So to a degree I’m thinking out loud here.

Engine is mostly done, just waiting for injectors to come back. It looks like my Time to commit to this car will dry up in about two weeks. So, I was thinking of doing a partial install so I can get the engine break in completed and troubleshoot any problems.

currently planning to redo the suspension,brakes, but funding may push that out.

so, I’m asking for opinions.

could I just install the engine without the power steering the air conditioner compressor torque tube, and a few other things. And just performed the engine braking procedure. It seems like it would be fairly straightforward and much quicker than to do a complete installation and not have the weather or road conditions to do a proper break in.

I could probably also rig up an external oil cooler to make that even easier. This way the only fluids I would waste would be distilled water for the radiator.

1. Has anyone ever done this?
2. Will the engine break in and rings seat properly without a transmitted load from the driveshaft?

my wife has been out of town for the last four weeks so I’ve been able to get a lot done. But that is coming to an end shortly and hunting season will be in full swing. So I am expecting that I will be fighting ample time limits, and whether to stay consistent .

We used to do this with engines for F/A-18’s.

OK, let me have it. What’s your thoughts. Thanks in advance.

 

I'm thinking mounting the engine in the chassis without the TT and transaxle, and running it would not be a good idea. As you know, the engine, TT & Trans form a rigid drivetrain system that is "suspended" from the chassis with 2 engine mounts up front and 2 trans mounts in the rear. The CG of the drivetrain is somewhere along the TT in between the 2 pairs of mounts. If you no longer have the rear set of mounts supporting the drivetrain, because the TT & trans are missing, only the front 2 mounts are holding up the engine, with nothing at the rear countering it from tilting forward or backward on these mounts. Statically, with just the engine in place, this condition is OK because the mounts are somewhat near the engine CG, but running it - I don't think Porsche factored that into the design - I guess it's feasible but would not recommend it. Even statically, having the engine sit there is asking more from the engine mounts than they were designed for (handling the front/rear tilting moments).

As far as break in, I suspect you would be best to do that in such a way that the engine is exposed to load, driving the car, on an engine dyno, etc. Running the engine under no load does not generate the same combustion pressures, bearing loads, etc.

 

Good Points,
Although firming up the assembly to account for the absence of drive line is possible.
Your points about the break in lead me to think the Juice is not worth the squeeze.

Thanks for chiming in and talking me down.

All the best,

John

 

Whats the hold up on the TT, and is this an auto or manual trans?
There is really no easy way to support a running 928 eng w/o the TT in place with it just bolted to two mm's, as it tilts forward and back, by the time you spend fabing something to hold it the TT could be done.

 

I rebuilt the TT about 3000 miles ago.

I am currently fighting the slippery slope.

things that need to be done just because.

front suspension
rear suspension
remainder of body fuel lines
painting underbody
Transmission work
etc.
engine has been a total rebuild so just wanted to get the break in done and not let it sit until time and money allowed me to finish.

 

IMHO I'd suggest fogging the cylinders plugging all ports and letting it sit, and not rushing it.
Although I'm sure want to see if/it runs OK, don't chance F'n it up at this point
The TT is in out and including rebuild is an afternoon at best, if its done, then why can't it be bolted to the bell?

 

I don't think you can move forward without the TT, but unless there is a problem with it, maybe you can get it in? Also, If you are going to do anything to your upper front A arms, for sure you want to do that with the engine out.

 

I run all my engines on a test stand, without any load. Even before I had a test stand, I'd install and run an engine for about an hour, before applying any load. My first 30 minutes of running are at a constant 2500-3000 rpms....wherever the engine is happiest.

Therefore, I highly approve of your idea.

Put the engine on the mounts and bolt the engine to the mounts. Put an appropriate height jack stand with a block of wood under the lower bell housing. Jack up the front of the engine with a floorjack (with a piece of wood) under the front of the oil pan until the rear jackstand is under slight pressure.
At this point, the engine will be rigid, extremely stable, and you can run it to your heart's content.