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Triumph TR6 - Breaking in, tuning etc...


My engine rebuild is finally reaching its end... There are some questions in my mind at moment.

1) Breaking in. There seems to be a lot of different opinions about how to break in an engine. Ranging from "drive easy for a few hundred mile, change oil and tighten the head" to "1500-2500rpm for the first 1000 miles, then 1500-3500 for another 1500 miles, oil changes in between etc". What have you guys done? The bottom end is "all new", I have a new head, only thing I haven't done is a rebore, just a hone and new rings.

2) SU needles. I know there might not be a definitive answer to this one, but... I have BAX needles on my HS6 carbs. I thought I would just go with these until engine is broken in, and not worry about it for now. Is this the right approach, to postpone the tuning until engine is properly broken in?

3) Distributor. I have a us spec '70 car. I've installed the SU's, headers, a lightly ported&polished early PI head (9.5CR) and an aftermarket street cam. As I understand it the stock distruibutor on my car is probably not the optimal choice. I was thinking about fitting early PI springs and distributor cam. But should I just leave that as well to when the engine is broken in, and go with the stock setup for now? Any thoughts??

So what I am thinking of is how to break in, and if I have a tuning session after that, preferably on a rolling road with O2 sensors etc, and not worry to much about it right now...?

That's my main concerns at the moment (before the engine is started.........). I'd appreciate any input, especially from those of you who have experience from any of this!



I did a similar rebuils last winter. I chose the first option you mention, my thinking being that after replacement of bearings and the like there will be microscopic grooves and high points that need to be seated, and hard work would heat those areas unduly. The early oil and filter change flushes the debris that unavoidably happens in a rebuild.

I installed Pertronix in the distributor and kept the stock setup, although your move to SU's might warrant some modifications.

A. J. Koschinsky

Another consideration is to not build constant heat in the engine. That is:

Avoid driving at one speed for any length of time. Vary the speed. 50 for a while, 40 for a while, 45 for a while, etc.

I'm told that we need to vary the temp and load of the engine. While this won't be, perhaps, as critical as it might be if you had bored the block it would still be of some importance to the rings.

Remember, seating the rings is important to performance and longevity. The bearings will thank you as well I'd suspect.


Jim Deatsch

SR, I've been told a few times by old mechanics to
run the the first couple hundred miles with a straight
oil, 40 or 50 weight non-detergent. It helps seat the rings in faster then an oil and filter change and back to a modern detergent oil.I did this with my engine and all is well. I don't know if it helped but I made
sense to me.
Christopher Trace

This thread was discussed on 08/03/2004

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