MFI pump ... what to do ?

philippeF · 06-03-2004, 02:29 AM

Hi all
I'm on the way to rebuild my 2.7 RS engine
it ran well before but leaked, shall i do something with the pump ?
Shall i replace some gaskets or any thing else, i'd like to do the more myself (money, money.....)
any advice, warning... ?

best regards
Philippe (burgundy, France)

sundaypunch · 06-03-2004, 06:40 AM

Did the engine leak or the pump? If your budget allows it certainly would be nice to have a rebuilt pump on your newly rebuilt engine. If the pump is working properly you could leave it alone. Rebuilding a MFI pump is not a do it yourself project. If I'm not mistaken it costs approx. $1500 US (do a search) to have one rebuilt.

Peterfrans · 06-03-2004, 06:40 AM

Hi Philippe,

Before being able to offer some help please tell some more about the engine, where does it leak etc. If the engine was running ok why do something on the pump? If you suspect that the pump is not ok anymore you could have it checked for approx €100-€150 (I had it checked at www.koller.de, ask for Hermann Sattelberger).
A lot of guys started their own rebuild and with the help of this board so can you. Be prepared however to spend some serious cash, porsche parts are not cheap and some parts need machining which you cannot do yourself. It just adds up, for instance your camshafts might be worn, to have them rewelded to original spec will costs approx €800 per pair, but then you also need new or reground rockers which also go for €40 a piece etc etc.

A first step would be to buy Wayne Dempseys engine rebuilding book. Another book I used is by Bruce Anderson and obviously the workshop manuals.

Early_S_Man · 06-03-2004, 07:34 AM

Philippe,

If the 'leak' is oil oozing or dripping from the MFI pump, the rubber gaskets on the side and bottom covers can be replaced by O-rings ... that is what I did to cure the oil leaks after I found that tightening the screws did not work!

Another solution would be to use silicone gasket replacement compound after cleaning the pump housing thoroughly with spray degreaser and rags.

philippeF · 06-03-2004, 12:43 PM

I'll rebuild the engine because it''s leaking a bit : bottom plate, case... it has not ran a lot because the previous owner had the car for 20 years and didn't drive a lot (20000kms/20 years), this is a track car project (72S with 911/83 engine), i want to be sure i won't burn the engine in a few weeks....
the pump seems to work well, but the engine was a bit capricious before 3000 rpm, i've ckecked an hazardous mass point with the distributor, no leak with the pump
can i clean the pump without problem, what should be the basics ?

many thanks
Best regards

you may have a look at the car

www.ifrance.com/autoprestige/lesporsche.htm

Philippe

michel richard · 06-03-2004, 02:03 PM

Philippe,

Almost guaranteed your pump does not need a rebuild. In any event, you should only decide on a pump rebuild after the engine has been rebuilt and you can't make it run right after checking and double-checking averything else.

Michel Richard
914-6 with 2.2 E MFI

Ho Hum 74 · Ho Hum 74's Garage

I'm still not following why the engine has to be rebuilt. What am I missing here? If the oil pressure is good and the power is still there (compression and leakdown check out) then why re-build at all? A few oil leaks are pretty normal and you can usually have most of them taken care of. Rebuilding the whole engine seems like overkill.

Tristan

philippeF · 06-04-2004, 12:33 AM

the car is under restauration as you can see
i've noticed the oil pressure was a bit low

btw, may you tell me what you think about it : as i start the engine (cold) oil press : 2-4 bars/idle-3000rpm
a few minutes after 60°C : 2-3 bars/2000-5000rpm ?

oil press. transmitter has been changed but shall i trust it ?
as i told you the car didn't run a lot.

advices appreciated

Philippe
France

AndreasLanghoff · 06-04-2004, 01:30 AM

Hi Philipp,

from your description it is not so clear how the condition of your engine is really.
I have gone through the same problem areas as you and my suggestions are:

1. Oil in pump area: On my car the pump bottom cover was oily, but the oil came from somewhere else. Usually it comes from the crankcase breather system. Once the engine is old and has huge ring gaps, then a lot of exhaust fumes start to circulate in the crankcase. The breather system cannot cope with that amount anymore and you will find oil in that area including the mfi pump bottom (that where the wind turbulences push the oil).
On my engine I suspected the pump, dismantled it 2 times, checked for the case through-bolt in that area, but nonsense, the real problem was worn out rings that caused the breather system to sweat a lot of oil.

2. Pump rebuild: I tried 2 times myself, no way!! You need the bosch work bench and flow meters and many special tools.
Send it to Turati & Cipponi, Cusago , Milano Italy. They do a professional job for about 400 Euro. (If interested, then I will look up their exact address)

MFI pumps usually run forever, so check throttle linkage and all the other stuff first. If nobody has messed around with the pump (it is a bad idea to play too much with the idle mixture!!) then you do not need a rebuild. Check other things first.

