69 911- Which Engine to swap in?

[HamiltonSeth]

Gurus,
Looking for some advice on which engine to swap into my 69 911t hotrod. The car has some suspension work, 911s brakes, roll bar, etc etc. What isn't done yet can be done to match the engine, and I have a realistic budget for all items. I am hoping to end up with a very visceral street 911 used primarily for canyon carving and wetting my pants on the way to work. I have a slightly modified 930, an 18 GT3 manual, and a few other fast cars, so it doesn't have to be a huge power 911, but just light and fun.

I am thinking something in the range of 250hp. I had an RS America with suspension work, Wong chip, full exhaust, and I loved the torque of the car. I thought about stripping the RSA down for weight reduction, but decided starting with an earlier lighter chassis would be wiser. So... how do I get some of that low end grunt in an engine that still have the right vintage feel, and very importantly the sound. The 2.2L with megaphones that is in the car now sounds wicked... but it lacks a good 80hp and tq.

My current thought is a short stroke 3.2 or a 3.4 with a new set of PMOs and engine mods to match should do the trick. I don't really want to spend more than $25k on a motor itself, so likely going with a wildly built 3.6 is out. Finding something already finished is ideal.

Thanks for the help!
Seth

[Matt Monson]

Budget $10-15k for your gearbox if you go anything over 3l.

[Steve@Rennsport]

Budget $30-35K for properly done 3.4 that will both make you smile & be reliable.

[HamiltonSeth]

Originally Posted by Matt Monson

Budget $10-15k for your gearbox if you go anything over 3l.

Thanks for the reply Matt. Why 10-15k? What about picking up a refreshed early 915? They come up all the time for under $5k.

[HamiltonSeth]

Originally Posted by Steve@Rennsport

Budget $30-35K for properly done 3.4 that will both make you smile & be reliable.

Thanks Steve. Yes, should I have a motor built it may be in that range. I have come across some cheaper, or runnings SCs with a built motor that I could pull the motor and trans and part out the rest bringing me back down to my ideal budget.

Are you suggesting the 3.4 would be the route you would go, or just commenting on the cost?

[jpnovak]

Lightweight would be key in the 69. I would build a mag case 2.8. Will hit your HP targets easily with the right cam. Also, won't have so much torque that you will twist your 901 to bits. Could easily run on a set of webers and would be electrically identical do your current engine.

[HamiltonSeth]

Originally Posted by jpnovak

Lightweight would be key in the 69. I would build a mag case 2.8. Will hit your HP targets easily with the right cam. Also, won't have so much torque that you will twist your 901 to bits. Could easily run on a set of webers and would be electrically identical do your current engine.

Likely sound advice, but deep down I am looking for a motor that would end up twisting up my 901. Also, how much of the mag case long term reliability is true? I would hate to be $XX,XXX into an engine that wont have good value down the road or for the next user.

[Matt Monson]

Originally Posted by HamiltonSeth

Thanks for the reply Matt. Why 10-15k? What about picking up a refreshed early 915? They come up all the time for under $5k.

Not one I would trust. And it’s not just bolt in and go. You need a lot more Parts than just a gearbox to install it.

[Evans, Marv]

I'm actually satisfied with mine as it's set up. Of course it might not be enough of a beast for you, but it's a really nicely balanced car. '77, 2.7L w/ Weber 40s, E cams, with a bunch of dry film lube and thermal barrier coated parts, ARP rod bolts, etc., etc., '74 915, monoballs, Elephant bushings, S brakes, etc. Doesn't have the AC, and a bunch of other weighty stuff it came with originally (although I have all of it if I ever sell it & somebody wants to put it all back on). I think a similarly set up 3L would be a good choice, because the 2.7L engines are disproportionately expensive to build now, which wasn't exactly the case when I did mine, plus I already had the engine. Like I said in another thread, they must have built a million '69s. It seems like every other person on here has one.

[HamiltonSeth]

Originally Posted by Evans, Marv

I'm actually satisfied with mine as it's set up. Of course it might not be enough of a beast for you, but it's a really nicely balanced car. '77, 2.7L w/ Weber 40s, E cams, with a bunch of dry film lube and thermal barrier coated parts, ARP rod bolts, etc., etc., '74 915, monoballs, Elephant bushings, S brakes, etc. Doesn't have the AC, and a bunch of other weighty stuff it came with originally (although I have all of it if I ever sell it & somebody wants to put it all back on). I think a similarly set up 3L would be a good choice, because the 2.7L engines are disproportionately expensive to build now, which wasn't exactly the case when I did mine, plus I already had the engine. Like I said in another thread, they must have built a million '69s. It seems like every other person on here has one.

Marv, this is some good feedback. So given the option today would you go with the 3.0 as you suggested, not go above that? I would assume the decision would be for a better balanced car?

