Another 914/6 sort of tribute

[brian in buddina]

I have recently purchased a Porsche 914/6 tribute, well sort of a tribute. Its a 1971 US delivered 914, which originally  came with a 4 cylinder motor, imported to Australia many years ago. Converted to RHD and re engined with a 1974 911 2.7 motor. The car has not run for 20 years and other than being told by the previous owner that: “it ran when it was parked” its history is less well known.

 

I am now starting the daunting, for an apprentice mechanic, process of getting the car back on the road. I going to try and do as much of the work myself. I have dropped the motor out to get a better look at it, as not much of the motor is accessible or visible in the 914. First up is to determine the extent of the internal engine condition and decide if its a total rebuild or something less.

 

The motor is the infamous 2.7 with the magnesium block. Its had the later model less leaky cam covers and pressure oil fed chain tensioner installed at some point in its earlier life. I am aware of the failed head studs and will confirm if they have replaced and are currently holding. 

 

In Wayne R. Dempsey’s book “How to rebuild & modify Porsche 911 engines 1965 -1989” he mentions about compression tests & leak down tests to determine the valve & ring condition. He recommends that to get an accurate result the engine should be warmed up. This is not possible at this point the motor is not running due to a variety of reasons not associated with the motor itself. Lots of rubber seals & hoses have perished, the issues with fuel tank & fuel lines.  I have removed the spark plugs and noticed lots of carbon build up on all the plugs, which according to the book is pretty common. I have put a little oil down into the cylinders and the motor does turn over easily, without any “noticeable” clicks or clunks.

 

Now, here is my question for the master mechanics. What things should I be checking to determine if I require a rebuild?

 

[Fishcop]

Personally... I'd get it into a frame and kick it over on the starter to measure compression and conduct a leakdown.  You don't need to have it running to to do this, but if you're feeling adventurous you could go the whole hog and set it up with some fuel and fire and get it running outside the car - lots of advantages if you can do that.  Right now you can pull the covers and check for pulled headstuds (which was their biggest weakness), pull the plugs and put a cheap scope in to check pistons and bores (bonus if you have nikasil rather than alusil).

By the looks of it, you have a 7R case (going off the CIS) which is a fine case to build something light and authentic - particularly with carburettors and cams I built my old 2.7RS spec engine using the Dempsey book (there's a couple of errors which you can google to get corrections).

Was the car previously registered with the 6 cylinder?  Does it have a full conversion to 5 lug wheels etc...?  Lots of options to hotrod these cars

Honestly though, long-term, I'd be more concerned about the body/monocoque and ensuring the foundations of your build - no point having a rocket-ship that is falling a part at the seams.

[brian in buddina]

Fishcop

The first project is just to get it working, with out too many hot rod mods, as there is enough to do. 
Yes the car was previously registered in the ACT. 
Yes 5 lug wheels. And I am told the 911 torsion bar front suspension. 
The rust is a big issue on these cars. So far its looking pretty good. There is some rust at the bottom of the front windscreen which will need attending to. Sills are good. I’m sure I will find some more bits. The underbody was undercoated and looks good so far. 

[Coastr]

A cold leakdown test can be done with the engine out and will still give you good information.   You'd certainly know if one cylinder has a bad ring or dropped valve doing the test.  I'd be inclined to believe the PO with the 'ran when parked' story - it would speak to the basic integrity of the engine itself.  It's been stored with all the intake and presumably indoors so I would start with the assumption that the internal mechanical bits aren't broken.  Everything else you can remove covers to inspect and check - valve covers, cam covers.  You can - as fishcop says - get an engine mounting rig and test fire it.  If you don't have any of the equipment to do that you can always stick it back in the car to get it running.

Other tests I'd be doing outside the car are a smoke test for vacuum leaks in the CIS and I'd replace the fuel lines as a preventative measure, and I'd be checking all the wiring carefully looking for broken/corroded connections.

This will be a very cool car when you get it wheels down, that's for sure.

