Running in engine

[Steve A]

I am still running my newly built engine in due to the car having to return to the bodyshop and have only managed 260 miles so far.
I have been running it in carefully keeping the revs below 3000 as instructed.
As it was dry today i thought i would take it out to put a few more miles on it, but when i started it the engine seemed to be running on 3 cylinders. I drove it around the block and got it upto temperature and still the same. I looked inside the dissy cap but all was fine and by pulling the leads off one at a time and found it was third cylinder from the rad which was the problem. On removing the sparkplug i found it was a bit sooted up and a little oily so i cleaned it put it back in and its running fine. Is this normal whilst running in or is it a sign somethings up? Oil pressure is 70 when warm and temp seems ok. It seems to drive fine apart from a few small oil leaks.
How many miles do i have to do to run it in 500? Thanks Steve

[Vegard]

Drive it properly. The days of the pansy running in are gone...

[Steve A]

i can't wait to drive it properly but just following what the engine builder told me.
Incidently i have noticed that the oil pressure is near the same warm or cold 70lb but when driving at around 2500rpm the pressure drops to around 60, pull up and it returns to 70 on idle? Every other mini i have had the oil pressure increases with revs? Am i being paranoid?

[Lord Croker]

No disrespect to Vegard, it's a matter of choice, but I personally do believe in running in newly built engines, but at around a 4000 rpm max & keeping the engine running freely with no heavy loading. As regards your oil pressure, if you have an electronic gauge, it may be doing strange things, if it's the old pressure activated gauge, it's possible that your relief valve is a bit sticky & causing pressure fluctuations. It's very easy for a small particle from a new engine & particularly the gearbox, to find it's way into the valve. The pressures you are getting are not putting your engine at risk, 70 psi at idle is excellent. You are correct in thinking that the oil pressure normally increases with revs, so no paranoia there!

[swifty]

i can understand what vegard means . A freind of mine run his new 1380 engine in to softly running on twin 1.5 h4 su. He ended up with glazed bores through bore wash

[1071 S]

The trouble is that different bits of the engine require different treatment....

Cams need an initial higher speed run (basically at no load) for something like 15 minutes on startup. Bearings need gentle treatment for a while - hence the usual "careful" run in instructions. Rings need to be loaded early on. They need to wear against the bore to achieve a proper close fit.

So, you run the cam in first. Then run the car up hill in as high a gear as the engine will take without lugging at, say, around 3K revs. Several miles of such treatment should be enough to bed the rings.

The bearings need gentle - but not constant - treatment over an extended period. Do not let them get too hot and don't subject them to excessive load (ie revs) too early. But, the most important aspect is variation in revs... So the deal is bursts of acceleration - say 3/4 throttle to 3/4 revs followed by deceleration. just avoid excessive - and constant - revs. Over several hundred miles you build up to full throttle, peak revs.

Good luck, Ian

[STG95F]

What can the drop in pressure be when the engine revs increase ??? . all the ones i have seen increase with engines revs ?

Ian

[Steve A]

The pressure is behaving quite strange, sometimes if i rev the engine it goes from 70lb up to 80lb and then to 60lb while still at the same revs? Its behaving a little weirdly and will need investigation.
I have quite a few small oil leaks now at 350 miles. Nothing major mostly around the transfer housing, just a small drip but i did notice a little drip from below the pressure releif valve where there is a grub screw or something in the block? Not sure exactly what this is? Anyone enlighten me? Cheers Steve

[Vegard]

Did you forget the O-ring?

[Steve A]

I didn't build it or fit it so i hope the o seal is fitted as i haven't got a clue where it goes lol
Is your question about the o seal related to the pressure fluctuation or the leak or both?
In relation to the leak i dont think its coming from the releif valve but the little indend an inch or so below on the block whatever this is?

[Steve A]

I could email a pic to you if it would help explain about the leak? Cheers Steve

[Spider]

I'd suggest following what ever instructions the engine builder gave you!

When I do mine, I just drive them normally, but keep the revs under 3000 for about the first 500 km for iron rings and 1000 km for chrome.

Usually reving them out or loading them up often and / or hard doesn't do them much justice or longevity

[Vegard]

I ran mine for 20 minutes at 2500rpm to bed stuff in, then straight to the dyno. The first four pulls it smoked a lot going up to 6000rpm, then gradually stopped. Now it doesn't smoke at all, tight as a tiger and is one of the fastest Minis on the track.

I guess I have ruined stuff

[Steve A]

Going back to last question on page 1?

[Spider]

I ran mine for 20 minutes at 2500rpm to bed stuff in, then straight to the dyno. The first four pulls it smoked a lot going up to 6000rpm, then gradually stopped. Now it doesn't smoke at all, tight as a tiger and is one of the fastest Minis on the track.

I guess I have ruined stuff

For a Race Engine, fair enough.

Going back to last question on page 1?

I'd be quite concerned about any oil leaks on a new engine, but I doubt these are related to oil pressure.

With what you've described, I'd say the Relief Valve is sticking.

If the engine has some warranty on it, go see the bloke who did the job.

[foxy52]

i can't wait to drive it properly but just following what the engine builder told me.
Incidently i have noticed that the oil pressure is near the same warm or cold 70lb but when driving at around 2500rpm the pressure drops to around 60, pull up and it returns to 70 on idle? Every other mini i have had the oil pressure increases with revs? Am i being paranoid?

...yes u are lol.... golden rules....dont let yr engine hunt ??!! ie,. right speeds for right gears ..do not over rev...plenty of gear changes up and down on local roads.. motorway use does not help run an engine in...ie high revs in top gear....yr oil pressure sounds great to me.. i get uniformly 60-65 ish...once u have done about 700-1000 miles carefully have yr oil and filter changed etc...a top qual 10/40 semi synth like mobil sell is good......and then get it strait to a dyno and have it rolling roaded and properly set up by a true mini specialist..i used peter baldwin and he was the biz !!!!!...what do i know eh ??!! but this was my experience after a total rebuild in 2007 and my cars fine for now !!! foxy52.

[Steve A]

But below the oil pressure switch is a little hole look like a grub screw or something in it? It almost behind the starter motor so hard to tell but i am getting a liitle oil leak from there so what is its purpose? I have looked on later blocks and it is blank on the casting.