2.4 T Rebuild

Dean DS · 03-30-2011, 06:47 PM

I have a '72 2.4 motor that needs a rebuild. My first thoughts were take it to an "E" spec but the cost of doing this seems to be increasing very quickly. Consequently I am looking at just doing a stock "T" rebuild. My question is what can be done to these motor's in the "T" platform that can make it a little more faster with a minimal investment. All suggestions are appreciated.

Dean

RSTarga · 03-30-2011, 06:51 PM

If you are going to do a proper rebuild the difference between T and E specs is not much.

Dean DS · 03-30-2011, 07:18 PM

Can you be a little more specific when your saying a "proper rebuild" say versus" non proper" or " Less than". I am new to this so I need a little more detail. I want to make sure I am getting value here from the motor builder.

pplkook · 03-30-2011, 07:54 PM

where are you located? Are you in southern Cal?

It sounds like you picked a shop?

-jack

regency · regency's Garage

Hi Dean, I recently rebuilt my 1973 "T" 2.4 engine back to "E" spec. I sent the throttle bodies to Matt Blast @ Eurometrix, where he rebuilt them and enlarged them to "E" spec. I replaced the "T" cams with "E" cams, I had the MFI pump rebuilt and set to "E" spec by Gus at Pacific injection, I had my heads completely rebuilt, springs, valves & guides rebuilt, I had my 84mm cylinders bored to 85mm by EBS in Reno, I purchased J & E 85's pistons from EBS. I also bought 6 new injectors and employed a MSD ignition........I don't really know how much HP this engine makes but it's a sweet engine, running very good.

Steve

73 911 T MFI Coupe, Aubergine

Flieger · Flieger's Garage

If you are going to replace pistons and cylinders anyway for other reasons, and you still have the 1972 MFI, go RS spec 2.7 liter.

Dean DS · 03-30-2011, 08:08 PM

Quote:

Originally Posted by pplkook

where are you located? Are you in southern Cal?

It sounds like you picked a shop?

-jack

I am in Canada, specifically British Columbia.

zotman72 · 03-30-2011, 08:11 PM

Are you still MFI? I went down your path once but only did the topend and new rings because of cost and my "rebuilt" T motor only lasted about 20K more miles as my MFI was running too rich and I had oil dilution issues. Second time around I went all out and built a true 2.4 S spec motor from my T core. Case went to Competition Engineering, I search high and low for S cams, stacks, MFI pump, pistons/cylinders, SC oil pump, etc and ported and rebuilt the heads. That was 10 years ago and the engine was a rocket but the cost was $5K in parts alone and I did the labor. Sadly I am not sure you can even find all the S stuff reasonably priced now.
An E spec 2.4 MFI is not a slouch and better than a rebuilt T, the lower and sooner availability of torque from the T stuff IMHO is bull at the levels we are talking. When an S or an E MFI engine comes on cam there is no comparsion to a stock T for excitement factor. If you can ($$$), I would recommend an 2.4 S engine as they are amazing and I never had a problem driving in it in traffic, a two pipe center sport muffler is your guardian angel for tailgaters too. YMMV

Dean DS · 03-30-2011, 08:40 PM

Quote:

Originally Posted by zotman72

Are you still MFI? I went down your path once but only did the topend and new rings because of cost and my "rebuilt" T motor only lasted about 20K more miles as my MFI was running too rich and I had oil dilution issues. Second time around I went all out and built a true 2.4 S spec motor from my T core. Case went to Competition Engineering, I search high and low for S cams, stacks, MFI pump, pistons/cylinders, SC oil pump, etc and ported and rebuilt the heads. That was 10 years ago and the engine was a rocket but the cost was $5K in parts alone and I did the labor. Sadly I am not sure you can even find all the S stuff reasonably priced now.
An E spec 2.4 MFI is not a slouch and better than a rebuilt T, the lower and sooner availability of torque from the T stuff IMHO is bull at the levels we are talking. When an S or an E MFI engine comes on cam there is no comparsion to a stock T for excitement factor. If you can ($$$), I would recommend an 2.4 S engine as they are amazing and I never had a problem driving in it in traffic, a two pipe center sport muffler is your guardian angel for tailgaters too. YMMV

I am MFI and going to an "E" spec motor will be a 56 horse power boost. Not sure what a reasonable cost is to upgrade but I see the dollars adding up so I am looking at options. So really what is a fair price? and What is really a proper rebuild? I am little confused as to what I should do.

