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16V swap options

maartenrink

maartenrink

Member
Joined
Jun 2, 2024
Location
Netherlands
Hi Guys,

I have a 244 with a B23a engine with M47 gearbox.
I want to add some power and have a 940 donor with a B234F.
I now this isn't a straight swap at all but what would be the best combo?
Take the entire engine or only the head? conditions of the engines are about the same.
I want a block mounted distributor but is that even possible on the B234 block? it has a external oil pump right?
and what about power outputs, would that differ between the 2 block?
 
Well, i get your point but turbocharging isn't an option at the moment so hats why i chose the 16v. But my main concern was the ignition but i found some post on easy wasted spark setups so I guess the B234 block is the way to go.
 
I was in your situation once and did not want to turbo my car. I was not familiar with turbos etc. I purchased everything I needed to 16v., after researching and reading of all the headaches with 16v and the money I had spent, I still needed intake and ex. manifolds. I sold it all and bought me a 15g turbo and some good stuff with the 16v money. I had alot of fun with 15g and the mods. It was easy peasey too. Just my advice.
 
maartenrink said:
Hi Guys,

I have a 244 with a B23a engine with M47 gearbox.
I want to add some power and have a 940 donor with a B234F.
I now this isn't a straight swap at all but what would be the best combo?
Take the entire engine or only the head? conditions of the engines are about the same.
I want a block mounted distributor but is that even possible on the B234 block? it has a external oil pump right?
and what about power outputs, would that differ between the 2 block?
Click to expand...

Wow... going back a long ways here. I seem to recall a fitment issue of the b234f block in the 240 chassis. Perhaps something to do with the oil pump? If it fits, it would go a long way to simplifying the swap but it doesn't solve all your problems. Perhaps another chap with a better memory can chime in.

If you use the 16v head on the b23a block you'll need
  1. a belt tensioner... lots of JY options but the most sensible is the yoshifab unit. Get the belt from him as well. https://yoshifab.com/store/16v-timing-belt-adapter-kit.html
  2. You'll need a wider round tooth crank gear... the b23 square tooth belt will physically "work" but there's not enough friction to keep the square tooth belt from slipping on the cam pulleys. I don't care if there's other people that have "done it". I've done it and it doesn't work. Don't take the chance. There are new suppliers of steel wide round tooth crank gears... like yoshifab. https://yoshifab.com/store/billet-steel-16v-crank-gear.html
  3. the 240 block mounted distributor will work but you'll need the peugeot 104 crab dizzy cap. Again... going back 20 years in my memory bank for this one... https://pbase.com/740atl/image/125409462 The only problem with the 240 distributor is once it's in there, you won't get it back out with the head on the car. If you're in the aftermarket EMS option, try the yoshifab DSM CAS.
  4. oh... yeah, the big one... the deal breaker... you're going to need an intake manifold that will fit in your chassis. The stock 16v unit will not work. You can shorten the runners on the stock unit, or leave the runners alone and weld on your own plenum, or go full klracing.se
Power differences? Stock 8v 240/740/940 makes 98ish rwhp... with a 16v head you're looking at 140 rwhp with no other changes. It's a nice power bump and super fun to drive even NA. https://pbase.com/740atl/image/125409519

Solve your intake manifold issue (the real issue) and it makes for a super fun powerplant.
 
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Wow thanks for the info man!
I will take this in mind. The intake is the big problem but i read some forums about smaller brake booster like rwd nissans or something like that...
But yeah the b234 would need custom engine mount but that doesnt seem like a big issue. I ofcourse will remove the balance shafts if i would keep the b234 bottom end
 
Yeah, it's just a step beyond the world of bolt on modifications. Very little fits well with the 16V in a 240. 740ATL's post is a good high level view.

I ran a turbo 16V in my 240 for a number of years. The first iteration was a log manifold on the exhaust side, and an 8V intake on an adapter on the intake side. Since you're not wanting a turbo, the stock 16V exhaust manifold should fit well enough.

But the 16V intake won't. The 8V on the adapter wasn't a great solution either, because the 16V mounts the manifold outward and angled upward compared to the 8V. So it still required some fiddling around. And the round port to oval port at the adapter was problematic, I matched the shapes up with porting but it wasn't ideal.

