1976 2.7 rebuild question

artisticent · 03-13-2007, 06:07 PM

I have removed this motor from my car to clean up and make preventitive repairs. My concerns are the oil water mixture I noticed once I removed the oil cooler. The engine did run well, it was a bit loud but I think that was the chain tensioners.
My other concern would be to check for broken or need to be replaced head studs. Opinions please
Thanks
Nathan

Eagledriver · 03-13-2007, 07:07 PM

That oil/water mixture shouldn't be there. That is outside the normal oil circuit. Did you notice a leak? Oil cooler could be leaking or maybe the seals. Rebuilding a 2.7 involves lots of decisions and upgrades. If it's running ok you may just want to treat any leaks and put it back in. If you start messing with things like the headstuds you'll probably need to do a full rebuild. With all the case mods to bring the engine up to snuff you could spend over 7000 thousand dollars.

-Andy

artisticent · 03-13-2007, 07:11 PM

exactly want I need to avoid. I will address new gaskets and a few clean up repairs. I need to figure out why water is even there. It does,nt look like water is even near that area.
Thanks
Nathan

Walter_Middie · Walter_Middie's Garage

Nathan,

Water condenses in the oil tank, and when it overflows or blows out into the intake box, it can look like that. Maybe you blew some oily water out at some time - maybe you had an oil leak and rain water drained down there - maybe the car has been sitting for a while? I'd just get the oil cooler cleaned at a radiator shop and make sure the new gaskets are on correctly to fix any leaks. And reseal the notorious leaks above that area also (oil pressure valve and oil breather).

While you have the valve covers off adjust the valves and try and identify the head stud nuts (they are 10mm drive hex head). Give each of them a little tug just to be sure they are not loose. You are not trying to re-tighten them, just seeing if any are loose. If any are loose, then re-torque just the loose ones (23.5 ft-lbs), and keep notes on which ones were loose. Then every time you adjust the valves, you can see if any are repeat offenders. The repeat offenders are probably head studs that are pulling out of the block.

The other place to look for studs pulling is the very back of the engine where the rear mount bar bracket mounts to the engine block. These are also notorious for pulling studs out of the block.

DohertyCM · DohertyCM's Garage

that 76 did have problems with its water pump....Heck they were so bad that the factory stopped putting them on most of the cars because of leaks....

sorry....a little humor never hurts...

but from what I see I would not worry about it, this may have been cause by someone using a high pressure washer in that area to clean it up and it got in to this "dead area" The oil and water mix that I see is in an area that is not circulated anywhere. Looks to me that oil leaked out of the seals into an area that had moisture in it. Sometimes you see stuff like this in american cars underneath the oil caps and sometimes underneath the valve covers. Doesnt mean there is a leak just means that moisture got in a mixed up with some oil.

My sugguestion is replace as many seals as you can if you are down to this point. Dont pull the heads if you dont need to but Re-torque the heads and do a valve adjustment. If you have a broken stud you will find it doing this. But no need to mess with them unless you need to. Also check out this thread on reducing foaming in your engine, this will also help reduce the oil leaking.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/309123-oil-spewing-oil-tank-breather.html#post2868821

Eagledriver · 03-15-2007, 01:48 PM

DO NOT RETORQUE THE HEADS!!!!

This is a very bad idea. You have a magnesium case engine. The headstuds like to pull out of the case. If you aren't doing a rebuild you don't want to disturb the headstuds.

-Andy

artisticent · 03-15-2007, 02:17 PM

I just checked to see if they move at all and they dont so I think I am ok there. Although I only check a few because I have to remove something to check the rest. IS THERE ANYTHING ELSE I SHOULD CHECK??

DohertyCM · DohertyCM's Garage

Andy, (and i have this converstation with the greatest amount of respect and I am in no way being a smart ass to you or anyone else)....Retorqueing the head studs is not at all a bad thing, infact you want to do it because if one is loose you will want to retorque it, if one is stripped you want to find it at this stage.

