RPM during break-in period

Submitted: Friday, Jun 13, 2014 at 22:30
ThreadID: 108237 Views:2480 Replies:18 FollowUps:31
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Just picked up my new diesel manual ute. Was wondering what sort of RPM I should keep to while normal driving (not towing). Max on speedo is 6000RPM. While on 1st gear, I easily reach 3000-3500RPM. Is that safe?
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Reply By: Shaker - Friday, Jun 13, 2014 at 22:55

Friday, Jun 13, 2014 at 22:55
Doesn't hurt to let it rev reasonably freely, the worst thing you can do is sit it one speed for long periods of time, vary it a bit.
No need to baby it too much.
AnswerID: 534310

Reply By: Honky - Friday, Jun 13, 2014 at 23:29

Friday, Jun 13, 2014 at 23:29
This is my own opinion and should not be used by someone with more intelligence.
Just flog it.
In other word words do not sit on a constant speed. rev it up and down along as it does not increase engine temperature.
I have done this to a lot of company cars at have done around 200,000 ks in each.
If it does not work than it is the next owners problem.

honky
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Follow Up By: dreamerman - Friday, Jun 13, 2014 at 23:37

Friday, Jun 13, 2014 at 23:37
Plan to keep my truck for at least 10 years so it will be my problem eventually.
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Follow Up By: Honky - Friday, Jun 13, 2014 at 23:47

Friday, Jun 13, 2014 at 23:47
If you can, read what they do to a racing engine in the running in period especially on youtube.
Most of my company cars were kept for 5 years and I flogged them all the time.
only dropped a couple of ks of max speed from 5,000 to 200,000. Note this was done in a controlled enrolment and a closed road.

Honky
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Follow Up By: Honky - Friday, Jun 13, 2014 at 23:48

Friday, Jun 13, 2014 at 23:48
environment
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Follow Up By: Ross M - Saturday, Jun 14, 2014 at 11:44

Saturday, Jun 14, 2014 at 11:44
Any company car or other car should do at least 200,000km so that isn't any recommendation.
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Follow Up By: Penchy - Monday, Jun 16, 2014 at 08:27

Monday, Jun 16, 2014 at 08:27
race engines have race internals, I wouldn't be flogging my own car during running in.
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Reply By: John and Regina M - Friday, Jun 13, 2014 at 23:34

Friday, Jun 13, 2014 at 23:34
Have u read the manual?
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Follow Up By: dreamerman - Friday, Jun 13, 2014 at 23:36

Friday, Jun 13, 2014 at 23:36
Yes but very generic stuff. Nothing about RPMs.
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Reply By: Echucan Bob - Friday, Jun 13, 2014 at 23:49

Friday, Jun 13, 2014 at 23:49
Dreamerman

My purely personal unscientific advice is that you keep the revs low. To me, that is rarely exceed 2,500, and almost never reach 3,000. My intuitive reason for this is that wear is due to the speed of the piston in the cylinder - keep the speed down and reduce wear. Also ensure that you run the engine up to operating temp before putting it under any sort of load.

Having said that, my mate is an engine fanatic who rebuilds antique Listers and such like. When I drove his V8 Toyota the way I drive my car he seemed very edgy, and asked me to rev it a bit more!

I can also understand that putting a lot of torque through at low revs must stress the piston rings, but there has to be a happy medium. For me that is about 2,500 rpm.

My diesel has done 206,000km and still feels like new.

Bob
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Reply By: Ron N - Friday, Jun 13, 2014 at 23:58

Friday, Jun 13, 2014 at 23:58
In the "olden days", strict instructions were given for running in, with low speeds and low engine RPM's for the first 500 miles (800kms) and easy driving with varied speeds up to 1000 miles (1600kms).

"Running in" periods and warnings and instructions for new vehicles, have gone the way of the dodo, due to vastly improved machining and manufacturing tolerances, better materials, and no more need for initially "tight fit" components, as in the old days.

Run your vehicle at normal speeds, normal acceleration, and include a reasonable amount of high speed running in the first 2000kms and you won't have any problems.
I have bought many diesel vehicles new and done many, many kms with each of them, and never had any problems.
The only thing you need to watch is the engine temperature if you buy a vehicle new in the middle of Summer, and need to do long runs at highway speeds initially.