There is barely enough room to fit a crab cab under the head where the 16V sticks out. I was using a Saab cap I think? Later on I converted to a newer MS box and ran Toyota coils and a DSM CAS where the distributor used to be.

You will probably want to, if not need to, carve some valve reliefs in the pistons. Some people seem to get by without it. Maybe test that theory out carefully on initial installation with some clay. For sure, it's interference, if the belt breaks the engine will suffer serious damage. But if it never gets out of time, then I guess the valves aren't open when the pistons are at TDC. I think Kenny found, after a long while of running his, that his valve reliefs were a bit too small for his valves (perhaps exhaust sized reliefs on the intake side?), but they'd never touched.

Probably a good idea to pair up a higher revving 16V build with a higher geared rear end and a lighter flywheel. That 16V is going to make that extra HP up higher in the RPM range.

And again, the alternative here is to spend money on a modified 8V head and a zippy 8V cam, keep it looking stock, and make similar HP. A stock 16V head certainly flows a lot better than a stock 8V head, but spend $$$$ on the 8V head and it closes the gap. And you'll spend a lot of $ and time and grief putting the 16V head in the 240. It's not a cheap thing to do.

16V version 2.0 - with a divided scroll front mount exhaust and a BW EFR turbo, and a custom intake manifold and coil-on-plug ignition:
ttiJp37.jpeg
 
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maartenrink said:
Wow thanks for the info man!
I will take this in mind. The intake is the big problem but i read some forums about smaller brake booster like rwd nissans or something like that...
But yeah the b234 would need custom engine mount but that doesnt seem like a big issue. I ofcourse will remove the balance shafts if i would keep the b234 bottom end
Click to expand...
No way to put a block mounted distributor on a B234 block. There's no intermediate shaft.
 
Why keep the B234 bottom end if you're removing the balance shafts? Why make an engine more buzzy?

B234 block will also require you to convert to 7/9 accessories. All that for 40 more hp. You'll end up fabricating everything besides the transmission mount, driveshaft, and exhaust than you would for something like a V8.
 
240 n/a 16v with manual trans is a fun setup. I had that for several years. As mentioned the intake is the biggest puzzle. I chose to keep the stock runner length and modify the B234 manifold to put the throttle body under the plenum. Still was tight at the brake master cyl but workable. If you’ve got LH2.4 you can run the stock B234 computers.
 
All of the above sounds like a lot of work for 150hp. You still would have that wonderfully weak m47 trans to deal with in either case. Im with John here. Have done the 16valve thing and given the choice to go back and do it again, a worked over 8 valve head with an enem cam would be a way better path to make more or less the same power. And it all just fits.
 
I know the arguments against the 16v head swap... while +T'ing an 8v b2x/2xx engine isn't rocket surgery and once done it's certainly easier to up the boost.... however as most of us know, it comes with its own special set of risks that NA engines do not. The 16v NA has a sweet power curve.... perfect for manual transmission. If you upgrade the valve springs (for the life of me I can't remember which springs we used to use) you can get more RPM out of it... I did the swap over 20 years ago now and almost regret turbocharging it... That engine was sent out to pasture a decade ago with a ventilated block and the head barely survived. To this day I still come back to the idea of a simple 16V NA 242. I must be getting old.
 
Marvelous3 said:
All of the above sounds like a lot of work for 150hp. You still would have that wonderfully weak m47 trans to deal with in either case. Im with John here. Have done the 16valve thing and given the choice to go back and do it again, a worked over 8 valve head with an enem cam would be a way better path to make more or less the same power. And it all just fits.
Click to expand...
Same thoughts here.
16v is fine, but man does it get expensive when you need to work on the heads. Valves now are $30-40 each 🤑

Though when you want to make 250+ NA hp the 16v makes more sense financially.
 
maartenrink said:
Wow thanks for the info man!
I will take this in mind. The intake is the big problem but i read some forums about smaller brake booster like rwd nissans or something like that...
But yeah the b234 would need custom engine mount but that doesnt seem like a big issue. I ofcourse will remove the balance shafts if i would keep the b234 bottom end
Click to expand...
A 960 booster can be made to fit the 240, you need to drill 4 holes, and figure out a way to retain the mounting for the stock pedal box. I cut the studs and a strip out of the stock 240 booster. I made a template to drill the necessary holes, it's linked in my project thread.

You'll need to use a 240 ABS master with it. But it looks good installed,and should clear your manifold.
 
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