R400D to R500D Anyone done it?

R400D to R500D Anyone done it?

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Pdelamare

659 posts

127 months

Thursday 22nd January 2015
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It's good to hear you can get through scrutineering/noise checks ok. This is my biggest concern, hopefully it's quiet enough to get through Bedford's 98db limit.

DCL

Original Poster:

1,215 posts

178 months

Saturday 28th November 2015
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Just an update on this thread

The engine had been extremely reliable last year, so this year I was tempted to play around with thinner oil grades to see if any power was on offer. Certainly there was more power, but one event saw oil temperatures getting rather elevated. I got the feeling that perhaps I’d pushed my luck too far.

The oil filter check confirmed a higher particle count than normal, but returning to a thicker oil for the final event of the year seemed to settle it down. But I knew a rebuild was needed, if nothing else, to give me peace of mind.

To give some perspective to what follows, the engine has completed 13 sprint events, and a similar number of trackdays, 6 rolling road sessions, 120 hours on the ECU, and about 1000 miles on the speedo. Reving to 8600, and producing up to 270 BHP

First impressions, when opening the cam cover, was that it all looked rather nice. The spark plugs were text book (if anything getting a bit hot) and the only thing that caught my eye was two small scores on one cam lobe.



In hindsight, the two little scores where a clue to a more serious problem. And yes, the bearing next to that lobe was in trouble.



There was noticeable wear on the cam bearing and the cap looked a bit distressed too. Luckily the unloaded side (the head itself) seemed not to have suffered to the same degree.



Now the cause of this is difficult to say for sure. The cam had two little hammer marks on the bearing surface which were within the oil groove most likely caused by it ingesting something via the oil.



But the bearing cap also looked porous, so maybe a problem there. Anyone’s guess to be honest.

One issue that played on my mind was the length of time this engine had been at idle. It has spent most of its time idling away, warming up, and waiting for sprint starts, so maybe low oil pressure played a part too - or at least assisted the failure.

I say failure, but it hadn’t failed really - the measured clearance was still within an acceptable limit, but it was not what you want on your race engine. The jury is out on the fix, but I will give it some thought, and probably look at the rest of the engine first.

Moving on to the bottom end, things looked much as expected at first. Big end 1,2, & 3 where all running normally. But number 4 had clearly picked up something and was showing signs of distress and failure was not too far away.



Particles were causing little dents and disturbing the wear pattern. Speaking to various suppliers, it seems the VP2 tri metal bearings are designed to behave like this - absorbing any foreign matter (out of harm’s way) and buying you some extra time.

Having looked at many Duratec big end bearings now, I would recommend regular replacements if you are using high RPM on a frequent basis.



The mains looked like a totally different engine: the printing still present and not signs of wear whatsoever. That was a big relief as they are the one item that is difficult to replace due to the numerous grades.

All the journals should be serviceable after a polish, certainly not at a regrind stage yet.


I was curious about the cylinder bores as this was the first engine I've run-in solely on the dyno. The initial results were outstanding on leak-down and BHP. But the second season did seem to take its toll and the last check suggested it had lost a little.



Clearly the bores have done some work, but I can't detect any measurable wear and all the ring gaps are the same as recorded in the build. There's no hint of any bore wash, and the honing marks are still visible, even through the heaviest of wear (more on that later). I'll give some thought as to whether to just lightly de-glaze the bores and rings, or do a full hone and replace the rings.


One unexpected surprise in cylinder 3 bore was a corrosion ring. The car is stored in the dry, and run on a regular basis so I was initially puzzled by it.



But thinking back, there was one occasion that I put the car to bed with a wet filter (it's a foam one). I guess the cylinder with the inlet valve open must have drawn in moist air as the engine cooled. It looks worse than it is, so hopefully it will come out with the de-glaze, or light hone.

But be warned if you have a foam filter - remove it from the air-box if it is wet!


There's not an awful lot to say about the Supertech pistons and Cosworth rods. They all came out with hardly a mark on them, just a hint of slap on the top edge.



But it's clear combustion temperatures were high as they were self cleaning around the exhaust valves. There's no alternative to forged pistons at this level of tune.


Duratecs don't have a reputation for cylinder head gasket problems, so I fitted the standard gasket on this engine. However, on close inspection, there's some evidence of movement and wear.



I think it would be fair to say that the standard gasket will do the job, but it probably has a limited lifespan at these sort of power levels.



Those with a good memory may recall the burr embedded in a cam bearing. When it was removed, it left a sizeable hole. Well, there seems to have been some healing going on, and it looks better now.



