Running-in Question

[Jer309GTi 3]

I've started running in my Mi engine after rebuilding it with new mains, big end bearings and piston rings, and I was wondering if using the car to get to work (3-4 miles roughly) would do the engine any harm after only being driven for 100 miles?

 

The engine would be fully warmed up as I have to go up a steep hill after I leave my house, but I'm a little worried that these short distances wouldn't do the engine much good after only covering a short mileage after the rebuild.

 

Can anyone confirm whether it will be ok for these short journeys?

 

Thanks

[phonecomz 0]

I've started running in my Mi engine after rebuilding it with new mains, big end bearings and piston rings, and I was wondering if using the car to get to work (3-4 miles roughly) would do the engine any harm after only being driven for 100 miles?

 

The engine would be fully warmed up as I have to go up a steep hill after I leave my house, but I'm a little worried that these short distances wouldn't do the engine much good after only covering a short mileage after the rebuild.

 

Can anyone confirm whether it will be ok for these short journeys?

 

Thanks

 

Personally from experience i dont think you have too much to worry about, as long as you get the car to a normal working tempreture and dont labour it heavy.

 

Though saying that, running in engines is quite a topic in itself, with many different opnions.

 

Have a look here, quite intersting i thought

 

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

[futura 3]

That's a very interesting read

 

But I am wondering, when he says:

Several factors make the older information on break-in obsolete.

 

The biggest factor is that engine manufacturers now use a much finer honing pattern in the cylinders than they once did. This in turn changes the break-in requirements, because as you're about to learn, the window of opportunity for achieving an exceptional ring seal is much smaller with

newer engines than it was with the older "rough honed" engines.

 

In addition, there is a lot less heat build up in the cylinders from ring friction

due to the finer honing pattern used in modern engines.

 

The other factors that have changed are the vastly improved metal casting and machining

technologies which are now used. This means that the "wearing in" of the new parts

involves significantly less friction and actual wear than it did in the distant past.

What does he consider as old as opposed to modern? I mean what about our 80's designed engines? Are they too old or can we apply this hard break-in method?

[Beastie 1]

You'll struggle to get any sort of agreement on running in procedures Its a complicated compromise and the only people who have a chance of forming a sensible conclusion are professionals. And even professionals often disagree wildly about the best way to do it. I'd suggest that if you have any engine which has been returned exactly to as new condition then you can do little better than follow the manufacturers instructions. A wet linered engine is one of the few engines which can be returned to original if you can get hold of OE pistons & liners. If you have an engine bored and honed then there is opportunity to deviate from the orignal techniqe - whether for better or worse and the best running in procedure may change. Other factors including tolerance of grinding on crank journals and pins and choice of wearing components will also influence the way in which an engine could best be run in. 1980s engines are modern compared to the engines our grandfathers (and for some of us our fathers!) had to run in but the running in procedure for them wasn't exactly the same as that for a new car today, largely because more is understood about bore finishing techniques. That doesn't mean to say that different techniques can't be applied to one of these engines at overhaul time.

 

The one thing you can be sure of is that there will never be a shortage of experts to tell you just how to treat your expensive rebuild. I'm certainly not going to add another voice to that crowd because there isn't a point. The best person to talk to is the one who built your engine. And if you built the engine yourself then you could always talk to the machinist you used for the job.

[KRISKARRERA 2 1 Cars]

XU engines do need running in. Miles told me.

[Jer309GTi 3]

So I should be ok for using it for work? I will take it for a good run each night, making sure it's run in correctly. Was just worried the short (ish) journeys to work and back would adversely affect the running in procedure

[boldy205 75]

if im not in the garage im always willing to help you run it in!!

[Guest BrainFluid]

an exceptional ring seal is much smaller with

newer engines than it was with the older "rough honed" engines.

 

I am by no means at all an expert on this subject but if you have used new liners and honed them yourself I suspect that you would have rough honed them no? Unless they did come honed already, could the manufacturer tell you how rough/smooth the liners were honed?

 

Just a though.