914-6 Motor Selection Question, 3.2 or rebuild a 2.7 or 3.0? Options

[Chuck]

I'm going to put a 6 in may car once the restoration is complete (about a year from now). I'm starting to look for a motor for it now though.

I really like the 3.2. Modern FI and with a Steve Wong chip and freer flowing exhaust, it's good for 250hp. But, all of the engines I am finding are high mileage meaning they are going to need rebuilding sooner rather than later. They are running around $5k.

So, I am wondering whether or not it might make more sense to find a 2.7 or 3.0 case and just rebuild from that with that same hp target in mind. It will cost more than the initial $5k the 3.2 will cost to buy the case and rebuild BUT it will be completely rebuilt when it goes into the car. A little more $$ upfront but won't have to take that 3.2 out in a couple of years and rebuilt it.

Thoughts?

[Johny Blackstain]

I don't know which way to point you but I can say if you go 2.7 make sure it's a later aluminum case & I believe the biggest it can go is 2.9L. Pelican has those pistons for $5K! (IMG:style_emoticons/default/dry.gif)

Carbed w/ crankfire ignition is very reliable & sounds great (IMG:style_emoticons/default/smile.gif) . Goes pretty fast as well (IMG:style_emoticons/default/happy11.gif) .

[So.Cal.914]

(IMG:style_emoticons/default/agree.gif)

The bigger 3.0L+ engines have great HP and lots of lowend. If you want a rev'r I would go with, no bigger than a 2.7. I want a 2.5S engine.

[Brando]

I'd suggest the 3.2 rebuild with the wong chip.

You can go with 964 cams (even more low-end torque and overall power) and up the compression. Go with the headers and a good 2-into-1 bannan style muffler, you'd be rockin for more than 250hp. Good part is, you can keep the motronic injection and it'd still be reliable.

[PRS914-6]

After just completing a conversion, my vote would be to go with a 3.2 (or larger) with EFI. It's so trouble free, gas mileage is good, power is fun and it's pretty much "plug and play". You basically get it all. If you go with an engine with CIS and are not familiar with it, you will go nuts. A 3.2 is worth the extra money and for a few bucks more you can get a 3.6

Only way I would "buy" a 2.7 is if it was really cheap. If you do get a 2.7 I wouldn't run from a mag case. Make sure it's straight, install the inserts, keep it cool and make sure it has the the later fan on it. You won't have problems. Most 2.7 problems came from thermal reactors and the subsequent overheating. Done right, you won't have either.

Good luck....it's a lot of fun!

[Chuck]

PRS914-6, I've been following your 3.6 conversion. (IMG:style_emoticons/default/pray.gif) and (IMG:style_emoticons/default/beer.gif)

sounds like a 3.6 requires more work in our cars than a 3.2? As I said, I really like the idea of modern EFI: starts right up whether warm or cold, better fuel economy, etc. I'd REALLY like a larger engine in there. Just wasn't sure if the extra $$ for a high mileage motor made sense in comparison to rebuilding from a 3.0 block.

I guess the answer is to buy the 3.2 and then just budget for a rebuild in a few years. (IMG:style_emoticons/default/biggrin.gif)

[rfuerst911sc]

I'm biased towards the 3.0 because that's what I have in my 911SC and the engine I purchased for my /6 conversion. I personally believe this is the best bang for the buck 6 for conversion but not with CIS, carbs are the way to go.

[PRS914-6]

I'm biased towards the 3.0 because that's what I have in my 911SC and the engine I purchased for my /6 conversion. I personally believe this is the best bang for the buck 6 for conversion but not with CIS, carbs are the way to go.

You might be right but what's a set of carbs cost?......I could almost rebuild a 6 for what a new set costs....over $3k now for PMO's and it'll never run as good overall for a street car as EFI. It might put out more power but not run better in all conditions.

Just my $.02

[HalM]

If you are going to "build up" as you refer to it, you want to start with a 7R case.

As for a rebuild on one 911 engine over another, the differences in costs are relatively small. . . Assuming you are going to do it right. You need to split the case, drill the oil galleys, replace the oil pump and true the alignment. 7R cases and up and going to cast basically the same. Once you get to the top end, the only difference will be the cost of the P&C's.

I am percolating on a 6 conversion too. Given that a 3.6 is just way too expensive, a 3.2 makes a lot of sense. Take your compression as high as you dare (or can afford if you twin plug), 964 or 20/21 grind cams and a free flow exhaust, tell Steve Wong what you have for a custom chip and you will have a great motor.

[Brando]

7R is magnesium. Bad idea. They have warpage issues, and lapping the case halves plus an align bore doesn't get cheaper. Keep in mind you can only do that so many times before you have other issues arise.

[SirAndy]

Thoughts?

