[knife]

i have been toying with the idea of making an engine stand that has the engine bolted on top and an electric motor on the bottom. then i would connect the electric motor to the engine via a belt. this way, i am assuming of course, you can run the electric motor at a specified/varied RPM and break in the cam without the risk of overheating/hard starting/long cranking times/bad timing/fuel problems etc. after you have run it for 20-30 minutes and the cam is broken in, you can pretty much take all the time in the world to drop the motor in, solve cranking problems and fine tune the setup. you dont even need to have all components hooked to the engine. you could do this to a bare long block even.

I would really like to hear some feedback on this. do you think it would work? has anyone done this, or something similar, before?

i cant add attachments, or i would post the sketch i have made for this idea.

 

[71350SS]

Sounds like a good idea on paper but you would have to find a way to heat the motor oil and coolant up to operating temps.The other concern might be damage to the rings from lack of combustion pressure.

 

[cam-copier]

We had an engine run in stand when I was in College. Im sure its ok for a production rebuilder, but I wouldnt run a performance engine in it.
The first time I saw it in use the teacher had a fresh short block installed and ran it for about 5 minutes. The cylinder bores ended up super hot since they could not put coolant in the engine. The camshaft did not break in since there was no spring pressure pushing the lifters down. I dont remember the RPM the engine was turning but it could not have been over 200 or 300 rpm. At this rpm the oil splash from the connecting rods would not be enough to keep the cam and lifters alive.
I would imake sure the engine could hit 2000 rpms, and fill the long block with coolant.

 

[allengator]

I have seen very nice stands for sell at local swap meets for the $600-$700 range.

These stands have a small gas tank, a radiator, electric fan, and a full gage package.

Another local swap meet vendor was using these stands to show off his used LT1's....
very impressive.... I will see if I still have any literature on the stands and post them.....

 

[engineguy]

Break in should be done with the engine running. Combustion temperatures are necessary for the rings to mate to the cylinder walls, which will expand significantly when warm. (This is the reason why most engine builders prefer to hone blocks with hot coolant circulating and torque plates installed).
Also, as mentioned in an earlier post, the RPM would need to be at least 2000 in order to get oil splash on the cam/lifters during the break-in period.

Smokey Yunick did develop the Spintron, which is sort of an external-motored test stand, but the primary purpose of this equipment is to study valve train harmonics at various (high) RPM levels.