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B230ft into 81 242

Loweredclass

Loweredclass

New member
Joined
Aug 18, 2013
Location
Edmond ok
My main questions are in relation to swapping a b230ft out of a 91 940 into an 81 240 with the m46 trans. I've been told the flex plate will not swap, and therefore need one from a b230 equipped 240. Is this true?
Also I've read that the bell housing of the older m46 to b21f won't necessarily bolt up?
Any other issues that you know of, please note
Thanks
 
Autos have flexplates, manuals have flywheels. You'll want to use a 9" dished flywheel with the turbo motor. If you go with LH2.2 the bellhousing is the same; if you go with LH2.4 then you'll need to notch the top of the bellhousing to accommodate the crank sensor.
 
Here's the thing. The B21 non-intercooled turbo cars and n/a cars used an 8.5" flat flywheel that really doesn't have enough clamping pressure to avoid slipping when used behind a healthy B230FT intercooled unless you use a custom clutch setup. Additionally, the LH2.4 setup uses a crank sensor which reads dimples on the edge of the flywheel. Flat flywheels and LH2.2 dished flywheels do not have the dimples. They can be added but it's much simpler to locate an appropriate flywheel from any LH2.4 240 or 7 series (89+ for 240's, 89 for n/a 7's, 90+ for turbo 7's). I did a couple flat flywheels with dimples here at the shop and I can attest they do not hold over 12 p.s.i. with a stock clutch setup.
 
swiftjustice44 said:
Here's the thing. The B21 non-intercooled turbo cars and n/a cars used an 8.5" flat flywheel that really doesn't have enough clamping pressure to avoid slipping when used behind a healthy B230FT intercooled unless you use a custom clutch setup. Additionally, the LH2.4 setup uses a crank sensor which reads dimples on the edge of the flywheel. Flat flywheels and LH2.2 dished flywheels do not have the dimples. They can be added but it's much simpler to locate an appropriate flywheel from any LH2.4 240 or 7 series (89+ for 240's, 89 for n/a 7's, 90+ for turbo 7's). I did a couple flat flywheels with dimples here at the shop and I can attest they do not hold over 12 p.s.i. with a stock clutch setup.
Click to expand...

N00b questions: I'll be doing this swap from b21f to b230ft as well, but doing a T5 trans swap. The clutches are different for a b21f and a b230ft, due to a slightly larger flywheel correct?

I have the later dog dish flywheel to go on... but have yet to see what my b21f flywheel looks like. I'd hate to have to buy 2 clutches, or wait to swap in my T5. Could i put the later flywheel onto the early motor in the mean time?
 
Chewy said:
N00b questions: Could i put the later flywheel onto the early motor in the mean time?
Click to expand...

Sure you can. Beginning in 84.5 when the intercooled 240's came out, they used the slightly larger dished flywheel w/ no issues. I can't speak to what the best answer is once you swap to a T5 as my only T5 swap was when I also swapped in a V8. Obviously you will need a T5 clutch that will have a pressure plate that can mount to the flywheel. Again...lots of threads on this. If you don't get good answers that way, start a separate thread.
 
Ok so I just need a fly wheel from any lh2.4 car? I have a local volvo salvage yard that should have all parts. I just want to make sure that's all I need
 
I did the exact same swap you are talking about. The dished flywheel can and will work, but a machined flat flywheel is oh so much better. You can upgrade clutches so much easier, it weights about 10lbs less.
 
Also of note: If you're using the stepped flywheel, make sure that the step height (from the friction surface to the flat where the pressure plate bolts) is between 24mm and 25mm. If it's more than that, have whoever machines your flywheel turn the step down until that measurement is 24mm.

It's not uncommon for these flywheels to have been surfaced a couple times already, and not everyone realizes that for every thou you take off of the friction surface, you should take a thou off the step so that the clearance there stays the same.
 
