Christer

As my car has started to leak oil slightly more recently (at 96k+ miles) and although I don't know whether I am still within the Porsche parameters for oil consumption (I think I am), I think it is only prudent to look to the future to see what should/must be done. I am therefore asking what you guys think as far as options:

1. If I just rebuild my own engine, I would definitely want to update to the later head design and p&c's in order to ensure as far as possible that the engine stays dry in the future. At the moment the best (most economical) way to do this would be to machine the heads and fit 993 pistons and barrels. There are other options such as 3.8 but the process is the same.

2. Do I fit a 993 (non-vario) engine? In this case, this would leave my exhaust system high and dry unless I can get an exhaust system thrown into the deal. Even then, it will not sound anywhere near as good as my existing setup. This would be the least favourite option.

3. Do I exchange my current engine for a reconditioned one? The upside here is that it is certainly economically attractive, especially if I can get an engine wich has the updated gasket set up etc. (and warranty?). NB Would there be a downside in as far as the engine number would not be original anymore? When/if I come to sell it, providing it has been clearly documented will it matter?.

This is something that has been on the cards for a while anyway, and because the engine has increased oil consumption from 1litre every 2000 miles to perhaps half that I reckon I might as well look at it sooner rather than later.

What do you think and why?

Richard H

Christer,
The spec for oil consumption is for burnt oil and does not include leaking oil as far as I am aware.
I have a leak from the cam housing to chain housing (probably o-ring) that has got steadly worse over the years. With 98k on the clock I face the same dilema as you. The engine still feels strong but if I'm going to repair the leak while the engines out it probably would benefit from a top end tickle. If you go for this then the gasket problem comes in and once the heads have been disturbed could leak further down the line if all the machining is not done (££££).
Like you I have considered a 92+ engine as replacement but also worry about non original engine number.
Only benefit I see is that at least you have the updated engine which could be a bonus for resale to the less informed out there!!!
Would be interested in others opinions as well.

Richard 1990 C2

Arjan B.

If the engine runs well, makes no strange noices and feel/runs good, I would let be as it is.

I have the same oil consumption as you so I think you don't have to worry much.

You could do a lab test for your engine oil to see the % of iron/copper/aluminium are.
Take some oil out of your engine and send it for a lab test, I did that a few times. Made me feel more comfortable.

DaveK

I think it depends a lot on the cost difference between 1 & 3. The advantage of a new engine is : new everything, but on the other hand - if your rebuild is done properly that shouldn't be so much of an issue anyway.

I wouldn't really be tempted by 2) - if you are worried about selling the car when you've replaced the engine with a new 964 one, think how hard it will be when you've replaced it with a 993 one. Which even if you found a low mileage one, would still be more "worn" than your rebuilt / new 964 one would be.

On the other hand, there might be a very good reason for choosing the 993 engine option. Would your exhaust fit a C4?????

tonytaylor

I have pondered the same as a "money shift" is always a possibility.
The problem with options 1 and 3 is the nagging doubt that whoever rebuilds the engine may not atain Porsche standards of engineering. Option 1 will get very expensive if you catch upgradeitis.
Personaly I`d favour fitting a late 993 engine, you don`t have to keep the varioram, as this is what the experts seem to do. Geoff Everett (ex AMD) fitted one to his 964 and 9M is a fan of the conversion ( but not the varioram). Perhaps you are "emotionaly" attached to your exhaust but its worth bearing in mind a complete custom system could be built for £1000.
I don`t think not having the correct engine No. is an issue really as 964`s aren`t classics in that sense - I`d prefer to buy a 964 with a 993 engine rather than a recon/rebuilt one ( but I`m more familiar with thecars problems than a the average new punter)

oldtimer

Sounds like oil leakage is the issue rather than oil consumption related to a worn engine with oil being burnt in cylinder heads because of worn rings / valves ....I'd live with it until it increased beyond reasonable.
On the action options , I'm inclined to agree with tony t .
I dont think originality of engine is much of an issue for 964s, the 993 engine with hydraulic tappets is cheaper to service / keep in trim and no issue with oil leakage..maybe even easier to source / cheaper to buy.

Wikkid911

Hi Christer,
I went through the same dilemma less than 12 months ago.
I think that the expense involved in any of those options is extreme so if your leak is not really bad its going to be way cheaper to continue to top the oil up.
That said, its much nicer to have a sorted 911 so I can see your point.

1) I like the sound of this option. 3.8 litres and guaranteed job keeping your original engine number.

2) Any 911 having an engine that wasn't in there from the beginning would make me walk away if i was going to buy it. I'm pretty sure you would too.

3) I had never considered this as a possibility. Are they readily available?
Do they come with warranty? How much of a saving over on a rebuild cost would it be?

For me the favourite has got to be a rebuild of your existing engine. The 3.8 conversion was too expensive for me but may not be for you. At least you know you are starting fresh all over again then.

Just my thoughts, interested to know what you decide.
Cheers.

Christer

Thanks for the replies, keep them coming pls!

So far, I do understand your points regarding a 993 engine but I guess in order for it to be economically viable it would have to be a secondhand engine with no indication as to the condition of such an engine (for example a 60k miler from Porschapart or similar). I might be stuck with an engine that needs a rebuild itself in 30k miles time, plus the fact that my exhaust which cost £2K will also be redundant. I don't see this happening. I suppose I could buy such an engine to source parts like the P&C's, conrods etc, but I would have to do more research. 9M have suggested this 'part sourcing' as well as the 993 complete install to me, so I need to do more research on that.

