2.4L Duratec

[JohnCh]

Time for another engine build thread!  For my incoming 420R, I'm swapping the 2.0L Duratec for a 2.4L version based on a short block from Esslinger Engineering who has a ton of experience building race and hot street Duratecs.  Unlike my last engine build, where I started with an existing engine, stripped it down, then upgraded everything, this time I'm assembling the engine from scratch.  Some aspects, such as having Esslinger supply one of their special sauce short blocks rather than me playing general contractor with the machine shop and various suppliers, should be easier.   Other aspects, like trying to use cryptic online parts sites to figure out all the little parts and fasteners needed to assemble a ready to-to-fire engine has been…well, less easy.

 

The short block is the heart of this engine.  Esslinger starts with a new 2.5L block from Ford, then performs a laundry list of machining operations and upgrades before adding a 2.3L forged crank with balance shaft delete, 12:1 pistons custom manufactured to their spec (shorter height with marginally larger bore (+ 0.078mm) and stout 0.886" wrist pins) and longer H-Beam rods to improve rod ratio. The entire rotating assembly, including the flywheel and pressure plate, is fully balanced, and the crank pulley is keyed.  The end result is a 2344cc engine vs. 2269cc for the stock 2.3L and 2488cc for the 2.5L.

 

Engine	Bore	Stroke	Bore/Stroke	Capacity
2.0L	87.5mm	83.1mm	1.054	1999cc
2.3L	87.5mm	94mm	0.931	2261cc
2.5L	89mm	100mm	0.890	2488cc
2.4L	89.078mm	94mm	0.948	2344cc

 

 

 

For the top end, I've purchased a new 2.5L head from Ford and sent it off for porting using starting specs provided by Raceline.  Cams, stiffer valve springs and Titanium retainers are also from Esslinger.  After much deliberation, I settled on their non-VVT Stage 4.  These are an asymmetric setup with different profiles for the intake and exhaust:

 

Intake:    0.460" (11.68mm) lift & 246deg duration @ 0.050"

Exhaust: 0.429" (10.9mm) lift & 235deg duration @ 0.050"

 

Air intake is handled by Jenvey 50mm Direct-to Head Throttle Bodies, and exhaust (for now) is stock 420R.  Dry sump is from Raceline who also supply the light flywheel, clutch, and a bunch of other parts necessary to prep the engine for a Seven.  With a properly sized exhaust, the engine should make ~270hp, but even with the smaller-than-optimal 420R exhaust, output should fall into the 250-260hp range. 

 

-John

[JohnCh]

First step after mounting the block on the engine stand was assembling the dry sump.  In lieu of instructions, Raceline sent several photos to help me figure out which part goes where and confirmed the torque settings in my wet sump assembly manual still apply.  After cleaning the sump, the various parts -- of which there were surprisingly many -- were attached and it was ready to dry fit to the block to ensure there were no issues.  Guess what?  Yep, issues.  Esslinger advised me to save my money and stick with OEM Main bolts as the ARPs aren't needed unless it's a boosted Duratec making more than 500hp.  Typically, I prefer to waste money and overbuild things, but this time I decided to be fiscally responsible and take their advice.  Bad choice.  It turns out the heads of the OEM bolts are really tall (>15mm), and although they would present no issue for a wet sump, they foul the dry sump pan as seen in the photo.

 

 

I'll call Raceline and Esslinger in the morning to figure out the underlying issue and how to address.  My suspicion is ARP main studs are much shorter and I'll need to swap them in.  I suppose the other possibility is Raceline sent me the wrong dry sump pan.  They do call out a specific version for the 2.5L, but I have no idea if that is for marketing purposes or if there really are design tweaks.

 

-John

[ashyers]

John,

Looks like fun!

 

If it makes you feel any better, I had to trim a few of the ARP studs to fit the dry sump to my engine. They needed to be flush with the pan rails so the scraper and windage tray would fit.

 

I look forward to seeing how this all works out. It should be a really fun engine, big displacement and revs .

 

Andy

[JohnCh]

Andy, was that the Raceline dry sump?   I'm looking forward to seeing how this works out too  

 

-John

[ashyers]

John,

It was a Pace dry sump, but I have a Raceline sump in the Shop. They're very similar as far as the scraper and windage setup.

