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RichardSIA Reader
8/21/20 10:42 p.m.

I'm taking over an incomplete Locost 7 build.

Originally set up for Mazzzzdaaa, yech!

So, I have a choice of engine upgrades available.

Warmed up Buick 231 and four speed, NOS (Zero miles) carbed Buick Turbo from the 80's with four speed (Will it fit under the bonnet?), and Buick 215 V8 with VERY hot 11-1 pistons, road race cam etc. All run surprisingly close for cost. The warmed up 231 is an engine I already have that was intended for a different build, so less out of pocket at this time.

The cheapest but more complicated and lighter path would be a Suzuki 1.6 16V. They can be found and rebuilt very cheaply but suffer from fuel-infection and ECM headaches. I'm not much of a fan of Japanese engines but the Suzi's are aluminum block and head with SOHC and around 100 HP which should be fun, but not a killer of inexperienced drivers.

The main factor to drive the decision is "What would sell best-most $ once completed"?

Suzy and five speed are simple, five speed can be added to the Buick's but drives cost up.

Not certain what the retail value of a nicely done Locost 7 is these days, I expect engine choice influences that fairly heavily.

Reasoned suggestions that do not involve LS!, Ford, Honda, Miata will be appreciated.

stuart in mn
stuart in mn MegaDork
8/21/20 11:05 p.m.
RichardSIA said:

The main factor to drive the decision is "What would sell best-most $ once completed"?


So, the point of this project is to flip the car when it's done?  If so, the engine needs to be something that appeals to the buyers.

Is there room in the chassis for the V6 engines?  I'd think the width of the frame on a Locost may be tight for a V engine. 

bentwrench SuperDork
8/21/20 11:07 p.m.

Of your 4 choices for best value I'd use the Suzuki, because of weight and the 5 speed.

It won't leave black marks to the next corner, but you won't have to slow down much to turn a corner. And it honors the Seven design concept ideals.

It will also leave you more foot room and fewer/easier engineering compromises

I would retain the EFI hardware and run it with a MegaSquirt.

Does the Suzuki favorably accept boost? A turbo would take care of any power deficiency.

SkinnyG (Forum Supporter)
SkinnyG (Forum Supporter) UberDork
8/21/20 11:07 p.m.

My Locost has a 4AGE, and it's a fantastic engine in this car.  Comparably, a Miata 1.6/1.8/20 would also be fine.

For my Locost #2 (still in the wings), I picked up a 2006 Ford 2.0L Duratec back in 2008, it's been in my garden shed waiting ever since.

While the Duratec was a wise and awesome choice 12 years ago, today I'd look at an Ecotec, preferably turbo.

The big factor here is mainly packaging - will it fit?

Followed by whatever rules you need to follow to whatever motorsports you want to participate in.


SkinnyG (Forum Supporter)
SkinnyG (Forum Supporter) UberDork
8/21/20 11:08 p.m.

Used Locosts tend to go for about $9,000-$12,000 depending on how pretty it is. There are LOTS of ugly ones.

bentwrench SuperDork
8/21/20 11:31 p.m.

There is a stock EcoTec motor that puts out 345 ponies!!!!

This is the motor I would use.

Incredible power to weight in a compact package that is completely tuneable.

RichardSIA Reader
8/22/20 12:48 a.m.

Rebuilt Buick V6 runs about $1,500 - $2,000 all in. Another $800 - $1,200 for the trans, add another $800 for new five speed. Buick 231 = 160 - 180 HP ands plenty of torque. Same McSorley 442 type chassis take SBF fairly easily but Buick is 4" wider so?

The Turbo Buick V6 is probably too tall for the whole package but remains attractive for it's being so unique. May have to find another project for that.

Remembered where I can get a Miata 1.8 complete drive-train cheap, but having had a Miata I'm not really a fan of that engine, the valve seals/head rebuild is a pain.

The race prepped aluminum 215 would be the winner if this were a keeper but it's not.

Goal to get this built quickly says keep it simple. I've never found F.I., ECM, CAT, etc. to be simple. Megasquirt is no longer inexpensive either. Other current or recent engines get just too complex with VVT and such.

Car will not be "Used" as it is a new build. To do better than break-even cost have to be kept in check. Plan to keep appearance close to original. Drove an original MANY years ago, it was incredible with it's tuned 1275 BMC engine. So almost any modern engine should provide a lot of fun, even a Suzy 1.0 would match original performance!