This is something I've noticed on aluminium bearings before - they seem to improve with age. The Bearing material seems able to move around to fill the imperfections.


The dismantling of the head concluded the strip-down. I'm pleased to say there were no problems with the valves or followers - nothing more than a light lapping of the valve seats and a clean and polish will be needed.


So what's the conclusion?

I Think I should have done it a year earlier! There's no doubt that once you go to 260+ BHP, the life reduces. At a guess, this engine is wearing out about 10 times faster than a road car engine. Possibly I encouraged the bearing issue with the thinner oil. This does release more power, but ALL your bearings do need to be in perfect condition. Probably something only for the race teams with big budgets, and plenty of spare engines.

The Duratec can be reliable at this state of tune, if not immune, from problems. But I would strongly recommend a seasonal rebuild/check/refresh if you are racing.

Edited by DCL on Saturday 28th November 17:56

panickyjabofoppo

52 posts

110 months

Sunday 29th November 2015
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Great detail, keep it up.

spanky3

258 posts

140 months

Sunday 29th November 2015
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Some really interesting detail in there.. thanks for posting.

BertBert

18,953 posts

210 months

Monday 30th November 2015
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Interesting to compare with a radical hyabusa that is 1500, 260bhp and is refreshed every 40 hours. The 40 hours is all running so a mix of on-load and idling or off-throttle. As a guess out of 40 probably 25-28 is on-load.

How did your 120 hours break down? For 1000 miles is that 15-20 hours on load? Not sure that computes!

Bert

DCL

Original Poster:

1,215 posts

178 months

Monday 30th November 2015
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BertBert said:
Interesting to compare with a radical hyabusa that is 1500, 260bhp and is refreshed every 40 hours. The 40 hours is all running so a mix of on-load and idling or off-throttle. As a guess out of 40 probably 25-28 is on-load.

How did your 120 hours break down? For 1000 miles is that 15-20 hours on load? Not sure that computes!

Bert
At first those figures got me confused too, but when looking at the ECU histogram for RPM, only about 20% was above 4000 RPM (driving RPM) and by far the biggest amount was at idle. So you're right - about 25 hours at high RPM and on load. You could say that if you are more than 130 BHP per litre, then 20 hours track time (racing) is really all you are going to get between re-biulds (if you want to keep it in good condition). Fifty hours would probably guarantee a failure of some sort.

Edited by DCL on Monday 30th November 14:26

JeffC

1,685 posts

211 months

Monday 30th November 2015
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BertBert said:
Interesting to compare with a radical hyabusa that is 1500, 260bhp and is refreshed every 40 hours. The 40 hours is all running so a mix of on-load and idling or off-throttle. As a guess out of 40 probably 25-28 is on-load.

How did your 120 hours break down? For 1000 miles is that 15-20 hours on load? Not sure that computes!

Bert
hmmmmm I was told to rebuild my 1550cc busa motor at 18 hours, I ignored the engine builder and continued to run it towards 20 hours which was all track use and it grenaded itself , was pretty much scrap frown

GreigM

6,726 posts

248 months

Monday 30th November 2015
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So what do you reckon is causing the issues - is the the basic power output being asked of the enine, or is it the high-revving nature (i.e. will I fare better with a lower revving FI engine?)

DCL

Original Poster:

1,215 posts

178 months

Monday 30th November 2015
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GreigM said:
So what do you reckon is causing the issues - is the the basic power output being asked of the enine, or is it the high-revving nature (i.e. will I fare better with a lower revving FI engine?)
It's the high RPM that does the harm. The oil feed to the big ends becomes problematic at high RPM. It has to pass through the main bearings and the center of the crank. The Duratec has some clever drilling of the crank, but this still results in the bearings suffering minor starvation and they get damaged over time. Eventually it will reach a point that the bearing will fail. Usually by getting very hot and melting the bearing material, followed rapidly by big end bolts, or rod. End of engine. The trick is to believe that a seemingly healthy engine will fail if use at high (above 8000) RPM for sustained periods.

A supercharged 7800 RPM limited 310 BHP engine is really not stressed in the same way.


Edited by DCL on Monday 30th November 20:08

dsl2

1,474 posts

200 months

Monday 30th November 2015
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Very interesting stuff, thank you for sharing your engineering prowess!

BertBert

18,953 posts

210 months

Monday 30th November 2015
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JeffC said:
hmmmmm I was told to rebuild my 1550cc busa motor at 18 hours, I ignored the engine builder and continued to run it towards 20 hours which was all track use and it grenaded itself , was pretty much scrap frown
Obviously not RPE then biggrin Although they are not perfect, I think that between me and Miss Bert we only totaled one engine and that was a 1300 with no history, had probably done a million hours and was driven by, well, [whisper]a girl[/whisper] if you get my drift!

