4.0 OHV into 4.0 24v COSWORTH

As the topic. It's based upon a 93:ish 4.0 bottom end and the rest of the bits are from a 2.9i 24v BOB cosworth. Just missing a few bits to be able to put it all togehter. But here are a few old pics from how a few bits fit together.

 

[Tobbe]

The rod modification:
Bush in small end increased to 24.0xmm
Big end reised to ford bearing size
New locking grooves where made for ford bearing
The big end with was narrowed and also a chamfer was added.
Did aslo make a oilspray hole just like ford rods got....

If I am happy with the car? Nope, it is lots quicker than a stock 2.9 24v, I out run my brothers scorpio cosworth with ease, if I pull from 1500rpm in 5th gear he can be at whatever revs he likes and he cannot keep up...

After 4000rpm the engine looses power, I've tested a few different setups, actually I was going to test another one last night but due to a fuel leak I had to cancel. But I think the main reason for lack of power is due the inlet manifold. Still the engine doesn't pull bad after 4000rpm, but I think it could pull better....

On the 4.1 engine a piston pin snapped, so I replaced the bottom end with a stock 4.0 one. But now the 4.1 bottom end have been repaired, uppgraded with a girdle, I hope to have it ready to spring. Then engine will have custom made inlet cams, a slider throttle with short runners etc...

I will make a movie soon, so you need to wait until then to see how it performes...


Cossie, I don't think the techs will tell that you got a 4.0 instead of a 2.9....

 

[Jakee]

Thanks Tobbe - What price did you pay for this work over there?

 

[Jakee]

Tobbe - Is there room enough to sleeve the 4.0 block and run a bigger piston? say 4.0 to 4.030" bore?

 

[Rutt4.0OHV]

I'm glad to see one of these finally run. The last person to get one running(Sven Pruett) would never comment on how he did it.

One thing I did notice that was different on Sven's setup was that he made his own intake to incorporate a larger Twin-throttle body set-up verses using the 2.9 stuff. I really wish I knew more, but all I have are pictures.

The DOHC heads are more than ample for the 4.0. Remember, the OHV has some of the crappiest heads on record.(1.68" in/1.36" ex) In fact, the intake actually flows more than heads can handle. This is the reason the OHV 'wakes up' so well with head work and a good cam.

The cosworth 2.9 intake was never really designed to flow well enough to support 4.0L's of displacement. The earlier pics/vids show a very small TB. If I had to start on one area, I'd start there. Look at the SOHC 4.0 intake for reference. I believe it has a 65mm TB. The ol' OHV has a 58-60mm.(I think, been a while)
I think that was why Sven opt'd to create his own.(I'll see if I can find the pic)
Anyway, the videos don't do it justice. That is one awesome motor. I remember in college I built a DOHC4.0(on computer), for my high performance class. I ran it withTwin Turbos running on race fuel. My approximate horsepower was near 1000 at 7800-8000 rpm. I was also running stage-3 ported DOHC heads with larger valves. I won the 'Dyno war', at least on the computer. I was up against a BBC, and a stroker ford v8. We had a budget of 10,000 dollars. I actually had to find all the parts and assemble the myself.(again on the computer)
The heads I found somewhere in canada.(taxi cab wreck yard) I found a local yard with a complete '92OHV for cheap. I called in some favors to friends at a machine shop, and got prices from them. I barely made it under $10,000 at$ 9800. This was assuming I did all of my own assembling, porting, and fabricating. One thing I didn't verify was just how long this setup would actually last, but that wasn't the goal. The goal was to make the most horsepower without going over the budget. I wish I still had the file with all that work on it, but that PC died and took all of my work with it. I still have my T-shirt and hat for winning. I also got accolades for being different.(and an 'A')

Has there been any more progress on this project Tobbe? I'd love to see more video.

 

[bigro]

hello tobbie

my name is bigro im new on your site im very interested in your 4.0liter cosworth engine
i wanted to do the same kind of project but on a 2.6 liter version of that engine where dis you get the part to do your engine how does it run good for your oil pump use the cosworth one or the 2.6 2.8 those pump turn in the oposite direction did you have to modified the water passage in your block any help would be appreciated

bigro

 

[bigro 007]

The rod modification:
Bush in small end increased to 24.0xmm
Big end reised to ford bearing size
New locking grooves where made for ford bearing
The big end with was narrowed and also a chamfer was added.
Did aslo make a oilspray hole just like ford rods got....

