Is the Motus V4 Baby Block Crate Engine the Future of Old School Hot Rodding?

Motus announces MV4 Baby Block crate engine pricing

Motus announces MV4 Baby Block crate engine pricing

Motus just announced pricing and availability for their all new MV4 Baby Block engine. You can reserve yours now for delivery this spring and summer, the price is $10,220 which includes the ECU, ride by wire intake, engine harness and fuse box. While most everyone here is focused on the Motus MST and MST-R motorcycles, the engine strikes me as equally, if not more important in many respects, because, in my opinion, it could represent the future of old school hot rodding.

We've covered a lot of motorcycle engine powered cars on The Kneeslider with V-Twins, inline fours, just about anything you could find in a bike has been shoehorned into a car, the small size and high performance is just too much to resist, but the brand new MV4 "Baby Block" engine designed and built for the Motus MST is different, it's a compact and lightweight engine with strong family ties to the automotive world, it's a cam in the block, pushrod V4 just waiting for all of the old school hot rodding that drag racers and hot rodders have been practicing for the last 60 or 70 years. At the same time, with gasoline prices well over $3.00 per gallon and CAFE regulations mandating dramatic increases in fuel mileage for new cars, the MV4 is a perfect way to transition from the old big block V8s while still being able to use all of the same hard won knowledge for boosting performance.

Look at the specs:
• 1650cc (100ci), liquid cooled, cast aluminum 90° V4 w/ steel liners
• Cam-in-the-block, 2 OHV
• Splayed lifters for maximum valvetrain stability
• Aluminum cylinder heads w/ splayed & canted valves for max. flow and combustion efficiency
• Automotive-style low mass, low inertia roller rocker arms
• Maintenance-free hydraulic roller lifters
• 4340 forged steel I-beam connecting rods
• 3-ring forged aluminum pistons with moly coating
• Wet sump w/ integral pick-up, serviceable screen, magnetic drain plug
• 4 bolt main bearing girdle for maximum strength and durability
• Investment cast 4340 one-piece crank w/ automotive-style plain bearings
• Gerotor oil pump, integrally cast internal water pump
• CFD optimized, precision cast water jackets
• Closed loop 250kBd multi-point fully sequential fuel injection
• Ride-by-wire w/ electronic throttle control (ETC)
• Cast individual runner manifold w/ 4 x 40mm contoured bore downdraft throttle bodies
• 12 bolt bellhousing (9.5” bolt circle) for easy application adaptation
• Spare bosses for alternate accessory drives and motor mounts

Motus MV4 Baby Block engine

Motus MV4 Baby Block engine

If you didn't know this was designed for a motorcycle, you'd be thinking you were reading the specs for some small displacement automotive engine, or airplane engine, or boat or off road vehicle or midget racer or whatever you can dream up. How about a Mini with one of these under the hood, or any small car, or ...

We wrote about this before and there was a long discussion afterwards, but after all of the hopes and doubts and wishes and skepticism that has surrounded this project and engine, the imminent availability of the MV4 as a crate engine just gets me all warm and fuzzy. And for all of you who may have missed it or forgotten about it, I've included the video of the prototype below, there's a few minutes of talk leading up to a short dyno run at the end. Listen to that dyno run with your speakers turned way up. Then, listen to it again. The future of old school hot rodding? Oh yeah!

Video below:

Link: Motus Motorcycles


  1. Greg says

    Soooo cool! This definitely does not have the feel of a fly by night, garage effort and I agree, Paul, there is something really interesting going on at Motus. I sent them a nice “thumbs up” note on their website and was rewarded with a couple of killer V4 ringtones by email. Unreal! I’d love to see it in a Polaris RZRe. Go Motus!

  2. sfan says

    I agree Paul. It may be of even more interest to the kit car world or UK small volume builder scene. It would certainly be a sweet engine in something light, for example Caterham 7 or something like the Beck 550.

    • Paul Crowe says

      A Caterham that sounds like a little NASCAR racer and goes like a rocket, plus the MV4 would fit in there better than the Hayabusa based V8s a few builders have installed.

  3. r4990 says

    It is sad that there are so few candidates for engine swaps out there with simple front/rear/mid engines and rear wheel drive. You could adapt it to transverse but it would be much more complex.

    Of the smaller rear wheel drive alternatives even the Miata would be too much weight. Of the older small candidates, cars like the Sprite are getting too pricey. A Lotus? Sacrilege! Likewise the 914 or the Beetle. I suppose you could always go the Kit Car route but they are even more expensive to build.

    Maybe I could put it in my Samurai.