I've had new Landcruisers sitting on high speeds (open-road Territory speeds and higher) for hours, with little more than 1000kms on the clock and they never gave any problems throughout their many years of life.
AnswerID: 534314

Reply By: Member - Silverchrome - Saturday, Jun 14, 2014 at 07:24

Saturday, Jun 14, 2014 at 07:24
Breaking in a diesel

It is a good question Dreamerman, and one that is seldom asked these days. Yoy will get many different answers from do nothing to the very specific. So I have attached a link which gives one perspective of what to do and what not to do. This article is from USA so is referring to probably larger diesel engines than yours but you can make your own judgements about the principles this article exposes.
Link (if above click-on does not work):
http://www.thedieselstop.com/contents/getitems.php3?Breaking%20in%20a%20Diesel%20Engine

Another aspect that I personally do after buying a new vehicle is change the oil 1/2 way to the first schedule service...i.e. if its 10,000km service change all oils at 5000km. It would not hurt to change the diff oils as well. If you plan to keep the vehicle for 10 years its worth doing it right in my opinion.
Cheers
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Follow Up By: AlbyNSW - Saturday, Jun 14, 2014 at 08:37

Saturday, Jun 14, 2014 at 08:37
My mechanic recommends to drop the oil at 1000 k when you go in for the complimentary dealer visual check tighten inspection
Says it doesn't hurt to get any residual swarf and assembly pastes out of the motor
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Reply By: MUZBRY- Life member(Vic) - Saturday, Jun 14, 2014 at 08:23

Saturday, Jun 14, 2014 at 08:23
Good morning Dreamer
There you are , by reading all that input, you just drive it to the conditions. I agree with the oil change , but that is only if you want. I had a few company cars and you treat the new one like the one you just got rid of .
Muzbry
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Reply By: get outmore - Saturday, Jun 14, 2014 at 09:29

Saturday, Jun 14, 2014 at 09:29
Have you read the operating manual?
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Reply By: Erad - Saturday, Jun 14, 2014 at 09:32

Saturday, Jun 14, 2014 at 09:32
Drive the beast normally - don't flog it. Drive it the way you are going to drive it later. Avoid max RPM for a while, but at the same time definitely avoid slugging at low RPM's as well. The recommended procedure for bedding in new piston rings used to be to warm the engine thoroughly and then take it out onto the road and from lowish speed, accelerate at max throttle in top gear up to 50 mph, then back to 15 and back up to 50 mph. Repeat this 10 times and the rings were bedded in.

I put new rings in a Sigma many years ago and without testing it at all, drove it at night on a 120 km trip. On the way out, I went up a steep hill (full throttle in 4th gear) and there was a car following me. In the mirror and with his headlights, I could see smoke coming from the rear of the car. On the way back, the same thing happened (a different car following) but this time there was no smoke. After that, it never touched a drop of oil between changes.

I bought a new Pajero in 2000 and because of illness, I was unable to drive it for several months. My wife drove it and would not exceed 80 km/h for the first 1000 km. The rings never bedded in and it used oil (about 1L per 1000 km) for the rest of the time I had it. The Magna we had at the same time never touched a drop of oil. Just before i traded it in, I had a catastrophe (my doing) and had to rebuild the engine to makel it saleable. The original honing marks were still visible in the bores and it had 235000 km on it at the time. I bedded in the rings as before, but never got to see how the oil consumption measuerd up.

Our 2 new cars have been run in according to the above rules, and neither of them use any oil between changes. My new pajero has done a fair bit of harder work towing but it runs very sweetly.

So my recommendation is to thoroughly warm the engine (to get the oil circulating properly) and to take it out and drive it normally for the first 500 to 1000 km. During this time, make sure that it gets an occasional burst of full throttle. If possible, towards teh end of the breaking in period, really load it up. Unless you are going to race the engine, it is not necessary to rev the hell out of it - just drive it the way you are going to drive it when it is run in.