I guess I could also consider having the engine rebuilt to the same spec as it is now, but this would mean no head update so I would have to hope that I don't get any problems in the future without a headgasket.

Has anyone had their engine rebuilt by 9M and how did you find them. I already know all about JZM's engine rebuild expertise, but I would be inclined to let 9M do it with a view of continuing the relationship with them with regards to Motec etc.

More comments would be appreciated.

robmug

Christer

I think I'd go for the rebuild/update (option 1).

The 993 engine as you say would be an unknown quantity, would be non-original in the car and is actually not that much different to the 964 engine.

Recon engine would, to me, only really be an option if I needed to reduce the time the car was off the road.

Option 1 for me, and I agree with you re 9M if you are indeed looking to go down the Motec route ultimately.

Edit - what are "P&Cs"?

johnfm

Rob

P&C - piston and cylinders.

Christer
Oil consumption guideline is 1 litre per 1000 km - which is about 620 miles - so you are still well within spec. If the engine isn't dumping large patches of oil everytime you park it, its not really a really leaky motor. However, as a victim of upgraditis, I understand the wish to spend money upgrading it. You've already done suspension brakes & exhaust, so that just leaves the motor!

A stock rebuild would just frustrate you - once you are paying someone 60 hrs labour the temptation for higher spec rods, bolts, valve springs, lightweight pistons, MoTeC etc will be very high. Then there will be the RS flywheel & clutch. I suppose you have to decide whether its a keeper, or whether you will moving on to, say, a GT3. The cost of a rebuild would cover 2 years of monthly payments on a GT3!!

Have you had compression, leakdown & dyno done, or are you going on oil consumption at the moment??

warmfuzzies

Christer, if/when you sell the car on, how long will it be and what do you expect it to be worth?
I say this because if you're going to keep the car for another 4-5 years say then the rebuild with new parts would be my choice. In a nutshell it would be easier to move on afterwards.
If you put yourself in the position of buyer, knowing not what you know now, but what you knew when you wanted the car originally what things would put you off buying a car? Wrong engine (993).... serial no:s not matching? IMHO these would make me sit back a little.....
But at the end of it all its what makes you happy,,,,,,,,, and your wallet lighter......

Kevin

Christer

So far, I am just going on the oil consumption. I guess what I really need to do is to give it a few months to see how much I am actually using. I just don't like to have these things hanging around. Service at JZM in Jan - maybe get the comp and LD checked out then...

Having said all that, the engine still feels 'strong' so I don't think there is all that much wrong internally, it just leaks.

RE GT3: I never buy anything apart from houses on credit.

Kevin, I plan to keep the car for a good while - but I don't like the wrong engine number scenario either because it might mean it makes it harder to sell. That is after all why I purchased a RHD car.

johnfm

How bad are the leaks - visually I mean. Big/small oil patches on floor?? Is the engine really wet after 1 week - 2 weeks - more or less??

It sounds like you've got a 'keeper', so I would find an engine builder you really trust, start putting some money aside and rebuild your existing engine with an allowance for some lightenes/stronger internals.

Have you had a quote for rebuild time on a part & full rebuild??

From memory, top end is about 35 hrs, full is 50+ all plus parts.

joey bagadonuts

I think JohFM's on the right track--you may be fine, enginewise.

My car consumes approx 1 liter/1,000 miles but I don't have any leaking or seepage. Of course, many of my miles are driven at the high-end of the rev range due to track outings, so I would guess that consumption would decrease if it were driven primarily on the street.

I'm not clear on the relationship between consumption, valve/ring wear and leakdown figures, but my latest 15K service yielded leakdown results between 4-5% across all cylinders. The low percentages seem to indicate a healthy engine but would the consumption suggest otherwise?

J-McDonald

911 oil consumption is a VERY, VERY inexact science - unless it's really extreme (like 1 quart every 200 miles) AND accompanied by the engine making white smoke at start-up or under load, you should NOT use it as an indicator of engine health.

As is stated in the owner's manual, over time water will condense into the oil, leading to higher indicated amounts of oil. When the car is run hot for an extended period of time, this water will boil off, leading to lower indicated amounts of oil. The result is that it may appear that your engine is using (burning or leaking) a lot of oil in a short period of time when, in fact, no oil was used.

Step one is getting the compression and leakdown tests done - that's the only way to know for sure what the health of your engine is. If you get bad results from the tests, consider a rebuild/replace. If you get good results from the tests, find out what it takes to fix the oil leak. If it can be fixed without removing the heads (which it sound like is true), have the mechanic drop the engine and fix the oil leak.

If you get bad test results, you'll need to decide whether to: (i) do a "top-end" rebuild (i.e., new pistons, new valves, new valve guides, machined cylinder heads); (ii) do a "full" rebuild (i.e., top-end plus splitting the case and rebuild the main (crank) bearings, connecting rods and bottom-end); (iii) replace your engine with a used 993 motor; or (iv) replace your engine with a factory remanufactured engine from Porsche (available from any dealership's parts department).

964 bottom-ends are extremely durable - it is extremely unlikely that you'll need to do anything other than option #1.

Good luck!