ClassA4x4

Before the install I observed how the KSB behaved - when energized, the idle would sound different and slightly increases engine rpm.

After the M&H install, it's doing the opposite, i.e. when the KSB is energized the idle is lower than before, and when I disconnect the KSB power, the engine rpm increases, about 40 rpm. It looks like the spacer is retarding the timing.

What's going on? The spacer is supposed to maintain stock timing at idle and advances it at higher rpms.

Rick 12v CTD

Yeah, I've noticed the same drop in rpm when it is energized, although my rpm is probably more prominent than yours. I'm not convinced it is a beneficial part, for me at least. I'm half tempted to remove it when I throw my heap on the dyno and see what happens.

ClassA4x4

Rick, do you notice any performance gain at higher rpms?

Maybe, this spacer is beneficial only for stock unmodified pumps and engines . . .

BC847

That statement makes it clear that running stock/OEM timing will give you that results.

In your case, there's a very good chance you're well advanced to start with. . . . right? You have already bumped the timing to begin with . . . right?

Applying the KSB in that setting simply makes it too much advanced ... to the point you're injecting fuel well into the compression stroke. The engine is essentially fighting itself.

You'll either have to back off the static timing, or stop using the KSB.

A lot of people fail to completely grasp the point of the timing spacer: Having the ability to maintain stockish low rpm timing for better turbo spooling/throttle response, an still enjoy more timing advance in higher rpms, so as to better utilize bigger injectors.

Rick 12v CTD

as for the higher rpm gains. I see, what I think is really good power through the low and mid range, but it runs out of steam as it nears 3000rpm. Then again, it is my opinion my truck has near stock timing, and has imo a lot of fuel for what it is. I've considered bumping my timing more to see what it does. as of right now I have it jumped a tooth, but all the way away from the head as far as it will go. I have lots of low end grunt, and a reasonable haze under light/med throttle. Half of that haze is my turbo though... I don't have a great top end with the ksb off. With it on, it almost makes me think I have too much timing just by how it acts. I haven't done a WOT run with it on though.

When I have the truck under load accelerating and if I turn my ksb on I notice an instant drop in smoke and a slight loss in power and boost too.

thrashingcows

I have a MH spacer as well. Had to for over a year or more. I have not installed it yet because I want to make sure my pump is set to stone stock timing before I install it. But I have not got around to doing the timing...and I'm still a bit uncertain on what to do.

ClassA4x4

David, I'm now convinced that my timing got advanced inadvertently in the process of resealing my IP last month, despite of locking the pump and marking where things were. I repeated the process so many times that I think I lost track of the static timing. I believe after the reseal, my pump got bumped 1/8 or 3/16. The loose gear may even have dropped a tooth from all the wiggling trying to align that damned (bad design) key/keyway.

Now, my question is: Which is more preferable: backoff the static timing or disconnecting the KSB power?

ClassA4x4

Just now came from a more thorough test drive.

I think the rpm drop is more like 25 rpm (not 40 as I stated earlier) when the ksb is energized at idle, cold engine.

I think it's more responsive with the spacer, lower egt's, in the higher rpms.

I did not see any dramatic increase in engine temp, maybe because I relocated my trans cooler and put a big electric fan in front of the condenser.

I wasn't able to monitor the exhaust. Is it supposed to add or remove smoke?

BC847

One can still advance your static timing while using the spacer, you just need to be aware as to how it works.


I actually adjusted mine somewhat backward from the typical thinking.

It's my opinion the spacer effectively widens the apparent dynamic timing range available. Going from, say . . . 10* wide to 15* wide (not real numbers, just for illustration).

With that line of thinking, after installing the spacer, I set my static timing based on WOT power on a dyno. With that nailed down, the spacer allows the timing to back-off further than it would without the spacer. Basically allowing a better, lower rpm timing while keeping the high rpm stuff in the money.

Make sense?

1972RedNeck

I put the spacer on mine and then bumped it an 1/8 inch. It has always had the lower idle with power to the ksb with the spacer. So will unhooking the ksb make it start better? (not that I have starting problems because I don't)

ClassA4x4

Yes, it does on mine.

Rick 12v CTD

For me, with the ksb on with a cold engine my idle drops 100 or more rpm. But it still starts easier in the cold with it on. I just have to give it a little throttle to compensate when starting. So I know it's still doing its job.

When warm the ksb still drops rpm a bit but it isn't as bad as when the motor is cold.

The truck sounds almost stock at idle with the ksb off. The rattle when I turn it on becomes fairly pronounced.

The ksb spacer is definitely doing its job. Much like what David said about the range increasing, I also think the same thing. I however, am wondering if the range of dynamic increase is almost too much with the spacer for many applications.

There is no way of knowing for sure without doing a wide range of testing on a lot of different trucks. I guess the important thing is most people are quite happy with their results.

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ClassA4x4

On mine, the rattle difference is very slight, just noticeable.

I'm thinking, maybe if I delete the extra m&h washer or use a thinner one, it would even up the idle rpms. Has anybody done it?

ClassA4x4

An additional observation is that on cold starts, the initial puff of smoke is less when the ksb is off. When the engine is hot the rpm difference, ksb on or off, the rpm difference is negligible, there's just a very subtle difference in the sound.

Rick 12v CTD

Sorry if I missed it but how close to stock is your static timing? I think I may tinker with mine tomorrow just to see what results I yield

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