Engine run in guidance...

[soulfire]

Good afternoon all!

I am almost at the stage of running in my 21/22r hybrid motor however I am a bit worried about a few things...

1st of all, i've read that you need to run in an aftermarket cam for about 10 - 15 minutes on its first run (idling at about 2500 - 3000 rpm) to *break it in* as such.

seeing as i have also rebuilt the bottom end, i run into a dilema. I need to be driving and not idling straight away as i want to be running the bottom end in as well. Idling for 10 - 15 minutes at that rpm could possibly glaze the bores over, or i just wont get a very good piston seal (burn lots of oil = bad).

And now here's the kicker. I'm going to be running in this motor with a pair of twin PHH40 solex's that were pulled from a 2TG, so I doubt they are going to be jetted anywhere near properly for my application!

Does anyone have any experience / insight to what I can do to make this easier?
I do have the car booked in to be tuned / run in at the same time at a well respected carb shop in brisbane, but I just want to minimise the risk of ruining all my hard work assembling this motor!

If worse comes to worse, I do have access to an ra60 celica which I can take the cam out of and run my brand new one in to alleviate some stress...

I guess the biggest issue is running in the motor with carbs that will be nowhere near setup for the application (and I'm still learning, so I haven't the foggiest on how to adjust them properly)

Thanks in advance,
Adam

[abently]

You should be able to tune it up well within 10K's of driving. Dilution of oil from over fueling is virtually non existant unless the bores weren't oversized.

The new camshaft shouldn't have any issues. As long as its coated in moly and oil is flowing as normal, it should be fine however you drive it. I'm assuming the tappets/lifters/fingers are all in good condition.

I believe the high-idle run-in procedure is just to check everything is normal and potentially save it incase something is not.

[KARNAGE]

my next door neighbour is a old school engine builder that has worked with heaps of sprint cars and he believes unless its a 2 stroke motor with very small clearances there is no need to run in the bottom end, they were running very high comp v8 engines and they used to take them out on the track straight away,

when i had my new engine i used a shitty oil to start with so the bottom end would bite in better then i changed the oil to a slightly better grade then after 500km put in a nice synthetic and the engine is still going good now.

[Billzilla]

my next door neighbour is a old school engine builder that has worked with heaps of sprint cars and he believes unless its a 2 stroke motor with very small clearances there is no need to run in the bottom end, they were running very high comp v8 engines and they used to take them out on the track straight away,

Yes that works for race engines just fine and they do put out good power but at the cost of longevity. For a road engine, you need to take your time and run it in a lot more slowly.
Low(er) revs, lots of throttle is the go.

[131OWN]

It will take more then 10 minute at 3000rpm to glaze bores, just uses good running in oil, I've have success with Penrite running-in oil. Once the cam is "breaked in", 10minutes, change oil and filter, I use, Penrite running in oil for the first 2000km then use a mineral oil after that for the first 7-10000km then over to synthetic, don't use synthetic earlier or you will glaze it up. Don't be too easy on it running it in, get the revs up and expose it to some load, and also make sure you show the engine some vacuum, engine breaking from 4500rpm back to idle as an example.

[abently]

I have to disagree about the "don't use synthetic" statement.

You will find most Synthetics contain the least amount of friction modifiers of all Oils on the market.

If you think these friction modifiers are the reason why bores glaze up, then I have news for you. I'll leave this argument for another thread, but OEM manufacturers that specify synthetics, also use it from start-up.

The only reason I don't recommend the use of Sythetics upon run in is the cost vs benefit factor. And to be honest I'm not sure how the Engineer's got that one past the bean counters also.

[Billzilla]

I agree that synthetics won't make the bore glaze, but I have experienced using synthetic oil too early in the life of an engine and it extends the run-in period quite a bit. Can take twice as long ....
I'd stick with a good mineral oil for at least the first 1,000km or so.

[soulfire]

Thanks to everyone for the sound advice!

I'm a lot less stressed out now! I know the motor will be in good hands when it gets run in / tuned on the dyno!

I have a feeling they are going to need to re-jet the 40mm solex's to suit the 2.4l application!

I've already got all the run-in oil / filters I need and I was going to be using a fully mineral based oil till about 5000 - 7000kms of driving!

I wasn't so much worried about how to run in the motor, moreso running it in a poor state of tune!

In saying that tho, the first 10 - 15kms will be done on a dyno obviously tuning the motor.. i've read conflicting information about running in motors on a dyno...

