Is the low friction version of the B23 a bad design? I have been told to stay away from any 200 series between 1985 and 1989, due to the low friction design.
Thanks
Jim

For a non-turbo, a non-issue. A bigger problem is the disintegrating wire harnesses up to ~1985 or so, can't remember exactly when they fixed that.

Yes, technically, the early B230F's are not as "stout" as the B23F, but I think that in a naturally aspirated motor it makes little to no difference.

We have an '86 240 in our family that has about 430K miles on it. The low friction/skinny rod B230F in that car is original and has never been opened up. Still has good compression (185-190 psi) and good oil pressure, still passes smog easily. Doesn't look like it is going to give up the ghost anytime soon.

Hi,

As far as I know you were told the wrong years. I think these started showing up in the nineties.

The term low friction is related to changes in the overall piston heights and the connecting rods being made more narrow on the big journal ends.
This was in an effort to lighten up the upper end to make the engine rev up faster. Mostly the Turbo models crowd got the engines first but it was not limited to them by 1993.

This modification went in full across the line production in a few years. I think this was due to the engines without squirters suffer more of a chance of generating a piston slap noise or tic when cold started. The noise goes away after the piston warms up.
So if you want to buy a red block listen to them when you know its block is definitely cold to the hands as other parts of the car at that time.

I have notice, on my used two out of three nineties cars, that it seems to happen somewhere past the engines “just broke in period” of around about 150k! (:-)
My recently aquired ‘93 has 200k and no noise at all. So it either helps or there are other variables at work here!

On the earlier 90’s engine red blocks you will see a change showing external bumps being casted on the exhaust side down low. There is a horizontal oil gallery passage going rearwards from the oil filter zone.
This extra metal was added to allow cross drilling depth so the oil squirters tubes could be added at the bottom the cylinders bores. They tap into the horizontal to put oil up high under the piston domes.
It’s my understanding some people get squirters from those used inside some BMW Engines.
I have not verified this to know what thread I need to put in the area to make them work.

So to say they it’s not such a worrisome problem going on.
I give more thoughts about belts, water pumps and alternators.

Phil

I'm not totally up on the exact facts here. But there was a discussion here about B2X engines and the B230 design regarding the crank and main bearings.
Try searching for: Why does the B230 have a Harmonic Balancer and the B21 and the B23 didn't.
http://forums.turbobricks.com/showthread.php?t=172520



Also this from an old TurboBricks Post: B21,B23,B230. The basic build of these three are the same. The B21 is 2.14 liters, low compression, and the B23/230 is 2.3 liters. The B23 is an early version of the B230, and had offered a high performance, high compression version, the B23E. The B230 has a somewhat de-tuned engine with fully electronoic injection compared to the B23 and a cast not forged crank through '92, but better after then with forged crank and connecting rods.

All of the 93 240's had the squirters. AFAIK - None have piston slap. So yours should remain quiet...:)
My 90 didn't. It was a little slappy when cold but that didn't prevent the engine from still running well at 300k with no engine work.
I believe that the 740's and 940's got the squirters a year or two earlier. Specifically the turbos.

hi jw- this is an interesting comment about the squirters and piston slap. my 92 245 was the last one not to have them. thought piston slap was primarily caused by premature detonation or firing of the gas air mixture too soon and the oil squirting on the piston sides would cool them and reduce slap. that condition can really damage an engine. have never noticed that problem in mine. engine runs very well and has about 250k miles. have never seen it but have seen the result of it- collapsed or shattered piston. a hot spot on the valve face or piston top can cause it. heard it can also bend connecting rods but never saw that. try to take care of the 245s engine and m47. want it to last as long as irv gordons tanker. uncle moe says no chance. thanks tons oldduke

Howdy Old Duke,

As Machine Man mentioned, I don't think piston slap is a condition that you need to worry much about. I've never heard of, or read here of a b230f engine being destroyed by piston slap. Just something to be aware of - that's all...

Not all of the b230f's get piston slap. If yours doesn't have it at 250k it probably never will...:)

Doubt the M47 will see Irv Gordon miles. The b230f's are a pretty robust beast though. I've read of them doing 500 or 600k. Hey, remember that Irv Gordon had his engine rebuilt at 680k and again at about 1.7 million. Don't know if it has been rebuilt a 3rd time. Maybe, since he now has over 3 million miles. Amazing!!!

J

hi jw- yeh irvs is certainly one hell of a tanker. regards oldduke