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Follow Up By: Erad - Saturday, Jun 14, 2014 at 09:34

Saturday, Jun 14, 2014 at 09:34
By the way, 6000 R/min seems rather high for a diesel engine. What is it?
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Follow Up By: Ron N - Saturday, Jun 14, 2014 at 19:11

Saturday, Jun 14, 2014 at 19:11
Erad, I thought the same - but the OP says "maximum on speedo (I guess he meant tacho) is 6000 RPM".
By my interpretation, I'm guessing he means the tacho reads to 6000 RPM - not that the engine does 6000 RPM.
It's rare to find a diesel that does more than 4000 RPM - but the new Mazda SkyActiv diesel does 5000 RPM.
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Follow Up By: Axle - Saturday, Jun 14, 2014 at 19:21

Saturday, Jun 14, 2014 at 19:21
G/day Ron .....Except a run away diesel!...I reckon my Mazda did 40,000 rpm....LOL.


Cheers Axle.
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Follow Up By: Ron N - Saturday, Jun 14, 2014 at 19:37

Saturday, Jun 14, 2014 at 19:37
Axle - Oooh, yes, seen that alright. I've seen a runaway engine in a Cat scraper when the governor broke - and they couldn't stop it. No-one had a piece of plywood ready to shove over the intake - and it was fairly screaming, anyway.

They ran it out of the workshop into the yard, stood on the brakes, and jammed the scraper bowl into the ground, to try and stop the engine - but it still wouldn't stop! The drive wheels were spinning at about 80kmh!!

One bloke ran out with a pair of bolt cutters, and chopped the fuel line - and the fuel promptly sprayed onto the red-hot spinning drive tyres - and set them on fire!!
The bloke in the drivers seat bailed out and everyone ran away - and the engine exploded a few minutes later, like a hand grenade, throwing parts all over the yard!
Then they had to try and put the fire out! Trouble was, the cut fuel line was still feeding the fire - and they only had hand extinguishers - and the scraper ended up burnt to a crisp, before the firies arrived!!

They had some trouble trying to explain the loss to the insurance company, I was told later!!
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Follow Up By: Axle - Saturday, Jun 14, 2014 at 19:49

Saturday, Jun 14, 2014 at 19:49
Hahahahahaha, ...Makes you laugh afterwards,... But sure as hell scares the crap out of you when its all happening!


Axle.
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Follow Up By: pop2jocem - Saturday, Jun 14, 2014 at 21:11

Saturday, Jun 14, 2014 at 21:11
Guys, if you haven't heard one of the old 2 stroke 53 series Jimmies run away and feasting on it's own sump oil, well you aint heard nothing yet. Those babies sounded like they were doing about 10,000 RPM when hitting there governed 3000 RPM.
We had a 16V-71 run away on the dyno once. Now these little beauties were basically 2 8V's bolted together. 2 blowers and 2 turbos.
This one decided to bolt. The bloke closest hit the 2 shutdown flaps but only 1 slammed shut, so we had one end in shutdown mode as far as it's air supply was concerned but not it's fuel supply. The other end was dragging it along like a dog with an itchy backside.
Fortunately the fuel tap got shut off quick smart.

AHH, those were the days...lol

Cheers
Pop
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Reply By: Athol W1 - Saturday, Jun 14, 2014 at 09:36

Saturday, Jun 14, 2014 at 09:36
Dreamerman
The only part of a modern engine that requires any form of 'run in' process is the piston rings, and the ring manufacturers suggest a full throttle acceleration from around 60kph to around 100 kph in a direct gear followed by a closed throttle deceleration back to 60 kph, and repeat this procedure for 10 consecutive cycles without the use of the brakes (does require using a relatively quiet appropriate section of highway). After this procedure the engine is considered to be fully 'run in' .

This is the process that I have carried out with every engine that I have rebuilt over the past 40 odd years and never had any issues relating to engine life.

Also the best engines that I have been involved with have all had a long highway drive very early in their life over some hilly/undulating roads where they have had plenty of variation in the load and speed that they were subject to.

