Ford Twincam + BMW m10 = hawtness

[Guest Anonymous]

Ford Twincam + BMW m10 = hawtness

That's what this thread is about.

This is the project blog on the ford twin cam head mounted to a m10 block. It's not about "what a travesty of bmw heritage to do this".. "I'd never do this because every part that touches my car is NOS bmw tellie bag'd because I'm a purist"

This was started with this thread here.

http://www.bmw2002faq.com/component/option,com_forum/Itemid,50/page,viewtopic/p,426623/highlight,/sid,667bcc8050987ee7eb1a57cf465b6f4d/

There's pictures of headgaskets on the block here

Goals for the project

Head bolted on

Timing Chain Setup Worked Out

crank gear/cam gear/chain

Tensioner functioning

Cams Cut or "re pressed"

So I've been busy the last week or two. Got some progress done last night. Bolted the head to the block. It does bolt on. The smaller head bolts for the 02 will probably need to be replaced. They are the wrong size for the hole in the head. It could easily move. I will probably drill and retap the block later and run some stang arp studs. Probably the easiest.

It looks oh so easy from now but I know it's just the beginning. Let me explain how the cams on the twincam ford are driven. The Exhaust cam has two gears on it. One gear to drive the chain to the crank for crank to cam timing and another gear on it to drive the intake camshaft via a short little chain. The intake cam only has one gear on it and a spacer block to shim a bolt. That gear is for the exhaust cam chain drive. In between the two cams is a hydraulic tensioner. This slides between the top and the bottom of the chain that links the two cams. Once pressurized it pushes out to maintain pressure on the cam linking chain. The cam to crank chain gear is offest out from the head a little far. My initial goal in this is to utilize the mustang tchain, crank gear and cam gear. I feel this is an easier start than the 02 one. As for the crank magically fitting onto a bmw crank. NO luck. It's about 1/2" diameter difference. Right now I'm leaning towards something like a speedy sleve on crack. basically a steel spacer to adapt the two diameters. The mustang chain is also a little long. About 4 links removed will fix it though. The construction of the chain though is just a bunch of links and the pins are just mushroomed on the ends. i don't think shortening the chain will be a big issue. If the chain sits to far out on the tensioner I'll just have to lathe some material off the stang cam gear and put a washer between it and the bolt.

Still lingering out there is the cams. The factory cams are pressed together so I may be able to un press them. rotate and repress them together although I'll be the first to say that's incredibly harder than it sounds. There's alot of pain in that one.

As for the ports and runnners. The ford twin cam head is kind of goofy. Each intake port is different in size and shape. It almost looks like they used a staged injector and cut off one runner below a certain RPM. One port is round and smallish. like 1.4" diameter and has no notch for injectors to spray so it must have been mounted further up. It's dirty on this used head. The valve is covered in carbon and looks like 50k miles of crud. The second port for the other intake valve is square, large CSA, and has a notch for an injector to spray. This port looks "as cast" new. I bet these ports generate a bitchen amount of tumble and swirl.

Just by looking at the head I can tell that a little bit of lift will easily carry this thing upto high RPM life. In comparison. My SR20det head ports are maybe 30% smaller.

Modular pistons. Well the forged mahle motorsports pistons arrived last week. They weigh in at 365 grams for a flat top. It's hard to find a partial skirt strutted piston with that kind of love for as cheap. With that light weight you could easily rev much higher on the same con rod. Realistically I'm hoping for a 8k RPM stable 02 with a nice idle. Hopefully I can wiggle this into some autox class and pwn everyone.

[Tommy]

I would be a little concerned about boring and re-threading the bolt holes in block. They sometimes crack from the holes as standard. It may be rare with the old style block and the reason may often be poor assembling (oil in holes). But still I think there's not that much material.

This is an interesting project and I hope to see it finished and working!

Tommy

[PSloan]

why not machine sleeves for the head rather than tapping the block?

[Guest Anonymous]

I guess you can do either. I was more worried about the sleves interfering with bolt torque vs studs. Arp studs for an 02 maybe the answer. The stock hardware well won't meet the torque requirements of the MLS mustang gaskets.

[Tommy]

I think that would be better solution. I don't see a problem if the holes in head are bigger than the bolts/studs. There are still the 2 sleeves that center the head and block and the bolts just squeeze them together.

Have you solved how to feed oil to the head? What about cooling flow? To me it looks like they are the most difficult tasks in addition to chain drive arrangement.

[Guest Anonymous]

Oil Flow to the head will be done with an external line. Like the way honda guys run pressure to the vtec solenoid. I'll take a TII oil filter block fitting and use the pressure line to goto the pump to goto the head. I poured some water where the oil goes in the head and it ended up in the crank case. I've yet to run water through the coolant but I think it won't be a terrible issue. I'm more worried about the port in the headgasket back where the oil feed originally came up on the stang into the head leaking coolant from the block. It's close. Timing and cams so far seem to be where the fun is. I ordered the pin bushings for the rods today so hopefully they will arrive this week and I can get the pistons on the rods for the forged bottom end.

[Guest Anonymous]

Ok so fiat pin bushings arn't produced any more.. wow

Found a toyota one to work. YAY for ITM catalog having pinbushings done by sizes.

[Guest Anonymous]

Pin bushings in.. chucking up the rods in a pin boring machine this week to get me a fully rotating assembly... forged bottom end will be very nice...

[maikelm11]

Nice..

Can you post some pics of the progress?

Thanks,

Maikel

[PSloan]

Nice..

Can you post some pics of the progress?

Thanks,

Maikel

x2

[Guest Anonymous]

I'm on it...

[Guest Anonymous]

This is a pic of the mustang pistons that we'll be using. They come in flat top or dished. I'm matching this with a non mustang eagle connecting rod. You can see how a partial skirt boxed design piston is superior to anything currently produced for bmw m10's. You can get them in 4032 low expansion alloy or 2018 alloy for high power. They spec about .003" wall clearance so no slap. Also runs a .866 wrist pin so it can be used with tons of lightweight pins. Piston weighs in at 364 which is almost half of a stock piston. The eagle rods are a hbeam rod sporting 5/16ths arp 2000 fastners. In their application they're rated for "only 8000rpm and only 700HP". They've been proven to atleast 500hp numerous times so I think they'll live just fine in an engine with less stroke and a lighter piston. I'm measuring to set the final connecting rod length when I install the pin bushings in the rods but we're looking at a rod that's atleast 4mm longer than a s14 rod. Because of that piston acceleration is way down and weight is way down. I think it's a combination that will allow a m10 to live at 8000+ RPM. Between the piston and the rod we'll save around 500grams a cylinder. or 2kilos of reciprocating weight through out the engine.

So far that's really all. I want to get pistons and rods sorted before I finish the head install. I think it'd be worth more to the community to get a piston/rod combo that's cheap and super light. Wish they came in a dome but no dice. Flat tops with the mustang head are 11.5:1 so it's not really going to be made. Alteast guys who want to go turbo will have a dished piston available cheaper than hunting them down.

[cheechthechi]

I am actively following this. Whether or not it will work, its cool to see someone take initiative to try something new. Props to you!

[maikelm11]

I agree!

Wow 2kg on the pistons & rods, that's a lot! But isn't that going to make a difference in torque? (less torque)

About the rods.. if they are going to be at least 4mm longer than the s14 (=144mm) What eagle rods are you looking at?

Thanks,

Maikel

[DB]

the 320iS (nick named the italian M3) uses rods which are 149.7 mm. maybe hard to get but they come up of ebay in europe occasionally. There is a set on http://www.s14power.com/parts.html for 500 euros.