I enjoy hearing all of this feedback as everyone has a differing opinion on what the right setup is. I am biased as I like huge power cars (have had some ridiculous ones). I guess I should also fess up and say I am 33 years old so perhaps I still think like I did at 16- that everything must be insanely modified and fast, even if that means sacrificing a bit of balance.

[Bill Verburg]

Build up an aluminum 3.0 block w/ S cams, ~9.5 cr pistons rods & oiling to allow low 7K revs, top w/ EFI & ITBs w/ a resonance manifold, back it up w/ a 915 w/ 3.1818 2.0000 1.3810 1.0800 0.8889 gears & lsd

It's be real nice to have rear SC flare to get a little more tire in there

[Matt Monson]

Originally Posted by jpnovak

Lightweight would be key in the 69. I would build a mag case 2.8. Will hit your HP targets easily with the right cam. Also, won't have so much torque that you will twist your 901 to bits. Could easily run on a set of webers and would be electrically identical do your current engine.

This is exactly what I’m putting in my 74 over the winter. I don’t think I can get the car under 2100# without a ton of fiberglass but I’m gonna try. Mate it to an asC-RS ratio 915 and I’ll be happy.
Seth, mag case engines are dead nuts reliable when rebuilt properly. If Ollie’s preps the case you’re golden. It was heat and emissions that killed them. Don’t forget that the 73 RS was a mag 2.7.

[Flojo]

A 2.7 or 2.8 would meet the style best imho.

Though a 3.0 to 3.2 tuneup will be more reliable maybe (?)

[BK911]

Stroke the 2.2 to 2.4 and add some E ish cams.
Light engine in a lightweight car with plenty enough power to get you into trouble.
That is what i would do, but my other car is a bug not a 930.

[HamiltonSeth]

Originally Posted by Matt Monson

This is exactly what I’m putting in my 74 over the winter. I don’t think I can get the car under 2100# without a ton of fiberglass but I’m gonna try. Mate it to an asC-RS ratio 915 and I’ll be happy.
Seth, mag case engines are dead nuts reliable when rebuilt properly. If Ollie’s preps the case you’re golden. It was heat and emissions that killed them. Don’t forget that the 73 RS was a mag 2.7.

How much of a weight savings is there really between a carb'ed 2.8 vs a 3.0?

[HamiltonSeth]

Originally Posted by Bill Verburg

Build up an aluminum 3.0 block w/ S cams, ~9.5 cr pistons rods & oiling to allow low 7K revs, top w/ EFI & ITBs w/ a resonance manifold, back it up w/ a 915 w/ 3.1818 2.0000 1.3810 1.0800 0.8889 gears & lsd

It's be real nice to have rear SC flare to get a little more tire in there

This all sounds pretty awesome. Thanks Bill!

[Matt Monson]

Originally Posted by HamiltonSeth

How much of a weight savings is there really between a carb'ed 2.8 vs a 3.0?

Not much. The weight savings gets done in the chassis. For me it’s just more period correct.

[boyt911sc]

This is a 3.0 liter SC engine I built for a friend.





The first several mins. of the video is not impressive but wait a few more minutes and you will see how the engine performed in the track passing everyone on sight. BTW, I did the rebuild for FREE because I only wanted to get the experience of building a race motor. Just watching this video put a grin on my face. Glad I accepted the challenge to build this one in spite of the limited experience in engine rebuilding.

https://www.youtube.com/watch?v=LGSdRdyNVgc

Tony

[HamiltonSeth]

Originally Posted by boyt911sc

This is a 3.0 liter SC engine I built for a friend.





The first several mins. of the video is not impressive but wait a few more minutes and you will see how the engine performed in the track passing everyone on sight. BTW, I did the rebuild for FREE because I only wanted to get the experience of building a race motor. Just watching this video put a grin on my face. Glad I accepted the challenge to build this one in spite of the limited experience in engine rebuilding.

https://www.youtube.com/watch?v=LGSdRdyNVgc

Tony

Another strong case for a 3.0 (pun?). That sounds amazing and clearly pulls well. What were the specs?

[Evans, Marv]

Bill is the one who knows his stuff, so I'd listen to him. I'd go for a 3.0L or 3.2L for potentially more power and longevity, although I built my 2.7L with longevity in mind. If you're 33, I have 43 years on you and longevity is of interest to me. I think you should remember you can hot rod it to the hilt but probably never make it beasty enough to compare with your other (or some of your other) cars as you described. So it's going to be a car to drive for its raw appeal. Of course you could always go the modern V8 or V6 route for power, but it would still handle like a fifty year old car. So if "everything must be insanely modified and fast", it might not ultimately be your thing. Some of the reasons I like mine is because I can get in it, it feels relatively roomy because you're not cocooned in, has simple controls and instruments rather than a lot of electronics and digital stuff, it's small and light, and I really like the shape of the longhood 911s. I just like the car and don't feel I have to prove anything when I'm driving it - maybe it's just because I'm pretty old.