If I am happy with the car? Nope, it is lots quicker than a stock 2.9 24v, I out run my brothers scorpio cosworth with ease, if I pull from 1500rpm in 5th gear he can be at whatever revs he likes and he cannot keep up...

After 4000rpm the engine looses power, I've tested a few different setups, actually I was going to test another one last night but due to a fuel leak I had to cancel. But I think the main reason for lack of power is due the inlet manifold. Still the engine doesn't pull bad after 4000rpm, but I think it could pull better....

On the 4.1 engine a piston pin snapped, so I replaced the bottom end with a stock 4.0 one. But now the 4.1 bottom end have been repaired, uppgraded with a girdle, I hope to have it ready to spring. Then engine will have custom made inlet cams, a slider throttle with short runners etc...

I will make a movie soon, so you need to wait until then to see how it performes...


Cossie, I don't think the techs will tell that you got a 4.0 instead of a 2.9....

hello Tobbe
My name is bigro 007 and I have see what you have done I like that very much me I want do the same thing but on a smaller and much older version of that same engine its the 2.6 liter and it was in the ford capri how did you get these head from ebay? how did you got these ship to you very interested in knowing that did you try these head and timing cover on a 2.8 block to see if the cover would actually bolt on that block if it does then the it will bolt on the 2.6 thank you very very interesting project that you have

tump up!

 

[Kevin777]

hate to revive the dead but were there any pics vids of it running? possibly a dyno video/ sheets. i think everybody here is still at least a little curious about how it turned out and what kind of seat time you've put in as well as how its holding up!:notworthy

 

[Richmond]

Hey guys, greeting from Russia. i have read this post and have some questions. I ride on Mustang v6 4.0 sohc 2005 MY. My serviceman told me that i can use 4.0 block with 2.9 Cosworth heads and it gives me over 400 hp.

Can u help me with information of setup ? also if i buy supercharger or turbo, what boost will be able ? also if there are any forged rods or pistons or how can i make it stronger to boost ?

Thanks !

 

[CDW6212R]

Hey guys, greeting from Russia. i have read this post and have some questions. I ride on Mustang v6 4.0 sohc 2005 MY. My serviceman told me that i can use 4.0 block with 2.9 Cosworth heads and it gives me over 400 hp.

Can u help me with information of setup ? also if i buy supercharger or turbo, what boost will be able ? also if there are any forged rods or pistons or how can i make it stronger to boost ?

Thanks !

Welcome. The 2.9 heads are not really much larger than the SOHC 4.0 heads. The rpm limits of the DOHC heads would be more than the SOHC heads, but if they don't flow much more than the SOHC heads, the gains would be limited.

There was one person who finished his 4.0 DOHC engine, but he didn't reply again after the initial start up. I think he didn't have good tuning to sort it out.

To make the DOHC head swap viable, they need to have more flow capacity than the SOHC heads. If I was doing it, I would begin by learning the flow of both heads, ask some engine builders what flow improvement would be worth the trouble for the swap.

 

[Richmond]

Welcome. The 2.9 heads are not really much larger than the SOHC 4.0 heads. The rpm limits of the DOHC heads would be more than the SOHC heads, but if they don't flow much more than the SOHC heads, the gains would be limited.

There was one person who finished his 4.0 DOHC engine, but he didn't reply again after the initial start up. I think he didn't have good tuning to sort it out.

To make the DOHC head swap viable, they need to have more flow capacity than the SOHC heads. If I was doing it, I would begin by learning the flow of both heads, ask some engine builders what flow improvement would be worth the trouble for the swap.

Thank you.
Please, tell me if there are any Forged pistons or rods for 4.0 ?
Also, what is better to supercharg or make Turbo ? What boost is good for stock ?

I want 400+ hp, can it be ok in stock ?

 

[CDW6212R]

Try this thread by a great member who has a supercharged 98 Explorer, 4.0 SOHC, 5R55E. It runs about 13 seconds, boost is up near 18psi. His engine is stock I believe, but there are some aftermarket pistons and rods I think. The engine is very capable, the 5R55E automatic is a little weak to push those power levels though.
My 98 super charged EX

 

[Richmond]

Try this thread by a great member who has a supercharged 98 Explorer, 4.0 SOHC, 5R55E. It runs about 13 seconds, boost is up near 18psi. His engine is stock I believe, but there are some aftermarket pistons and rods I think. The engine is very capable, the 5R55E automatic is a little weak to push those power levels though.
My 98 super charged EX

That's very interesting. But i m afraid that my engine will be killed as soon as possible on 18 psi.