The MOST important thing with ANY engine is never to apply too much load at excessively low engine speeds (lugging the engine), Revs, up to their designed maximum, will not harm them and it is better to have a few more revs rather than not enough revs.

The biggest killer of engines is heat, whether that be excessive heat or a lack of heat when subject to heavy load, it is also advisable to get the heat into the engine as quickly as possible after a cold start up, and that is by driving the vehicle with moderate loading until normal temperature has been attained. DO NOT start a cold engine and allow to idle for lengthy periods to warm it up, as a cold engine operating at low speed suffers from a lack of lubrication.

Hope this helps
Regards
Athol
Retired Motor Mechanic
AnswerID: 534324

Reply By: Michael ( Moss Vale NSW) - Saturday, Jun 14, 2014 at 09:43

Saturday, Jun 14, 2014 at 09:43
Read you service book that came with it! That's will tell you what you need to do! You'll get fifty different answers here and they all won't be correct, Michael
Patrol 4.2TDi 2003

Retired 2016 and now Out and About!

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Follow Up By: garrycol - Saturday, Jun 14, 2014 at 10:29

Saturday, Jun 14, 2014 at 10:29
The engine would have been run in at the factory - they would have flogged it harder than you would think.

As suggested above read the handbook - most information given here may have been relevant 50 years ago but not relevant now on a factory new engine.

Garry
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Reply By: wholehog - Saturday, Jun 14, 2014 at 11:52

Saturday, Jun 14, 2014 at 11:52
Just get in it and drive the bastard, hook up what ever ya tow even, just drive the damn thing.

Some people seem to get a sort of 3rd person empathetic personality to a piece of suck squeeze bang blow reciprocating machinery.
AnswerID: 534329

Reply By: Ross M - Saturday, Jun 14, 2014 at 11:54

Saturday, Jun 14, 2014 at 11:54
Why would you be revving it to 3000rom or even 3500rpm in 1st gear ever in it's whole life?
1st is a crawler gear and used for starting the mass on the vehicle moving and then selecting higher higher speed/ lower ratio gearing as you speed up. ie, once the vehicle mass is moving so should the gear stick. Is drag racing a necessity?

Just because the manufacturer has additional numbers to print on a tacho which are far more than the engine will safely rev to, isn't a reason to try and use them.

Just drive it normally without high revs and high loads or low revs under load, so it has a chance to microscopically run in/wear in the high spots of machined surfaces.
You can rev the crap out of anything and surprisingly many last for a while but not as long as a "cared for" engine.
AnswerID: 534330

Follow Up By: dreamerman - Saturday, Jun 14, 2014 at 16:54

Saturday, Jun 14, 2014 at 16:54
I must be doing something wrong with 1st gear reaching 3000rpm. Will start changing to 2nd at not more than 2500rpm tomorrow and see how it feels like.
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Follow Up By: Ross M - Saturday, Jun 14, 2014 at 21:16

Saturday, Jun 14, 2014 at 21:16
I would rarely go above 1600rpm when it's time to change to second. I can't imagine what revving it higher will do for you. Second and using the torque is far more effective. Then 3rd and the rest.
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Reply By: Idler Chris - Saturday, Jun 14, 2014 at 15:07

Saturday, Jun 14, 2014 at 15:07
Took delivery of a brand new HR Holden (company car of course) on 23rd Dec 1966. Next day 3 mates and I headed to Surfers for Christmas. Once past Shepparton with 134 miles on the clock we reckoned it was run in and from there we sat on 100 Mph for most of the rest of the way. Had that vehicle for over 200,000 miles and it was one of the best cars I have ever had. I use to give the Valiants a bit curry I can tell you.
What other people think of me is none of my business.
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Follow Up By: Axle - Sunday, Jun 15, 2014 at 14:51

Sunday, Jun 15, 2014 at 14:51
Lol Idler Chris,.....The trouble was the speedos on them where 30mph Fast.!..


Cheers Axle.


Ps, the 186 was a good motor ,Their performance engine the 186s put out nearly the same power as the 225 slant six valiant...140bhp.

But they reved a bit higher than the val,so hence a bit more performance.