 

I chucked the studs up in the lathe and trimmed them a bit for clearance. I suspect you could do the same with the bolt's heads with no ill effects.

 

Andy

[JohnCh]

I just got off the phone with Peter at Raceline.  He confirmed the ARP main studs aren't needed and as Andy notes, do require a little fettling to fit the dry sump pan.  However, because Ford won't sell the OEM main bolts in the UK, he only has experience with the Mazda equivalents they use instead.  While we spoke, he measured the height of the head on a spare bolt sitting on his bench; it's only ~10.5mm high, so much shorter than what I have and fits without any clearance issue.  I'll call Esslinger later this morning once they open.

 

-John

[JohnCh]

The mystery of the main bolts is solved.  The OEM items were suddenly hard to get due to supply chain issues.  Rather than delay my short block build any further, Esslinger opted to use a different OEM bolt from an Ecoboost that shares the same critical dimensions.  The one difference is head height.  For the Ecoboost application, Ford uses a taller head that is drilled and tapped to receive a small fastener.  Esslinger now has the OEM main bolts on hand which measure under 8mm high and should fit without issue.  Once those arrive, I'll swap them out and get on with the build. 

 

-John

[JohnCh]

The replacement main bolts arrived from Esslinger yesterday and went in this morning.   The sump pan now fits correctly and is installed along with the oil pump.  

 

 

 

After taking care of that, I swung by Beachman Racing to pick up some of the parts I've ordered for my custom dash setup.  While there, I had the opportunity to see a Caterham with the new rear LEDs installed.  To my eye, they look better in person.  The big surprise though was the new reversing light built into the same fixture that houses the license plate light.  Insanely bright!  It will be hard for someone to miss when backing out of a parking space.

 

-John

[John B]

I'm following this build with interest. First of all, I love engine builds. Secondly, I've already gone down the 2.4 Duratec road myself. Will this engine be dyno'ed? If so, I'll take the over on 270 hp 

[JohnCh]

@John B I've looked at your Hasselgren 2.4L thread on more than one occasion   From the dyno picture, it looks like you're using shorter air horns with the roller TBs to keep everything under the bonnet.  Is that correct?

 

Once the Caterham is done, it will go on a chassis dyno.  270hp should be more achievable based on the spec, but initially the stock 420R exhaust will likely cap the fun below 260hp.  My plan is to drive the car in what I'm referring to as restrained-mode for a while and see how it goes.  If I'm scaring myself silly, then I'll leave things as-is.  If not, then I'll explore longer air horns with a through bonnet filter and/or a custom exhaust manifold and Raceco exhaust.   

 

I received the following message last night from the shop doing my head:

"I just finished the last of the flow testing tonight after a few days of trying to pull out some reasonable gains without getting carried away, and I am happy to tell you it was worth it! You should easily meet your performance target and everything is coming together well." 

 

It sounds like it will arrive here next week. The next hang up is the mechanical timing chain tensioner which is still dragging from Raceline.  I spoke to Peter again this morning who promised to get something sorted soon.

 

-John

[JohnCh]

Finally picking this back up after some unavoidable issues meant the head didn't arrive until 10 days ago. Last weekend after installing the ARP head studs, dropping the head gasket and head into place, then coating the washers and nuts in ARPs lube, I began placing those last two items onto the studs in preparation for the torque sequence.  That's when I discovered there were 10 studs, 10 washers, but just 9 nuts.  I didn't count the nuts before opening the bag so I can't confirm I was shorted, but I did it all in one area of the bench and searched everywhere afterwards.  Either it is shacking up with all my missing socks or it never made the trip.  Regardless, a replacement was ordered and arrived Friday. 

 

Head and cams in place and torqued:

 

Below is the factory VVT front cam cap setup. Unlike the non VVT engines, which use separate caps for each cam, this uses a one-piece cap for both and has provision on the intake side for a solenoid that drops into the downward facing port on the right.  The Raceline VVT delete replaces the factory solenoid with a machined part with journals that maintain oil to flow to the intake cam journal. 

 

 

Because I purchased a new, bare head, the pivot pin for the timing chain tensioner arm needs to be installed, but that turns out to be a very tight fit. Before trying to configure some type of press, it's getting an overnight soak in the freezer with attempt number two happening in the morning.  