I think about 4.0 sohc block + 32v Cosworth heads + supercharger or twin turbo with 7-9 psi.

Have any ideas ?

 

[CDW6212R]

The stock parts of the 4.0's seem to be capable of handling 400hp or so, which is common for OEM Ford engines. The higher boost levels and less than perfect tuning will kill any parts, but more so with stock level stuff. If you can keep the boost reasonable and make the computer programming a priority, it will survive, and you can raise the boost some.

The DOHC idea is great and it does improve the reliability of the valvetrain. I have a SOHC 4.0, and I look forward to swapping it out some day.

I'd still start by researching the flow of the 2.9 DOHC heads. If they are not a decent amount better than the SOHC heads, it's hard to justify hunting for the 2.9 heads, plus the intake, plus the work to make it work together. If the flow is better, than it will be a fun project.

 

[Devan]

Hey cdw
Im makin close to 300whp on my Eaton m90 4.0 sohc more power soon lol, replacin blown head gasket currently lol waitin on better bolts, ARPs eventually but i would like very much to do this quad cam cosworth head swap with an m112 on it, perhaps even compound boost lmao im jus wondering if my intake manifold will fit those cylinder heads like the ones pictured on the early pages of this thread. I have decided that im gonna keep this a v6 truck cuz ive been very invested with the v6 setup plus i wanna keep 4wd and ac lol but id swap in a stick if rlly nec. but im gonna get a previous gen 2 dr sport and do a 4.6 DOHC m112 with 4wd if theirs room lol plus if i really need the OHV block then id have it lol but based on what reading i skimmed thru here and prior knowledge i think the blocks are the same or similar. Id jus be concerned bout timing and id like to keep the stock pcm so i have no issues tuning with my current setup but if i really had to go with an aftermarket system of some sort i prolly wouldnt mind that much if i culd make it work. Id also wanna make sure the heads are ported jus about as much as possible or jus enough to flow properly, high performance valve/springs of course and prolly stock cam or a slightly better one to work with the setup, perf block internals. I also noticed ppl on here wer talkin bout mix matchin the cradles of the blocks and oil systems and what not. Id have to figure all that out and more when it comes time to do the build and i rlly wanna go with that setup but for now im jus gonna stick to these head gaskets lol.

 

[CDW6212R]

The whole set of DOHC parts etc, are interesting for sure. But the bigger discussion should be the actual head flow of the DOHC heads, and the capacity of the 5R55E.

Several people have done well with the trans, that may be a hit or miss issue to have those survive at higher power levels. I would concentrate on the transmission in every way, cooling, VB upgrades, the PCM tune(after VB work), every possible modification is what I'd do there. I would not rely on luck to have the 5R55E survive at those power levels.

The DOHC heads on a 4.0 have not been documented in any useful way. Actual power numbers are needed, a full power graph, plus head flow figures. If the heads don't flow any decent amount more than the SOHC heads, than the whole big DOHC project is not worth the trouble. Given the age of these now, I wouldn't rely on finding results data from others.

I would locate the DOHC heads and have them flow tested, even if that could be done in Europe(before shipping if you found them there). I don't know what the SOHC heads flow either, there is not much useful data about the results(details besides power) of that engine either.

In a SBF head, flow should be way over 200cfm for performance, stock GT40's hit around 190cfm, those are low performance heads. Most older aftermarket heads could hit or be ported to the 250cfm range, high used to be 270cfm. Now prices have gone up, but the flow has too, 270 is somewhat common($1500 heads), but 300cfm is more common too($1800+). Top end stuff is easily 320cfm and up to over 400cfm($4k stuff). The TFS heads I found to build my boosted SBF flow about 315cfm.

You should hope the SOHC and DOHC heads flow 200cfm at least, and potential be there for 230cfm or more. I have no clue about those, just a random guess seeing the port sizes. Airflow is power, the boost adds more to that. If you can increase port flow by 30%, the power should go up some similar amount. So adding 30% more boost won't add 30% more power, restriction and heat(IAT's) cost a lot of that.