3.2L or bigger. if you have the $$$, don't even bother with anything smaller/older.
modern FI, bulletproof design, plenty of HP out of the box with stock internals.

you won't have any regrets ...
(IMG:style_emoticons/default/shades.gif) Andy

[HalM]

7R is magnesium. Bad idea. They have warpage issues, and lapping the case halves plus an align bore doesn't get cheaper. Keep in mind you can only do that so many times before you have other issues arise.

You're right. . . My mistake. 7R were the last of the old cases used on the '74-77's. Better than the older 5R but not much. A 3.0 SC case and newer is a much better choice.

[drgchapman]

(IMG:style_emoticons/default/agree.gif)

I have had a 1986 3.2 Carrera motor in my car for 2 seasons. It was reported that the engine had 66K on it when I bought it. Runs great, starts right up every time. I would estimate 1 hr of autocross runs and 6 hours of track time on the motor in 2 years. I drive it to most events and on the weekend sometimes.

Just a/x'd this morning, shared the car with Britain. Tires are shot, last one of the season.......No motor plans for next year.

[Chuck]

If I go with the 3.2, I probably won't build it up beyond a chip and an exhaust. That would be enough hp for me. I was just wondering if, cost wise, it made more sense to buy the 3.2 with high miles (my preference really) or buy a smaller longblock and rebuild from the getgo.

[pete-stevers]

i would say 3.0 or bigger.....
and i would stay away from a 2.7, unless it was darn cheep...or had been rebuilt ...and was cheep.....
some good books available on the subject
if you are planning on rebuilding dollar costs for a 3.0 or 3.2 will most likely be cheeper than a 2.7 due to machining costs on the case
my two cents

[rfuerst911sc]

I'm biased towards the 3.0 because that's what I have in my 911SC and the engine I purchased for my /6 conversion. I personally believe this is the best bang for the buck 6 for conversion but not with CIS, carbs are the way to go.

You might be right but what's a set of carbs cost?......I could almost rebuild a 6 for what a new set costs....over $3k now for PMO's and it'll never run as good overall for a street car as EFI. It might put out more power but not run better in all conditions.

Just my $.02

I picked up some Weber 40's local to me for 810.00 in great shape. I agree FI is better across the board in most conditions but carbs a average guy can work on if need be. What ever floats your boat.

[J P Stein]

Yes, stay away from the 2.7. I got only 7 AX seasons out of mine....actually, it came up one AX short of 7 full seasons. Now I gotta tear into the thing & figure out why it's not running right. That'll prolly cost me a couple grand....what a POS!
Not only that, I figure I was getting 2.5 MPG out of the thing.


Way back when I was young, an old fella told me
"I hates snakes & spiders & talkin' to ignorant people."
That seems appropriate here. (IMG:style_emoticons/default/biggrin.gif)

[LvSteveH]

I don't get the 2.7/mag case hysteria. There are some amazing 2.7 RS+ spec engines that will walk all over a motronic 3.2L. It's true that the mag case isn't as strong as aluminum, but that doesn't mean it will turn to dust if you build a performance motor out of them. Once the case updates are done, they are very reliable and have a good service life. For a street motor, there's absolutely no reason to be afraid of using a 7R case. Plus a good 2.7L core can be had for next to nothing.

It just depends what you want. A late model fuel injected motor makes for an awesome daily driver, but there is just something cool about an antiquated, fully mechanical motor, a la 60's/early 70's.

A new corvette is an amazing car in terms of performance and value, but would you rather spend the weekend racing a corvette or a 914-6 GT, or perhaps a Carrera RS? Different strokes for different folks I suppose.

[John]

I'm biased, but would say 3.2 any day.

The track car now has 14 years track events on it. I put that one in a long time ago. It gets annual valve adjustments and oil changes. I changed spark plugs a couple times and fuel filters a couple times.

The biggest issues it has had:

1. an air flow meter go bad
2. an idle stabilizer went bad
3. a DME relay had corrosion inside which caused it not to start once.

That is it.

I liked it so much, I put one in my street car. It gets better gas mileage than the stock 2.0 4-cyl.

I did use a fresh 901 trans that I put together with a billet intermediate plate. On the street, it should last a long time as long as I take it easy in 1st.

[Nick]

I'm happy with the 3.0 with CIS. I have a 911 with ~150,000 miles that I bought with at 98,000. Never had a problem starts right up rain shine freezing cold etc. This car is a daily driver or was when I was in the US. The 914 has a CIS 3.0 with 964 cams and headers. That too has been very reliable and makes enough power for the car to be scary fast. If I rember correctly it put out 188HP at the rear wheels when I took it to the Dyno with a nice flat torque curve. Only reved it to 6K. Taking it to 7K I would guess it would have been near 200HP at the rears. HP and torque had not even started to level off at 6k.

Nick