Running in mileage/rpm

[William2]

My rebuilt engine was fitted with all new bearings (cams, mains, big ends), original pistons with new rings and the cylinder bores were honed. As no rebore and new pistons were necessary does this mean that the process of running in can be achieved in less mileage than would normally be required? I will change the oil at 500 miles as a matter of course.

[rgh0]

The thing that drives the duration of the running in procedure is bedding of the rings in the bores and the cams on the follower tops. Everything else happens much quicker.

If you have new rings and honed bores then you need to follow a full running in procedure to bed in the rings. I have documented in other posts what I personally believe this needs to be.

Whether this is shorter or longer than what you intend to do is a a personal choice

cheers
Rohan

[William2]

Thanks for the advice Rohan, I will follow the full run in procedure.

[ftsoft]

Rohan

I had my engine rebuilt a few years ago and the rings are not seating after perhaps 2000 miles. Is it too late for me to do the running in procedure?

Frank

[rgh0]

maybe maybe not - no real definite answer but try it and see.

Try a series of full throttle accelerations in third gear from around 2000 rpm to 5000 rpm. Do that for around an hour. This may bed in rings and break down the glazing on the bores if the rings have not seated. It seats the rings in a newly honed bore with new rings. It may not work in a bore that has been smoothed by lots of light passes of the piston but with not enough pressure to wear in the rings to match

What are the symptoms of your rings not seating - excessive blow by gases or excessive oil consumption or something else?

cheers
Rohan

[ftsoft]

Rohan

Symptoms: I have blow by. If you drive behind the car you can see a thin wisp of blue smoke. Not much oil consumption it seems. Lots of smoke on starting, but that's probably something to do with seals?

Frank

[rgh0]

Hi frank

Oil smoke when driving and lots of blow by says that neither the compression rings or oil rings have seated. So you do need to try to seat them now, if no success then you live with it or re-hone the bores and fit new rings and get them seated correctly. Honing correctly is not easy to do and needs a proper machine shop to get correct. Doing it by hand with a set of honing stones and an electric drill requires a lot of luck (or supreme skill and experience) to get right

Oil smoke on start up and when you pull away after idling for a period is generally due to excessive clearance on the valve stems in the guides. The are no stem seals as more modern cars have and the guide to valve stem clearance is critical and many re-builders get this wrong.

cheers
Rohan

[ftsoft]

Thanks Rohan. I'll give it a try. My engine was done by D&D classics in Covnigton Ohio. They do a lot of Rolls and Jaguars, but I think this was there first Lotus.