Precautions/Advice new engine

[SilverShadow]

Hi,

Can anyone give me some advice in how to turn over a newly built M20 e.g. what brand of oil to use, how to determine oil pressure etc.

Any information about bedding in the new engine would be great, I did carry out a search but didn’t get any solid results.

I have had the head rebuilt ”“ guides, stem seals. Block crank regrind/polish and balanced, new big and main shells, new rings and block honed.

Thanks in advance.

[Speedtouch]

Just use normal engine oil, e.g., 20W50. Take the spark plugs out, and spin the engine over on the starter until the oil pressure light goes out - that should only take a few seconds, at most.

Then, replace the spark plugs and she should be good to go - obviously, keep the revs down at first until you're sure everything is bedded in.

Replace engine oil and filter after the first 1,000 miles or so, and check the tappet adjustment.

[SilverShadow]

Just use normal engine oil, e.g., 20W50. Take the spark plugs out, and spin the engine over on the starter until the oil pressure light goes out - that should only take a few seconds, at most.

Could I do the initial start by using pins 11 and 14 from the diagnostics port?

Replace engine oil and filter after the first 1,000 miles or so, and check the tappet adjustment.

Is there a specific driving style for the first 1,000miles? keeping the revs low and odd bursts?

Will the standard 25 thou tappet setup be suffice? The engine is a 2.7 setup with 6 branch manifold?

[polsta]

I've done about 400 running in miles so far, not gone above 4k revs , plenty of gear changing and not many constant 5th (motorway) miles , just take it easy , after about 300 miles i started giving it slightly more spurts of acceleration in 3rd/4th but still keeping under 4k

Plan oil and filter change at 500 and then again at 1000 miles and ajust the tappets, and after that , possibly gradually build up the revs taking it higher and higher every 50 or 100 miles or something ?

[Speedtouch]

Indeed, important to vary the engine speed frequently, and avoid slogging along in a high gear for long.

You could indeed spin the engine over using the diagnostic socket, if you so wish.

The standard tappet clearances should be fine, unless you have a high-lift cam that demands otherwise.

[polsta]

Also just keep a close eye on all the pipes and everything and re tighten as you go, things can work or come loose as you clock up the miles and a few teething problems

After a little air leak/hunting and then the manifold to downpipe started blowing after a thread issue, new gasket and thread and a re tighten of everything - my engines sounding very quiet and happy, its a good feeling having a rebuilt engine under the bonnet

[capnmchl]

Because you've changed the rings and honed the block, don't pussyfoot around; once you've got the engine up and running and warmed up, drive it 'purposely'. You need to bed those rings into the bores.

Read this before you even think about starting the car up.

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

This guy (Stephen Merchant) pretty much hits the nail on the head.

You only get one chance at this.

[Kos]

Nail it

[Kos]

You'll note in the link below that Polsta doesn't actually have a clue and is repeating some of what was said to him yet he ignored the correct advise

http://www.e30zone.net/modules.php?name ... t=#2731238

The link from capnmchl is spot on advise

[polsta]

Yawn.

Having spoke to a few people in the real world and the person who did the engine work, and people who had ran in re built m20s before, not 1 single person I spoke to said re that link - to get in it and go flat out full throttle and rev the fook out of it, not 1 single person. And as someone who has actually just put in a rebuilt engine and running it in, all I'm doing is passing on my expirience , unlike some who just hang around here with other intentions.

Maybe instead of just trying to pick at people over the internet kos could actually tell you how he re built and ran in an m20 engine ..

[polsta]

In that article he mentions mororbike engines a lot and running it in on a dyno...

Also

"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.


Im not sure how an engine developed 30 years ago tallys with that

[Speedtouch]

I would indeed be sceptical about caning a freshly rebuilt engine right from the off. After all, most rebuilt engines have new oil pumps, timing chains, bearings, etc., that really need to be carefully bedded in by keeping the revs sensible and varying the engine speed and load regularly.

Also, most freshly built engines (particularly older classic engines with carbs) won't be properly set up as regards ignition timing, fuel mixture, etc., so won't necessarily run that well at first.

[clarko74]

I've never run an engine in, but here's a quote from Ant and he knows what he's talking about:

whats all the running in with a slushbox BS all about ??

fit it, run to 2K for 15 mins, bleed coolant whilst maintaining RPM

check oil and water level, start car again, whip up road in 1st, 2nd and maybe 3rd using ALL the rev range, no shortshifting BS, run from 2K to 5K in 2nd for 20 miles up and down the range, no labouring !!!!

rings will bed in in the 20 mins, nurse it for 1.5K miles and she'll be a slow one IMHO, runs the risk of polished rings and bores, remember Adam patchtons 2.8, nursed to 3K , always burnt lots and lots of oil.........

[AardHawk]

I think that there is a huge difference between a brand new Honda and a home rebuilt M20. Machine shop equipment and techniques havent changed in the last 30 years. No machine shop (assuming that you can actually find one in the uk) will ever duplicate the machining and finish of a manufacturers engine plant.