 

One of the interesting things about the 2.5L engine is it doesn't use a lower guide for the oil pump chain but does use a larger tensioner.  The first picture below is from the CSR 260 engine assembly manual. Although Cosworth doesn't use that guide with their dry sump, you can see the two bolt holes for mounting it circled in red.  The second photo is my engine and as you can see, there are no holes.   

 

 

 

 

If I have time tomorrow, I'll time the cams and button up the engine.

 

-John

Edited February 27, 2022 by JohnCh
Fixed photo issue (I hope!)

[Croc]

13 hours ago, JohnCh said:

If I have time tomorrow, I'll time the cams and button up the engine.

 

 

I can predict confidently that will not happen.  I predict that some good looking chap with a big bag of doggy treats for the furries will arrive to disrupt you.  

[JohnCh]

1 hour ago, Croc said:

I predict that some good looking chap

 

I didn't realize you were bringing someone with you.  Thanks for the heads up!

 

-John

[JohnCh]

The pivot pin for the tensioner arm went in this morning. Between putting the pin in a deep freeze overnight and heating up that section of the head with a propane torch, it didn't take too many taps with a hammer to drive it in place. Once that was done, the remainder of the timing assembly was installed, along with the water pump and thermostat housing. However, as @Croc predicted, I didn't have time to dial in the cams.   Hopefully that happens next weekend.

 

 

-John

[JohnCh]

I've had a few self-inflicted delays to finishing up the engine.  First was indecision over a mechanical timing chain tensioner vs. the factory hydraulic version, then was a realization that I forgot to order a replacement degree wheel.

 

I'll go into some detail on the timing chain tensioner in this post since it might be of interest to anyone contemplating building a Duratec. Most of the UK Duratec tuners recommend a mechanical version of the tensioner as the plastic teeth on the hydraulic version's ratcheting mechanism can supposedly break when the throttle is abruptly lifted at high rpm.  The mechanical versions swap out the ratcheting mechanism for a bolt and lock nut setup as illustrated in the images shamelessly stolen from the internet. On the left is the stock hydraulic tensioner with the ratcheting mechanism extended. On the right is a mechanical tensioner that replaces the ratcheting component with a bolt.

 

 

My 2.0L uses a mechanical tensioner I purchased from Raceco many years ago.  I had one on order from Raceline for this engine, but after 7 months of waiting for production, I decided it was time for a rethink.  Speaking with Esslinger, they felt the factory unit is fine provided it's the older style cast iron version rather than the new aluminum item Ford currently supplies.  Given they have extensive experience building and refreshing race Duratecs, I decided to follow their recommendation and a cast iron item was ordered (Melling still manufactures this as part #BT5514.)  I then made the mistake of cruising Caterham's parts site one evening.  It seems they also used a mechanical tensioner for the R500 (the one pictured above) and had some in stock.  Hmm… Deciding to err on the side of caution, I placed the order and triggered my first delay
 

After the new tensioner arrived from Caterham sans instructions, I dug up the old email from Raceco that explained how to set the tension. It contained a line that didn't apply to my 2.0L installation so never stuck in my memory: 
 

"I prefer to use a good used chain. If you use a new one it will initially wear quite quickly and the chain will need to be re-tensioned which involves a timing cover removal. "

 

I have no desire to go through the hassle of pulling and resealing the front cover shortly after getting the car on the road, so I've decided to stick with the hydraulic version for now, then swap to the mechanical tensioner the next time I pull the engine.  In the meantime, I'll see if I can take some chain deflection measurements to monitor over time as an indicator of broken teeth. 

 

-John

 

[JohnCh]

The next delay was down to forgetfulness.  I had planned to order a new degree wheel for this project; something I failed to do.  The Kent Cams wheel I've used in the past is small (<6-3/4") which means the difference of 1/2 degree on the wheel is really tiny and requires a lot of care to ensure timing is just right.  A larger wheel has greater spacing between the degree marks and is therefore a little less frustrating to get correct.  
 

As long as I was waiting for the new wheel to arrive, I thought I'd mock up and 3D print a better degree wheel pointer option than using an old piece of solid strand wire wrapped around a bolt.  The plan is to use the factory TDC bolt to put #1 at TDC, center the degree wheel so the pointer is on 0, then remove the bolt and confirm TDC with the dial indicator.  If it's off by a small amount, simply loosen the thumbscrew and slide the pointer to the correct position on the wheel.  It seems this will be less frustrating and more precise than re-bending the wire or repositioning the wheel.  