[lexsmaz]

Just remind them that it is a new cam & hasn't been started yet, so they will hopefully do the right thing & run it in properly ..

Also i would ask them, or do it yourself but you need to make sure the car is getting oil pressure before YOU OR THEY start it up, the best way is an external oil supply hooked up through the oil pressure switch port which floods the oil galleries with oil, but not an easy tool to get, ( good engine builders will have one ) the 2nd way is to get a good oil can & using a flexible line ( i have used the hose off an oil pressure gauge ) & again through the oil sender port pump oil from the can in, 2-3 can fulls at least & then crank the motor with the plugs out till you get oil pressure ( but take note if you don't get pressure within around 20 seconds repeat with more oil from the oil can .. the first start up of the system is very important especially as far as the oiling is concerned ..

[TERRA Operative]

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

Another viewpoint to consider. He seems to have some valid points.

[andrew_mx83]

I believe the high-idle run-in procedure is just to check everything is normal and potentially save it incase something is not.

cams are run in to work harden the lobes. how is higher revs going to save it if something is wrong?

[soulfire]

lexsmaz - I have been told to prime the oil before first start! However the tips you have provided make a lot of sense and I will be doing this the morning before the run in!

terra - i will be following that guide like the bible, nearly every point made, makes sense to me. This was just about initial turn over and getting it tuned in say the first 10 - 15kms of driving.

Thanks for everyones advice once again!

[abently]

cams are run in to work harden the lobes. how is higher revs going to save it if something is wrong?

Work harden.... do mind defining that ?

Most cam manufacturer's/grinders treat their newly cut cams to a hardening process. Possibly to save on warranty/faulty claims by carefree customers.

[Rodger]

My opinion on this:

I agree running the motor for 10-15mins at that rpm will not harm the motor. It will get up to temp and will do nothing to the bore/pistons/rings or bearings. And fiddling with carb tune and balance will not harm it either.

It will give you a chance to set timing and carb balance and check for oil and water leaks.

Before it is started though:-

As long as they are in good condition, jetting for the Solexes: Mains can be left alone until you are driving it as they will not be flowing at no load, low revs, but let us know what it is anyway.
Pilot size for a 2lt 18R-G is normally #63.8 if you have the #57.5 this will be lean for the 2.4lt, given that the Idle mixture screws ideally should be 1.5 turns out. I can supply you with four bigger, #62.5 or #65 to help.

Do not worry about venturi sizes yet.

Balance the carbs by eye. Turn the balance screw out to break contact with the rear throttle lever. Turn back the idle speed screws until they just seat the levers then turn forward two turns to open the throttle plates up. Set the balance screw so both front and rear carbs hit their full throttle stops together. This will give you and fastish idle and be close to balanced and be running more on the Pilot jets so idle mixture screws are not as much in play.

Start with no plugs and the coil lead disconnected and run it on the starter until you see oil pressure (light goes out, if no gauge) and the rattle of the chain tensioner dissapears. This will get oil onto the bearings.

Prime the Solexes with fuel poured into the bowls through the jet covers. this saves having to run it again on the starter motor to get fuel up into them. If you have an electric pump then run it to fill the carbs. Check that the pump jets function at the same time use this to prime the inlet tracts with fuel. Do not use or set the starter/chokes.

Put the plugs and leads back in.

Connect the coil lead and set the timing by eye/ear, with the pulley mark at the pointer and listen for the click/spark of the points as you rotate the dizzy back and forwards. Start it up, maybe needing to pump throttle lightly as it is firing to richen it up and then baby it by holding the throttle, if the idle is slow, at 1500 until it can idle on its own. Then check timing with a light and adjust as needed.

Once the engine is idling at a stable condition, it maybe fast and you may need to adjust the balance to get it running smooth, then you can start the "first ten minutes" to get it hot doing all your checks.

When it is hot and running well at the fast idle then adjust the carbs (idle speed, balance, mixture and timing ) to get an idle at 900-1000.

Then you can drive it. As you are not sure of what jetting is there only use 20% throttle a couple of times around the block. Once you are happy that it runs smooth at these speeds then it can be tested on the road or dyno for mains jetting.

You need to achieve all this before you can start running it in, weather on the dyno or on the road.

Have fun

Regards

Rodger

[Rodger]

Oh and while it is hot you can check hot valve clearances.

Then when it has cooled down you can check/reset head bolt torque.

Regards

Rodger