Tear Down and Rebuild of My R400 Duratec Engine

[mph]

Nothing to say, except posting so I can subscribe to the thread It's fascinating to follow — thanks for posting all the details James!

(My R400 is the same age as yours, and therefore I suspect has the same engine. Albeit mine has now been fettled by PPE — 170+ torques, 230hp+ at 7600, on E10 fuel. I was happy with that outcome)

[aerobod - near CYYC]

I'm trying to finalize the piston compression ratio at the moment.

I'm currently tending towards the Supertech P4-DU88-P7 pistons with the following characteristics on the 2.0 Duratec:

Bore 88.0mm

Stroke 83.1mm

Dome volume 7.8cc

Head compression volume 42cc

Static compression ratio 12.6:1

If I combine this with the Kent DTEC35 / Raceline RLD250M cams, the inlet valve timing gives a closing at 68 degrees ABDC, leading to a dynamic compression ratio of 9.7:1 at sea level or 9.0:1 at my typical 1000m track altitude, with a 12.9 bar / 190 PSI cranking pressure. I'm thinking I should be safe with this sort of compression ratio and moderately aggressive timing running on 93AKI / 98RON fuel.

I think if I dropped to a lower compression piston, I'm leaving a fair amount of top end power on the table.

Any thoughts on my estimations and logic on compression choice?

[7 wonders of the world]

Hi James,

Pistons are fine no issue there same model I use albeit mine are standard bore

Bearing in mind these cams are based on power figures achieved at lower altitude so you are likely to see circa 10% less at 1000m.

Are you planning on reworking the head or leaving it standard, a little work as in my previous mail will yield good results, I would also consider the longer duration of the detec45 cams too.

Your calcs are based on the timing figures Kent list however in reality they normally require more Lift @ TDC

 

[aerobod - near CYYC]

Hi Neil,

I will be aiming for sea level power outputs in The 240-250bhp range, too much more work to hit that at 1000m and not up the rev limit above 8200RPM, but I will advance the timing to benefit from 98RON/93 AKI at altitude and look at using higher octane or an octane booster if I do track days in BC where the best tracks are at more like 300m altitude.

I will do some head work as you suggest. From a cam and throttle body perspective, I will probably follow the Raceline Duratec-R 250 parts inventory, using their RLD250M cams, which are close to the D-TEC35s. If I go with a higher duration cam (such as the D-TEC50, as they don't seem to have the D-TEC45 in their catalogue at the moment), it will drop my dynamic compression ratio from 9.0:1 to 8.3:1 and cranking pressure from 190 to 172PSI at 1000m altitude. The D-TEC50 cams are also optimised for power up to 8500RPM, but I will keep to my 8200RPM limit to see if it will help me get to 20,000km of hard track use before a rebuild.

I will chat with Chris when I finalize the Raceline parts order and see what he thinks about a more aggressive cam (such as their RLD270M) and see if I can still maintain the power, rev limit / longevity and drivability goals.

[7 wonders of the world]

Hi James,

Kent still list the d-tec45 cams, understand what you mean about the DCR falling however this is only due to the increased overlap however you will reap the rewards higher up as the scavenge effect comes back to benefit you, these gains can best be seen on the rollers where inlets lengths etc can again be altered to maximise your investment

Used the d-tec45 a couple of times with good resutls though not with Kents timing figures !

[aerobod - near CYYC]

Hi Neil, I will see what pocket size the pistons have and what Chris can offer as a Raceline package that is similar to the D-TEC45 (also being cognizant of the limitations of the stock Ford valve size and strength with a higher lift cam).
 

Tried to order the Supertech pistons today, but I'm being told over 2 months lead time to get a set. Looks like I may be able to get Wossner K9220D050 88.0mm pistons with a 12.5:1 compression ratio that seem to be in stock in Ohio, so could be here in a week.

[7 wonders of the world]

 The US has a considerable number of Supertech dealers I'd be surprised if they were all out of stock....

[aerobod - near CYYC]

The problem seems to be the oversized pistons are not commonly stocked, Vivid Racing went to Supertech and got the info direct from them, can't find any other supplier online that isn't showing "special order" for them. I actually prefer the Wossner pistons if I can get them, just didn't seem easy to get last week from suppliers, until I talked to the right person at Wossner US today. Probably about 25% more for the Wossner vs Supertech ones, but time is more important for me to get some momentum in the build, now that the Maxspeeding rods are ordered.