Best regards

Andreas

philippeF · 06-04-2004, 04:47 AM

thanks andreas
it helps !

i'd like your Milano adress

best regards
Philippe

Ho Hum 74 · Ho Hum 74's Garage

Quote:

btw, may you tell me what you think about it : as i start the engine (cold) oil press : 2-4 bars/idle-3000rpm

Philippe,

Your engine can read 0 (psi) on the gauge at idle. My new rebuild of the same engine reads 20 psi when warm. You should get 15 psi per 1k rpm. I'm not sure what the translation is between bar and psi. I guess the Euro gauges are different.

Here's what I would do first and it will only cost you a couple of dollars (or Euros). Get the upgraded oil cam restrictors. These are smaller orifice plugs which go into the cam area and feed oil into the cam timing chain housing on the rear of the engine (the one facing you as you open the engine bay). You will need two. These are the 930 turbo ones. They increase oil pressure in the system by restricting the amount of oil flowing into the chain housings. They will raise your oil pressure. Try these first and see what happens. You can install them with the engine in the car. You'll need these for your re-build anyway.

ok, I found the info on Pelican...

A relatively recent upgrade has been identified by Lee Rice and Steve Grosekemper of the Porsche Club of America. All of the 911 Porsche engines from 1966 through 1989 use the same cam oil line adapter to connect the oil lines to the camshaft housings (Part # 901.105.361.00). In 1991, the factory replaced this adapter on the 911 Turbo with a new updated part that had a greatly reduced center orifice. This new part (Part #901.105.361.01) has a circumferential groove around the adapter to differentiate it from the original adapter.
This change was adopted to supposedly address oil foaming problems in the crankcase. This foaming occurs when there is an excess of oil in the crankcase, which becomes whipped up into a foam by the rotating internal components. The source of this excess oil originates from too much oil being fed to the camshaft housings. Excess oil is dropped from the rockers to the bottom of the camshaft housings, where it returns to the bottom of the engine crankcase.
The addition of this restrictor adapter adds a few benefits to the oil system of your 911 engine. It decreases the amount of potential foaming in the engine by reducing the flow of excess oil to the bottom of the crankcase. This decrease in excess oil and reduction of foaming allows the scavenge side of the oil pump to transfer oil out of the crankcase to the oil tank significantly faster. This maintains greater consistency in the oil tank level and generates more accurate oil level gauge readings. Reduction of foaming also reduces oil losses through the crankcase breather system.
In addition, the installation of the restrictors increases oil pressure throughout the system, without reducing the oil flow feeding the camshaft housings to inadequate levels. Oil pressure is higher at the main bearings, the rod bearings, the piston squirters, and also the pressure-fed Carrera chain tensioners. Engines that normally read low or near-zero oil pressure at warm idle, will show increases of 10-20 psi from simply installing the flow restrictors.

They're $5.50 each. Cheapest mod you can do to bump your oil pressure.

Let me know how it goes. If that doesn't help then further investigation is necessary.

Regards,
Tristan

AndreasLanghoff · 06-04-2004, 08:32 AM

Here the MFI rebuilder in Milano
You can also ask for an appointment to set the linkage etc. properly up.

It is an approved BOSCH service center since about 1940.
Talk to Mr. Cipponi

(in case make reference to Mr. Andreas, with an orange 911S Targa ,2.7RS engine)

1. TURATI CIPPONI
49, V. EUROPA
20090
CUSAGO MI
Tel. +390290119653

AndreasLanghoff · 06-04-2004, 08:35 AM

Very briefly regarding oil pressure:

In very hot engines (105 degrees) oil pressure can fall to 0.5 bar at idle.

Above 5000rpm you must have >5 bar.

At normal operating temperature 1000 rpm corresponds to at least 1 bar.

Oil senders can fail, so test also with special tools if in doubt

Andreas

philippeF · 06-04-2004, 12:46 PM

thanks again andreas

i glaube du lebst in deutschland ?

I thought about oil restrictors, i still want to open my engine, as i was studying engines at school,
it'll be time for me to go back to passion, btw i'm going to work on details : case improvement, head flowing improvement, moving parts balancing, new bearings...
i'll wait with the pump : you all are right i'll check it when i'm sure everything else is fine (clearance, new parts...)
another thing : i must find something to do while the car is going to be paint !

i keep the silver metallic, and red carrera stripes (did someone do that?) another proposition ?

thanks for reading my non academic english style..

Philippe