Engine Rebuild - Running In Theories?

[Al 450]

Hi all,

Just got my baby back after a total engine rebuild, new rings, bearings, cam, too much to mention, the works!

Sounds fantastic now and really missed it over the last few weeks. Just interested in everybody's ideas on best running in practice as I couldn't find much info on this in the forum.

My current scheme is: -
'Running in' oil Duckhams 20W40
Timing retarded slightly
No labouring of the engine
Under 2500 rpm for first 500 miles
Oil and filter change at 500 miles more Duckhams, tighten heads, adjust timing.
Under 3000 rpm for next 500 miles
Oil and filter change at 1000 miles for proper long term oil.
then mucho hoonage...

Some people have implied that holding the revs too low will result in glazed bores and higher oil consumption in later life. Is this true?

Edited by Al 450 on Sunday 28th October 20:02

[ray_von]

Can whoever did the rebuild not tell you? Tighten the heads? That doesn't sound right

[GreenV8S]

I would expect the person who fitted the engine to take care of any re-tightening that was required. They should also have told you how to run it in.

The general advice is that you should keep the revs down at first until the bearings have had a chance to bed in, this happens quite quickly though. The next concern is to bed the rings in without glazing the bores. You have to put some load on the engine, but not at low revs and not sustained for longer than a second or so at a time so that everything stays cool. Beyond that, just keep varying revs and load. As the mileage increases you can gradually increase the range of revs and load, hold the load for longer and so on. By 5000 miles you can treat it as normal. It'll continue loosening up for the next 5000-10000 miles.

[Al 450]

ray_von said:

Can whoever did the rebuild not tell you? Tighten the heads? That doesn't sound right

Sorry you've got the wrong end of the stick, this is what they told me and they will be tightening the heads. Just interested in other people's ideas about how to drive the car afterwards.

[Al 450]

GreenV8S said:

The next concern is to bed the rings in without glazing the bores. You have to put some load on the engine, but not at low revs and not sustained for longer than a second or so at a time so that everything stays cool.

What kind of revs are we talking about here? Just the occaisional foray into 3-4000 rpm?

[GreenV8S]

Al 450 said:

GreenV8S said:

The next concern is to bed the rings in without glazing the bores. You have to put some load on the engine, but not at low revs and not sustained for longer than a second or so at a time so that everything stays cool.

What kind of revs are we talking about here? Just the occaisional foray into 3-4000 rpm?

Go with your engine builder rather than me, but I'd say under 3000 for the first couple of hundred miles and don't give it any torque at all below 2000 (that leaves you quite a narrow band to work in), after that gradually open the rev range up to 4000 and try to keep it varying between 2000-4000 with brief doses of moderate power. After 1000 miles you can gradually increase the rev range and hold the power on for longer. By 3000 miles it's more or less run in but don't let it spend long in the upper region of the power band; by 5000 miles you can treat the engine as normal.

Ideally, each time you start the engine from cold you will go through a similar cycle i.e. start off at lower power in a narrow rev range and gradually extend the operating range as it warms up.

There are two ways to get it wrong.

If you labour the engine (too much throttle at too low revs) you can glaze the bores. If you do this the rings won't bed in and it'll never ever seal properly.

If you don't put any load on it the rings won't bed in and again it won't ever seal properly.

[That Daddy]

I have always run any of my fresh builds with the just drive it attitude,no heavy loads(well not until it as some miles under its belt),careful warming up,let the revs wind up and down,the 1st 100miles approx are most important(revs not not excessive that in the RV8 case below 4.5k for example)no screaming or constant speeds e.g driving round the M25 at a steady 60mph for 100 miles,if something breaks or locks up or worse total failure then the motor as not been built properly in the 1st place incorrect bearing clearences etc,and those problems will come to light later in the motors lifetime anyway,oh one thing you will gain from nursing a new motor is glazed bores followed by exessive oil consuption(nice easy problem to rectify,,,,,,NOT)be warnedbefore anyone comments i have never suffered engine failure during running or any problems related to running in later during the motors life,most of these have been very heavily modded Ford pushrod 4/6 cyl units(X flows with over twice stock outputs)anyway do it your own way but dont nurse itIMHO as usual.

Edited by That Daddy on Sunday 28th October 22:51

[Germs]

Which part of the M25 do you drive on where you can manage a steady 60mph!

[Al 450]

Thanks for the tips so far, I wanted this thread to be a reference for anyone else who is running an engine in sometime in the future.

On the subject of glazed bores, aren't those Porsche owners dipped in egg?