    I remember when I bought a 1972 914 in good shape and put a V8 in it. It only cost $2000 for the car. I bought the adapter kit from Rod Simpson and I was in business. The total cost was only about $6000. Those were the days.

    • BigHank53 says

      Colin Chapman would have sprained both his arms to get an all-alloy engine putting out 165 hp into one of his cars.

      Have you checked out the LoCost book, a guide to building a Super Seven copy on the cheap? His numbers are unrealistic, but it can be done for not that much cash.

      If you live someplace where you can find a rust-free sample, one of the old Toyota Starlets would be a hoot with this motor in it.

          • Wave says

            It doesn’t really matter how much heavier it is, when it costs less than a tenth of the price! I assume that todd is talking about a Toyota 3S-GE engine. If so, according to Wikipedia, they weigh about 143kg (315lb) and that’s with an iron block.

              • Kyle T says

                Half the weight? I don’t think that the Motus engine weighs 150 pounds.

                Of course, a 1-liter sportbike engine weighs 150-200 pounds and makes 150-200 horsepower. They are also the same size or smaller than the Motus engine.

                There are LOTS of good options out there for small, light 150-200 horsepower powerplants for swap applications. The idea that this is a game-changer is nonsense.

              • Wave says

                I agree with Kyle T. There are plenty of modern 4 cylinder car engines which will do the job. Ford Duratec (Focus), GM Ecotec (Vauxhall/Cobalt/etc), the list goes on. If you want to keep the weight down, the Mazda MX5/Miata engine is pretty light, and with tuning and/or turbocharging it will make the power required. Similarly any of the Honda VTEC engines would be a good transplant candidate, or a Mazda rotary.

              • Wave says

                Brian from Motus has just commented below that the engine weighs 135 pounds, which is very impressive! It would actually make a good spec engine for an open-wheel racing formula, like Formula Ford. A small hillclimb special would also be a good application. It would be a shame to put it in a street car, they would just weigh it down!

  4. Renegade_Azzy says

    I would love to toss one of these into a small track style car ala the Ariel Atom, or maybe into a Suzuki based tube buggy for the woods.

  5. Walt says

    Last year at the annual rod and custom show a guy showed up with an old school coupe (deuce or something like it) powered by a GM Quad Four. The engine looked good and losing weight up front is always smart, unless you are a female porn star. This V4 would make another great power plant. I have to wonder, though, how many would spend $10K and choose to buck the tradition of the small block crate V-8.

  6. Adam says

    Wasn’t this engine supposed to feature direct injection? They mention it in their video, but direct injection is no longer mentioned anywhere on their website.

    I’d love to shoehorn this motor under the hood of a Datsun 510.

  7. Jobie says

    Adam~ GDI was ditched on the production motorcycles for unknown reasons. The production models run traditional fuel injection and come in two forms MST and MST-R, 165hp and 185hp.

    • Adam says

      The loss of the GDI system is somewhat disappointing, that was a feature I was really looking forward to seeing.

      When you consider the power output of this engine compared with similar size engines from the automotive arena, the peak power isn’t overly impressive. Honda’s F20C 2 liter 4 cylinder engine made 120 hp per liter. NIssan’s SR16VE 1.6 liter 4 cylinder engine made 107 hp power per liter. The Motus KMV4 makes 97 hp per liter in MST tune.

      The power per liter deficit grows even further when compared to smaller, high performance I4s found in super sport motorcycles.. A BMW S1000RR makes almost 200 hp per liter.

      However, the automotive engines are producing peak torque near their redlines, creating a narrow and peaky power curve. Drivability is lost. The super sport engines are worse. The Motus engine makes peak torque at almost half it’s redline, creating a HUGE power band.

      This motor will be a monster.

      • Greg says

        Jobie and Adam, the GDI sounded intriguing, but I recall reading (maybe Car&Driver or Hot Rod?) that modest power/efficiency gains with GDI were overshadowed by resistance of the dealers (Motus’ customers), aftermarket tuners and end users who were enthused enough to justify the increased complexity/training/diagnostic equipment,etc. I am glad they kept the ETC as it should lead to traction control, power modes, ABS, and cruise control over time (if not on the first ones).

        As far as the power goes, their intent seems to be torque, not hp (although 185 hp in a 500 lb bike isn’t too shabby) and with 120+ ft lbs around 4000 rpm, the MST-R could be one of the most satisfying bikes ever…HP is great for racing, torque is what satisfies me when I ride the twisties. I wanna ride a Motus…bad.

