Running In Rb30/25

[menthol369]

Ive just rebuilt a 25/30 with bearings and rings ( no oversize, all stock parts)

im just wondering what the best method is for runnign the motor in, ive read that starting with higher rpm cycles, letting it cool and then doing lower rpm cycles is the reccomended method.
The hastings box was kinda vague with " accel from 30mph to 55mph"

I was hoping some guys on here with real time exp could help out.

Cheers

[DanielH]

Minimal idling to start with and as much load as you can (without being too silly) is crucial, I've had some engines that are bedded in within 10 mins of running/revving and others take some driving, guess it comes down to bore finish, rings, oil etc.

First start is very crucial, once you're satisfied with oil pressure bring the revs up, 2000rpm idle is fine (and necessary with new cams), keep water topped up and gradually give it some revs as it comes up to temp, if you think you have air in the cooling system shut it off before it boils.

Once you're on the road drive it normally for a street car, not abusive but use all of the rev range and as much load (boost) as you can depending on tune.

And always use mineral oil until its bedded in (good compression/no blowby).

That's all I can think of at the moment

Edited January 21, 2015 by DanielH

[DanielH]

Provided that your oil is up to it, there's no harm in running an engine like this in HARD, if its gonna be abused it may aswell do it from day 1, some people may disagree with that though, but the only items to "run in" are rings and cams/lifters, and rings bed in by high load/pressure forcing the rings out, cams are straight forward, if using old cams no need to worry!

[GTRPSI]

You need some load to bed in the rings, start light loads, keep the revs to under half of redline at the start, decelerate to pull the metal off the walls after accelerating, gradually building power as you go along progressivly, drop the oil after 10-15 minutes and repeat the load cycles.

Dont baby it, dont wring its neck at the start, drive it normally with load on it, its the load that forces the rings against the walls to bed them in, its the decel that pulls the crap off the walls.

Also remember that fresh walls are the roughest, the most heat and wear happens in the first few minutes so you dont want too much load for th first few minutes as it will create a lot of heat due to friction.

[XKLABA]

Interesting read

http://www.mototuneusa.com/break_in_secrets.htm

And how I did my R34

[menthol369]

Cheers guys this helps a lot, I'm using purpose run in oil that penrite sells, how many ks should I do before I take it back to the dyno?

And I suppose once it gains compression across all cyls is when you tell its bed in.

Reads 150 across all 6... Apart from cyl 3 which reads zero. But after a leakdown test the exhaust valves arnt sealing ( lifters arefresh so no oil in them yet either)

[DanielH]

150 is pretty good already if it hasnt been run/or run much.

I'd go easy with the Penrite running in oil as I find its pretty thin when its hot, it's great stuff but I wouldn't give the motor too hard a time with it in there, that's just my preference though.

My preference would be running in oil for initial start up, and then maybe 500-1000 K's or so of fairly sensible driving after the first service, then I would switch to a high performance mineral and take it to get tuned and then go to whatever oil you plan to run it on.

[DanielH]

And what GTRPSI said about decel is correct, engine braking/decel is just as beneficial as load is, bringing the engine down from 5-6000rpm without braking will achieve this.

[menthol369]

Do with the rpm cycles do you do that for say 15minutes at a time? Then let it cool. Rinse and repeat till compression raises?

[GTSBoy]

No, each cool down on the dyno is about 15 minutes. You do a few pulls with decent (not massive, just decent) load and revs, then allow the dyno fan to cool the engine back down.

You should only need <10 dyno pulls like that, separated by cool downs to bed the rings. Similar number of pulls on the road.

One of the main things to avoid is to spend much time at constant and light loads for the first hour or more of running it. You really need to give the engine constantly varying load and speeds between light and moderately heavy/fast. This is far more important before the rings have bedded, but still important even after those first few run ups.

[menthol369]

Right so ive attempted runnign the motor in,
FIrst drive - 2nd/ 3rd gear going from 2k to 5-6K rpm, letting it decel all the way to 2 k again. did that 10 times roughly then let it cool.
same again with the second drive ~~

Comp tested it as soon as i had it back in the garage and got 140 across all 1-5. battery died at 6 and only showed 120~ but thats understandable.
will comp test again when the engine is cold.

Now that its had about 15-20 min of driving with that penrite run in oil, should i drop it and put some mineral oil in and do abit more driving like above?

[GTSBoy]

Drop the oil certainly. But you could consider doing a 1000 kays on another batch of run in oil. The main thing with run in oil is not so much that it's mineral rather than synth. It's more so that it contains a lot of detergents and whatnot for helping to clean up the crumbs and blobs of foreign material generated by assembly and the running in.

[DanielH]

You should be fine with mineral now, it will continue to bed in further if needed with mineral oil.