240: 'A' Cam vs. 'B'?

[Ryan_R]

Has anyone much experience with the 'A' and 'B' cams in a B230F?

They seem pretty darn similar on paper. Do they drive similarly? I'm really familiar with the 'A', and I love it. The 'B' looks like a very slightly more aggressive 'A' cam. Is it?

I guess to give a cross forum bump to the For Sale post:

http://forums.turbobricks.com/showthread.php?t=337537

Thanks!

-Ryan

[2manyturbos]

I think it is just the opposite. An A is more aggressive than a B cam, IIRC. Somewhere on here there is a link to a table with cam specs on it.

[sbabbs]

http://www.turbobricks.com/resources...ontent=camspec

[2manyturbos]

Originally Posted by sbabbs

http://www.turbobricks.com/resources...ontent=camspec

Thanks Simon. I have that book marked now. The specs there say that the B cam is slightly more aggressive. That is contrary to the TB lore I've heard.

[PromiseRing]

Originally Posted by Ryan_R

How's the 'B' relative to the 'A'? I've got an 'A' in a 240, and a B230FT, and I love them. The 'B' looks like it's got mad lift!

Thanks,

-Ryan

Originally Posted by PromiseRing

The B cam has .1 more lift than the A, and 2 more degrees of duration.

http://turbobricks.com/resources.php?content=camspec

From the thread you just linked. I had already linked the cam specs.

[dl242gt]

I put a B cam in my friends 1990 B230F manual wagon. It made it drive a lot better all around.

[LC4CARL]

"B" is for: bad-ass, big-power, bountiful-torque, bodacious-revs...

[KeizerBrickGuy]

Originally Posted by LC4CARL

"B" is for: bad-ass, big-power, bountiful-torque, bodacious-revs...

[Ryan_R]

Thanks guys!

I love the 'A'. If the 'B' is a smidgen better, I'm in. I'm going to put the spare AW-72 in this car so I can take advantage of the extra breathing in the higher rev range!

-Ryan

[mark244turbo]

Interesting discussion...I am also looking to swap in a better cam to get rid of the horrible M-cam.

Here's a thread about A/B cam HP increase - bone stone B230F....that covers the differences between A and B.

Looking at the cam specs, the A and B are almost identical. But apparently they are not.
Most people agree the A is more agressive than the B.

One interesting comment came from stealthfti. He gives a comprehensive summary of the differences between the skinny cam familiy, the fat cam family and the dual cam familiy.

Originally Posted by stealthfti

As has been stated, the stock cams are just that: stock, OE, emissions testing sensitive camshafts.

That said, the skinny cam family....T, A, V.....offer more bottom end than do the fat cam family cams.....B, D, K.

The M is of the dual pattern cam family.....M, VX, H. With the M being really emissions sensitive oriented, resulting in poor performance. M's go in the scrap bin at my place. I've done back-to-backs M-to-T: a definite difference with the T. stonger bottom end torque, better around town driveability. And that has been on some cars with stock OE sized exhaust.

A lot of the improvement that you 'can' get by going to a 'bigger' cam than the M is going to be dependent more on what size exhaust you run. If staying with the stock ~2in OE NA exhaust, yeah, you'll see some improvement going from the M to the B.

But, if you really want to see some improvement, go 2.5in from the twin pipe merge [of the front pipe] on back. With a setup like that, even a T performs impressively up to 4500+. BTDT. And talk about stump pullin' bottom end like that....

If you want to do the job right, you will check and adjust the valve lash clearances. And do that without the 'silencers' [or 'hushers', or 'absorbers'] in place. Then, after the clearances are right, remove the cam and install new hushers. I have yet to do a cam swap and NOT have to adjust at least 4 of the 8 clearances.

good luck

TF

One good takeaway from this discussion is that you need a 2.5" exhaust (240 turbo has 2.5" exhaust) from where the twin pipes of the exhaust manifold merge. All cams would benefit from this. Even the T-cam.

Or even better: get a manifold like this:

[LC4CARL]

Very happy with my B cam and exhaust. But I think almost any cam will be better than the M.

[KeizerBrickGuy]

Originally Posted by LC4CARL

Very happy with my B cam and exhaust. But I think almost any cam will be better than the M.

[dl242gt]

One reason why I always mention the enem V15 is because it is a cam with the lift of the K cam but the duration of the B cam. So it has a wide powerband with torque at all rpms. But if you must have a stock cam a B or A are miles better than the M. The A and B are probably the easiest to get here in the US. Also you can get a V cam out of a Penta engine. All of them will improve your M cam engine and make it a better running engine that still doesn't pollute or have bad driving habits.

[Ryan_R]

Thanks all! Trigger pulled on a 'B' cam vs. getting another 'A'.

Ultimately, I'm looking for DD stuff. I've an 'A' in what was the 5-spd 245 (now parts car, engine's going in a 745) and a 2nd one in the 945T. For me, the 'A' is a "liberation" cam. Advanced a smidgen, it just lets the engine be better all around. If anything, fuel economy improved, and in adverse conditions you can downshift without the engine screaming at you. I'd love to have been a fly on the wall when Volvo engineers decided to use the 'M'.... it's terrible, and if you have a manual trans, you become a slave to the narrow power band.

In the turbo car, with a few added PSI, the 'A' makes things 16-valve smooth, but with much better torque delivery.

-Ryan

[2manyturbos]

Originally Posted by mark244turbo

Interesting discussion...I am also looking to swap in a better cam to get rid of the horrible M-cam.

Here's a thread about A/B cam HP increase - bone stone B230F....that covers the differences between A and B.

Looking at the cam specs, the A and B are almost identical. But apparently they are not.
Most people agree the A is more agressive than the B.

One interesting comment came from stealthfti. He gives a comprehensive summary of the differences between the skinny cam familiy, the fat cam family and the dual cam familiy.



One good takeaway from this discussion is that you need a 2.5" exhaust (240 turbo has 2.5" exhaust) from where the twin pipes of the exhaust manifold merge. All cams would benefit from this. Even the T-cam.

Or even better: get a manifold like this:

That's because you can not tell that much about the power band a cam will produce from simply looking at the lift and duration specs. The lobe separation angles determine overlap which greatly affects flow characteristics. Also, ramp angles play a big role. The A cam with its slightly lower lift and shorter duration may indeed make greater power than the B cam.

[dl242gt]

In talking of cams though. Both A and B cams are low overlap mild cams. They both have better power bands than the M in any n/a engine and work well in turbos. Volvo was just too conservative with the M and T. One of the best changes I've made to my Volvos over the years was getting rid of the M and T cams.

[KeizerBrickGuy]

A or B cams are just fine for an inexpensive upgrade for some better performance for an NA or Turbo redblock. I am running a T cam in my Wife's car and even that made a difference over the M.