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T O P I C    R E V I E W
mellePosted - 09 May 2020 : 18:14:04
I've wanted to build a fuel injected V4 for years, and I've started a K-Jetronic (Bosch mechanical injection) conversion project a long time ago that's still not finished. I've collected all the parts I need, done the basic design work and built an engine test bench, but living far away from my workshop and having a few other projects going doesn't exactly help progress. In other words, I'm nearly done, bar the actual build.

Because my flight to NL got cancelled due to corona just before Easter and I was running out of projects I could work on in Bath, I decided it was time for another injection project. I've learned a lot about engine timing in the past five or so years; it's a fascinating subject that led to the desire to build an engine with a fully programmable motor management system, like Megasquirt.

Although I can do a lot of work on developing an EFI (electronic fuel injection) engine at home, the engine will ultimately get built in the workshop again, so don't hold your breath for the end result.

I know a few people who've converted V4s to EFI, and each had their own approach. A chap from the US who used to frequent this forum a while ago has a nice build report from his EFI project on his website: It's all done to a high standard and it looks great, but using all new parts and spending lots of cash is not exactly my style.

The Ford 2.8 and 2.9 V6 came with EFI, and I thought it would be cool if I could massage a V6 manifold and plenum to fit a V4. I acquired one of each and started comparing them to the V4 manifold using a printout from a manifold gasket template from my website (2.8 left in pic, 2.9 right).

The 2.8 originally came with K-Jet and was only sold with EFI one model year; the manifold is not really suitable to convert to fit the V4 because the cooling layout of the 2.3/2.8 engine is different, so I decided to use the 2.9 manifold. 2.9 manifolds are relatively easy to get and not very expensive, whereas the 2.8 manifold is rare as hens teeth and will hopefully pay for the rest of the project (I got it cheap!). Here's a side-by-side comparison between the 2.9 V6 and the V4 manifold. The V4 one looks tiny in comparison!

The V6 is 12cm longer than the V4, so that's the amount the manifold needs shortening too.

Because the cooling layout differs between the engines, I'll need to create a cooling channel, which looks to be fairly easy. Some of the webbing will be removed, holes created and a bottom plate welded in. I don't have a mill, but I've had good luck milling aluminium with a router and a jig made of some rails before; just take it slowly and use a decent quality bit or a carbide burr and plenty WD40 as a lubricant.

I did some quick Photoshops of the envisioned end result, looks pretty good to me (ignore the blue tape), V6 for comparison first.

I'm VERY tempted now to get the hacksaw out, but a sensible voice in my head tells me to wait until I'm back in the workshop and use proper/ power tools. I'm not saying it'll be easy, but I've convinced myself today it's doable. I don't have a TIG welder, nor do I have any experience with TIG and aluminium, but I have a mate who can melt it together for me. I'm going to line everything up the best I can with a jig (thick piece of straight material where I can clamp/ bolt the parts to), tack weld it with the MIG and have my mate fully weld it. If there's any warping I'll have the contact surfaces milled by a machine shop.

Slightly worried about the height, not sure if this will fit under the bonnet of a 95/96, the hinge bar may be in the way. I think I can remove 1cm from the bottom of the plenum and about 1cm from the top of the manifold too if needed; with lower engine mounts I think I can gain another 1-2cm. Lowering the engine mounts might be advantageous anyway as I plan to slightly raise the suspension of my 95. We'll see, I'll measure a carb + air cleaner at some point but not the biggest issue now.

As for the management side of things, I think I'm going to use Speeduino (, an open source system based on a Arduino microprocessor and very similar to Megasquirt (it uses Tuner Studio software too), but much cheaper. The ECU will control both fuel and spark, so the distributor will eventually go. The layout of the ignition will be a bit like Borstlap's Megajolt project, but without the EDIS module (although I think one can be integrated to create a limp-home mode in case the ECU dies):

Next step is to rebuild and test the injectors I have and decide on the ECU I'm going to use. As things look now, I'll be ordering a Speeduino DIY kit at some point and do all the soldering myself. Not something I'm very experienced with, so should be fun.

Just to be clear, I'm not aiming for maximum power or anything, I just want to build some nice engines and enjoy figuring everything out. I drive like a granny and I'm not one to build useless muscle anyway. I'll write about my K-Jet project another time.
15   L A T E S T    R E P L I E S    (Newest First)
DirtbikerPosted - 23 May 2021 : 16:30:48
That looks ace!
mellePosted - 22 May 2021 : 20:25:47
Tapped most of the threads today, unfortunately I'd forgotten to bring my NPT taps from the workshop so I couldn't do the last two. Now I need to find someone who can turn the final injector bosses for me and TIG weld them in.

