billb123

I'm at a crossroads. I bought my '85 911 about 21 years ago and it was my daily driver for about 19 years. For the past two years it has been a weekend/ perfect weather car with the occasional DE outing. Recently, after three hard days at VIR, it appears that the engine suffered a catastrophic failure - maybe a valve guide seal, maybe something else, don't know yet. Major ticking/sputtering noise and plumes of white/gray smoke poring out of the exhaust. With 180+k miles and something major wrong, I think I'm facing an engine rebuild.

One of my goals for the car is "to be buried in it" (but not anytime soon). I love the days at the track, but I'm not thinking about any kind of club or class racing, so any kind of mods are ok with me. I'm also not planning on gutting the car to make it a pure track machine as I want it to be a fun drive about still. I would have spent my money on suspension and safety, but now it seems that I'm faced with an engine rebuild before any thing else.

If I'm going to spend the money on an engine, I'd like to get more power.
- I'm not interested in a turbo.
- A 3.6L, preferably with VR, seems attractive, but not cheap because of the necessary mods
- I'm not sure what I could achieve by rebuilding my core with mods. Is there a 3. 4 conversion with new cylinders? new cams? carbs v. EFI? In North Carolina, for a car this old, I don't have to worry about passing emissions to stay legal, so that gives me some flexibility.

I would really appreciate any thoughts on options, including the complexity/cost and the benefits of each.

BTW, I'm not an experienced home wrencher, but I enjoy it. I'm not sure I would take on a complete rebuild, but maybe. The cost of making my garage suitable is another story.

theiceman

Ed just did this to his car so I am sure he will comment. For sure you will need a healthy budget for this.

packet

Get a copy of Wayne's rebuild book. There's a chapter that goes over all the options and the expected output horsepower. It gets expensive quickly, but the sky is the limit.

JE makes a bunch of different pistons these days depending on how wild you want to get:
http://www.jepistons.com/Catalogs/Au...e/Porsche.aspx

There are quite a few different cam profiles available based on your application. The 964 profile tends to be incredibly popular these days.

The trade off is if you're going to a higher compression engine with more aggressive cams, you're increasing the stress on the engine. That means it'll need a rebuild sooner. Also you tend to get the valves closer to the pistons which increases the chances of contact.

For reference, I just rebuilt my 3.0 and it came out to a little less than $15,000 including new heat exchangers. While you're in there, you might want to consider rebuilding the rear suspension. The trailing arms are worlds easier to get at when the engine isn't in the way.

Steve Weiner-Rennsport Systems

You have a lot of options available to you that include:

1) Doing a 3.4 or 3.5 conversion.

2) Installing a 3.6 VR.

I always ask my clients three main things when considering the options:

1) What kind of performance do you want?

2) How long do you expect the new engine to last?

3) What is your budget, since that's really what frames what is going to be possible to do?.

The answers to these questions will guide you toward the best and most cost-effective solution to your objectives.

KaiB

The answer here is actually very simple.

Call Steve and tell him you'd like the KAIBACH special.

Steve Weiner-Rennsport Systems

LOL,...That one will certainly make you soil your skivvies,...

Ed Hughes

You can build your motor and make pretty decent power, without losing dependability. I ended up at 230-something HP at the wheels. Headers, cams, 3.4, compression bump and twin-plug. Someone like Steve could've thrown a few tricks at it and done more with the same, I'd bet. It ain't cheap, however. This is my build.

https://rennlist.com/forums/911-foru...ild-redux.html

I'd seriously consider a build like this over a transplant, unless you truly know the motor you are buying. With a newly built motorm you know what you have. I know of several people who have bought used 3.6's, transplanted, and had motor failures. That gets pretty expensive too.

billb123

Thanks for all the advice. I'm learning a lot already.

Ed - I've started on your thread, but haven't finished. I'm about 8 pages into it. I'll admit that it seems like a challenging task for someone of my limited experience to take on.

I already have "101 Projects.." and I just ordered Wayne's book on rebuilds. While I was at it, I also got "Porsche 911 Performance Handbook..." by Bruce Anderson and "The Used 911 Story" by Pete Zimmerman. I figure $10s on books might save me $100s or $1000s on the choices I make.


Steve, you ask great questions. I'll try to answer in reverse order.
3) I am hoping to keep this on the lower end of a custom job. Not Meister levels, but maybe $12k or less. Am I kidding myself?
2) I plan to keep the car for another decade or two, and would like the engine to last. That said, I might only put a few thousand miles per year on it, definitely some at that track. So, let's say 50k+ hard driven miles is the goal.
1) The most performance that is possible consistent with answers 3 and 2 AND is still suitable for regular around town driving - e.g., 93 octane

I'll read through the performance chapter in Wayne's book and see if I can start to develop a general plan. Based on Ed's comments and a few trips through eBay looking for used motors, I think i'm leaning towards a rebuild of my core with a 3.4 or 3.5 solution. First, I wouldn't want to go to a lot of trouble to put a tired or uncertain 3.6 in my car. I would want a rebuilt 3.6. The costs then start to rise dramatically. Also, given that Ed is getting 230+ hp at the wheels, using a 15% drive train loss, he's at 270+ at the crank, which is 3.6L territory anyway.

Thanks again for the input.

One more question. Anybody got a favorite mechanic/ experienced rebuilder reference in the North Carolina?

Ed Hughes

That really was my point-that your motor can be built nicely. I was just dumb enough to try it myself.

I think you are on the right track rebuilding vs a transplant. As to $12K, that is probably a bit light, but you can call Steve and get his pricing and suggestions. If you stick with 3.4L, you won't have to machine your case. Good luck on this.

Steve Weiner-Rennsport Systems

JMHO, so here goes,...

3) I don't think any good performance build can be done for $12K without cutting a lot of corners and making a good many compromises. I know I'll hear from many DIYer's on this one to the contrary, but based on experience, I stand
firm on this one,......

2) Understood. Just remember, some inexpensive engine components are almost all done around 50K miles, so thats something to consider as it affects resale vale.

1) A moderate compression, twin-plug 3.4 runs fine on 93 octane as will any 3.6 (they have knock control and are adaptive) so the real answer lies with your budget.

A word about 3.6 conversions: these provide the biggest gains in street performance due to the sheer quantity of torque, however most used engines require work and some need a lot of it for durability.

Budget this project accordingly including the clutch, transmission, and additional oil cooling so look at this holistically. The Devil is in the Details if you want reliability,....

Good luck!

Beverly393

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Ed just did this to his car so I am sure he will comment. For sure you will need a healthy budget for this.

Ed Hughes

No contrary from me on that-I got your back!

theiceman

hmm i wonder what that was about .. anyone else not see red x's ?

billb123

OK. I'm modifying my budget expectations. I don't want to cut corners at the expense of durability. I just might not include all performance options - e.g., I won't pursue the Extrudehone I've seen you guys talk about.

Ed Hughes

Spambot?

I never did the EH. That's pretty much external, and something you can do later, if you deem it necessary.