But actual airflow of the critical parts(heads, intake, exhaust), should achieve much closer increases to the flow gains, versus boost gains. Mainly in very restrictive combinations, like the stock 302 Explorer exhaust issues, and the stock heads. The V6's have much better exhaust manifolds than the 302, plus the slightly smaller engine(4.0 versus 5.0, 20% less).

 

[Devan]

The whole set of DOHC parts etc, are interesting for sure. But the bigger discussion should be the actual head flow of the DOHC heads, and the capacity of the 5R55E.

Several people have done well with the trans, that may be a hit or miss issue to have those survive at higher power levels. I would concentrate on the transmission in every way, cooling, VB upgrades, the PCM tune(after VB work), every possible modification is what I'd do there. I would not rely on luck to have the 5R55E survive at those power levels.

The DOHC heads on a 4.0 have not been documented in any useful way. Actual power numbers are needed, a full power graph, plus head flow figures. If the heads don't flow any decent amount more than the SOHC heads, than the whole big DOHC project is not worth the trouble. Given the age of these now, I wouldn't rely on finding results data from others.

I would locate the DOHC heads and have them flow tested, even if that could be done in Europe(before shipping if you found them there). I don't know what the SOHC heads flow either, there is not much useful data about the results(details besides power) of that engine either.

In a SBF head, flow should be way over 200cfm for performance, stock GT40's hit around 190cfm, those are low performance heads. Most older aftermarket heads could hit or be ported to the 250cfm range, high used to be 270cfm. Now prices have gone up, but the flow has too, 270 is somewhat common($1500 heads), but 300cfm is more common too($1800+). Top end stuff is easily 320cfm and up to over 400cfm($4k stuff). The TFS heads I found to build my boosted SBF flow about 315cfm.

You should hope the SOHC and DOHC heads flow 200cfm at least, and potential be there for 230cfm or more. I have no clue about those, just a random guess seeing the port sizes. Airflow is power, the boost adds more to that. If you can increase port flow by 30%, the power should go up some similar amount. So adding 30% more boost won't add 30% more power, restriction and heat(IAT's) cost a lot of that.

But actual airflow of the critical parts(heads, intake, exhaust), should achieve much closer increases to the flow gains, versus boost gains. Mainly in very restrictive combinations, like the stock 302 Explorer exhaust issues, and the stock heads. The V6's have much better exhaust manifolds than the 302, plus the slightly smaller engine(4.0 versus 5.0, 20% less).

I forget the name of the company but they used to make red bands for the 5r55e, along with other types. the company name was very reputable I'd have to research that I forget. But I think I might have the last of their red bands that they make or used to make LOL. At least that's what the guy on the phone told me he said they were the last ones they had nd that they were just sitting on the shelf. But now they're sitting on my shelf LOL. I got a whole bunch of upgraded performance parts for the 5r55e. but I'm even thinking those red bands might be too much and snapshit within the trans under serious shifting loads. I haven't had time to build my trans yet, I got way too much **** going on. but I still have the original 5r55e from my 01 sport which is what I'm going to be rebuilding along with the original motor (so it can be numbers matching lolol), and i jus recently installed my 3rd rear axle, the first axle was an open so I got an LSD out of a Sport Trac with the leather power front seats as well. On the second axle I spun one of the bearings within the axle tube so I said I'm not wasting any time with this one on to the next. Took the third one down to bare metal and painted it up just like the second one and I got one of those diff covers that supports the bearing caps. (Don't ever get like a square shaped diff cover they don't circulate oil properly, if you're going to get an after-market diff cover make sure it's shaped similarly to the stock one, i think gale banks has done excessive research and videos on this with some custom plexiglass diff covers so that you could see the difference within the differential assembly while it's in operation, I laugh when I see heavy duty trucks that have like a stupid squared diff cover on it.) Im at 334k on the odo. Also im getting rdy to do an SOA conversion in the rear, I have all the necessary parts I want again no time to do it LOL. But I'm also going to keep the sway bar in the rear. And I just got all the parts necessary for the superlift front suspension lift and then once I do that I'll ditch the torsion bars and get coilovers. I was even thinking ttb but that's too much work and I think I'd rather stick with the rack and pinion. plus the thing about these two door sports is they handle really good and hold the road really good but the suspension is really rough and most people would agree with that.

