gtracer

need some advice on building a 2.o vintage engine, We are allowed up to 46 webers and twin plug all internals free would like to build it once and well. any comments , specs, experiences welcome

Steve Weiner-Rennsport Systems

Hi:

We've done a good number of these things over the past 20 years and here is an example of what a real good 2.0 race engines would look like:

80mm cylinders with .010 or .020 overbore & custom JE pistons around 11.7 to 12:1.

Pauter rods

Aluminum or Mag case; fully boatailed and relieved, oil bypass mods and Carrera oil pump. Oil passages enlarged for crossdrilled crank

Stock crank; balanced, micropolished, and cross-drilled.

Custom cams

VERY good heads with titanium valves and titanium valve spring retainers, Aase race springs, lots of work in getting these to flow. Here's where the differences lie,....

46mm Webers and tall PMO manifolds with flow-matched runners.

Twin-ignition distributor with MSD-6AL's and high-vibration Blaster coils.

George's headers in 1 /58" and a custom race muffler: lengths are very critical.

Thes rest of the engine stuff is "normal" like new bearings, Carrera tensioners, new chains, sprockets, idlers and such.

Lightweight racing clutch & flywheel using 5.5" Tilton twin-plate setup. Very expensive but well worth the $$$$. This is a MOI thing,....

Last,... a good set of close-ratio gears and a ZF-type LSD.

Depending upon your budget and how you do all this, you can see between 200 and 235 HP.

gtracer

Great info Steve it all is well appreciated, can someone however clarify the difference between the 906 cam, G60, G80 in respect to performance as well as driveability and reliability and what is the deal with the exhaust lenght?? thanks again for the great info

Steve Weiner-Rennsport Systems

There are differences in each cam profile. Lift, duration and lobe centers all work to offer different power and torque curves. I would tell you that the 906 cam is rather old technology and there are newer profiles like the GE-80 and GE-100 that offer similar peak power to the 906 cam but with better overall torque and off-peak drivability. We do our own cams here, in some cases.

You should bear in mind that a 2.0 litre engine making more than 210 HP will not be pleasant below 5500 RPM. With these small engines, you will always make compromises. Remember, peak power isn't everything. You'll have faster lap times with less peak power but a better torque curve by using a GE-80 or something close. For maximum engine durability and long life, keep the peak operating RPM to 7800 RPM and below.

FWIW,....we've also done some long stroke 2.1 litre engines that made 238 HP with really good mid-range torque. Not cheap to do,.....

Regarding exhausts; while I won't divulge speed secrets here, I'll tell you that you need a minimum of 12" between the header collectors and the mufflers. You will also need a crossover tube before the mufflers or a single dual-in/dual-out muffler. Stay away from megaphones unless you can live with a very narrow RPM range.
Both of these measures increase the spread of torque as well as make better peak HP. Amazing, eh?

Best of luck, Sir.

gtracer

Thank you again Steve for your help and insight, it is all a learning experience and you have put me on the right track, much appreciated.

Edmond

Some very interesting facts Mr. Weiner.
Thank you.

If I may impose, could you please answer the same question for me? The engine is a 2.4T and I do have a set of 2.7 rs P/C and will purchase whatever heads and cams are needed.
.............please............:-)

Your time and experience is MUCH appreciated.

Steve Weiner-Rennsport Systems

Edmond:

You are most welcome,....happy to help anytime,.....

Assuming that you are asking about camshaft selection,.....Figuring out which camshaft to use in any engine is one of the toughest decisions to make as this really determines the "personality" and drivability of this thing. Too many people think "bigger is better", and in most cases, this results in nice dyno numbers and less than idea lap times or poor acceleration.

Your 2.4 (soon to be 2.7) still has rather low compression and must be taken into consideration when making these choices. The other questions are the car's weight, gearing and usage: street/track or competition.

One of the very best combos is some variety of 2.7 RS engine using "S" cams and modifying your heads to "S" specs with larger ports.
This really makes good power and is very drivable on the street and in DE events. With some close-ratio gears, its lots of fun and very quick!!

There are lots of other thing you can do with a sufficient budget however, a 2.7 with 8.5:1 CR and the above mentioned cams & head configuration will work very nicely. You'll need the appropriate induction system of course; carburetors or "RS" spec MFI.

Hope this helps,...

JPIII

On the subject of 2.7L P/Cs on 2.4L cases, no one asked me, but.........

There were (apparently) 3 cases used on the 2.4L engine: 3R, 5R, & 7R.

The 5 & 7 have wide spigot lands. The 3R doesn't.
Since the case has to be bored to accept the larger dia 2.7L cyls (from 92 to 97mm, 2.5mm on the radius), I would avoid doing this on a 3R case......for what it's worth.

Edmond

Hello Mr. Weiner, Thank you for your response. I'll have more questions at a later date. ( ignition )
Regards, Edmond
JPIII, I appreciate your imput as well.
Thank You.

Dave Banazek

Would this minimum pipe of 12" after the collector apply to larger engines as well or would the length increase? To get the necesary lengths it would seem like something like a dual in dual out flowmaster muffler in the "stock" location would let you have a longer exhaust length and server as the crossover.

Thanks for your time.

PS I am working on a 2.8 race motor.

Steve Weiner-Rennsport Systems

[quote]Originally posted by Dave@dartauto.com:
<strong>Would this minimum pipe of 12" after the collector apply to larger engines as well or would the length increase? To get the necesary lengths it would seem like something like a dual in dual out flowmaster muffler in the "stock" location would let you have a longer exhaust length and server as the crossover.

Thanks for your time.

PS I am working on a 2.8 race motor.</strong><hr></blockquote>

Hi Dave:

BTW, good talking with you on the phone, today. Hopefully, I can be of service on this project for you.

Indeed, you'll need 12"-15" between the collector and the muffler to make this all work properly. We use that Flowmaster with inlets/outlets on each end mounted crossways (like the OEM unit) and that that works just dandy.

Hope this helps,......