[7 wonders of the world]

Either brand will be fine James, 

 

These don't say special order as many other do however thats no guarantee they are sat on the shelf   

https://goturbo.net/sptp4-du88-p7-supertech-ford-mazda-2-0l-2-3l-88mm-bore-7-8cc-dome-12-6-1-14-1-1-cr-pistons-set-of-4-p4-du88-p7

[aerobod - near CYYC]

That's why I picked Vivid initially due to "In Stock" for the P4-DU88-P7 pistons, but it was not to be, unfortunately. I've dealt with them before and had good customer service (buying a 480BHP supercharger kit for my old Z4M from them).

[7 wonders of the world]

Cant for the life of me remember the US dealer I've bought 2 or 3 sets from, again good service.... let me search my emails...

[aerobod - near CYYC]

Thanks Neil, I will contact them if the Wossner purchase doesn't work out. I've taken to calling suppliers before doing online orders for speciality parts these days due to the variability of stock since Covid, as opposed to the order just going into a blackhole waiting state.

[7 wonders of the world]

Here you go IPGparts.com

https://ipgparts.com/

 

 

[aerobod - near CYYC]

[aerobod - near CYYC]

Got the pistons in today and gave them to the machine shop for checking dimensions before they commence the re-bore. Also now have the connecting rods, too:

The piston pockets seem to be 3.5mm below the crown of the flat-topped standard pistons, so should be OK for the highest lift cams available for the Duratec.

In terms of machining the flywheel, does anyone have the specs for minimum machining depth, this is the standard R400/420R machined steel lightweight flywheel fitted by Caterham with the AP clutch? I'm hoping to get away with about 0.1mm of a skim if possible, but the machine shop wants to know the maximum depth they can go to.

[7 wonders of the world]

Think you'd be easily safe with 10 thou, is yours the plain back version or the one with sections machined into it - seen a couple of these which had distorted pretty badly. 

Good news on the piston and rods arriving, and news on the big box form the UK...? did you get a final spec sorted..?

 

[aerobod - near CYYC]

I have the flywheel with the machined out back sections, Neil. Seems to run true, but I will see when they machine it.

No final spec for the UK parts from Raceline yet, talked to Chris a week ago and just need to finaIise the cam to finalise the order, he was going to get back to me with the RLD270M cam spec to see if was close to the D-TEC45, no word yet.

[aerobod - near CYYC]

I finally got the cylinder block and flywheel back from machining this past week, and set to work taking measurements yesterday.

The flywheel is effectively scrap due to distortion. Now machined with the friction surface to run true, the thickness of flywheel under the friction surface now varies from 4.45mm on one side to 4.90mm on the other. This correlates to about 20g imbalance which would require about 10 6mm holes 10mm deep to correct. This is too far out for my liking. The variation in thickness of about 10% would also likely lead to more distortion fairly quickly.

The cylinder block is looking very good with good cross-hatched surface finish in the bores and machined right to the 88.00 -0.00 / +0.01 spec:

The piston clearance is right at the specified 0.07mm:

I machined up a tapered sleeve to fit the piston rings from a piece of 6061-T6 pipe turned to 100mm OD, 94mm ID tapering to 88m and 50mm deep. Cost me $11 for the material, compared with $100 for a typical delivered price of a comparable tool online:

The piston skirt slides in nicely:

There is plenty of room for the rings to be gently compressed down to the bore size, I tested with the old pistons and rings, requires only gentle finger pressure to insert the pistons into the cylinder bore:

Measured the big end bearing clearances with the old bearing shells to see what size I need to purchase. The axial clearance was 0.025mm (spec 0.014 to 0.035mm), radial clearance at between 0.035 and 0.040mm (spec 0.025 to 0.052mm), according to the Plastigauge sizing:

Also measured the main bearing clearances with the old bearing shells, all seem to be within spec (0.019 to 0.035mm) at between 0.025 and 0.030mm, according to the Plastigauge sizing:

There is some slight wear on the upper #3 bearing with the thrust surfaces (all other 9 shell halves have no noticeable wear), but end float at 0.33mm is within the 0.22-0.43mm specification. I plan to replace all bearing shells anyway:

Also measured the valve to piston clearances:

The valve clearances to the Wossner pocketed pistons are 6.7mm on the inlet side and 5.5mm on the exhaust side at TDC with no head gasket.

I measured the head combustion chamber depth relative to the old head, 0.20mm has been skimmed, plus an additional 0.05mm of the cam cover sealing surface. The original head was 123.90mm thick, the refurbished one is 123.65mm thick. The original 0.5mm thick head gasket will be replaced with either a 0.76mm or 0.86mm thick gasket, the Cometic 0.86mm one seems to be more readily available than the 0.76mm one and I could do with taking compression ratio down from 12.5:1 to 12.3:1 with the extra 0.1mm thickness.

