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Oct 23, 2021 16:31:17 GMT
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After months of planning and collecting parts to build an average pinto I stumbled across a partially built NA YB Cosworth engine that I couldn't say no to (it was cheap, and I'm bad with money). While I can find tons of info on building a pinto information on NA YBs seems to be more scarce, especially when it comes to building a road use engine instead of a rally / track only one, has anyone here done this?
I'm aiming to keep things relatively cheap and simple by using a distributor and twin Weber setup instead of converting everything for EFI, has anyone here got experience with doing this? As it's going on the road I plan on setting a rev limit of 8000rpm (its fully forged and the crank is dowelled so it should hold together fine), so the focus will be on mid range torque and power over maximum BHP.
Any input / advice / pub stories of 300bhp NA YBs is greatly appreciated!
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Last Edit: Oct 23, 2021 16:31:44 GMT by bagpuss86
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Oct 23, 2021 18:51:58 GMT
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This sounds very interesting I've never heard of one. Have you thought about a bike carb kit? Maybe R1,1100rr etc? Giving it a carb per cylinder . I'm going to either buy or try and build a set with gsx750 carbs on my 1.6 bluebird. Was quoted £900 for a carb kit and £2200 for throttle bodies
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Oct 23, 2021 19:02:55 GMT
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I did debate that, but there really isn't much difference in cost between the full bike carb setup and a pair of second hand Webers on a YB manifold. I did also briefly think about ITBs but the cost of a loom and ECU makes it a very expensive option compared to a dizzy and carbs
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stealthstylz
Club Retro Rides Member
Posts: 14,924
Club RR Member Number: 174
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Building an NA YBstealthstylz
@stealthstylz
Club Retro Rides Member 174
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I built one for a guy, they're not very good imo. They look nice in the engine bay, curse word for making power though.
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I'd have thought that with current technology, you'd be getting the same sort of power from a standard duratec? Don't forget that the cosworth is basically 80/90's, and things have progressed quite a bit since
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Darkspeed
Club Retro Rides Member
Posts: 4,841
Club RR Member Number: 39
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Building an NA YBDarkspeed
@darkspeed
Club Retro Rides Member 39
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A search on the Turbosport forum will give you all the info you need. Most advice will be not to bother as the heads just don't breathe well enough.
Burton Power site guide kind of sums it up....
A different route, and still popular way to tune the YB, is to return it to the original N/A application, which involves raising the compression. For this, we stock Accralite forged pistons to increase the ratio to as much as 12.5:1 although they can be machined to lower the CR since they have raised CROWNs for this purpose.
On top of this modification, the head needs the ports seriously opening out and for ultimate horsepower applications, larger valves installed. The cams too need swapping for non-turbo profiles although they aren’t designed to work with the standard YB hydraulic lifters and therefore need converting to solid lifter type.
The bottom end is fine for this type of aspiration since the rods and crank are both steel. We would recommend however, that the rod bolts are upgraded for high-revving applications. For ultimate power though, we also stock steel H-section rods. Lastly, you will need to swap the turbo inlet manifold for a twin DCOE type allowing either 45/48 side draughts or throttle body fuel injection. In this form, you should be able to achieve in excess of 225bhp+.
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stealthstylz
Club Retro Rides Member
Posts: 14,924
Club RR Member Number: 174
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Building an NA YBstealthstylz
@stealthstylz
Club Retro Rides Member 174
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Just to add to my comment above - personally I'd sell the bits used to convert to n/a and go back to a turbo. They are a stonking engine with boost.
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Oct 24, 2021 14:55:11 GMT
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My bad, I forgot to list the current spec of the engine, that would've helped! It's as follows:
Forged high compression Wossner pistons Forged Williams racing rods with ARP studs Double dowelled crank dowelled flywheel to match ported and skimmed YB head (138.1mm height) with solid lifters, running ford cams but not the standard turbo ones - unsure of duration and lift.
So the bottom end is already done, and the head has already been machined for NA use, unfortunately going back to the turbo setup would be an expensive route!
There's certainly something to be said for modern engines and the powerband they produce, but where I'd save money on building the engine I'd end up spending thousands on mounts, a modified tunnel, adapter kits, a new prop and an ECU + loom. The YB will drop straight in and bolt up to my current gearbox.
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stealthstylz
Club Retro Rides Member
Posts: 14,924
Club RR Member Number: 174
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Building an NA YBstealthstylz
@stealthstylz
Club Retro Rides Member 174
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Oct 24, 2021 19:57:13 GMT
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The problem with the one I did was to get the air flow to make reasonable numbers the cams were a bit wilder than I'd ideally use for a road engine. Looking at the spec I'd just go for it and see what happens, it's probably £8-10k's worth of engine as a done running unit so worth making it work anyway. I think maybe I'm just spoilt as a very basic 2.0 Duratec makes the same power for about 1/4 of the price.