Seriously though it seems that varying the engine speed once warmed up is the way to prevent this. I think that this is also the reason a mineral oil is recommended for the first 1000 miles?

Is this problem fairly common on the RV8? My engine builder didn't mention it.

Does anyone know the mechanics of what causes this condition? The bores are smoothed rather than acheiving a matt finish, allowing an imperfect seal that much I know but how would low engine revs/excessive idling cause this?

[2Munkys]

I've done about 2,000 miles on my new motor now. I 'ran it in' in a manner not dissimilar to GreenV8S and That Daddy's suggestions. It was also in line with my thoughts and in complete accordance with the assemblers instructions. I used a dedicated running-in oil for the first 700 miles; changed the filter and used a good mineral oil for the next 700. Currently using Silkolene Pro V Expensive . . . . . . it's burning oil like a good un; Saddam's oil fields spring to mind. It needs to be discussed and resolved.

Going back a few years now and picking up some Wiseco slugs from Alan and Graham Nash of NCK (which I believe became TVR Power), they told me that they ran in new rings by 'giving a bike a darned good thrashing up the 1/4 mile'. Probably got bugger all relevance here but. . . .

[Incognegro]

Just took Cebera into TVR Power yesterday for tappets after 1000 mile run in. They said it looked in perfect shape after how I ran her in. As advised by Dom I stuck to under 3k rpm for first 200miles then after the that I was still changing at 3k but going sharper through the gears. In 4th and 5th I would occasionally see 4k rpm but only by blipping and not holding it there.

On the way home I saw nearly 5k rpm then lost nerve as the world was going by very quickly! The car feels solid as ever and very happy with the engine/de-cat and EPROM map.

Hope that helps

[Jhonno]

All the important stuff is bedded in within 50 miles I believe..

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

Edited by Jhonno on Wednesday 3rd July 09:54

[carsy]

Jhonno said:

All the important stuff is bedded in, within 50 miles I believe..

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

Here here. It will always be a controversial subject a bit like what oil to use, but i fully agree with the above. I read a simlar article by an engine builder years ago, which stated as soon as the newly built engine is warm find a long straight road and 2nd or 3rd gear, floor it, wind the engine right up and then throttle off alowing engine to revs to fall back down on their own and then repeat. continually repeat this over and over again for about 20mins. Job done.

[slippery]

GreenV8S said:

By 5000 miles you can treat it as normal. It'll continue loosening up

5000 miles running in! I've never heard anything like that before. Not saying you're wrong because I'm no expert, but I owned an RV8 Discovery from new and it was nothing like that.

[rigga]

Jhonno said:

All the important stuff is bedded in within 50 miles I believe..

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

Edited by Jhonno on Wednesday 3rd July 09:54

This all day long ....most of you are over complicating the procedure and are probably doing more harm than good.
Once the bores are glazed due to the rings not being forced into the sidewall of the cylinder hard enough, its game over ....only way to clear is a strip and hone.

[LordGrover]

Blimey! I thought it's nice to see greenv8s back, but then realised it's a six year bump!

[Chimune]

After a top end rebuild by one of the supposed respected usuals, I was v carefull in the run in period using your procedure + mineral oil and 3 changes up to 1k. After that it was expensive Valvoline VR1 and proper warm ups/no high revs etc. 4k later and the crank let go (no-ones fault). During that rebuild worrying level of cam wear were reported. Annoyed to say the least.
Maybe 200 miles then ragging it would have been better !

[rigga]

2Munkys said:

Going back a few years now and picking up some Wiseco slugs from Alan and Graham Nash of NCK (which I believe became TVR Power), they told me that they ran in new rings by 'giving a bike a darned good thrashing up the 1/4 mile'. Probably got bugger all relevance here but. . . .

Its an old post, but hits the nail on the head nicely...too much light use and revs on a rebuilt motor and you might as well not bothered.

[slippery]

And there was me thinking if I bought myself a recently re-built RV8 engined car I'd be doing myself a favour. Buying one of these is like rolling a dice.

[TVR Beaver]

The first thing you want to do is run the cam in... from start up and checking nothing is leaking.. go straight to 3K for 20 mins.. this will run in the cam.. This is done on mineral oil so once it's done, change the oil for some more mineral oil....
Then take it to a big hill and thrash it up and down for 30 mins to bed in the rings... Do about 750-1000 miles on the mineral oil but don't let it labour over this time... keeps the revs varying so no motorway cruises... Then oil and filter at 1000 to semi symth to flush.. a few miles and then onto what ever your going to use oil wise...
You need to run in the cam.. and bed in the rings!

Edited by TVR Beaver on Wednesday 3rd July 11:54