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2.0L Duratec Rebuild


JohnCh
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I'm very late starting a thread on my engine rebuild, so I'll begin with posts over the next couple of days to catch up everyone on the status. For background the oil pressure relief valve appears to have failed, taking with it the mechanical oil pressure gauge. The simple solution was to replace the gauge and the oil pump and quickly get back to the end of blatting season, but sadly I don't do simple. Instead, I've opted to do things the slow, pricey, hard way with a full rebuild and performance upgrade. My garage is now in chaos.

 

Garage-sm.jpg

 

The first 8,500 miles of my 2.0L Duratec's life were covered with stock internals, while the last 24,000 were with Kent DTEC10 cams, stiffer valve springs, some head work, and ARP Rod bolts. For the latest iteration, cams are changing to DTEC20s, pistons to Omega (11.7:1 vs. stock Mondeo 10.8:1), rods to forged items from K1, crank will be keyed and the bottom end fully balanced. The goal is 225-230hp, with limited torque loss from 2000-3000 rpm, similar torque from 3000-5000rpm, then a noticeable jump from there to 8000rpm with the ability to rev higher if needed.

 

Cam selection was a struggle. After much internal deliberation, protracted mulling over specs, and multiple conversations with people of various expertise, I decided that for my specific goals, DTEC20s were the right choice. Interestingly, feedback from everyone but Kent was consistent: if you are going through the effort of changing pistons so you can add more lift than DTEC10, you should step up to cams that can support 250+ hp. Although Kent makes cams in that category (the DTEC35 are essentially the R500 cams and they have even more aggressive grinds available) they alone told me I wouldn’t be happy with the bottom end of anything with that much overlap. Also, and this is something that particularly resonated with me, the gap between the DTEC20 and DTEC 10 is much larger than the gap from stock Mondeos to DTEC10. Since I previously make that switch and was pleased with the performance increase, it seemed to me that the jump to DTEC20 would suffice.

 

The chart shows how the various cams under consideration compare and includes the stock Mondeo cams and DTEC10s for baselines.

 

cam table.jpg

 

-John

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Although the engine came out without issue and initial disassembly went well, it did reveal the first potential problem with engine health. As covered in this thread, the throttle body for #1 and to a lesser degree #2 had a lot of carbon deposits and there was evidence of overfuelling or blowback of unburnt fuel. There is nothing obvious about the cause but the engine had intermittent misfire issues throughout the years that were eventually traced to a failing engine loom that was subsequently replaced 2years ago, so perhaps this is simply the result of that old problem?

 

Things turned a bit south when it was time to remove the windage tray that forms part of the Raceline wetsump assembly. It attaches to the mains girdle via five M6 dome head screws held in place by red loctite. The problem is twofold; first,the all alloy girdle and block create a giant heat sink, so it takes a lot of heat on the screw head to get the loctite to the proper temperature to release. Second, the tops of those little dome headcap screws become soft when heat levels are too elevated and subsequently strip very easily. Although I was able to remove two of the five, I had to call in a mobile welder to attach 4mm hex sockets to each remaining screw to aide removal.

 

windage tray.jpg

 

windage tray bolts sm.jpg

 

To avoid this issue in the future, the screws for both windage trays are being replaced with Torx Plus dome head screws from McMaster Carr. The drive profile enables the application of a lot more torque before stripping than the hex drive head of the stock items. Or at least that's the working theory.

 

With the windage tray out of the way, the crank, rods, and pistons could finally come out for inspection. Not all was as good as hoped. There is some burnishing on the middle crank main journal that is not visible on the mating bearing surfaces and does not go all the way around journal. Not sure what caused this or if it's a problem. Next, there is some odd staining on the bores of #1 and #2 that looks similar to water spots on glass. Closer examination also shows some damage to #1 in the form of small gash running horizontally about 2" down from the top that easily grabs a fingernail, but is difficult to photograph. The Duratec block can safely be over bored by 0.5mm, so I'm hoping that is more than enough to clean things up. If not, it's time for a new block.

 

crank sm.jpg

 

bore issue.jpg

 

-John

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Possibly, but from what I've seen replacement blocks are cheap, so probably not worth the effort. I'll know more once my slot opens up at the machine shop. BTW sorry for not taking your suggestion of titling this thread "Eye Candy" but I thought Croc might take that as an invitation to start posting selfies.