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Oct 24, 2021 20:03:31 GMT
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sounds like a great spec, it's probably worth quite a bit to a guy with a mk1 or mk2 escort or something like that.
But if all the hard work has been done, then go for it as is.
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You might be better off putting something like a megajolt set up on it rather than a distributor, the cost isn't much different (compared to a custom distributor) and it gives you so much more opportunity to set it up to drive nicely. If you want to keep it vaguely original looking you can mount the coil where the distributor would go.
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My brother built one years ago. Wossner pistons, L1/BD3 cams solid lifters, ports bored to 1”, twin 48’s and it struggled to make 200bhp. He stripped it and took it to Russ Tyler to see what the issue was and he said they just don’t make the power. He said you could cam it up to get the pub figures but it wouldn’t be be very good. If it’s a road engine, who cares they look and sound fantastic. What are you putting it in?
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Last Edit: Oct 25, 2021 9:44:49 GMT by jonsey
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Darkspeed
Club Retro Rides Member
Posts: 4,841
Club RR Member Number: 39
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Building an NA YBDarkspeed
@darkspeed
Club Retro Rides Member 39
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Sounds like the bottom end should be strong enough. The rest really depends on the head cams and carbs - I expect that if the valves are stock you will be approaching 200BHP with good porting work and 45’ s. With a big valve head extensive porting and 48’s then 240+
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Oct 25, 2021 10:25:15 GMT
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How often do people use more than 200bhp on the road anyway other than short bursts? Not as much power just means you have it screaming more of the time 😁
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Oct 25, 2021 11:08:39 GMT
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How often do people use more than 200bhp on the road anyway other than short bursts? Not as much power just means you have it screaming more of the time 😁 I would agree, if it were just about power you are on a hiding to nothing against boosted engines, but for something that sounds great and drives well and has a nice linear response 200 bhp will be fine, I'm guessing it's going in something with a less than state of the art chassis as well for which too much (particularly laggy boosted) power can make the driving experience closer to terrifying than exhilarating!
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Oct 25, 2021 11:33:37 GMT
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Belive it or not it's going in a Cortina P100, so not something I plan on going over 100mph in! It'll definitely make for a fun and unique vehicle though, and that's my main aim (no photos yet, it's going in to the restorers at the end of November for major welding and some fancy paint).
I've never really looked in to Megajolts / Nodiz setups, all my previous cars have had EFI, are they simple to set up? Would there be a way to use the distributor as a trigger wheel?
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slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
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Building an NA YBslater
@slater
Club Retro Rides Member 78
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Oct 25, 2021 12:31:25 GMT
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Like all NA engine building it all kinds of revolves around what cams you're going to use. That's what I'd be looking at first. If it's a road friendly profile I can't seeing it pushing the limits of anything but you will need to end up at a different compression ratio etc so if the engine was built to rev you might find you've got a bit of work there.
No brainer to go for megajolt or similar tho. You must be able to get a trigger wheel kit for these off the shelf I'd have thought? No messing about.
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Oct 25, 2021 13:35:53 GMT
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The quote I got for bike carbs was to run alongside the existing distributor fire an email to danstengineering he might be able to help with advice, best setup and costs
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Oct 25, 2021 15:10:04 GMT
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I mean, 100bhp/litre is pretty respectable. Yes it might not be the 200bhp/litre you'd get from a turbo version, or the 120-130bhp/litre you'd get from an NA Honda engine/Peugeot TU/BMW SXX, but it's a respectable figure nonetheless.
It'd be interesting to see what the limiting factors are. Whether it's something hard-baked into the design, or an example of people applying tuning approaches from a different engine that don't work on the YB. Mainly asking because you see a lot of people who are used to turbo engines just hogging out inlet ports and killing velocity, and other bits and pieces like that.
Although I suppose there's enough folks out there into Fords that most things will have been tried already with something as ubiquitous as the YB. It's not like the Rover 2600 where you can count the people who have tried anything with it on one hand, so no-one really knows the capabilities of it.
I wonder what prevents them getting higher (again, 200hp out of an old-school 2.0l is pretty good going anyway!)...
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Last Edit: Oct 25, 2021 15:10:34 GMT by biturbo228
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Oct 25, 2021 15:47:24 GMT
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Cam profiles are a point I'm looking for advice on, my initial plan was to go with a high lift, short duration cam and try to keep the powerband usable on the road, but as you say the CR with high compression pistons may be too high for this - I guess the answer is I need to get the static CR calculated first.
You can get trigger wheel setups for them but I've never liked the look of the aftermarket kits, always makes an engine look untidy. If there was a trigger wheel I could hide in a distributor housing I'd be all over it.
If I could make 100BHP/L I'd be more than happy, really I'd be happy with anything above 170bhp!
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