1
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Reply By: pop2jocem - Saturday, Jun 14, 2014 at 15:22

Saturday, Jun 14, 2014 at 15:22
The worst treatment of any engine but particularly diesels is to idle them for long periods whether warm or cold. Pussy foot around with it and the rings will not bed in properly. Don't flog the gonads out of it with high revs but a good load applied at mid range RPM will do it the world of good.
Consider that when the fuel mixture goes bang on top of the piston the rings get pushed to the bottom of their grooves and gas gets between the piston and the back of the ring. This forces the ring against the cylinder wall thus helping to seal the expanding hot gasses from escaping into the sump. It also helps the rings with the bed in process.

Cheers
Pop
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Follow Up By: Member - 2517. - Saturday, Jun 14, 2014 at 16:16

Saturday, Jun 14, 2014 at 16:16
Concrete trucks idle for hours on end does not seem to do them much harm.
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Follow Up By: Bob Y. - Qld - Saturday, Jun 14, 2014 at 16:45

Saturday, Jun 14, 2014 at 16:45
More likely to be at high idle, 2517. Especially if they're dumping mix.

Bob.

Seen it all, Done it all.
Can't remember most of it.

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Follow Up By: pop2jocem - Saturday, Jun 14, 2014 at 18:50

Saturday, Jun 14, 2014 at 18:50
I wouldn't class turning an agitator with 6 meters of concrete on board as "idling". When they reverse the agitator to dump they get a pretty good fistfull of revs.
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Follow Up By: Ron N - Saturday, Jun 14, 2014 at 19:26

Saturday, Jun 14, 2014 at 19:26
pop2jocem is right. Excessive idling is the worst thing ever for diesels. Run them for 3 mins maximum at idle.
At idle, the combustion process isn't complete, and you end up with unburnt fuel in the cylinder.
This unburnt fuel goes past the rings into the sump, and you get "crankcase oil dilution".
It's quite common to get COD even when a diesel is running flat out.

Ever seen a little early Jap diesel with the aneroid-controlled fuel pump (the ones with the butterfly-type throttle in the intake) racing along, pedal to the metal - and pumping out a stream of black smoke??

That's raw unburned fuel you can see - and half is going out the exhaust - and the other half is going past the rings into the oil.
That's why you'll find the engine oil black as bitumen, and about as tarry, on these little Jap engines that have been flogged consistently at high speed and high loads.

COD is the worst thing ever for diesels. It dilutes the oil with raw diesel and blackens it with soot, making the oil lose its ability to lubricate properly. Keep this up without shortened oil changes, and you'll seize the engine.

Excessive idling produces similar results. The diesel content of engine oil can get at high as 10 or 12% with excessive idling - and that's bad news for engine lubrication.
In addition, tips can burn off injectors with excessive idling - and the injector orifices can carbon up quite rapidly.

Finally, exhaust emissions increase rapidly with excessive idling. In many American cities, they have strongly-enforced laws against idling diesels in confined areas (truck stops, warehouses, bus depots) for more than 3 minutes.
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Reply By: Bigfish - Saturday, Jun 14, 2014 at 15:58

Saturday, Jun 14, 2014 at 15:58
SO THE RESULTS ARE...
1. Change oil 1/2 way to first recommended oil change....smart move.
2. Do not lug the engine...possibly glaze the bore and use more oil later.
3. Stay at about mid range revs..3000-3500 rpm.
4. Do not sit on a constant rev range for hundreds of k,s....vary the revs.
5. Do not allow to sit idling for long periods of time.
6. Modern diesels, like most modern motors, are virtually run in at the factory.
7. Don't be a fool and rev the bejesus out of it wherever you go...especially on start up or when cold.
8.Regardless of what the manual says...change oil every 5000 klms....oils cheap...engines aint

good luck
AnswerID: 534342

Follow Up By: garrycol - Saturday, Jun 14, 2014 at 16:26

Saturday, Jun 14, 2014 at 16:26
You forgot - if in doubt read the instructions.

