72 -2.4 "E" euro 7R case using pump gas whats the highest output/mod with this case?

cparker · 08-20-2006, 11:02 AM

Hi guys new member here. I have a 1972 2.4 E motor with 7R case. I am researching options of rebuilds with this motor. How much power can I expect to squeeze out of this block using pump gas with moderate reliability. Rarely driven on the road. Would like a fun fast track/ weekend car. Thanks for any input!!!!
I love the thought of 2.8 RSR type power - is it possible???

Steve@Rennsport · 08-20-2006, 01:25 PM

Hi:

The first question I would ask you is; "What do you mean by 'moderate reliability'?"

The 300+ HP 2.8 RSR engine was a 25 hr motor and sometimes a lot less.

Since you didn't post where you live, what octane fuels do you have?

Finally, what is your budget for doing this?

Eagledriver · 08-20-2006, 02:45 PM

IMO the best you can do is an RS replica motor. If you go with Mod S cams and racing valve springs and keep the revs to 7200, you can have a reliable motor with about 220 to 230 HP.

I don't think you can reliably rev a mag case engine over 7200 RPM and you can't safely bore for over 90mm cylinders. If you want more get an aluminum case or go with a 3 litre.

-Andy

cparker · 08-20-2006, 06:42 PM

Thanks for the input. I live in Florida and we have 93 octane for premium gas. moderately reliable means at least a year of play before the grenade goes off. Budget thats a great question. I have a fantasy of trying to spend 10,000 or less. However I am throwing that figure out in the dark as far as my knowledge of Motor = Money Math goes. I have owned this car for 5 years and now what to explore more power.

Andy what is needed to make the RS motor . I am running weber carbs 40's if that helps at all.
Thanks again love the input.

kenikh · 08-21-2006, 07:48 AM

Sounds like you have the basics. I'd buy some 90mm P/Cs using 9.5:1 JE pistons using Mod-S cams with the 40mm carbs. The P/Cs will cost $1800 and the cams $750. The rest will be in machine work and basic rebuild parts. If you do it yourself, under $10K will be easy. Having it built by someone else, you are going to be in that ballpark.

Steve@Rennsport · 08-21-2006, 08:55 AM

Quote:

Originally posted by Eagledriver
IMO the best you can do is an RS replica motor. If you go with Mod S cams and racing valve springs and keep the revs to 7200, you can have a reliable motor with about 220 to 230 HP.

I don't think you can reliably rev a mag case engine over 7200 RPM and you can't safely bore for over 90mm cylinders. If you want more get an aluminum case or go with a 3 litre.

-Andy

Andy:

Good suggestion,...

One can certainly have a very reliable & durable 2.7 or 2.8 that pulls hard to 7600 if close attention to details are followed and thats really the key.

Everything must be precisely balanced and mag cases require a lot of preparation.

Jparker:

You'll get a lot of opinions, but I'd offer that a good 2.7-2.8 cannot be done properly for anywhere near $10K, depending on what components you already have.

911SCfanatic · 911SCfanatic's Garage

Steve, what preparation should be done for a 7R case for a 2.8L application, for example.

cparker · 08-21-2006, 07:41 PM

Thanks for the suggestions .... I like the sound of the 2.7 230 hp ...... I do plan on doing most of the work on the motor except for the machine work. Does shuffle pinning fall under the neccessary work to be done?
I currently run a light weight flywheel, pressure plate/ clutch on a 901 transmission. What are your opinions on the standard(heavier) vs. the lighter (more expensive) clutch packages. I guess what I am asking does the heavier flywheel affects performance at the track negatively?

Again I appreciate any input as this is my first opportunity to ask these questions that I have had rolling around in my mind for a long time!!

Eagledriver · 08-23-2006, 07:15 AM

I wouldn't build a high performance mag case engine without shufflepins. Case mods would include: align bore, shuffle pin, oil bypass mod, and case savers/timecerts.

You'll get plenty of conflicting answers on this next suggestion but I'd use dilivar studs. There have been pulled studs even with timecerts on mag cases with steel studs.

Keep in mind a mag case rebuild is expensive due to all the machine work on the case. Also if you get the case bored you may need oversize main bearings. These are a dealer item only and the last set I bought cost around 500 dollars.

-Andy

safe · safe's Garage

Whats the probability that a mag case will need an align bore?

I'm asking since I have mag cased 2.7 that might need a rebuild soon.
This is a euro 2.7 that never had the thermal reactors and living in Sweden it has probably never seen any temperatures above 230, for any longer periods of time.