Coming together nicely!
mellePosted - 19 May 2021 : 14:57:08
You're right, no need for a cooling/ warm-up channel in an injection manifold, but you would indeed need a way to channel the water from the back of the heads to the thermostat housing (which of course can as well be located elsewhere/ remotely). I think a channel would still be the easiest and neatest way, it could either be machined as an open channel and later closed off with a piece of aluminium strip as I was planning to do with the converted 2.9 manifold, or a piece of pipe that runs between intake the runners.

An alternative approach to machining a manifold from billet, would be 3d printing either a model or a mould, and casting it. The casting will still need fairly extensive machining though. I have a wire model of a manifold in CAD and may give fully modelling it a go at some point, but if only the lower part is needed I think it's cheaper and easier to modify a standard manifold, 1bbl ones cost next to nothing.
AnttiKPosted - 18 May 2021 : 19:03:38
Yes, quality looks very good especially in the more complex throttle body adapter. And the price is quite cheap. I think the material costs here in Europe for the aluminium billets would be noticeable part of the price, probably.

This makes me think that what would be the cost for the injection intake manifold or just the lower part of the manifold, where the upper part could be welded 'easily' or modified from V6 manifold. Certainly cheaper than the new crossflow manifolds (2000-3000) for V4.

The cooling channel in the lower part of the manifold would be a challenge, but I think it is not necessarily needed to be there, because front water channels are blocked from the cylinder heads and the fuel mixture is not needed to warmed up by coolant in injection engines. Coolant lines could have connection flange in rear part of the engine.

mellePosted - 18 May 2021 : 17:17:18
Got my machined parts yesterday. I had them made in China through and my expectations of the quality and lead time were very low for the money (200 incl shipping). To say they exceeded my expectations would be a gross understatement, well pleased with what I got. The quality of the machining and anodising is excellent, and the parts are free of any blemishes, machining marks or burrs. There are some intricate details in the design and they're all perfectly executed to spec. Quoted lead time was a month, the parts were delivered in just two weeks. (I sound like an influencer now don't I!)

I'm tapping all threads manually as it saves me modelling them and reduces the chances of error (it's not something I do every day...). Perhaps it makes the machining a little cheaper as well, but I haven't tested that as I would still need to model them (you can get instant quotes on the Jiga website, so it's really easy to compare different designs).
AnttiKPosted - 07 May 2021 : 06:37:23
Nice work Melle! Especially the separate moveable engine bay looks very handy to test the part fitment

307 cooling fan looks quite big. Probably smaller one will do the job as well.
mellePosted - 06 May 2021 : 19:25:08
It's been quiet here for a while, but I've not been sitting on my hands! in December we went to NL for a few weeks, and a day after we arrived the borders closed. We ended up spending nearly three months there, which meant I got a chance to enjoy all sorts of nice things I can't do at home, such as cycling on my recumbent, driving the 96, ice skating and playing in the workshop.

First thing I did was building a trolley for an engine bay I've had kicking around for years. I got it from a friend who's converting a 95 into a camping trailer.

Engine bay with random engine block ready for test fitting different injection set-ups and cooling system ideas (here with K-Jet manifold):

EFI engine

I started by trial fitting a Saab 9000 radiator with a Peugeot 307 fan in front of it. I'm not entirely happy with the fan yet, I had to cut into the lower valance and bend the metal out a bit to make it fit. Not a big issue and fixed with a little welding and grinding, but if I can find a shallower or slightly smaller OEM fan that fits without any metal work I'll use that. Yes, I could use a Kenlowe fan, but where's the fun in spending money on new stuff if you can mess with scrap parts! The bonnet does fully close, but it's missing the catch pin for some reason (give me a shout if you happen to have a spare!).

All was looking rosy with the V6 manifold until I tried it onto an actual engine (the mock-up I have at home is just two heads on a plywood base):

Ooops, it seems I completely forgot about the timing gears being in the way... The 2.9 has a chain instead of gears. I've been giving this some thought and there are basically two solutions: modify a chain set-up from a 2.9 and have a custom cam made () as it rotates in the opposite direction, or graft the top end of the V6 manifold onto a V4 manifold. I'm planning to do the latter, but that'll have to wait as I have so many other projects at the moment.... In the meantime, a pattern maker with extensive Saab and rally engine building experience has offered to make me an EFI manifold from a standard 1bbl one. So, even if I don't have time to build a cool plenum manifold any time soon I could use his to get an EFI engine running and start playing with the ECU.