 

-John

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Part of the plan for this project is to correct a few things I never liked with the original engine installation. Back in late 2003 when the order was placed with Raceline for the Duratec conversion parts, I was only the second person to try their kit in a Westfield and the first one with a LHD car. This created unexpected problems like an alternator mount that placed the alternator directly inline with the steering column, a header that fouled the right front wheel on full lock, and engine mounts that were out by a couple of inches on my frame. The local shop that was hired to build my roll bar was also engaged to make a replacement header to Raceline's specs (kind of a long story that may get covered later) and craft new engine mounts based on the Raceline items. Unfortunately when they fabricated the engine mounts, I hadn't yet installed the dipstick tube. Not a big deal, right? Well, when trying to install that part a few weeks later, I discovered their design placed the left hand mount directly over the dipstick port in the Raceline sump. My workaround was a hand formed copper tube attached to a pressure fitting that threads into the port. Although it worked, it didn’t look very professional and always bothered me. The replacement uses a flexible 6AN PTFE hose with a 30 deg fitting that just clears the engine mount and can be easily snaked around the engine mount up through the DTHTBs and looks much better.

 

dipstick sm.jpg

 

Next on the annoyance punch list is rectifying the lack of a low oil pressure switch and finally installing the mechanical oil temperature sensor that has spent the last 15 years recording under bonnet temps. When designing the interior and dash, I went with Racetech mechanical gauges including a dual gauge for oil pressure and temp. What I didn’t realize until the installation is that the mechanical temperature bulb is big and the only mounting option with my setup was a modified sump plug. For some reason I always put off doing that mod until now. The plug was drilled and tapped to accept the 5/8-16 end of an adapter that mates with the Racetech's 3/8 BSP fitting.

 

oil temp sensor bung sm.jpg

 

The pressure switch was another challenge. Heck, just attaching the 3AN fitting at the end of the hose that fed the pressure side of the gauge was a PITA back in the day. The Raceline oil filter plate uses an M12 port. At the time, I was unable to find an M12 to 3AN adapter, so something was cobbled together from 3 fittings that (going from memory) took it from M12 to 8AN, 8AN to 6AN, and finally 6AN to 3AN. Fast forward to today, when Pegasus comes to the rescue. First, they now offer an M12 to 3AN adapter. Second, they have a 3AN female to 3AN male coupler with a 1/4 NPT port on the side -- perfect for taking an oil pressure switch. Here are the old and new adapter setups:

 

oil pressure adapter.jpg

 

-John

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Speaking of the block, as per the Cosworth CSR260 assembly manual, various areas including the mains bearing journal edges, head oil drains, and mains oil feed drillings were de-burred. Here are some before and after photos. As you can see, the state of the head oil drains was pretty nasty. Whether this clean up actually makes a difference, I can't say, but it's easy to do with a small file and a Dremel. If a new block is required, then I get to do it again. BTW for some reason when I copy and paste the text for these posts from another app, the space between random sets of words disappears which doesn't help readability. Apologies if I missed any. I should find an admin and complain...

 

Before:

block before.jpg

 

oil drain before.jpg

 

and after

block after.jpg

 

oil drain after.jpg

 

-John

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I was just questioning the degree of improvement. Better oil flow is a good thing, but it's not clear to me if this is fixing an actual problem with the Duratec (i.e. stock oil flow is insufficient at this rpm level) or just an improvement in the strictest sense that doesn't make a practical difference.

 

-John

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I was just questioning the degree of improvement. Better oil flow is a good thing, but it's not clear to me if this is fixing an actual problem with the Duratec (i.e. stock oil flow is insufficient at this rpm level) or just an improvement in the strictest sense that doesn't make a practical difference.

 

-John

 

All the Nth degree things. Sometimes you know, sometimes not. A friend was big into turbo charging engines and started to have his intakes, ports, etc. honed with an abrasive slurry (forget the name of the process). Conventional wisdom was that this is a waste of time, since the turbo will push as hard as needed or tolerable, but in the end it did yield HP. PS: Ferrari boxer engines.

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Excellent thread - we have not had a good engine build thread in a long time. This will put you in the sweet spot of engine power/torque for a road-focused seven that does the occasional track day. Any more and you lose your license the moment you wind out second gear.

 

Shane - Not sure you want to sleeve a Duratec block - they are pretty thin walled to start with. Sleeving works well on the older engines with a ton of excess metal and less fine tolerances. Fortunately, they are cheap to buy.

 

John - You should link the CSR260 engine build manual to this thread or attach it (preferably). Lots of good information in there that I had forgotten about. Pity all those nice photo icons are so small.

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Raceline used the dome head screws due to clearance issues, so not enough room to use that option. The Torx head replacements should do the job, and if not, I'm keeping the phone number for the mobile welder on file :)

 

Mike, someone provided a link to the Cosworth manual on another thread. I'll see if I can find it and add it here. Unfortunately the copy I downloaded is too big to attach to a post.

 

EDITED: Found the link: http://duratecindetail.com/pdf/CSR260_Build_Manual.pdf

 

-John

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One interesting realization for me when looking at the Cosworth build manual is that there are physical design differences between the 2.3L and my 2.0L block. If you compare the left side and right side oil drains on the 2.3L as captured in the screenshot from the Cosworth manual, you will see they are different, whereas they are mirror images on my 2.0L. I wonder if this is a a running design change on all Duratec blocks or is a consistent difference between the 2.3L and 2.0L?