  8. jon spencer says

    I hope that someone puts one or two of these into a boat.
    Don’t know if it would work better as a inboard or inboard-outboard.

  9. Ecosse says

    while i share the enthusiasm for this engine, and bike powered cars, as the author i seriously doubt it will be replacing any big block.

  10. Steve says

    This would be a great motor for many applications. How about a three wheeler Morgan copy. The peak HP is a bit lacking compared to most DOHC motorcycle (HP per cc’s) engines but the power spread is real nice and that kind of tractable power is usually better on the street. And the sound…fantastic! Really too bad that the direct injection didn’t work out.

  11. B50 Jim says

    Oh, wow — too bad my ’73 MGB rusted away! This would be a righteous engine to put into any English roadster. 165 horsepower doesn’t seem like a lot, but the B’s stock 4-banger pushed it smartly with just 70.

    On the matter of cost, a rodder would have to be highly dedicated to building a rod around a Motus. For the same money they can buy a new-generation crate Hemi from Chrysler Performance, with enough left over for a Torqueflite.

    However, the possibilities are endless for Motus-based racing series — how about a mini-stock version of 60s-era NASCAR? Make ’em half scale, drop in a hot-rodded Motus and run like crazy!

  12. todd says

    I find it interesting that it comes with the transmission. You would think that, if the target audience was automotive, they would have offered the tranny separately.


    • Russell B! says

      I’m not seeing anything about the trans being included. Maybe I’m looking in the wrong place…

      • todd says

        probably not, just judging by the picture at the top of the page. The exploded CAD model doesn’t show the trans though.


        • says

          Maybe Brian from Motus can elaborate as to whether the transmission is included; and whether the trans could be purchased separately. I’d be interested in the transmission for a bike project

          • says

            But Doug, this was going so good without any elaboration.

            The MV4 gearbox is separate, so automotive, marine, aviation and industrial customers will be able to adapt the turn-key long-block (or is it half-block?) to just about anything. All cast aluminum, 135lbs.

            However, let’s say you had a Radical, or a T-rex, or a RZR, then you would want the whole MV4 motorcycle powertrain with our gearbox to drop in and just mate up the chain final to your rear diff. Remember, it’s only 185hp in the bike, because anything too much more than that in pushrod/small block architecture would need to stay on the dragstrip. Very fast, very torquey as is, even at 160hp. But comfortable. Engine is capable of so much more than that if you know what you’re doing. It’s designed to handle some serious abuse.

  13. Jim Kunselman says

    Yeah, B50 Jim,
    I had a ’67 Triumph GT6 and ’72 Lotus Europa, that sound of the howling Motus engine in either car would have me howling at the moon. Imagine the fun of trying to keep them in a straight line under acceleration, too. Ahhh! Wishful thinking.

    • B50 Jim says

      No problem, Jim; just replace those skinny Michelins with some good, wide rubber and have at it! Yes, that Motus howl makes me dream of the Mulsane Straight…

      The beauty of it is, it’s very possible. Plenty of old English sports cars exist, and the Motus boys will be happy to crate up as many engines as you need. All it takes is great bags of money!

  14. Russell B! says

    I would like to see it in a Westfield XI, the kit version of the Lotus 11. The Westy is designed for the BMC Spridget 1275cc engine that’s good for 70HP on it’s better days.

    I saw the Motus bikes when they were doing their tour a while back, they landed at a Houston dealer for an afternoon. Very impressive looking machines.

  15. SpiceBot says

    I had stated before that, funds being no issue, I would drop a Hartley H1 into everything that I drive. I may now have to re-think that statement.

    • Russell B! says

      The Hartley makes a ton more HP but the Mutus might be more fun to drive,what with the oodles of torque.

      Has anyone else imagined a 3.3 litre V8 version of the Motus? Call it the MV8 “DoubleBaby Block”. Hee hee hee.

  16. B*A*M*F says

    Does anyone know if there are automotive transmissions that mate up to this unit, or if Motus has a plan to make kits to adapt this to something automotive?

    • Greg says

      According to listed specs, there is a “12 bolt bellhousing (9.5” bolt circle) for easy application adaptation and spare bosses for alternate accessory drives and motor mounts” so that sounds relatively straight forward for adapting to various transmissions. The proof is in the puddin though….

  17. Manxman says

    Reminds me of the little european Ford v-4 motors from the 60’s, 70’s and 80’s. They were used in the Taunus, Capri and even in the Saab Sonnet. I think the smallest was 1200cc and the largest was 1700cc.

    • says

      Hi Manxman, the largest V-4 in a Ford was probably the Essex 2000cc as i have in my old Tranny van. Very nice engine, but only 86hp compared to the mighty Motus.