I measured the consistency of all the inner and outer bearing diameters, although my equipment is only accurate to the nearest 0.01mm, whereas 0.001mm is more desirable for clearance measurements (hence the use of Plastigauge to verify):

Block & cradle main bearing housing diameter: 57.03mm

Crankshaft main bearing diameter: 52.00mm

Big end bearing connecting rod housing diameter: 50.03mm

Crankshaft big end bearing diameter 47.00mm

One thing I need to investigate is if the part number on the bearings is different for the different shell tolerances (that are colour coded), I'm not sure if the letter on the main bearings indicates tolerance (Perhaps "G" for "Green" in my case?).

Upper main bearing shell (upper positions 1,2,4,5):

Upper main bearing shell (upper positions 3):

Lower main bearing shell (all lower positions):

Big end bearing shell (all positions):

 

[7 wonders of the world]

All heading the right way now James,

For the Flywheel look at TTV - superb quality, you can use the AP cover or they now offer their own cover, with a choice of 3 spring weights and either organic or cerametalitc plate too, had this ben available when I rebuilt mine I would have chosen this over the AP

I run the TTV 0635

http://ttvracing.com/product/ford-duratec-2-0-2-5-i4-215mm-supalite-race-ap-clutch/?referrer=product-listing&iframe=true&width=80%&height=100%&type=flywheels&engine=ford-duratec-2-0-2-5-i4&manufacturer=ford

Clutch

http://ttvracing.com/product/ford-duratec-2-0-2-5-i4-215mm-supalite-race-ap-clutch/?referrer=product-listing&iframe=true&width=80%&height=100%&type=flywheels&engine=ford-duratec-2-0-2-5-i4&manufacturer=ford

speak to Ben Crisp @ TTV 

The cam cover seal will accommodate a 20thou discrepancy between head and timing cover any more and you need to have it milled down. 

[aerobod - near CYYC]

Thanks for that info Neil. I was looking at potentially just using the Raceline supplied flywheel and clutch, as the shipping and customs charges will be a lot more reasonable if I package everything else together in one shipment, but I will see what they come back with with the overall quote,

[7 wonders of the world]

The Raceline one was the same Titan pocketed version you had unless they have changed now.

I'm sure you have this in hand but since AP moved their manufacturing premises the tolerance of balance is not what it was, 

I wouldn't even consider building without having the rotating crank mass balanced, you can do the pistons and rods at home.

 

[aerobod - near CYYC]

Chris at Raceline had advised not to get the AP clutch, they had a number of alternatives, will ask what they are when I speak to them this week. They also had a fairly lightweight (4.7kg) 8.5" compatible flywheel matched to it for £345 in addition to the clutch cost.

[7 wonders of the world]

Demon Tweeks were cheaper on the TTV, but Ben will do a package deal fir flywheel and clutch 

[aerobod - near CYYC]

I did a check on the combustion chamber volume and piston void volume from the plateau on top of the piston to the bottom of the valve pockets in the crown. Used Play Doh putty and a rigid and flat piece of plastic to flatten it into place: 

 

 

Using the weight of water displaced when placing the putty into a full container, I measured the volumes as follows:

Piston void volume measured = 14.4cc, additional volume of piston cylinder to plateau above piston land (0.5mm below block deck height) =  21.3cc, with a piston clearance of 0.35mm extending to the piston ring 10.6mm below the plateau for a volume of 1.0cc, leading to piston effective volume in combustion chamber volume of 5.9cc.

Combustion chamber volume in head measured = 42.4cc. Head has been skimmed 0.2mm, this has removed about 1.1cc from the standard head, leading to a standard head combustion chamber volume of 43.5cc (I've seen 43.2cc quoted for this, so measurement seems close).

Putting all the measurements together with a 0.7mm head gasket thickness leads to:

88.0mm bore with 83.1mm stroke = 505.2cc cylinder volume

0.5mm piston land below deck height = 3.0cc deck volume

0.7mm gasket with 89.5mm bore = 4.4cc gasket volume

42.4cc cylinder head volume and -5.9cc effective piston volume

Therefore total volume is 549.1cc, leading to a static compression ratio of 12.5:1

[7 wonders of the world]

Interesting ways of checking I use a pipette and grease the top ring.

It's also important to cc check each chamber to check for variation after and machining. Balancing the chamber is equally a important as checking rotating mass.