zotman72 · 09:12 PM

Not sure where you are getting your reference information but my friend it is plain wrong. If 56 hp is from a mechanic you might be contracting to rebuild your T engine be very wary and alarmed.
Most references have a MFI 2.4T at 140 hp and 2.4E MFI at 165 hp. Torque was 196@4K for the T and 206 @4.5K for the E. The S is 190 hp and 216 @5.2K (easier source for me was the specs out of the Porsche 911 Forever Young book but you will find similar figures in other respected Porsche references). An E engine will not get you 56 more ponies --bottom line. A S engine will get you close. Time for you to do some quality early 911 engine research, and this site and Early S would be a good start. Get Wayne's Engine book and Bruce Anderson's one as well. AND UNDER ANY CIRCUMSTANCES, DO NOT CONTACT MotorMeister when you get your rebuild sticker shock. We all are here to help you honest.

Porboynz · Porboynz's Garage

I can recommend a 2.4 E engine over a stock standard 2.4 T engine. Its well worth the effort as those extra horsepower and addn torque make a very nice drive. My old 2.4 T motor was carburetted so maybe not as drivable as a T engine with MFI but what a difference the 2.4 E made. I then fitted 2.4 S pistons and barrels and made another 10 HP over the stock E engine just from the small increase in compression (I kept the std E cams and heads, port sizes, intake stacks etc) In fact I reused my old 'T' heads and had them drilled for the MFI because the E heads were cracked where some idgit fitted new valve guides with a hammer or something. I have dyno results showing 174HP from this build and it will pull away in 4th gear from about 1500rpm if you are inclined. If you have 7R cases you can probably go for a 2.7/2.8 motor but I am very happy with my 2.4E/S hybrid.

tobluforu · tobluforu's Garage

I just went from a T to a solex cam and there is a good amount of increase in feel via the but dyno, but its not 55hp. The difference in feel is the mid to top end, but the T I had had a funky grind on them, and my car had amazing low end which was great for auto-x. Since you want more umph go E, solex, mod solex or s cams. Besides pistions (2.7) there pretty much is only one way to make power and that is cams. Yes, there are other ways, but that is your bread and butter. And you don't have to have your stacks bored out so that will save some cash. You can also keep the port size the same in the heads (saving money), but you will have to have the pump recalibrated/rebuilt and that will run you around 1500. These engines are pretty damn expensive to build so be prepared.

deathpunk dan · 03-31-2011, 04:40 AM

Could he go with 2.2 T pistons for a high compression T motor? How much of a difference would that make?

pplkook · 03-31-2011, 07:17 AM

Quote:

Originally Posted by Dean DS

I am in Canada, specifically British Columbia.

Are you planning on sending your engine to a shop in Southern California for a rebuild?

Just curious....

-Jack

JerryL · 03-31-2011, 09:30 AM

In the above T to E comparison builds, no one mentions the crank, I would think the swap to the CW Crank vs the non cw T crank would be one of the core upgrades, smother more rev's stronger for the other mentioned HP & torque. With all the $$ being spent why not strengthen the core??
Am I missing something on this??

Regards

TWJ · TWJ's Garage

My '72 T engine has 2.2 S pistons & cylinders for high compression. Simple, relatively inexpensive and it runs pretty sweet. Not sure what the HP increase is but it sure surprised my mechanic, who though it was a stock T...and he KNOWS his 911's.

cowboyrolo · 03-31-2011, 09:48 AM

TWJ - Are you running MFI and T cams?

TWJ · TWJ's Garage

cowboyrolo,

I am running MFI. I believe it is the stock T MFI and T cams. Not 100% sure as the work was done by a previous owner about 12+ years ago. The piston and cylinders are documented and I can see them (the cylinder fins have a silver, shinny finish as opposed to the 2.4 T ones that have a dark look to them). Maybe someone more knowledgeable about this upgrade can speak to it?

It's not blow the doors off fast but it's a bunch of fun to drive!

cmcfaul · cmcfaul's Garage

Can be done in stages.

Do as much as you can afford to the internals without going too far.

1. increase compression - 9.5 / 1 (new pistions and rings)
2. cam grind to e-specs or DC 30 (cross between E and S specs)
3. top end rebuild

Later you can make the MFI / TB mods to get it all to match but it will work in the intrem

Chris
73 911 E