I will be building another as a keeper for myself, Triumph 1500 drive-train for simplicity and cheap. I have other cars for crazy speeds so my own 7 will be more in tune with original performance and power.

Not sure just how much power is "Required" by most buyers these days. Seems like everything has to be a "Could have been a Cobra" now. For a Locost I was kind of hoping the low stance, open cockpit, nimble handling, would make excess power unnecessary.

Have to go pick it up, then take a tape to it. I have core engines and trans to trial fit.

So, which is more important in engine choice these days, simple or latest tech? I lean toward simple but I'm not the intended end user.

8/22/20 4:53 a.m.

Lemme see...

You are building it to flip.

Car was built for a mazda engine, gonna guess miata, one of the more reliable engines you can get with huge brand recognition and an awesome gearbox. People who are not you, would consider that a plus and buy the car. 


You want to go to the trouble of picking a different engine and making it fit and run. Lotta work,Lotta $$.

If you cant sell it as is after a bit of clean-up and parts organizing, and make a profit, then chances are you are going to lose money going further down the rabbit hole. 

Pete Gossett (Forum Supporter)
Pete Gossett (Forum Supporter) GRM+ Memberand MegaDork
8/22/20 5:59 a.m.

I've seen a lot of unusual engine choices for a Locost - hell, I started building one years ago with a VW 1.8L. I agree with the posts above, a Miata engine absolutely 100% makes the most sense today. 

  • Most people are familiar with them
  • They're reliable
  • Parts are cheap
  • They're plentiful
  • They fit
  • Their use one a Locost is well-documented.

A 12A or 13B wouldn't be a bad choice, but it will also scare away some potential buyers. The only other option I'd suggest you consider would be an LS(but only with a manual). It meets most of the criteria of the Miata BP other than fitting into the chassis as easily. 

DeadSkunk  (Warren)
DeadSkunk (Warren) PowerDork
8/22/20 7:13 a.m.

Just to be different....Toyota 1NZ-FE......aluminum block and head....goofy delayed intake valve closing to reduce the compression ratio to 9.5:1 form 13:1.     That suggests that a cam change could increase the compression.....errr, maybe.

Common as dirt, too.


Isuzu v-6? Really. Aluminum, light, lots of transmission choices, at your local u-pull-it.

Is this car titled? If so, I'd seriously look at a liter-bike engine, or Hayabusa. Talk about honoring the original 7 idea.

Volvo? Cheap as dirt and bulletproof.

Bimmer? I don't know them well, but they are slanted, and thus a little lower than they'd be otherwise.

Datsun truck or 510 engine? Now I'm definitely stretching.



pres589 (djronnebaum)
pres589 (djronnebaum) PowerDork
8/22/20 8:01 a.m.

To flip?  Miata 1.x BP.  Not even a discussion. 

Buick V6 of any sort doesn't even register in this conversation.  Like I read the words and my mind went blank for a solid minute before I came to.  Fun car, light weight, nice sounds, universal appeal?  No Buick V6.


RichardSIA Reader
8/22/20 8:39 a.m.

Originally was being built for a Mazzzzdaaa rotary, yech! Just too weird and their reputation is not that great. 

Japanese engines designated by jumbled random letters are incomprehensible to me, I have no clue what is being discussed. Buick V6 is the daddy of the GM 3800 which should be familiar to everyone. It's one of the most successful designs of all time and very simple to work with. Chevy V6 (Think Camaro) is another option and I think they are a bit narrower.

Miata 1.8 I have access to is over 200K miles, so even though it "Runs great and has no smoke" I know the valve seals will begin sucking oil any moment now. Would have to be rebuilt.

I am resigned to F.I. being the default these days so Miata 1.8 or Suzy 1.3/1.6 may get the nod.

Since I will be building it I would like to avoid a steep learning curve. From observation it seems cars that retain the vintage look and feel sell for more than cars with drive-trains that will soon be obsolete and unsupported. No Pinto, Vega, Zetec, etc. Yes that does argue against the Suzuki's.

Wish I could think of a decently modern and light American engine that is not overly complicated by reliance on computers. I seem to recall that there is a V6 version of the LS but that is hardly vintage in flavor and still an iron block.

I need to see if the wrecked MGB-GT I knew about is still around. That would keep it nearly all British which seems to be attractive to some people.

Never titled, so engine choice may affect how easily that is done too.

XenaFordPrincess New Reader
8/22/20 8:49 a.m.

