13 replies to this topic

[Pairaminis]

I was curious how people do the initial 2000+ RPM 20 minute break-in on a new engine if their car has a center speedo set up and no rev counter.

Jack

[Alex_B]

You can get a multimeter with an inductive pickup that shows engine speed, I got mine from maplins. That is what I would use 

[Gulfclubby]

Hook up the timing light (which you will need for initial setup anyway) and have that display the rpm.

In the old days, they would just do it by ear.

[HarrysMini]

It isn't really crucial to have it at 2000RPM, just don't let it idle at anything below that. In all honesty, you could probably do it by ear. That's what I'll be doing.

 

But as above, either a timing light or a multimeter would work. 

[Stiggytoo]

Just do it by ear. Ideally try to vary the revs between 2000 and 2500.

[dklawson]

You have just spent a lot of money rebuilding the engine so spend a little bit more to protect your investment.  Buy an inexpensive meter as suggested above by Alex and Ben. 

 

The advance timing lights with a built in tach are VERY handy and compact.  They will cost a bit more though.  If you want to do this on the cheap, visit eBay and look for used "engine analyzers" or "dwell/tachs".  Those tune-up meters were once common but have hardly any use on modern cars so they are typically available for very little money.  Some automotive multimeters also have tachs built in.  Those are a more modern instrument but the meter can be used around the home (not just on cars) which may make it a wiser investment than a dwell/tach.  Just make sure the meter has a built in tach before you invest in it. 

 

OR... buy an inexpensive tach that you would like to add to your car's dash anyway. 

[Alex_B]

This is my Multimeter, its far from the best but it does what it says on the tin, I would imagine you can get similar ones in RadioShack as I believe Maplins is owned by RadioShack.

http://www.maplin.co...ve-pickup-n58fu

[HarrysMini]

I use Fluke multimeters. Very good for the money.

[dklawson]

Fluke meters are great but I have never seen that they offer one for automotive use (that will have built in dwell and tach functions).  If they do have them, they will cost many times what a basic automotive tach will cost.

 

Jack, until Alex's last post I had not noticed you were in the U.S.  Radio Shack is not likely to have a decent automotive multimeter and most of their meters are overpriced.  If you are comfortable with Harbor Freight... they have an automotive meter that sells for $35.  You will find Actron brand on sale at places like Advance Auto and Autozone.  However, you will also find lots of inexpensive automotive multimeters on eBay along with the used dwell/tachs.  Don't forget Amazon while shopping.  That is where I got my Actron brand advance timing light with built in tach.  Amazon had the best price I could find on it anywhere.

Edited by dklawson, 20 August 2014 - 11:43 AM.

[Captain Mainwaring]

I use Fluke multimeters. Very good for the money.

 

And so they should be - they hardly fall into the budget weekend mechanic range though.

[Pairaminis]

I had originally thought of using a timing light or multi-meter but didn't really want to stand in front of the car with a tester while holding the throttle open for 20 minutes.  I guess I could just adjust the idle screw up a bit though.  I also considered buying a cheap rev counter and running temporary wires into the cabin for the initial start period.

The first start was done easily on the Porsche I recently rebuilt.  I just put my wife in the driver's seat let her start the car up and hold the RPMs above 2000 while I stood at the rear and checked for oil leaks and other possible problems. 

I was just wondering if someone had a unique way of doing the run-up with the Mini.

Kind of a dumb question now that I think of it:)

Jack

Edited by Pairaminis, 20 August 2014 - 12:22 PM.

[Ethel]

The only dumb questions are the one's you don't ask. You might get an idling engine up to 2000rpm using the fast idle screw for the choke.

[dklawson]

As Ethel said and you suggested, use the idle speed screw (but not the fast idle choke screw) to hold the engine at 2k RPM. Don't have a helper try and do that with the gas pedal.

 

Give some thought to whether or not you want a tach on the dash.  If you do... this is a good time to go ahead and buy one.  If you have a meter with a tach and don't want to buy a dash tach... use the meter during the start up. 

 

Startup Suggestions:

If you have not set the static ignition timing, do so and arbitrarily set it for 5 to 8 BTDC.  It may not be right for your engine build but it is conservative and good enough to get most engines to start.

If you have not adjusted the valves, do so with the engine cold.

Remove the spark plugs and turn the engine over on the starter until you develop oil pressure.  Refit the plugs.

Unlike the Porsche, keep water/coolant handy. 

Leave the radiator cap off.

Have a fire extinguisher handy.

Start the engine and bring the revs up to 2k RPM using the idle speed screw.  Adjust the speed down as necessary as the engine warms up.

Watch the coolant level.  When the thermostat opens the coolant level will drop.  Top up the radiator.  Keep watching.  The t-stat will open a few times so you should expect to top up 3 or 4 times during the 20 minutes.  Do not fit the cap at this time.

Watch for coolant and oil leaks.  Address as necessary.

Watch the exhaust down pipe.  If it starts to glow cherry red, richen the mixture a bit.

At the end of 20 minutes, lower the idle speed where you want it to be. 

 

Some say to re-torque the head immediately.  I don't like working on supper hot engines so I let it cool before re-torquing the head.  After the engine has completely cooled (and the head has been re-trorqued) re-adjust the valves.

Top up the fluids and go through a proper tune up setting the timing and mixture.

[Pairaminis]

Great information Doug.  I appreciate it.

Jack