Loweredclass said:
So culberro, from which vehicle do I need the flywheel?
Click to expand...
He's talking about using either the flywheel you have and get it machined for the crank sensor dimples or going with a custom made flywheel. No question the lower mass of a flat flywheel turns up faster. Speed costs money...a custom flywheel and a stage 3 clutch kit can easily top $750. A used dished flywheel and a new stock clutch kit more like $200 if you shop around.
 
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How do you machine the dimples? This sounds more plausible. And if I'm using my bell housing, the how/ where is the sensor going to attach
 
The sensor attaches to the block, right behind the cylinders. You may need to notch the aluminum bell housing for clearance, takes about 10minutes with a die grinder and carbide burr.

Machining the flywheel is easy peasy. If you know anyone with a machine shop, it can be done fairly cheap. I could do it for 150 if you send me the flywheel. Then you need it resurfaced, but that's about $50. Or just run it with the old clutch and hope for the best.
 
click the second link in post 5. It's a bit vague but gives you the general idea. As to the crank sensor, it attaches to the back of the engine and the bell housing needs to be cut out. By 84, the bell housing actually had the area for the cutout embossed on the under side and it was simple to cut out with a die grinder. This is a pic of an M46 from an 84 car...the notched area was cut out w/ a die grinder to fit around the crank sensor...
100_0049.jpg
 
Thanks a lot guys. Any images of the flat flywheel with the needed machined dimples? We have some lathes and things at work that I could use. Albeit, I don't know how, but there is a first time for everything :roll:
 
If you have a milling machine with a rotary table, or a digital read out, you can machine a flywheel. You can even add a new bolt pattern for a heavier duty pressure plate. All my pictures were eaten by my last phone but I'll see what I can find. Also, use the automatic flex plate as a guide. I'm not sure what the indexing is for the missing tooth part. (17 deg maybe...?)
 
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Here's a pic of one of the two I made bolted up.
100_0319.jpg

112_0020.jpg

Here's actually drilling the dimples with a flexplate used as template.
112_0019.jpg

You folks can make it as complicated as you want but it isn't really rocket science I used nothing but a brake lathe and a drill press. The first one took me 2 hours...the second time about half that.
 
Chewy said:
N00b questions: I'll be doing this swap from b21f to b230ft as well, but doing a T5 trans swap. The clutches are different for a b21f and a b230ft, due to a slightly larger flywheel correct?

I have the later dog dish flywheel to go on... but have yet to see what my b21f flywheel looks like. I'd hate to have to buy 2 clutches, or wait to swap in my T5. Could i put the later flywheel onto the early motor in the mean time?
Click to expand...


There is nothing wrong with reusing your B21F flywheel, clutch and pressure plate, but you need the tone ring for the LH2.4 crank position sensor....a machine shop can cut the teeth, using your B230FT flexplate as a template.

In the world of 240's, Turbo cars had STIFFER pressure plates....but the size of them vs. NA was the same...you can interchange them on the same FLAT flywheel.

Volvo started using the dog dish flywheel in '85, when they started the B230....heavier for better city driving...more stored inertia. It uses a larger diameter clutch and pressure plate...

As for your T5 riddles....all you NEED for the T5 swap is a new clutch disk to suit the diameter of your pressure plate...whatever you choose, and has the splines for T5...That gives you two options...say you use a flat flywheel, with machined tone ring....you can use a clutch disc from a 2.3L Ford Mustang....228mm disc with T5 splines....goes right in. Or, say you go a different path, with a dog dish flywheel....call Oleg at ClutchNet and tell him what you have...he'll make you a 9" clutch disc for your Volvo stuff, with T5 splines...usually under $200

Both flywheels will physically fit & work, and each have their own unique advantages...

You could, also, call John at JVAB, and see if he has a BRAND NEW, STEEL Flat flywheel...they way some absurdly light 14 or so lbs. He drills them for darn near any pressure plate you could dream of, and he's got some with that LH2.4 tone ring...

Good luck
 
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