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4.0 OHV into 4.0 24v COSWORTH

Discussion in 'Need for Speed!' started by Tobbe, January 13, 2007.

^^Searches ExplorerForum.com^^





  1. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    Very good, it's nice to hear from you. I saw some used DOHC parts on eBay from England two months ago. I'd still like to try it if I had the right application. Regards,
     
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  3. daniel.S

    daniel.S New Member

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    have anybody more pictures ??
     
  4. Rob_DOHC

    Rob_DOHC New Member

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    Hi there Tobbe,

    Hope it is all still going okay!

    Why did you not install into a Sierra in the end?

    Quick question, Although you say the 4.0 block is some 20mm taller could you have installed the crank into the 2.9 block with different pistons and con-rods?

    I would quite like to install this into an XR4x4.

    Cheers and all the best

    Rob,
     
  5. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    Welcome Rob. I like this project as well, but the flow of the heads is critical for being useful on a larger engine. The flow of those DOHC heads should be carefully analyzed to determine if it's worth it to do.

    Find out how they flow stock, and with a reasonable porting job.

    What are the actual dimensions(specs) of the 2.9 engine? What is the block deck height, the piston pin height, the rod length, and crank throw?

    The aftermarket has a ton of amazing parts for stroking most engines. Most Ford engines have plenty of room to accept much greater strokes, and some can be bored quite a bit. I would not be surprised to find that the 2.9 could take almost the same stroke as the 4.0, but the specs decide that.

    You need to have a rod/stroke ratio of better than about 1.5:1 to be useful or feasible. As the number gets smaller, the piston design is much more critical, and expensive. If you can work with existing aftermarket pistons, then it might be feasible. Regards,
     
  6. Rob_DOHC

    Rob_DOHC New Member

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    Hi there!

    Thank you very much for the fast reply. I will have to dig out all the specific dimensions of the 2.9, however the DOHC heads supposedly flow well enough as standard for 300 brake...

    As it stands i would like a twin turbo, 24v 4.0l for my car!

    But to be honest im not overly bothered whether its a 24v or a 12v. I know the 12v would be the more reliable option any day, cant beat a push rod for reliability! and a big leaf blower :D should make most flow restriction negligible (to a point).

    However there is a company here who make all the appropriate turbo headers for the 24v heads.

    http://www.chevroletls1.com/ford_cosworth1.html

    From what i hear 7PSI is giving a solid 320HP with nearly 400 ft·lbf and 14PSI is giving over 400HP and mountains of torque. This is from the 2.9 with the 24v heads.

    I am not a big fan of turbochargers! or turbo lag. So 2 small turbos four litres and between 7 and 14psi should yield a relatively powerful low lag engine.

    As with most of life this will be on a budget, i can stretch to custom pistons and H-beam rods but not a custom crank im afraid :( so it will have to be the 4.0l crank in the 2.9 block (the easy option) or do with the 4.0L block and mess around with the oil pump etc...


    Let me know what you think.

    Rob,
     
  7. Rob_DOHC

    Rob_DOHC New Member

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    Sorry CDW6212R,

    I Don't think a porting job would be of much good :( the ports are of a very open short and unrestricted design, i guess you could improve slightly by removing and casting marks and giving them a slight polish, but other than that there is not much material to remove before hitting a water gallery etc.

    I have the heads in my garage so at some point i will take some good photos of them for you guys.

    Rob,
     
  8. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    I figured that about the heads, they flow well, but not great for big cubic inches and rpm.

    I would research more about the heads, and the best possible porting. I'm not suggesting just find a big name company and hope for the best. I'm saying see if you can find expert advice about those specific heads. I wouldn't have anything significant done to them unless it was done by a pro who knew that specific head from experience. A mild bowl blend etc may be the only choice, and that could be fine. The point is that you need to know that, in order to match the heads to the engine(cubic inches, rpm).

    The OHV 4.0 is a very solid engine, with poor heads. The SOHC 4.0 is a fragile engine with great 2V heads. Do not build the SOHC for high power, it's not feasible compared to better choices. You have a 2.9 for a small car I assume, so that's your engine platform.

    The power numbers you just mentioned are nothing really special, for a true high performance build. My 347 engine(5.7 liters) I have yet to run is going to make 400hp NA on pump gas for my truck. It's not radical, fully streetable, but the stroking parts and heads are about $3000 of it. The heads are the key, mine are capable of 500-600hp given the right rpm and camshaft.