With respect to your point 8. Is old information that is relevant to old slow revving dirty Jap engines. Doesn't apply to modern high speed diesels - again if in doubt read the instructions.
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Follow Up By: Bigfish - Saturday, Jun 14, 2014 at 17:31

Saturday, Jun 14, 2014 at 17:31
I have always changed oils at 5000k intervals..turbo troopy, hand grenade nissans, 1700 cc Harley, xr8 and others. Buy oil in bulk is dirt cheap..especially for diesel.....car and bike run on synthetic, expensive but necessary.. 8 liters of diesel oil is about $60.00...absolutely nothing. Change filter once a year.i.e..every 10,000. Old habits die hard but peace of mind is fantastic. Naturally a new car will be sent to a stealers for its servicing.
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Follow Up By: garrycol - Saturday, Jun 14, 2014 at 18:00

Saturday, Jun 14, 2014 at 18:00
If I had a troopy I would be changing the oil at 500km too - as well as the oil filter. Modern diesels don't need it but they are very particular with what oil is used.
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Follow Up By: pop2jocem - Saturday, Jun 14, 2014 at 18:59

Saturday, Jun 14, 2014 at 18:59
What Bigfish said x2.

Especially about the price of oil compared to engine rebuilds.

And as has been said, a good read of the handbook, pay a bit of attention to the bit about unusual, extreme, usage and the oil change period recommended.

As a now retired diesel mechanic just in case you were wondering if I knew what a diesel engine even looked like. (;-))

Cheers
Pop
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Follow Up By: Ron N - Saturday, Jun 14, 2014 at 20:04

Saturday, Jun 14, 2014 at 20:04
Bigfish is right on the regular and shortened oil changes - particularly if you're in dusty conditions, in extremely hot conditions, or towing heavy loads.

The reason why manufacturers are now increasing oil change intervals is to reduce maintenance costs.
With less oil changes, they can brag about the lower servicing costs, and therefore lower running costs than Brand X.

The problem is that the manufacturers aren't real concerned about engine life.
If your engine blows up because the oil got too thick with pollutants, or diluted with fuel from blowby - then, hey! - guess who gets to sell you a new engine!

There's another factor at play here, too. With increasingly tighter emission laws, manufacturers are looking at every angle they can to reduce tailpipe emissions.
One way they do that, is to drive the pollutants down past the rings and into the engine oil. This makes the tailpipe cleaner - at the expense of the engine oil.

The newer engine oils have been re-formulated with substantially-increased detergent levels to cope with this vastly-increased pollutant level in the engine oil.
But the problem is - the pollutants are still there - they're just held in suspension in the oil by the additives.
Increased oil change periods only see a larger load of pollutants in the engine oil.

So .... if you want your engine to last, shorten the oil change periods over the recommendations.
5000kms is for extreme condiitions, 10,000kms is O.K. for most conditions - but I personally wouldn't take any diesel to 20,000km oil change periods, as recommended by some manufacturers.

The 40,000 km "extended drain interval" periods as recommended by some manufacturers is enough to make me shudder.
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Follow Up By: pop2jocem - Saturday, Jun 14, 2014 at 21:26

Saturday, Jun 14, 2014 at 21:26
What Ron N said. Also I am amazed by the amount of people who think changing the filter only and not the oil and filter at every oil change to save a few bucks is a great idea and leave the old cruddy oil in the sump. Sure you have a nice new filter and it is trying to filter old oil right from the first startup. The filter only removes particles down to whatever micron size the engine manufacturer thinks is suitable. All the water, fuel and whatever crap is not filtered is still there getting circulated through your engine.

Cheers
Pop
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Follow Up By: Erad - Sunday, Jun 15, 2014 at 10:57

Sunday, Jun 15, 2014 at 10:57
Agree about more frequent oil changes - oil is cheap. I know of one early model Falcon which had 3 engines in 100000 miles. It had short runs all the time and virtually never got warm. But the owner had the car serviced by the book, and that said oil change every 2000 miles??? Whatever, he changed it as per schedule but SHOULD have changed it far more often.

Diesel engines rely on engine oil to do a lot of the cooling. They spray oil to the underside of the pistons and dump the heat to the sump. Some of them even have oil coolers.