As far as the DOHC and SOHC head flow numbers, when the time comes to get them on the flow bench I'll let you know stock flow numbers of the cossie heads if i even get em and stock flow numbers of the SOHC heads too. And I'll also be sure to include flow numbers after porting of course. But that's a ways off so don't expect anything anytime soon LOL I'm currently moving into a new house and working on five or six cars nd my own cars and family cars, taking care of both of my half acre lawns etc etc the work never ends. but when the time comes I'll be sure to post flow numbers here and send them to you CDW. I wish the guy that started this thread would chime in again I'm sure his build is done by now. But damn did that thing look cool. Have you tried asking supersixmotorsports or Tom Morona Motorsports for flow numbers on the stock heads? Super six Motorsports makes some pretty good cylinder heads, expensive but damn good and they know they can charge out the ass for them. But they should be able to tell you stock flow numbers and flow numbers of the performance cylinder heads that they offer. you should call them up and say something like look I'm very interested in your top-of-the-line cylinder heads but I want to know how many cfm's overstock they pick up or something along those lines LMFAO. I'm sure they have that data but who knows if they're actually willing to share it. Plus there's a couple engine sellers on eBay that offer performance built 4.0 SOHCs along with other motors of course and they might have some data for you unless they're just selling the motors and not building them lol. But they want outrageous money for that **** and once again they know they can get away with that because there's not really anybody else that offers performance built 4.0s.

I would imagine it's probably pretty difficult to get those cossie heads in the US unless you know somebody or you get lucky on eBay. But I would also imagine that they're probably not that hard to get in Europe, u think im right about that? However it was probably easy to get em a decade ago LOL nowadays who knows. But even if need be Id buy a whole junk motor with those heads if I had to as long as they were in good shape of course. But like you said before since there is no flow numbers and not much data anywhere other than what we may have seen here in this post, there's no way to know if they're actually more viable than the SOHC heads although I would firmly believe that they would be, especially after some Port work, (hahahaha voice recog typed in "port twerk" hahaha) machining and rebuilding. Unless we're comparing them to some fully ported SOHC heads but even then who knows. Would you happen to be able to tell me all the vehicles that these Cosworth heads come in? I think some guy earlier in this thread referred to them as Bob Cosworth heads? On Tom moronas website under 4.0 stuff he has a couple items there relating to Cosworth heads like for example I see ARP head studs and the application says 4.0 v6 with cosworth heads and he also offers springs that say for ohc 4.0s and cosworth heads so maybe he has some data pertaining to what you're looking for.

 

[Devan]

http://www.supersixmotorsports.com/_pdf/2018/SSM201840SOHCHeadsCams.pdf

O here we go I think I found something at least. Supersixmotorsports says their stage 3 cylinder heads make 236 cfm on the intake side and 176 cfm on the exhaust side. If they had said that their cylinder heads pick up ## cfm over stock then we would know stock flow numbers. although I think when I spoke to somebody from supersixmotorsports they didn't seem like they were too inclined to want to help me out LOL so if you get in touch with them you might have a hard time with them over the phone LOL. If I find any additional data pertaining to flow numbers for the Cosworth heads or the OHC heads I'll be sure to let you know. Although I would imagine stock SOHC cylinder head flow numbers should be out there on the web somewhere. If you have access to alldata or fords PTS the information might be there. But like I said if I find anything out I'll let you know CDW. How's the mail truck going

 

[MrQ]

Sounds like a cool project!

On a side note:
Holy crap Super Six is proud of their work! $2000 for heads!! The shortblock is $6000!! $500 for ARP head studs!! You could build a 347 stroker for all that!
Yeah I know the SOHC can be made to make power, but after you put all that money in it and try to beef up the transmission to hold it, is it really worth it??

 

[CDW6212R]

Yes from what I've read it's much more expensive to build a SOHC 4.0 to anything but the stock level. My mail truck has the SOHC, and I wouldn't want to put big money into something that may not last, or still need special work occasionally. I prefer the 306 I planned. It would be about a 9.7:1 engine to run the same regular gas as stock, have heads that should be in the 230cfm or so range, GT40 intake that flows 260cfm or better, and a dual exhaust. I would bet 275hp is feasible, depending on how well the exhaust manifolds I'll make, turn out. That's way more than stock, and reliability would be very high for a long time.

 

[jwrezz]

Wow! I haven't seen so much talking on this thread in years! I'd think trying to build a SOHC motor would have moved on to an all electric conversion with tesla components by now!