2.4 T whit 2.4 E pistons.

DP911-70-2,7 · 06:48 AM

I have a 2.4 T 1973 911 engine. I will put in some 2.4 E pistons in it. Anyone know how many hp i might gain on this ?? It runs whit 40 Zeniths...

B.A

Plays with cars · Plays with cars's Garage

Experts will jump in soon I'm sure, but I'm pretty confident saying that you won't gain meaningful power changing pistons. The compression ratio difference between the two is nominal; the big difference is the size of the valve pockets that allow you to run a bigger cam which is where you could gain more power.

nickyclyde · nickyclyde's Garage

There is a lot more difference between an E engine and a T engine than just the pistons.

DP911-70-2,7 · 11-05-2013, 10:48 AM

I have just bought the 2.4 E pistons to use in this 2.4 T engine... 84V53. What cams can i use..?? The S, or do i have to go for the E cams. Will port the heads moderate, and go for some bigger venturi size and main jets. 32 and 135...is that ok ?

Anyone done this before.... any idea for how many HP this will get me ??

B.A

DP911-70-2,7 · 11-07-2013, 02:26 AM

No one know if i can use the S cams whit E pistons

tom1394racing · 11-07-2013, 10:14 AM

You can use either cam. E will give better low end power and will be better in a street driven car.

You should upgrade to the 2.2T heads for the required airflow to support the improved cam

DP911-70-2,7 · 11-10-2013, 10:13 AM

What about using MFI E cams in a 2.4 T engine whit 40 Webers and 2.4 E pistons ??? is that a good mix ??

tom1394racing · 11-10-2013, 03:22 PM

Ideally, you should use heads with the larger intake port size like those on the 2.2/2.4E and 2.2T heads. The 2.4T heads have too small of an intake port. Since you are using carbs, you do not need the E heads with the MFI holes and can use 2.2T heads. Alternatively, you could have your 2.4T heads ported.

DP911-70-2,7 · 11-10-2013, 10:11 PM

Thx Tom.... will port them. I have an 2.2T engine as well, but ripping the heads of this just for using them on the 2.4 is no good.... its a complete and running motor...and porting a have done some of when driving Italian cars...

crummasel · 11-11-2013, 03:25 PM

Hi BA,
probably the colleague refers to the heads of the US 2,4 MFI which indeed have 30mm ports.
If you have a carburetted Euro 2,4TV you will have 32mm.
2,4E Pistons are inferior to 2,2E pistons as they provide only 8:1, while 2.2E give you some 9.3 on the 70,4mm crank.
You should also care for the 40TIN carburettors which need min. 32mm Venturies, If you do not have corresponding material you may open up the stock 28,5mm Venturies to some 31mm when you are careful and a crack on the lathe. Rejetting is self understanding
If you stick to the 2,4E pistons (and have real good barrels with it) you may shave the heads off 0,5mm or lathe the base of the barrels the corresponding amount to come to some 9:1. Deleting the chainhouse gasket (as long as the housings are really plane at their crankcase mating surface) with using of loctite 274 (really here you have to work perfectly) you can keep the concentric orientation of the cam/chainhousing interface with a leaksafe interface.
Dont tell the others, they wouldnt believe.

32mm ports are OK, porting to 34 is better imho.
Among lots of others i made several mild street engines that way and they were really fun with a very high longvity.
Greets,
Robert

DP911-70-2,7 · 11-12-2013, 08:08 AM

Thx Robert....

I will go for the E pistons i have and try get me som E cams....and just go for the modrat upgrade i think. Why... .. money is an issue in this home after a loooong season motocross for me and 2 of my sons...

I guess i will take the E Coupe back to, or close to original look. And a fresh 2.4 is enough.

PS: This is B.A`s wallet speaking...not himselves

swade · swade's Garage

B.A.

I have a set of 2.2E cams from a 1970 motor. I will be back in Norway on Monday and can send you some photos.

Wade

DP911-70-2,7 · 11-14-2013, 02:01 AM

Sent you a PM

procan · procan's Garage

I have a similar build going on (2.4T engine with solex cams, 9.5:1 JE pistons, 2.2T heads, Zeniths). I have a set of 34mm venturis that I will be using. Any advice if 34mm venturis are too big? Crummasel mentioned at least 32mm venturis. I've seen 34mm venturis used on 2.7 engines, but am hoping the 34mm will be good for the 2.4.

crummasel · 11-15-2013, 06:38 AM

Depending at what you are aiming at.
Basically 34s are working also but transition can get critical which may reduce driveability on normal roads.
Its just more detail work on jetting and emulsion tubes.
Cam timing plays a role also.
Starting with 32s in the beginning is quite save and you may upgrade...

DP911-70-2,7 · 01:14 AM

I have bought another engine. Its a 2.2 T whit 70.4 crank and 40mm Weber carbs.

The heads have parts nr: 901.104.306.OR Is that T heads ????

The carbs are IDT whit 27 venturi size. If i change them for 32 mm venturies, what other parts in the carbs need to be changed, and to what size ?

B.A

crummasel · 11-17-2013, 03:34 AM

IDS_zpsfe0bfc39.jpg Photo by FennLane | Photobucket

Somewhere in this range you find a good starting point but you will have to work out the corrct setting for your individual situation.
Best would be to inform yourself comprehensively about carburettors and their way of working.
And, first thing, adjust a proper and reliable float level, fire brigades will welcome that and its also better for a potential reseller price of your car. ;-)

DP911-70-2,7 · 11-24-2013, 11:25 AM

The 2.4 T engine is sold to an English man.... but i still have the 2.2 T engine that we have measured to 70.4 mm chrank.... looked into the spark plug holes today whit a small spy cam, and it has the 2.2 T pistons.
The Weber carbs has the 27 mm venturis. I will change this for some 32 mm and 1.35 mains 1.80 air correctors, and .55 idle jets, and F1 emulsion tubes that i know work well together. Any idea how many hp this will give me....??? If you have some fantasy nr thats ok, i do like them better then the realistic ones...

B.A