an AFR meter will be essential in dialing in the MFI with any cam change. Cams and higher CR compliment each other nicely as more aggressive cams will have more overlap and increased VE (volumetric efficiency) and thus need higher CR. just need to get good at adjusting the MFI for proper mixture in all ranges. Too lean is fast but will cause detonation. Too rich will run good but not at full HP potential.

Chris

Hi, that's awesome - my '72 is a huge project that has quite away to go. Suspension is done, but I am doing rust repair now and paint afterwards. I plan to start some motor work while this is being done. Feel free to reach out to me anytime - I am in Huntington Beach.

The details of 2.5LS build are coming together. I decided to not split the case as a couple folks have suggested to keep costs down. I am starting to tear down the motor. The MFI mods are where I am going to start. Pump being shipped to Mark Jung soon. Talking to Aaron Burnham about the t boddies and stacks. I do have a question for the group. Once I am done removing the top end, I would like to clean out the case. How can I properly clean out the case since it will not be split and still have the crank and oil pump inside? Sorry if this is a crazy question.