Agree about not idling engines to warm them up. At idle, the injectors give only enough fuel to keep the engine turning. This isn't going to get much pressure behind the rings to expand them, expecially compared to full load. Excessive idling will eventually lead to glazed cylinder bores.

Another point about running in - bearings need breaking in as well, hence my comment above about getting the oil warmed up before starting to really work it hard.

Drive it gently until it warms up then work it normally - whatever normally will be.
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Follow Up By: Ross M - Sunday, Jun 15, 2014 at 12:34

Sunday, Jun 15, 2014 at 12:34
Bigfish

Do you realize the statement:

3. Stay at about mid range revs..3000-3500 rpm.

Is in excess of 75% of most engine revs and the 3500rpm is getting near maximum engine revs and is FAR above the 2000rpm where it will be running on the highway.
Are you therefore suggesting, the owner of a new vehicle should drive on the highway, in a far lower gear so to keep the revs up near maximum for the run in period?

Sounds crazy to me.

you also said " Don't be a fool and rev the bejesus out of it wherever you go...especially on start up or when cold." so what is reality here?

If 3500rpm isn't revving the" bejesus" out of it then what is?
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Follow Up By: Bigfish - Sunday, Jun 15, 2014 at 14:40

Sunday, Jun 15, 2014 at 14:40
6000 revs is the redline on his new vehicle, as stated in original thread. I wouldn't consider 3-3.5 excessive...Diesel motors prefer higher revs than being lugged around. Modern diesel motors rev higher mow than 10 years ago..
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Follow Up By: garrycol - Sunday, Jun 15, 2014 at 17:13

Sunday, Jun 15, 2014 at 17:13
No where does he say the redline is 6000rpm - just that the tacho goes to 6000rpm.

My tacho also goes to 6000rpm but the electronic cutout is 5000rpm. When driving quickly I regularly see over 4000rpm when in "drive" but when cruising on the highway in 6th the engine is only doing about 1200-1500rpm. So I agree that when driving normally in a steady condition 3000-3500rpm is a bit high - somewhere about 200kph in my car.

Garry
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Reply By: The Bantam - Sunday, Jun 15, 2014 at 16:32

Sunday, Jun 15, 2014 at 16:32
As was said earlier, everthing about how motors are machined and built has changed.

Accuracy of maching has moved forward considerably...materials have moved forward too.

back when we where running pushrod motors with either rigid or hydraulic lifters there was a whole lot of stuff that needed bedding in in the top end of the motor.....that was the point of the first low rev period of the run in..to allow the valve train to bed in.

the next phase was to allow the bottom end and the rings to bed in.

Of course after the run in peroid the head bolts where re-torqued because the gasket had squashed down a bit...and the valve clearances where re adjusted.

as has been said all this is a thing of the past....in the modern twin overhead cam motors, the valve train is far simpler and more direct and many ovehead cam vehicles never have their valve clearances adjusted ever.
The head gaskets don't need re-torquing and modern assembly is better than the balancing and blueprinting that would have occured in race motors of 25 yeras ago.

Just the chaenge in valve seats alone is a quantum leap...back in the day the valves where ground and seat was cut directly in the head and some poor schmuck had to sit there for a couple of hours lapping the valves with a lapping stick and compound....and run in was definitely required.

these days the valve seats are hardened material and are very accurately "multi-facet machined"..some will tell you no lapping is required at all or at least very llttle and more or less no run in.
Hell I know a bloke in the next street that has a multi facet vale cutter in his garrage...who knows what the funkiness the big manufacturers have.

Besides...if the manufacturer realy thaught the engine needed some sort of restriction in the run in peroid...they would programe that into the ECU.

You would be wise not to flog the thing espacielly when cold , but babying it is equally unwise.

cheers
AnswerID: 534415

Reply By: dreamerman - Sunday, Jun 15, 2014 at 17:39

Sunday, Jun 15, 2014 at 17:39
Thanks all for your views. I tried to keep the rpm down today but it is just too hard. My ute is brand new with 11kms on the odometer when I picked it up 2 days ago. I just drove it carefully on the slow lane and did rev up to about 3000rpm a few times when required.
AnswerID: 534425

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