[Top] [All Lists]

Re: Breaking in a rebuild engine (kinda longish)

To: "Triumph List" <>
Subject: Re: Breaking in a rebuild engine (kinda longish)
From: "jonmac" <>
Date: Wed, 12 May 2004 23:56:21 +0100
At the risk of length, this is what happened at the factory and how
Engineering treated their evaluation cars and all Press cars.

Stage 1 - Engine was motored over (i.e. driven by an external source via the
flywheel) at varying speeds for about 15 minutes with plugs in place.
Coolant in place but fuel not connected
Stage 2 - Engine transferred to the Run Dynamometer and run under its own
power across its full rev range - reasonably heavy load at low rpm with load
decrease to zero at 5500rpm for 30 mins.
Stage 3 - Change oil (for same ENSIS water absorbent type) and filter and
pass off engine for vehicle build.

Drive car on road under varying traffic conditions (NOT Freeway) almost
continuously for 500 miles at between 2500 and 3500 rpm. Let it rev to 4000
under light load. Top up with conventional mineral oil as required.
Strenuously avoid full throttle use even for very short intervals
For the second 500 miles, allow engine rpm to climb on short duration to
4500 rpm max and light load.
Throughout both periods let it get good and hot. During this time, make
frequent gear changes and let car weight drive engine on over-run.
At 1000 miles, torque down head, re-check valve clearances, change oil for a
quality brand 20W/50 mineral or synthetic and filter. Treat power unit
considerately for a further 1000 miles.
This was the technique used for all Press cars and they really performed.
I've followed it since then with later cars I've owned myself and only last
weekend did the same with the rebuilt 2000 engine on an 800 mile/24 hour
charity run and the difference is incredible.
In about a month (or less) I'll be driving it quite hard and I'm confident
there won't be any problems. If nothing else, the oil available today is
light years better than 30+ years ago, so what is there to worry about?


Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (
Version: 6.0.637 / Virus Database: 408 - Release Date: 20/03/04

<Prev in Thread] Current Thread [Next in Thread>