 

[ATTACH=CONFIG]16170[/ATTACH]

 

-John

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John,

 

I'm no expert, but Ken at Cosworth told me the CSR motors used a Ranger block with a Focus head, as there were differences in blocks and heads for those two applications. He said the truck block lacks the counterbalance stuff and the car head breathes better. There may be other differences he didn't mention. This may account for the difference you're seeing?

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One of the reasons I'm at this stage for what should have been a simple oil pump change, is my aversion to the Duratec's lack of a key to lock the crank pulley and cam chain sprocket in place. Although the factory design, which relies entirely on friction washers and clamping force to keep things in place, does work, it's all too easy for a klutz like me to allow a degree or two of slippage when torquing down the bolt, thus affecting timing. It's also a little tough to do that process with the engine in the car or do it solo. Keying the crank assembly resolves those issues and provides additional assurance that no slipping will occur over time.

 

There were a few options to have this work done. To minimize the risk of things turning out badly, I opted to buy pre-keyed crank pulley, timing chain sprocket and 3mm key from SBD in the UK, and then have a local machine shop cut the keyway in the crank to SBD's instructions. This approach added about $150 to the total, which I view as cheap insurance. As to why my aversion got me to this stage? Well, if you're going to remove the crank to key it, you might as well remove the pistons and rods and balance the assembly. If the pistons and rods are coming out, might as well replace them with something better. If new pistons that allow for greater valve lift are going in, it would be a shame not to replace the cams to take advantage of that. As long as bearings and seals are removed, replacement with new is an easy decision. Of course if those things are new, it would be a shame if another consumable like the water pump or clutch slave cylinder went out shortly after the car was back on the road, so might as well replace those too. Etc. Etc. Etc…

 

keyed assembly sm.jpg

 

John - Czar of the Slippery Slope

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With the engine out of the way, this is a good time to clean up the under bonnet area. First up was removing the peeling aluminized heat barrier cloth from the exhaust side of the tub and replacing it with gold heat reflective film. The heat cloth was originally affixed to the inside of the tub to protect the fiberglass from the heat of the primaries which are snaked into a very confined area. The gold film is supposedly just as effective as the aluminized cloth, but is a little lighter, and adds a touch of under-bonnet bling. I'm all about the bling.

 

tub heat shield.jpg

 

The header situation was foreshadowed in an earlier post. As previously mentioned, the header from Raceline fouled the right front wheel on full lock. Raceline decided it was better for me to have a local shop fabricate the replacement with my car on hand to ensure it would fit, rather than remake it themselves to measurements I supplied. The shop used the Raceline header for tubing diameter measurements and followed Raceline's instructions for tubing length. This is where things got interesting. Raceline explained that a Westfield has slightly more room for the secondaries than a Caterham, but for manufacturing simplicity, their Caterham and Westfield manifolds share the same dimensions. However, secondaries longer than supplied were better for performance. Given my car theoretically had room for slightly longer secondaries, they instructed the shop to make the primaries to their standard 30-31" length and the secondaries "as long as possible."

 

The thinking was that my setup would gain perhaps 2" in secondary length. Seems simple enough, right? And remember, the shop had the original Raceline-supplied manifold on hand for a pattern. Imagine my surprise when I arrived at the shop to admire their work only to discover this:

 

header.jpg

 

It seems they had taken Raceline's instructions as a challenge. Rather than follow the template of the Raceline header, which had gradual bends and placed about 1/3 of each primary tube outside the tub, they opted to snake the primaries to such a degree that those tubes and the collectors fit inside the tub allowing them to really make the secondaries "as long as possible." In this case that's about 21".

 

Consensus among various Duratec tuners is this extreme length is probably costing power, but because no one seems to have tested such a setup on the dyno, it's not clear if it's a lot, a little, or if it is actually bumping up other areas of the torque curve with minimal impact to peak power. Next year, I plan to have this remade to a more conventional design with slightly larger tubing to take advantage of the cams, but first I'd like to spend some time becoming familiar with the new torque curve and extensively researching exhaust manifold design.

 

-John

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The gold film is supposedly just as effective as the aluminized cloth, but is a little lighter, and adds a touch of under-bonnet bling. I'm all about the bling.

 

 

Duratecs pump out a lot of heat. Is there a body melting temperature that you have to worry about? Never thought of that until reading your post?

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Purely down to paranoia and cheap insurance. I knew that portion of the tub would be subjected to a lot of long term heat and I was concerned that over time there might be some discoloration or slight deformation of the fiberglass. I never would have done it if the primaries weren't snaked into that area so tightly.

 

-John

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