33 replies to this topic

[Ado1379]

I’ve tried a search and found nothing. It’s my first engine strip and rebuild, And I’m just trying to get all the info I can. Sorry if this is stupid question but is there a running in (bedding in) period after a rebuild? Or is there a common procedure that most people do with if the first few drives?

Thanks

[alex-95]

I followed this kieth Calver guide when I run mine in and ran it on the lean side https://www.calverst...in-new-engines/.

[Spider]

The manufacturer of your piston rings usually provides advise on this, though, often you need to go digging for it. On top of this, if you have a new or reground cam, there is often further advise regarding their procedure for 'breaking in of these parts.

 

Many of us have our own ways, methods and ideas on this, but that is where I strongly suggest you look first. As an example, I've just read though this;-

 

 

 

I followed this kieth Calver guide when I run mine in and ran it on the lean side https://www.calverst...in-new-engines/.

 

 

With the rings and honing pattern I usually use, following this advise would result in glazed bores and the engine would be a smoker. I'm not saying this advise is wrong, it's a case of not one size fits all and that's why I haven't suggested here to you, how I do them.
 

 

[Ado1379]

Brilliant, looks like I have even more reading to do ? haha! In all fairness I’ve learnt a lot by just simply turning spanners. Thanks again!

[Chris1275gt]

Drivers handbook 1275gt 1975. I don't think you can go far wrong if you follow this I have on 2 new and 2 old minis after rebuilds and never had a problem.

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[Steve220]

As Moke rightly points out, if you've put a new cam (and therefore followers) into an engine, you'll need to knock that in first.

 

Knocking in a cam

Use the cheapest 20w50 oil you can find as its not going to stay in there long. DO NOT let the car idle. As soon as it starts, get it to 2500 rpm and leave it there for 20 minutes. Make sure there are no leaks. If you spot anything serious, shut the engine off and stop the clock. Once complete, I do an oil and filter change as it will have been the first time the car has ran, so will clean out the engine prior to run in.

 

Running in

You can allow the car to idle, but only for short periods. The key here is to not give what runs, use 60-75% throttle runs to 4-4.5k rpm and let it engine brake all the way back to cruise around 2k rpm; engine braking is just as important to the run in process as throttle load. Let the engine cool for 10 seconds then do it again. If you're going up hill, use 3rd if you have to, but i did most of my running in for both versions of my engine in 4th. Put around 100 miles on, and the majority of your run in will be complete.

 

Remember when running in an engine, the primary reason is for the piston rings to bed. Every good engine builder i have spoken to says the rings bed in within 40-50 miles of use, so it critical you get some load behind them.

[Steve220]

Also worth having a look at HP Academy's run through of breaking in an engine

 

[Bobbins]

Use a good running in oil (eg. Millers) and drive it like you stole it. Change the oil after 500 miles.

[Ado1379]

As Moke rightly points out, if you've put a new cam (and therefore followers) into an engine, you'll need to knock that in first.

Knocking in a cam
Use the cheapest 20w50 oil you can find as its not going to stay in there long. DO NOT let the car idle. As soon as it starts, get it to 2500 rpm and leave it there for 20 minutes. Make sure there are no leaks. If you spot anything serious, shut the engine off and stop the clock. Once complete, I do an oil and filter change as it will have been the first time the car has ran, so will clean out the engine prior to run in.

Running in
You can allow the car to idle, but only for short periods. The key here is to not give what runs, use 60-75% throttle runs to 4-4.5k rpm and let it engine brake all the way back to cruise around 2k rpm; engine braking is just as important to the run in process as throttle load. Let the engine cool for 10 seconds then do it again. If you're going up hill, use 3rd if you have to, but i did most of my running in for both versions of my engine in 4th. Put around 100 miles on, and the majority of your run in will be complete.

Remember when running in an engine, the primary reason is for the piston rings to bed. Every good engine builder i have spoken to says the rings bed in within 40-50 miles of use, so it critical you get some load behind them.

This is quite enlightening. So technically I could do this in the garage using the choke to control RPM and engine load? I can also keep eye on leaks and stuff. Does anyone see any issues with this?

[cal844]

You could do it in the garage but how do you load the motor?

[Spider]

 

As Moke rightly points out, if you've put a new cam (and therefore followers) into an engine, you'll need to knock that in first.

Knocking in a cam
Use the cheapest 20w50 oil you can find as its not going to stay in there long. DO NOT let the car idle. As soon as it starts, get it to 2500 rpm and leave it there for 20 minutes. Make sure there are no leaks. If you spot anything serious, shut the engine off and stop the clock. Once complete, I do an oil and filter change as it will have been the first time the car has ran, so will clean out the engine prior to run in.

Running in
You can allow the car to idle, but only for short periods. The key here is to not give what runs, use 60-75% throttle runs to 4-4.5k rpm and let it engine brake all the way back to cruise around 2k rpm; engine braking is just as important to the run in process as throttle load. Let the engine cool for 10 seconds then do it again. If you're going up hill, use 3rd if you have to, but i did most of my running in for both versions of my engine in 4th. Put around 100 miles on, and the majority of your run in will be complete.

Remember when running in an engine, the primary reason is for the piston rings to bed. Every good engine builder i have spoken to says the rings bed in within 40-50 miles of use, so it critical you get some load behind them.

This is quite enlightening. So technically I could do this in the garage using the choke to control RPM and engine load? I can also keep eye on leaks and stuff. Does anyone see any issues with this?

 

 

More often than not, you need to get some load on the engine and usually right away, otherwise, there's not enough pressure behind the rings and rather than them bedding in, they'll merely glaze over along with the bores, then it will forever be a smoker.

This doesn't always seem to be the case, but all rings I've used in the past are.

[sonscar]

How do mainstream manufacturers do this?run every engine on a dyno for 20 minutes to bed the rings and cam in?Just interested,Steve..

[Quinlan minor]

How do mainstream manufacturers do this?run every engine on a dyno for 20 minutes to bed the rings and cam in?Just interested,Steve..

I can't speak for all mainstream manufacturers.

I do know, when I visited the Porsche Factory, every engine went from the line straight to the dyno, where the horsepower output was checked, before they were fitted in a chassis.

[PoolGuy]

You could do it in the garage but how do you load the motor?

I agree, 20 minutes at 2500rpm stationary sounds like madness to me. But as someone pointed out very early in the thread, you’re going to get a multitude of answers from people who think that their way is the best.

[Midas Mk1]

You could do it in the garage but how do you load the motor?

I agree, 20 minutes at 2500rpm stationary sounds like madness to me. But as someone pointed out very early in the thread, you’re going to get a multitude of answers from people who think that their way is the best.

It’s not madness, it’s how Steve has put it, it’s how you run a cam in properly.