How long to rebuild a 911 2.7 (1975)?
 

Hi,

I'm going to do a rebuild on a 2.7 engine on my Carrera. I need to know how long it will take to plan ahead with holidays from work to get her back on the road and enjoy the ride.

Does anyone know how long it take usually? Bear in mind I do NOT plan to rush this as I want to perform at the highest standard, but at a average time scale.

Thanks

Man, that's a tuff question. Are you a skilled Porsche engine mechanic or never done one but read all the books and ready to jump in, or somewhere in the middle of these. It would take a few chats with machine shops, engine builders to figure out what you want to end up with. Then, several days to order parts, a week or two to remove and tear down. Several weeks to months to have the parts machined/repaired/rebuilt. Now, having all the parts you need along with all the tools and fluids, the actual assembly should take about 2-3 days to get it ready to be re-installed. A lot of the equation is in the hands of the machine shop so real hard to fix a timeline but if most of the engine is ok and all it needs is normal machining, 2-4 months total from shut down to re start. IF everything goes well.
You can be cleaning/painting the engine compartment and engine parts while most of the parts are out. do a new clutch package and CV joints while in there along with new hoses, ignition wires, new alternator and belt. A/C? You will be busy-not much down time, and scream through $$$$ like a congressman!

In my garage, I'd give it about six years.

Best,
Tom

it will take months to get that Mg case checked and align bored by a competent, 911-experienced machine shop - you'll likely need to ship it

Whatever:rolleyes: It's a case, machine shops know how to line bore. It's not rocket science.

Outside of shipping the case to the only guy in the world who knows how to work on them via secret squirell shipping lines, I'd plan for a solid 40-50 hours. That's about what it took me to build my mag-cased engine. By the way, I had a local excellent machinist do the work on my dreaded 7R mag case and he did a fantastic job for very reasonable cost. If you need to ship it, PM me and I'll give you his name. He's in Seattle.

Nate

Not a chance in hell that will only take 50 hours. I would budget 150 hours even if you have done a couple of V8 engines and you are a solid DIY wrench and you follow directions really really well.

It sounds like Vondy doesn't care about hours, he wants to do it right the first time.

First, I would get Wayne's book on rebuilding Porsche engines. I would read it before I started. There is a lot to consider. Everything from powdercoating your engine tin to what kind of tensioners you want to use. If you have never rebuilt a mg cased Porsche engine there is a lot to know. You want to find a machine shop familiar with Porsche engines. You want to have case savers installed, you want to figure out how much if any of the mag parts you want to replace (chain boxes, valve covers) you need to figure out what type of cylinders you have, nikasil or alusil and then you have to figure out if you want to reuse them, chrome them or buy new. Everything from what color case stud o rings to use to what kind of case sealer to use. You will have 50 hours of reading before you buy any parts! If you go to the engine building section there are plenty of threads on them, and there is a lot to read. Good luck.

Exactly.

A pro would charge 40h.
As DYI, count at least 100h. Many of these hours will be spent on cleaning.

Thanks all for the replies! Really appreciate it and impressed by the response time of people!

I work in a Merc garage at the moment as a trainee so I have some experience with engines. Although Merc engines are not exactly the same as Porsche flats, but the concept is the same.

I have bought the books, and will read them first without a doubt, as correctly suspected by James Brown, I want to do it right the first time.

I should mention that the 911 I just bought is a non runner, apparently the cam nut on the left bank got loose and fked the timing meaning that the valves may have hit the pistons (this isn't known as the engine was never stripped), so I'm not sure if I will have to replace them until I strip it. I was planning on rebuilding anyways so it doesn't bother me.
Would you say that if the engine was kept in top condition and regularly serviced all her life that the bearings have worn? I would like to know if it is common for people to replace them...

An alternate question, were these engines built with soft cell valves or hard? So I know if it can endure unleaded fuel if the valves are ok and reuse them.

Thank you.

I would guess that most shops charge 40 hrs worth of labor to drop the engine, tear it down, send it out, get it back, reassemble it, and then stuff it back into the car. I think just assembly of the engine - about 25 hours or so.

-Wayne

Nate, I am curious who your machinest is. I am up her in snowing seattle and have a disassembled 2.7 that needs some love.

The amount of time to assemble the engine is peanuts compared to the time it will take to source parts, clean/inspect reusable and new parts and perform or wait for needed machining, rebuilding, heat treatment, powder coating, balancing, plating, painting and/or other outsourced labor.

Sherwood

'75 Carrera? Love to see some pictures.

My first time was about 8 months, but 3 were waiting for the machine shop.

My last go, where I did not split the case, was about 3 months. Mostly weekends. Keep in mind, you'll spend HOURS cleaning and looking at stuff. Oh, budget $ for a respirator and $150 for brake cleaner.

My first time took 16 years, but that was mostly sporadically, and I was waiting for my daughter to grow up. :)

Sherwood