 

[Fishcop]

On 17/04/2022 at 22:02, brian in buddina said:

Fishcop

The first project is just to get it working, with out too many hot rod mods, as there is enough to do. 
Yes the car was previously registered in the ACT. 
Yes 5 lug wheels. And I am told the 911 torsion bar front suspension. 
The rust is a big issue on these cars. So far its looking pretty good. There is some rust at the bottom of the front windscreen which will need attending to. Sills are good. I’m sure I will find some more bits. The underbody was undercoated and looks good so far. 

I'm just not familiar with the 914-6 series bodies like I was with the 911 shell.  I have a soft spot for the 914-6 and did some homework back in the day... I understand that there is a "hell hole" around the battery area - that is apparently the source of much heartache when it comes to cutting  and fixing rust.  The "911" front suspension is standard - interchangeable in every way, the rear not so much  

I'd check for what you can with the engine out (studs/leak-down) replace rubber/plastic lines and clean up your wiring, and then get it back in the car and run it.  If it's apparently running fine then leave it alone for the time being and concentrate on getting it back on the road and importantly registered in your name (on club plates to reduce cost).  Then you can go to town fiddling and fettling, and perhaps a bit of hotrodding with out worrying about getting it registered down the track (particularly if you're inclined to play with wheels/seats and track-day stuff).

[9er]

The jacking point (with the sill covers removed) can get a bit ugly.

The clutch cable tube through the centre tunnel can also cause problems.

[KERMIT]

Hi Brian

Good luck with your project and I hope it all goes well. I'm almost finished a 914/6 to 3.6 project that's taken 3.5 years, but the end result is worth every minute and grey hair!  They are a hidden gem.

I had the engine in my 77 Carrera 3.0 rebuilt a few years ago and the start of that was to do with pulled head studs. I asked around a lot in regard to what was available, as I couldn't see why I would replace like with like. 

Bingo!! I was told about Raceware Engineering in the USA, who manufacture Aerospace Quality Engine Fasteners. (raceware-fasteners.com) 

They were around the same price as the others, so we gave them a go and all is good. Certainly worth thinking about.

Good Luck!!

[brian in buddina]

Results of my torque test on the head studs: FAIL! 
Bugger, a few good studs but far too many loose ones. 

[brian in buddina]

Pulling the case apart to have case savers installed due to the pulled head studs and the results are in. I received the kind of assistance from a local Sunny Coast 914 expert, Geoff,  who has two 914/6 and is very familiar these motors. It would have taken me months to pull the motor apart without his knowledge & special tools. After 2 days of disassembly wrenching the motor, its pretty good news at this point.
I was concerned that I may have had the the disposable Alusil barrels which were used on this motor for a short period of time. But I have the Mahle barrels and they look in good shape, no scoring. They have yet to be measured. 
Splitting the case no orange sealant was used on the joining surfaces which contributed to the oil leaks. This may mean the case has been pulled apart in a previous life.  
The crank and bearing surfaces all look really clean with very little wear. But again, not measured yet. 
The crank bearings are marked as ‘std’ standard so this leads us to believe it has not been previously machined. 
The motor will require the internal oil mods. Yet to be determined, that the  pistons are within spec or line boring will be required on the crank.
Lots of carbon build up in the combustion chamber & piston crowns, as is normal for these motors.

Now to decide if I build it back to standard spec, with the 8.0:1 compression or do some additional mods. In Wayne Dempsey’s book on pages 112 & 113 are 3 options for this motor  The third option shows on page 113, that I can remain with the CIS injection, use new JE higher compression 9.8:1 pistons and a 964 cams. Has anyone here done this option? 
 
As a ball park figure, has anyone got a rough idea of what costs I am looking at for standard parts & machining for the 2.7 motor? This is assuming I can do the labour myself, with assistance.

I tried to add some photos, but a window came up that I am out of memory. I have cleared my mailbox of older messages but still no memory. 
 

[Coastr]

Easiest way to host photos is to use Imgur.  Once photos in there you can copy the link and paste the url in.  The site storage is limited.