On this engine I want to try and run an electric water pump instead of the mechanical one, controlled by the ECU. Not sure about the order of projects, so ideally I want to be able to run it as a stand-alone system as well, perhaps with the K-Jet engine. I was looking at Davies Craig EWP80 pumps (, but they're fairly expensive. A few people on RetroRides suggested BMW/ Pierburg pumps (, of which I now have a few.

Pierburg CW200 to the left and CW400 to the right:

One of the pumps I bought turned out to be broken. Too bad but that's what you sometimes get when buying the cheapest stuff you can find on eBay, and a good opportunity to take one apart. I'm impressed with the design, these pumps are fully sealed with o-rings and have a brushless motor with through coolant. The only real weak spot I found was the rear carbon bush the motor shaft runs in, which was broken and can't easily be replaced. Because the motor has through coolant and the armature is magnetic as hell, I guess once the tiniest piece of metal/ rust enters it, it jams up due to the small tolerances, and the bush shatters.

My top tip when using second-hand OEM parts is to always buy multiples. Parts that are now cheap and easily available from scrap yards/ eBay will be difficult to find and expensive in a few years time when they may need to be replaced.

Because I won't need the mechanical pump any more and I'm using an electric fan as well, I've modified a timing gear cover. The bathroom was my workshop of choice this time, and I only used hacksaws, files and emery as all my fancy tools are in NL:

Came out pretty nice I think. The hole will be plugged with a brass freeze plug after blasting.

K-Jet engine

First, I confirmed the manifold with the Porsche TB and air intake boot fits under the bonnet. It was a huge relief to find it does, only just:

I then found a nice spot for the air box with fuel distributor head. The one in the photo is from a Golf, but even if I use a different distributor, I can fit that to the Golf airbox as that tucks behind the headlight quite nicely. I'll have to modify the exhaust a bit, but that's not a problem as I'll be making 1.3/4" custom downpipes anyway.

I was going to just push the injector bushes into the bosses, but then I wasn't really comfortable with them just being held in place by friction. OEM bushes are no longer available and the quality of the aftermarket ones is very poor and they disintegrate over time. A potential recipe for air leaks... I've cut 3/4" BSP threads on the injector bosses so modified garden hose connectors can be screwed on as retainers. I could have used off-the shelf ones, but I couldn't find any that were skinny enough. Did I already mention everything's a tight fit?

The injectors all sit at different angles due to the lack of available space, and some spray more or less straight into the wall of the intake runner if I don't make any adjustments. I've sliced two heads, so I can fit them up to the manifold and see exactly how the injectors sit in relation to the runners, and how much material I can remove for the maximum amount of free flow without cutting into the water jackets. I can also still slightly adjust the length of the injector bosses if needed.

Lastly, the adapters for the throttle body and the thermostat housing/ WUR/ AAV are now being manufactured from 6061 aluminium, and they should be here within a couple of weeks. When I've decided on the final lengths of the injector bosses I'll need them TIG-welded in, and I need to drill and tap a hole for the thermo-time switch, and that should be the manifold done.

Sorry for the terrible photos, my phone's camera is on the way out it seems.
mellePosted - 29 Nov 2020 : 18:49:54
Very interested in following progress on the wheel hub conversion, please start a project thread!
AnttiKPosted - 29 Nov 2020 : 18:40:39
Good progress again Melle! Especially the Jetronic component layout looks brilliant!

In my project I got the engine block bored to 91.3mm OHC pistons and polished 1.7 crank with STD bearings back from machine shop. Also I am working on a wheel hub conversion to 4x100 with Golf III front hubs, Polo -97 driveshafts and Megane I rear drums. So there will be nice hobby for dark winter evenings
mellePosted - 28 Nov 2020 : 13:45:41
They won't run this year, that's for sure, and with my snail pace I doubt I get either of them running in 2021. No problem for me though, it's about the journey etc.
WoodyPosted - 28 Nov 2020 : 12:57:25
Very inventive, way over my head !
DirtbikerPosted - 28 Nov 2020 : 12:07:37
Coming on really nicely!
James RanaldiPosted - 28 Nov 2020 : 09:01:07
Genius Melle. Can't wait to see this one fired up.

1968 V4 96 ,LHD
1984 99 GL
1987 C900SC 2door
1993 C900 LPT Convertible
1987 C900 2 Door
mellePosted - 27 Nov 2020 : 19:49:58
He uses a turbo, which I'm not planning to do for these builds. I can't expand the video because I don't have a Facebook account, so can't study his set-up in detail (it doesn't help that most of the time the wings are in frame instead of the engine!).
UK_SubPosted - 27 Nov 2020 : 19:23:37
Have you seen this setup (sorry if this is a hijack), but it looks similar to what you're doing and the exhaust exit is worth a look too!

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