JeffC

1,685 posts

211 months

Tuesday 1st December 2015
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BertBert said:
JeffC said:
hmmmmm I was told to rebuild my 1550cc busa motor at 18 hours, I ignored the engine builder and continued to run it towards 20 hours which was all track use and it grenaded itself , was pretty much scrap frown
Obviously not RPE then biggrin Although they are not perfect, I think that between me and Miss Bert we only totaled one engine and that was a 1300 with no history, had probably done a million hours and was driven by, well, [whisper]a girl[/whisper] if you get my drift!
my first ever 1300cc standard Busa managed 7,000 track miles when I sold it and never had one issue in that time that was back in 2005 and the engine is still going strong today although its only done road miles since I sold it ! my experience on bike engines is leave them standard !

GreigM

6,726 posts

248 months

Tuesday 1st December 2015
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JeffC said:
my first ever 1300cc standard Busa managed 7,000 track miles when I sold it and never had one issue in that time that was back in 2005 and the engine is still going strong today although its only done road miles since I sold it ! my experience on bike engines is leave them standard !
I'd second that - I hammered my standard busa for about 4 years and only once replaced the shells/bearings (as the scavenge pump failed and thought it was wise), I then sold the car and the new owner has hammered it for another 2 years with absolutely no engine issues and still putting out enough grunt to get him round the 'ring in 8.04.

BertBert

18,953 posts

210 months

Tuesday 1st December 2015
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back on topic, my first reaction was that I would have expected more run time from a Duratec. Not from any experience or technical view, just from its bullet-proof reputation and my experience in Radicals - although not directly comparable.

Very interesting and thanks very much for sharing DCL!

Bert

DCL

Original Poster:

1,215 posts

178 months

Tuesday 1st December 2015
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This engine was being used as a bit of test bed. Also some further investigation suggests that number 4 big end may have been carrying a fault (more later). So the figures above are maybe a bit conservative side for the Duratec.


BertBert

18,953 posts

210 months

Tuesday 1st December 2015
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Yes #4 big end looks nasty, especially when compared to the mains. As you say close to proper failure!
Interesting to find out more.
Bert

DCL

Original Poster:

1,215 posts

178 months

Tuesday 1st December 2015
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Going back to number 4 big end. I had assumed that it had picked up something from the oil, but a close examination of the crank showed that it was a knock on the edge of the oil way that seemed to be causing the damage. Although small it did protrude more than the photo suggests. That raised the question about whether this was something I had done, SBD when the machined it, a hard particle in the oil jamming while it was running, or simply a result of coming out of the factory like that. It was a new crate engine before I upgraded it, and I still had the original shells, and sure enough, number four has a scratch.




But it cleaned off and all the jounals polished up quite nicely so I'm confident it is a problem resolved. But it just goes to show that you can never take anything for granted. It probably happen very early and survived 2 seasons like that but it shows even new factory engines can have faults. In fact, rebuilding a good second hand engine is probably a better bet in terms of reliability.




Megaflow

9,345 posts

224 months

Monday 7th December 2015
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When you say you ran a thinner oil, how thin and what does the duratec take as standard.

DCL

Original Poster:

1,215 posts

178 months

Monday 7th December 2015
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That's a tricky question! There's too many factors to answer simply but here goes (IMHO) . . .

Taking the standard engine first; it's designed to run on a 5w30. For a 2L engine that was quite ambitious, and was one of the factors that make the Duratec a it highly efficient engine. To achieve it, the factory engine uses graded bearings to keep tolerances within a very tight spec.

But when you tune the Duratec it is difficult, to maintain such tight tolerances with up-rated aftermarket bearings. In fact, it often desirable to increase clearance as the engine will tend flex and expand more as the level of tune increases.

So it tends leaks more oil from the bearings and it's normal to use a 5w50 oil once you raise RPM and power significantly. For racing a 10w50, or even a 10w60, is need to give a similar level of protection as a standard engine using 5w30. However, you can gain some power by using thinner oil and accepting a shorter engine life.

This year I used a 5w40, which is fine for sprint events, but maybe not for longer track sessions. it certainly added to the cost of this refresh and was probably not worth it - unless your budget is not a problem of course.

k20erham

372 posts

125 months

Monday 7th December 2015
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Hi not that you need the tip, but just look at all that lint/fibers on the crank casting from your clothes/rags, it's a bugger to get off, lovely analysis and reporting, look forward enjoying the next chapters, glad you managed to avoid any damage.