The article doesn't talk about caning a new engine. What he says is a bit contradictory. He says you only have about 20 miles to do the job properly and to warm the engine up thoroughly, but not thrash it (which will take at least 10 miles of spirited driving) and then in 2nd, then 3rd and finally 4th gear to run it though the rev range and most importantly when at high revs to lift off the throttle completely to get maximum back pressure to allow the rings to bed into the bores, down to minimum revs and to repeat this several times in each gear.

There is no talk of bearings, oil seals, cams and rockers.

What are your experiences using his method?

[Kos]

Yawn.

Having spoke to a few people in the real world and the person who did the engine work, and people who had ran in re built m20s before, not 1 single person I spoke to said re that link - to get in it and go flat out full throttle and rev the fook out of it, not 1 single person. And as someone who has actually just put in a rebuilt engine and running it in, all I'm doing is passing on my expirience , unlike some who just hang around here with other intentions.

Maybe instead of just trying to pick at people over the internet kos could actually tell you how he re built and ran in an m20 engine ..

You've done nothing, you paid some one to rebuild it so don't keep going on and what you've done. Also this is the first time in your life you've had an engine that needs running in

My experiences of re built engines are CVH's in XR2's and RS Turbos, R5GTT and M20's

The same principles count on any 4 stroke engine

Start it, Check it for leaks, drive it and get it to temp, check everything again and nail it. Don't bounce it of the rev limiter, that would be stupid but hard acceleration is best and it takes no more than a few hundred miles and 2 oil changes. The first oil change should be done after the first running of it. Then run it hard for another 200 miles, change the oil to your prefered type (fully synthetic is best) and you're done.

My old XR2 it's still going strong and making 110bhp at the wheels 16 years and 80,000 miles after I had it built and burn no oil and compression is perfect. Its a nice loose, powerful engine

In terms of machining, what's been done to yours polsta ? Give had new rings but was your block re honed ?

With mine, I had blocks and cranks machined.

I know of several M20's running huge power that have all been run in on a rolling road and race tracks and there's nothing wrong with them either.

In regards to what speed touch has said, with engines set ups/mapping. This is irrelevant to an m20 unless it's been tuned. All the ignition, fuel, cam timing is fixed

When modified like the ones I know of (turbo & stand alone management) the builder has various safe maps and set ups for the the running in process, once that's done he maps them

His personal 724bhp m20 has been going well for a long time. Gets nailed every time he uses it.

The guys who I advice I take as gospel on this subject have a combined 70 years experience and worked on every type of engine.

[capnmchl]

I don't understand people moaning about damage to bearings etc. Bearings float on oil, there should be no metal to metal contact once oil pressure is established. Camshaft's should be well made to ensure they can be run at higher RPM's and lubricated with the CORRECT lubricant. Even Piper suggest the following

"8. Do not idle engine during the first twenty minutes of operation; rpm should be kept at 2500 or above. In pushrod engines oil throw-off from the crank may not be sufficient to lubricate the cam followers. Also contact stresses at the nose of the cam are very high at low speed. If adjustments need to be made during the twenty minutes break-in period, shut the engine down. DO NOT IDLE." http://www.pipercams.co.uk/pipercams/ww ... lation.php

Same applies to rockers.

Either way you can't win. Something has to be sacrificed, but as it's your rings that seal the piston and combustion chamber, they're probably the most important thing to seal.

[reggid]

drive it hard to bed the rings but dont over rev it or run at constant speed for long periods. new cam needs to be run in at speed like 2000rpm minimum. do not baby it. lotsa zinc is needed

[SilverShadow]

Either way you can't win. Something has to be sacrificed, but as it's your rings that seal the piston and combustion chamber, they're probably the most important thing to seal.

Lots of mixed opinions on this topic....

Just to reiterate I have used the original head components including the cam and rockers.

My main concern would be on the rings and combustion chamber as you mentioned Capnmchl.

"drive it hard to bed the rings but dont over rev it" I'm reading this a lot, is there a initial rev range to drive it hard? Im assuming "don't over rev it" means don't redline it?

[Speedtouch]

A newly rebuilt engine will (or should) feel a bit tight to begin with - just rev it to what feels like a safe/comfortable point, and gradually increase this over a period of time until it loosens up.

[capnmchl]

Either way you can't win. Something has to be sacrificed, but as it's your rings that seal the piston and combustion chamber, they're probably the most important thing to seal.

Lots of mixed opinions on this topic....

Just to reiterate I have used the original head components including the cam and rockers.

My main concern would be on the rings and combustion chamber as you mentioned Capnmchl.

"drive it hard to bed the rings but dont over rev it" I'm reading this a lot, is there a initial rev range to drive it hard? Im assuming "don't over rev it" means don't redline it?

Well, as everything else is a bearing, I'd be driving it very hard to get those rings sealed.

Think of it like this:

You want those rings to be forced into the cylinder walls as hard as you can, and as much as you can. The best way to do that would be a big bang and high engine velocities. Therefore you want to aim for WOT at the point of highest torque, as pressure on piston = torque. So that doesn't mean rev it to the red line but run it up through the points of highest torque.

Take my engine here for example. Using this torque graph, if I wanted to run it in, I'd probably aim for WOT between 3 and 5k rpm as that's where the most torque is. Highest torque = highest pressure in the cylinder = largest force on the rings.

[Kos]

So, there we have it. The general consensus is that driving hard is the way to go