My mechanic is recommending the following and I would like some experienced thoughts please.

1) Raise compression from 8.5 to 9.5 or 10.0
2) Port and polish heads
3) Port intake runners
4) Machine throttle body
5) install euro spec cams
6) install euro fuel distr
7) new ssi headers and b & b exhaust-3' outlets
8) will increase hp by 40-45hp
8) running me around $6000.
9) includes lots of new parts as part of rebuild-complete valve job, piston rings, etc--everything is basically gone through. The name on the sheet he gave me is "3.0 Motor Rebuild Stage #1".

Does this sound reasonable? am I wasting my money? I'm new to this so I need some feedback. Thanks!

 

I think the estimate is conservative, I'm willing to bet it may be as high as 10K if you do a complete job. A top end re-build will be 4K, then add pistons,$1400 , new rods $1200, euro fuel distributor,$700(?), and you might as well twin plug the heads and go to 10.3:1 cr, (maybe $900 for twin plugging). The SSI's will be $1000, (I could be wrong ) Then you'll need a new distributor,(for the twin plug set-up), Electromotive,crankfire, $1700.
Be careful...
(all costs listed above are ONLY estimates, IMHO)
Good luck !

 

$6000 estimate does not include the cost of the ssi or exhaust.

 

I believe that you have a "small" intake port engine, which was used for the US market from '80 until '83. I believe that you should already have a higher than 8.5 compression ratio. I have not been impressed by efforts to increase power in these engines by altering the intakes that I have seen. (These cars had 34 mm intakes, while all other 3.0 motors had 38, or something like that.) I would just go for the SSIs, or, better still, spring for a 3.2 Carrera motor. The motor upgrade may cost somewhat more, but it would be a much better improvement, and better for resale.

That's just my two cents' worth.

 

Another option you have, instead of port intake runners is to install the intake runners from a 78-79 SC, which uses a larger size than the 80-83. Since you obviously don't have to worry about emissions testing, why wouldn't you drop the CIS injection and put Webbers/PMO carbs on? Bruce Anderson has some good discussion of this and other 3.0L options in his "911 Performance Handbook". Also, I'd agree with Howard that you want to have $10K+ in the bank before starting down this path. And if you have that, you might want to consider selling your existing motor and dropping a 3.6L engine in.

 

[quote]Originally posted by JonT:
<strong>My mechanic is recommending the following and I would like some experienced thoughts please.

1) Raise compression from 8.5 to 9.5 or 10.0
2) Port and polish heads
3) Port intake runners
4) Machine throttle body
5) install euro spec cams
6) install euro fuel distr
7) new ssi headers and b & b exhaust-3' outlets
8) will increase hp by 40-45hp
8) running me around $6000.
9) includes lots of new parts as part of rebuild-complete valve job, piston rings, etc--everything is basically gone through. The name on the sheet he gave me is "3.0 Motor Rebuild Stage #1".

Does this sound reasonable? am I wasting my money? I'm new to this so I need some feedback. Thanks!</strong><hr></blockquote>


Believe what these guys are saying! The expense will grow not only because of the unexpected things but also because, "well, while we have it apart we might as well...." I know, because I'm involved in the same process. I started on the right track but somewhere along the way I ended up so far from my original goal. Have at least $10K ready. <img src="graemlins/c.gif" border="0" alt="[ouch]" />

 

There is a good article on (real world) performance upgrades for CIS at:

<a href="http://www.pelicanparts.com/techarticles/911_engine_rebuild/911_engine_rebuild2.htm" target="_blank">http://www.pelicanparts.com/techarticles/911_engine_rebuild/911_engine_rebuild2.htm</a>

This actually looks less involved than what you are looking at.

 

Figure 10-15k to do it right. My father just did a 3.2 (bore on a 3.0) with 10:1, dual plug, etc, etc on my 79 SC.

