breaking in rebuilt track engine.

[Alan L]

I am doing some top end work on my 930 track machine - some suspect rings and valves - so far nothing broken, but one side yet to strip.
But once re assembled, how do you break an engine in that is only used on track - thinking of the settling of the torque values in the heads etc. Dont want to spring any leaks , but it seems the only option is to go out and do a normal track/race day?
Thanks
Alan

[MBruns]

check for leaks and all settings and put it to work, keep the idle to minimum and basically drive it normal, when we break new race builds in on the dyno (with all clearances set to race spec) we put about 20 to 30 min. varying the load and getting a bit of heat/time on it, then begin the pulls at full throttle to check timing and sneak up on A/F and when thats safe full RPM and tuning.

Mike Bruns

[Alan L]

Thanks Mike.
So, if I did a practise day ending with some WOT and then retorqued etc, then full on next day?
Alan

[MBruns]

If you have the time that would be a good plan, I would also run some break in oil and dump that at the same time to ensure a good ring seat. look at the filters and screens so you can start fresh when you put the race day oil in and do the end of day inspections.
Mike Bruns

[KenGreenfield]

To those of you reading this thread I would like to add a bit about Mike Bruns. Mike is employed at JB Racing here in FL. He builds some of the best Porsche engines in the U.S. He also runs them on the dyno after they are built. Mike and JB Racing build motors for every type of racing in the U.S. to include Vintage, SCCA, ALMS, etc. JB Racing also builds some wonderful items including one of my personal favorites their distributor which can be run on twin and single plug Porsches. These are a work of art!

Mike is building a 2.8 twin plug motor for me now for Vintage racing. He has also helped us set up and dyno a 2.4. He is a class guy and an enthusiasts dream. He is generous with his time and if you hear something from Mike, you can take it to the bank. Ken Greenfield

[Alan L]

Nice to know there are such classy guys on this Board. Thats what makes it soooo useful.
I am on my own tracking my 930 in this country - with one exception who does not use his regular anymore. I am hundreds of miles from any P center or even a race 911. I keep my beast running based on near 100% of the information from this Board. Could not do it otherwise.
Thanks
Alan

[cstreit]

Many of us know Mike's credentials, but I'm sure he appreciates the vote.

To OP's question, actually I think the track is a great place to break in an engine... If you baby an engine too much the rings may not seat as well. For the most part this and seating rockers to cams is really all you're doing breaking in an engine these days. I've done it a number of times.

After starting and idling for a few minutes to check for leaks, I then load on the trailer... A few sessions short shifting at about 75% of the rated RPM allowing decceleration in gear. Check again, and then run the piss out of it. Never had an issue with it this way....

[333pg333]

I think this is an age old conundrum for many of us who have had street/track motors built. On one hand you've got the time honoured tradition of running it in on restricted rpms (and boost if applicable) and then up the ante when you'd done say 1-2000miles on the motor. Yet you have the very opposite with a track motor where people either run them in on the dyno or on the track and work up to full boost/rpm relatively quickly by comparison. There are also those that suggest any motor should be run in hard. There does seem to be some contradiction on face value for the end user?

By no means arguing with the likes of Mike Bruns etc, just asking out loud.

[Alan L]

Chris - at what stage would you re torque the heads?
Agree with patrick - but more than happy to follow the advice of Mike and Chris.
but it does raise the thought that the 'normal' proceedure on the road may be inappropriate - given that the track engines have a higher level of performance edge required, and are subject to more scrutiny. Maybe breaking in on the road is somewhat impractical given access to 75% rpm and 'running the piss out of it' may not be an option in commuter traffic :-)
Alan

[MBruns]

Well that is a good point, but in the performance/race engine builds all the running clearances are set to race spec and ready to go to work so to speak, whereas a new tight street engine that has hopes of doing its job for many thousand miles start off on the tight side and "loosen up" as they go through breakin and daily driving. I like to run in street engines a little briskly they seem to seat the rings well with higher pressures or at least greatly varying cylinder pressures rather than easy steady pace. The oil consumption and performance is a good indicator of how well the first few hours are handled.
My .02, Mike Bruns

[cstreit]

Alan,

I usually do it after the first weekend of running. Typically when I have a new race engine I break in as above... After that, I drain oil, check filter, check head studs (rarely if ever had one loose) and double check valve clearances...

Personally the "normal" procedure always concerns me. I always worry that the rings won't seat.

[333pg333]

Originally Posted by Alan L

Chris - at what stage would you re torque the heads?
Agree with patrick - but more than happy to follow the advice of Mike and Chris.
but it does raise the thought that the 'normal' proceedure on the road may be inappropriate - given that the track engines have a higher level of performance edge required, and are subject to more scrutiny. Maybe breaking in on the road is somewhat impractical given access to 75% rpm and 'running the piss out of it' may not be an option in commuter traffic :-)
Alan

Alan, why don't you wait until the All Blacks choke in the Semis and then drive the piss out of it!! At least it will be worth it. That's a Southern Hemisphere neighbour joke guys.

I'm guessing you're in the North Is. as the South Is. seemed to be a perfect place to run a motor in on the road. What a place for a Porsche!!

Mike, that makes perfect sense in terms of clearances of course. Something I didn't take into account.