  18. says

    Forget all the other crap you could put this in… Imagine this thing in an actual MOTORCYCLE.
    Love it. Love the Motus company direction…

    But I’d Chopper the hell out of this thing.

  19. Rob says

    That motor is one lovely piece of kit. I don’t think it will be a future hot rod engine, it is too expensive. V8 crate motors start for under $2000, the Modus will be for custom one off builds with some sponsorship behind them. It’s designed for motorbikes and that is the only place it can compete. If you need a small car engine there are a million cheaper options that have spare parts and racing development. The foundation of hot rodding was based on mass produced vehicles that were cheap to tinker with. Japanese in line fours and Harley twins that feature here in some many projects are the current choice for most people wanting to hotrod a bike, the inline fours being cheap to come by though pricey to modify and the Harleys expensive to buy but cheap to work on. The future might be a large capacity Chinese engine if they ever get around to making one (or several million).

  20. Paulinator says

    I do like this engine, but I don’t know why they didn’t take the 60 degree v6 rout. My Chrysler Trenton engine sported a tiny little iron block with 3.8 liter displacement. Even with aluminum 2-valve posh-rod actuated heads, the unit cranked out over 250 ft lbs of torque and almost 200 hp. The engine was designed to push around vehicles that weigh over two tons with anvil-solid reliability. Amazingly, the valve covers span 13 inches!!! I would love to tuck one under a set of fat bobs.

  21. Velocitré says

    Well, it may be sacrilege, but I bought a ’68 Bug for my RC51 engine. I was originally looking for a mid-60’s Fiat 500, but realized that the transaxle wouldn’t hold up. It’s gonna be a hoot, as soon as I can get some garage space….

  22. Robert says

    The engine is cool, no doubt. But as many have posted above, you could save so much money sourcing out a great engine from a wreck, such as a Honda S2000 engine. Rolling chassis for Lotus Seven clones are everywhere, good sources including Westfield.

  23. says

    I could envision this thing with a baby Roots blower on top, with finned valve covers and side pipes, in a smaller-sized T-bucket roadster.
    That would be a blast to ride around in.

    [Beach Boys voices} I’m gettin’ bugged driving up and down this same old strip
    I gotta finda new place where the kids are hip[/Beach Boys voices}

  24. Al says

    Maybe an interesting swap into a tr6 bit pricey though when ford 302 v8 swaps are so well documented.

  25. matt lynch says

    I used to own a Miata, and had been thinking about going with the monster Miata v8 kit, and a friend’s donated 5.0 lump. a v4 Motus powered miata would be insane. does anyone want to give me about 25k? i’ll have it done in a month. 😀

  26. says

    I could see this in a ligjyweight car, just use an aftermarket tranny such as a tremec tko that was never in a car yo begin with. Or a custom midengine car.

  27. hate2wait says

    Everyone wants to compare this V4 to the likes of the H1 V8 derived from Suzuki Hayabusa uppers. Yes the H1 V8 is quite an engine weighing in at 200 pounds and putting out 400 hp. But the price of $30,000.00 sends it clear off of the map as far as hobby use. This is seriously expensive and for what? the heads, valve train and cylinders are already manufactured by Suzuki. The 30 grand is just for purchase of the Suzuki parts and the crank case with rotating assembly. Enter the Motus V4 at $10,000. Complete engine all built by the same engineering co. Seems as though the H-1 is price gouging to the tune of say about $20,000. Motus are at least more honest about the value of their engines. Also the Motus is a hardy design which will likely outlast the H-1V8 several times over. They are out to build fun for the masses, not fun for a very few so the masses can watch others have fun. The Motus is just what the doctor ordered. Thank you Motus, put me down for one V4 to go.

  28. Jim D says

    From the first moment I saw this engine,I knew I was going to put one in my TR6. AWESOME! AWESOME! AWESOME!

  29. says

    The person behind Motus came from Confederate Motorcycles. They had a plan once to slice two cylinders from an American V8. Unfortunatly nothing came of it. I thought that idea was very interesting. The current Motus V4 project has been in the works now for many years. All I’ve seen to date are two prototypes. They are now looking rather dated. All they while a used Ducati ST2 or Aprillia Futura look like a better bike at give away price. I don’t see any market for this bike or engine at all.
    Whilst I like the idea of small American motorcycle manufactures combining with the American automobile industry. I feel Motus should have gone with a far more strikeing design than a staid sports tourer. It’s like they are trying to take on Ducati and Honda, and we all know how that one ends.