    My point is that the heads are the big key, if they flow enough take advantage of them. If not then do not spend too much money trying to get a lot out of them. I think you grasp that, why spend say $3000 on crank/rods/pistons/cam and only gain 100hp.

    FYI, turbochargers are great when done right. I would love to have a turbo. There does not have to be any turbo lag, don't believe that. The key is in the proper selection of two things, the turbo and the inlet section to it. Only a real expert can select those to match your application. Amateurs can guess at it, but you end up paying for their poor guesses.

    I suggest that you consult with an expert for the turbos. I suggest that you consult with an expert for the camshafts. There is a ton of power to be gained with any engine by the proper cam selection. I've learned this more just recently. Do not rely on any personal suggestion, or a parts seller, or any cam maker(Comp Cams etc). The only people that you should buy a cam from is someone who literally designs that cam, for your engine.

    That means no off the shelf cams, all of them will make less HP than any custom cam. The cam needs to match the engine, the heads, the vehicle, the intake, the boost, the exhaust, the rpm band etc. None of that is possible with an OTS cam. A custom cam for most common V8's is $400, but OTS cams run about $300. Why save $100 or so for a lower powered cam?

    Get your specs of the 2.9 DOHC, and see how far off they are from being able to use OTS stroker parts. A stock crank is strong enough to take the power you are planning, but the 2.9 crank likely can't take too much offset grinding. Look at the spec first though. Regards,
     
  9. Jakee

    Jakee Well-Known Member

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    CDW - What are you talking about, "don't build the 4.0 SOHC for power?" Are you kidding?

    The OHV uses pretty much the same rods and pistons as the SOHC except the compression ratio on the piston is lower. This is one reason it's not as powerful.

    The SOHC is fragile? Darn, 500 HP for one season is not all that shabby and I can't think of ONE ohv that has done that sort of thing.

    Yes, I'm partial to the SOHC and I despise what you just said about the motor cuss I feel its false information 150%

    When you get the 347 completed we can find out how “fragile” the 4.0 SOHC is if you’d like. ;)
     
  10. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    Sorry Jake, but IMO the Ford valvetrain of the SOHC is not well made. The design is very good but the parts should last longer in every single one of them. It is great when it's right, but the two cam chain tensioners are far too fragile. I'm not condemning the cam chain cassettes, as Ford redesigned those in 2002, five years after beginning production. That's a loaded statement I know, I meant for it to be.

    The number of people who have come to this one site looking for help with their SOHC valvetrain is huge. If one or two or a dozen had issues with SOHC's of normal mileage, that would be no big deal. There have been way too many of these engines turn up with serious valvetrain problems, factory built problems. Ford did not recall the engines, nor did they offer to fix them all. Ford only was forced to replace a few parts due to lots of failures in low mileage SOHC's. They wouldn't touch the rear cassette for free because of how expensive(labor) that is. Yet it is the same plastic material that seems to only fail up front.

    I'm sorry but that's my opinion, the reliability of the SOHC does not lend trust for building it for higher power. The power levels are great, no doubt, and they don't really stress the valvetrain more. But when and if there is a problem, the engine is much more expensive as you have built it, and the mess will be big.
     
  11. Cossie

    Cossie New Member

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    Hi I´m from Denmark.
    I have a Scorpio 2,9 24V Cosworth.
    I´m member of a club in Denmark for Ford Scorpio Scorpioklub.dk

    Your engine, is it an engine from an Explorer 4,0 with a cylinder head from a 24V Cosworth?

    Is it possible to make my engine (2,9) into a 4,0 without a new engine, only by make the cylinders bigger and new pistons, crank, cam
     
  12. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    Welcome, we haven't heard back from Tobbe since the video clips he posted. He used the 4.0 OHV block and crank/rods/pistons.

    The SOHC 4.0 shares almost those same parts I have read, but the block is modified slightly for the SOHC heads and other parts. So I'd suggest using the 4.0 OHV block if you do that conversion, Tobbe did a good job of detailing what he did.

    We can only speculate about what the results were. Assuming the parts did function properly together, that leaves the head flow capacity and camshafts. The DOHC heads are made for the smaller engine. If I made the conversion, I would try hard to have different cams made. For use on a 4.0 engine, more cam should be needed to make the 2.9 DOHC heads work well.
     