I know you said no Ford, but what about a 2.3L out of a Ranger or Mustang.   Shouldn't be too hard to find one with a 5 speed and all the electrics fairly cheaply.

bentwrench SuperDork
8/22/20 8:58 a.m.

2.3L Ford is too tall and twice as heavy for the power level. 


Here you go, everything you need and more, including a VIN & a title for $1000!


Ian F (Forum Supporter)
Ian F (Forum Supporter) MegaDork
8/22/20 9:02 a.m.

The idea of a 3.5L Rover V8 in a Locost is not something I needed in my head. Damn you... 

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) GRM+ Memberand MegaDork
8/22/20 9:10 a.m.

If the chassis is set up for a rotary, the first thing you'd need to make sure is that you'd actually be able to lower the crank center line far enough to accommodate a boinger without messing up the rear axle mounting. Assuming that it's been built up that far.

IIRC the only Seven-esque car that came with a V6 is the Brunton Stalker, and IIRC that's generally bigger and taller than your average Locost.

8/22/20 9:24 a.m.

If it really was built for a rotary, then other engines might be had to fit. Something about the crank being low or highor I dunno, but big pain if you wanna do miata rotary swap.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/22/20 9:28 a.m.

Just finish it with a carbureted rotary and move on. Easiest option, and the weird rotary has a big fan club. Might actually help with resale. 

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) GRM+ Memberand MegaDork
8/22/20 9:33 a.m.

In reply to NOHOME :

"Crank" aka the eccentric shaft is much higher up in the engine in a rotary - basically in the middle of the "block".

lotusseven7 (Forum Supporter)
lotusseven7 (Forum Supporter) HalfDork
8/22/20 5:33 p.m.

I currently have a Mazda 13-B turbo in a Rotus and it fits easily and makes 255rwhp. The Rotus chassis is larger than what you are working with but a 12-A or 13-B should easily fit with a carb set-up. I'm also building an RM-8(Westfield copy) with a Honda F20C and the motor is really too tall for the application. GREAT motor and K20/24 is the same basic thing but with better reputation and support. In the past I had one powered by a Toyota 4AGE and it was a blast! I built one for my uncle with an MGB driveline and that was done on a CHEAP budget but turned out to be a great car. I believe he bought a running donor for $500 and we took the engine, trans and rear. Sold the rest for something like $200 to a friend.





RichardSIA Reader
8/23/20 1:29 a.m.

Leaning toward using the fresh built 231 V6 and CR T-10 I already have on hand. Engine was supposed to go into my Trick-6 but that may be years down the road and I can build another when needed so long as I begin gathering the rest of the internal parts ASAP.

That engine is probably about 180+- HP, more than adequate without being a snap-oversteer Death-Kart. Part of my hope is that this Locost might go to a younger enthusiast with less experience in overpowered cars. Or so my musing goes.

I know for certain that a Miata is the same height top to bottom as an Alfa Romeo 2000. My Alfa build became expensive when I had to dry-sump it to fit under the Dio-Tipo bonnet.

It turns out that a "V" engine is typically shorter than many OHC type. Will try to measure the height of my Geo 1.0, if that is good a Suzuki 1.3/1.6 may become the other choice as it seems Weber manifolds can be gotten. Suzy is a bit out of date but has a large following and performance parts are available. Their very light weight and fairly high red-line is pretty attractive.

I just cannot get interested in the latest engines due to their over-reliance on computers for so many basic functions, VVT and variable intake tracts are just plain EVIL!

lnlogauge HalfDork
8/23/20 5:49 a.m.

This thread is pointless. You already decided your Buick engine, so why bother asking? Every single reply from everyone else is convincing you it's a terrible idea, while every post from you is convincing everyone what a great idea it is.

This is the wrong group to convince Miata is unreliable. 

pres589 (djronnebaum)
pres589 (djronnebaum) PowerDork
8/23/20 6:57 a.m.

At least Buick V6's sound good near their 4700 RPM redline! 

mblommel Dork
8/23/20 9:59 a.m.

I did a bit of internet research on possible Locost powerplants and it seems like the Mazda L / Ford Duratech 2.0/2.3 is incredibly light compared to other powerplants. They are extremely inexpensive and bolt directly to the excellent manual from a NC Miata. They also have a pretty good (and expensive) aftermarket to provide more power. The only issue I believe is the height. 

Not sure if Caterham uses a dry sump or shorter wet sump to package this engine in a 7, but the results speak for themselves.

For a light car like a Locost an iron block V6 seems like a boat anchor. 

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