 

 

 

I hope to finish the engine work this weekend.

 

-John

[JohnCh]

I realized I never updated this thread.  Although life got in the way a bit, the engine is effectively done and ready for installation.  The cam timing setup worked well after a slight redesign to how the wheel attached to the crank pulley.  The initial design used a bushing that allowed a tiny amount of slip when the crank bolt was rotated.  The new design rigidly attaches the wheel to the pulley with bolts that fit through new holes drilled in the face of the wheel which align with existing holes in the pulley.  I also made a slightly different version that allows me to use the setup with the front cover in place as shown below.  If you haven’t already joined the 3D printing movement, it’s worth exploring.  Lots of things you can design and make that help out in the garage.

 

 

Initial cam timing was set to Esslinger’s specs, but we’ll use the adjustable cam gear verniers to play with that on the dyno.  I’ll reiterate something from my 2.0L build thread; buy a good quality dial indicator and adjustable holder.  They make the job a lot easier and infinitely repeatable.  Also, a bigger degree wheel helps.  In my case, the new degree wheel's spacing between degree markers is over 60% wider than my old wheel from Kent Cams, making it easier to get a precise measurement.  I tapped out after getting the cam timing less than 0.25 degrees from target, although TDC was dead on.  

 

There were only a couple of minor issues with the remainder of the assembly, with the two big ones related to the multiple versions of the Duratec that exist.  First was bolt length for the front timing cover.  Since I am using the front cover from a Mazda based on the recommendation from Esslinger, I also ordered the bolts from the dealer at the same time.  When torquing them in place, it was clear there was a slight issue with one that screwed into the Raceline dry sump pan.  After disassembling everything, it became clear that the Mazda bolts were a few mm longer than the Ford version (28mm vs. 25mm.)  Although this didn’t matter when screwed into the mating holes in the block and head, or into two of the bolt holes in the Raceline plate, it was about 1mm too long for that remaining hole.  Next was the bolt length for the water pump pulley fastener.  I purchased the water pump, pulley, and bolts from the same Ford dealer; however, the bolts were too long and fouled on the water pump.  Both issues were easily addressed with new, shorter bolts.

 

 

I still need to decide on injector location.  I’m leaning heavily towards mounting them in the Jenvey’s this time around and have temporarily installed them in that location.  Until I am certain though, I’ll hold off on installing the aluminum plugs that seal the unused ports.  For now, I’m sticking with the 40mm velocity stacks with the plan of a cold air induction system with no hole in the bonnet, but I will probably print up a set of 93mm stacks (the other size available for the 50mm Jenveys) to test on the dyno.  If that makes a big difference in an area I wish to improve, then I’ll buy the longer stacks and cut the bonnet.  E.g. if it produces a big torque bump at 4000rpm, but I’m finding that torque in that area is already as much/more than I want, then no point in making the change, but if I want more in that area, then longer stacks go in.

 

 

-John

[Pokey]

Thanks for sharing John!

[ashyers]

John,

I'm curious about the front cover you're using. I still have the Ranger cover and at some point would like to replace it with a version w/o the fan pulley in the middle. Do you think the cover you're using will work on an older 2.3? If so do you have the p/n and source?

 

Thanks!

 

Andy

[JohnCh]

My understanding is the 2.3L and 2.5L are interchangeable, but I would confirm that using a Ford parts search.  As I recall, Esslinger uses this particular cover because it has a port over the timing chain tensioner that enables you to insert the pin that holds the plunger in place.  My 2.0L has this same port, so my guess is that Ford may have removed it at some point, and Esslinger standardizes on the Mazda item which continued to use it.  

 

The Mazda part number is: L3AW-10-500.  However, the part I received from the Mazda dealer (mazdaswag.com) was hideous.  The worst new casting I have ever seen.  After receiving my photos, they confirmed another recent sample sent by Mazda was in the same condition and appears to be the new norm.  To their credit, they refunded my money without any pushback -- really good customer service.  I then purchased a used one from a wrecking yard and spent time cleaning it up.  That casting was much, much better.

 

-John