  13. 410Fortune

    410Fortune Flood season Staff Member Moderator

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    I wonder what that engine is worth on Ebay? the 2.9L Cosworth

    I know some off road classes only allow 3.0L max, the old 2.9L was really built up for this, big $$$$ in Southern Cali for these builds...hmmm
    I dont miss my old 2.9L anymore........but 300+ HP from that V6 is impressive!!!
     
  14. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    I have seen used DOHC heads twice on eBay, and one time almost the whole 2.9 engine was there. It is possible, but the cost will not be cheap, and operating it with a SOHC PCM would be best.
     
  15. Cossie

    Cossie New Member

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    I hope you understand, I´m not very good in english.

    I have heard that, when they was making the scorpio Cosworth, that the engine had more power, but I don´t know how much and how they made it.
    topbossperformance.co.uk
    I have an extra 2,9 cosworth engine, that I maybe could try to make bigger.

    It´s because of the law in Denmark, cars over here is very expensive.
    Mustang in Denmark 680.000 kr = 130.500 $ (used car) If new it cost 158.350 $
    When I make it with another engine I have to pay a lot of money in tax.
    But it is legal to make it more power with the original block without turbo. and no tax
    Or I can only get 20% more power total 248 HP, and if only 248 it is waist of time.

    Then I prefer to make my 2,9L block up to 4,0, if it is possible, and 6 new pisons, 6 rods, crank and 4 camshaft and another settings in chip. What more can I do to get more power without turbu and blower (compressor). And how much power can I get? I got 207HP (only) now.

    Is the 4,0 a 12V sohc?
    Is the 2,9 a 24V dohc?
    why then sohc pcm (what is pcm)

    If possible, is it not easier to use the block from a 2,9 and bore it up to 4,0 than use a 4,0 and the other pistons, rods, crank and cam.(dimensions of pistins, rods, crank and cam) It has to be the same dimension as on the originally 4,0L?
    All other on the engine should fit on?
     
    Last edited: August 31, 2009
  16. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    The 4.0 blocks are taller, I think that's where Tobbe went with his. His post #4 tells us that the 2.9 can be bored/stroked to 3.7 liters, and can make about 287hp with all other stock parts.

    If you have taxes over there which hurt you for changing engines, I'd stick with the 2.9 block and open that up. That sounds like your best solution there.
     
  17. Tobbe

    Tobbe New Member

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    Haven't been in here for ages...... To make a 3.7 version of a 2.9 isn't the best solution, it is very expensive and it will brake. It uses a 2.9 block bored into 95mm, 4.0 crank stroked into 86mm, opel frontera 2.4 pistons, 2.9 rods with a small end bushed into 22mm. There are so much material turned off the crank for clearance so it will need an extrernal balance, the piston squirts are milled for clearance for the crank, even the liners are milled for clearance for the crank.. And if you rev it up to 6000rpm you might get a rod comming out of the side.

    The 4.0 24v options is the cheapiest solution, and at least where I live the 2.9 24v is very rare so no technition the mot will not notice if you got a 4.0 24v in the car......

    I'll give you an update later on my 4.0 and 4.1 engine.....

    But there are several people that are building 4.0 24v engines now, hopefully they will be finished soon.

    And I do also know that Cory got something really special, wow is the word that came into my mind when I found pictures of a few of his bits on a racing forum....
     
  18. Cossie

    Cossie New Member

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    Thx for all the answars!

    I understand that it is not good to make a 3,7 or 4,0 out of my 2,9.
    It is better to use a 4,0, but in Denmark is it not possible, because of the tax I have to pay about 60.000 $. So I can´t use any of them, but it is very interesting any way.

    I think I have to change my 2,9 into a 3,3 only with new pistons,arank and rod and other stuff.
    I will read about it in a link that I got from Tobbe, thx
    www.fordpower.org.uk

    Cossie
     
  19. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    Very good, it's good to see progress. Tobbe, how did the car end up finally, do you like it?
     
  20. Jakee

    Jakee Well-Known Member

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    Tobbe - While your still around, can you confirm what you did to the SBC rods?

    - You used I-beams
    - You had the big end width narrowed to fit the 4.0 crank
    - You had the big end bore opened up a little and used stock 4.0 bearings

    Let me know if this is correct.
     
  21. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    He used H-beam rods, very strong for boost.
     

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