 

I went through this process about 7 yrs ago. My advice? JMHO, get the cleanest low milage 993 or 964 engine that you can find and transplant it. I did back then, very little support was available that has totaly changed,<a href="http://instant-g.com/Products/36Conversion/index.html" target="_blank">Dr. Timmins 3.6 conversions</a>
Even without the support I am totally satisfied with the results and would do it again. With the support and pathfinding experience of others it is an even more appealing avenue to explore. the only reason not to go this route is if you plan on racing, the class rules will define precisely what is allowed in that case.

'My Pelican Home' has an outline of what I did.

 

That's a lot of money for 40-45 hp. As long as you're giving up the "stock" aspect of your car, which will drastically effect resale, I'd agree with the engine transplants vs. lots of internal modification, unless, as stated previously, you're going to use it strictly for the track. I'd go with the 3.6 if you can afford it, and apparently you can. Have fun! <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

 

No expert, but done a lot of reading about mods for SC's. Here are some rambling thoughts, in no particular order:

1. Euro cams? I just looked, and USA and ROW cams have the same part number. Maybe he means 964 grind, or one of the more agressive CIS compatable grinds, like a Webcam 20/21?

2. According to my Owners manual, my 82 has 9.3:1 compression ratio. I think they were the same in 80, but I could be wrong.

3. RE machining of the throttle body: I have always read that the weak point of the CIS system was the sensor plate. I have heard of using an oversize throttle body, but never seen any hard Dyno data about HP gains. I would think if this actually worked, there would be a lot more tuners making and selling them. I would also think Bruce Anderson would have mentioned it in his book.

4. Regarding swapping Fuel distributors, there is some info in <a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=1&t=002416&p=" target="_blank">This thread.</a>

5. Why no displacement increase? Bruce Anderson mentions that going to 98mm P&C's is good for about 20HP on an otherwise stock engine, If I remember correctly. May blow your budget though, as this is around $3K.

6. Any reason you are sticking with CIS? Webers will allow you to go to a more radical cam, and if you shop around they are not prohibitively expensive. If you live where they do smog checks this probably isn't an option.

You are probably better off looking for a 3.6 to swap in.

Tom

 

I'll join the chorus. There's not a lot of value in trying to hot rod an SC motor. Unless you have a compelling reason to stick with it (like classification issues with a group you run with), my advice would be to get a low-mileage 3.6. You start with 250 reliable horses -- and a chip, intake and headers can add another 30-35 to that figure. All of this comes without the race-engine reliability problems that often accompany hopping up a lower displacement engine. And even if you figure 10K for the total cost of the engine, adaptation parts and labor, you've still get money back from selling your current powerplant (3-4K? More?) to bring that figure further down.

And again, you won't be dealing with the headaches of stretching 3 liters of displacement further than the Porsche engineers thought it should go. Instead, you get rock-solid reliability, unrivaled torque and -- at least in the engine rebuilding game --economy.

Why don't mechanics suggest it more often? It's about dollars... for them. Consider the difference in labor between tearing down an engine (gleefully upselling 'While we're in there' improvements all the way) and simply pulling one and putting in another. It doesn't take a rocket scientist to see why they will often try very hard to get you to turn your old motor into a 'masterpiece.'

 

You are getting some very good advice here.I have to ask , what are your objectives for the car ?
There are some items on your list that are not necessary, like the throttle body, I'd suggest getting some Dyno numblers from people with the 3.0 engine and the mods they used to get there, for example , my 83SC got 174Hp/175ftlb with just a K&N filter and a cat by-pass and a Bursch muffler,all costing under $500.00 for about a 20Hp gain ! This Dyno run was last month and my 83SC has 230,000 miles.

 

[quote]Originally posted by JonT:
<strong>. . . "3.0 Motor Rebuild Stage #1".

Does this sound reasonable? am I wasting my money? I'm new to this so I need some feedback. Thanks!</strong><hr></blockquote>

JonT:

Do you care to share with us the name of the mechanic (or shop) who is recommending this work?

Some of those mods sound like mods recommended by a certain shop that I know of.

Best to you,

 

German Auto--Omaha, NE