Disturbing the head studs - no such thing, if it is stripped or weak you want to find now rather than finding it after you get the motor back together. I have been a mech far to long to know that checking torques is a good thing and not a bad thing. Engineers designed these parts with torque values instead of "elbow tight" methods we use on other stuff. Torqueing to spec is a good thing. If it strips before you get it to torque specs then the stud was pulled anyway and needs to be repaired. Infact this fact is backed up by Dempsey in his book.

Mag cases had failures due to heat mismanagement, the temps that some people run these things at far exceeds the limit at which any porsche motor should be ran. This was evident by the guages with just a red line somewhere in the 280's or 290's...my friend had one and I couldnt believe the redline area..

Anyway back to point, if you control your heat you should not have any trouble from the case. Case in point, I run the CRAP out of my motor, as hard as it will run, BUT - i also dont run it above 210-220 on the track. I have all the mods for the car which keep the temp of the oil low and I also maintain the motor with care and dont neglect it. I have yet to pull a stud...infact my 7R case has never had a pulled stud. I didnt know this until I tore down the motor (for engine mods) and checked. Yes I have retorqued the heads on 2 different occasions not counting the rebuild I am going thru now. If you mod anything, make the first mod a heat management modification...

Now if you are going to put mods in like high compression pistons then you need to add "Case Savers"from competion engineering. They are better than time certs and last time I talked with the guys over there they have yet to see a failure of one.

By the way..if your name implies you are a F-15 pilot, then be glad that your mechs check torques and recheck torques...

artisticent · 03-15-2007, 04:50 PM

Doherty--What engine are you rebuilding now?? Again thanks for all the help, this is the first time I have ever really gone in to a porsche motor. Its been very easy to get to the long block, But unkess I really really need to, I dont want to go any further in to it which is why I am asking these questions.
Thanks
Nathan

DohertyCM · DohertyCM's Garage

I decided to do an upgrade on my motor because I am making it a full time track car.
I am putting the Power Clutch on it, 911S heads, 964 cam along with a Piston re-ring, all new seals, new chains, new gaskets and a potatochip for a flywheel...I think the box weighs more than the part...and now my pistons are getting valve valleys cut in them. I decided not to go with the JE setup for now.
Not to mention a good old fashion cleaning...because all of that dirt and stuff helps lock in heat...bad thing....
All in all I guess I am looking for any weak parts....As a good Porsche Mechanic friend tells me "You never break your engine, you just find the weak parts!"

artisticent · 03-15-2007, 07:47 PM

I like it. I have a 73 911 I am building an RSR out of, and I am still deciding what motor to use for that. I am being advised to get a 95 993 vario 3.6 motor but they are expensive. As far as the 2.7 I have its going in to a 76 car that was a targa but being converted in to a turbo look C2 cab. Even though I feel its pathetic to have a turbo looking car with a 2.7 in it, the 2.7 can be a quick enough motor if looked after. Tell me your thoughts on these pics such as the tensioner safety things, ETC
Thanks
Nathan

artisticent · 03-15-2007, 07:51 PM

eapcpa · 03-16-2007, 11:40 AM

From the pictures of the engine I see that you first need to disassemble to clean and inspect everything. You will certainly need new timing chains, they are streched to the limit. Notice how close the left chain is to the tensioner mount and the right to the upper ramp. JMHO

artisticent · 03-16-2007, 12:13 PM

Thankyou eapcpa,

I will do that. I do recall this motor being on the clanky loud side before I removed. It was the kind of noise you would expect to hear if the chain tensioners were getting old.
Thanks
Nathan

Eagledriver · 03-18-2007, 10:47 AM

My reasoning behind not torquing the heads comes from reading Bruce Andersons book. He talks about rebuilding mag cases without timecerts (or casesavers). He says the heads may torque up but will probably pull a short time later. He also has said numerous times in his columns that we do not retorque 911 heads. Generally I agree that checking torques is a good thing but in this case I disagree. Magnesium yields too quickly and easily for me to want to "disturb" it.

-Andy