Running In

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Page created by T, submission by Qute June 7th 2008:

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EFI VK Engine installed in an HZ Kingswood. Click to Enlargen. Photo by T.

Running In:

A fairly common question asked on the Forum is: What's the best way to Start and "Run In" a newly rebuilt motor? The following is how I ALWAYS Start and Run In a new motor and it has neverfailed me. Many, many, many more rebuilt motors are ruined by being Run In too easilythan too hard. 

Engine Oil:

Always use a non Friction Modified oil in a newly rebuilt motor and ALWAYSmake sure you have oil pressure BEFORE you actually start the motor for thefirst time. You can buy specific "Running In" oils but I have always justused a fair to good mineral based oil for the first fill.**I won't delete the original because I'm certainly no expert, but the instructionswith my brand new Crow Cam and lifters specifically states "do not crank engineto achieve oil pressure prior to cam/lifter run-in". It goes on to say you can do damage to both in those first couple hundred revs on the starter. It also recommends at least 2000-3000 rpm to run-in these components.** It is important to make sure your motor is up to normal operatingtemperature before asking it to work hard. This ALWAYS applies but is VITALin the running in process and all the following assumes you abide by thisadvice. 

Camshaft Run-In:

Once the motor is running, leave it at a fast idle (1500 RPM) for 20- 30 minutes to run in the Camshaft. THIS IS VERY IMPORTANT. Some peopleprefer to run the car for 5 minutes, stop it and allow it to cool down, thenrun it for another 5 minutes and so on until the 20 - 30 minutes of runningis completed. It is NEVER a good practice to rev the motor excessively atthis stage. 

Cooling System:

You can also use this time to finish bleeding the cooling system (or checkit anyway), do the final Timing Adjustment, etc. Once the Camshaft is run in, stop the motor and check the oil level, etc. 

Valve Lash Adjustment:

If you are running in a Red Motor with an early head, now is a good time todo the final Valve Lash Adjustment as the motor will be up to normaloperating temperature. Once you are confident the motor and car are OK to drive, take it for adrive. Keep your throttle usage to a minimum and keep the revs down to amaximum of 2,000 RPM. Under NO circumstances should you allow the motor toLabour. Not allowing the motor to Labour (using too few revs for the workyou are asking it to do) is REALLY important all through the Run In process. 

First Oil Change:

Once you have covered about 100 K's on the new motor, it is time for thefirst oil change. A new Oil Filter at this stage is not a bad idea as theremay have been little bits of swarf and metal filings still inside the motorfrom the reconditioning process and you don't want them passing through yourfilter and floating around inside your beautifully rebuilt motor, do you?  

Throttle Use:

For the second 100 K's, run the motor up to about 3,000 RPM through thegears as a matter of habit (once it has warmed up) and as far as ispractical given your gearing and the local speed limits. Start using a bitmore throttle as you go along but still avoid very large throttle openingsat this stage. I tend to work my way from a 2,000 RPM rev limit up to 3,000rpm over the course of the 100 K's rather than suddenly increasing the revlimit by 50% in one hit. 


From 200 – 300 K's, work up to 4,000 RPM and from 300 – 400 K's work up to 5000 RPM. If the "state of tune" of your motor allows, work up to over 5,000RPM in the 100 K's from 400 – 500. At no time during the first 500 K's should you allow the motor to maintaineither high revs OR a constant revs for any significant period of time.  


If you decide to go for a drive in the country or along a freeway/highway torun up some quick K's, do not sit on one speed/revs for more than a minuteor so at a time. At various rev points, different parts of the insides ofyour motor will be hot. You need to vary the revs so no one part gets toohot (remembering that you have more friction in a new motor becauseeverything is still wearing in). When you change the revs, you allow the hotparts to cool down and cause other parts to heat up. 

Throttle Closure:

When using more than "normal" revs (say, over 2,000 – 2,500 RPM) whilerunning in your motor, NEVER hold the revs up there. ALWAYS allow the revsto drop back down IMMEDIATELY. This will cause oil to be drawn up into thecylinders (under the pistons) which will help to cool everything back downto normal again. Many people will perform another oil and filter change at 500 K's but I havealways waited until I have done 1,000 K's. Basically, it's up to you. 

Increasing the Load:

Between 500 and 1,000 K's, you now MUST give your motor a bootful ofthrottle and make it work for a living on a regular basis. This causes therings to be forced against the bores by the combustion process and assistsin preventing glazing of the bores. See also 2 paragraphs up. If you have a big HP motor, you MUST be VERY careful where you do this ifyou want to remain on intimate terms with your Driver's Licence AND yourlife... The trick I usually use is to give the car a bootful in second(while maintaining traction so you are loading the motor up), run it to therevs I can/want to/need to and then IMMEDIATELY drop it into top gear tobring the revs back down to more normal levels. You don't need to rev it ALLthe time, but you do need to rev it regularly. 

Observing the Oil Level:

Be especially diligent in checking your oil level throughout the running inprocess as it is almost certain your new motor WILL use some oil while beingrun in. This is VERY normal and not a cause for concern unless the usagereaches high levels.  At 1,000 K's, another oil and filter change are performed but this isoptional if you did one at 500 K's IMHO. 

The Next Oil Change:

The next oil and filter change should be done at the usual 5,000 K mark. DONOT use Friction Modified oil until the 10,000 K oil and filter change ATTHE EARLIEST. Keep a closer than normal eye on your oil level for the first 10,000 K's assome motors will continue to use a small amount of oil for this period oftime. You should now have a well run in, clean, crisply running new motor that will give you many kilometers of faithful service.




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