It seems like most of the guys who have used solid lifters have good things to say about them. But I've also been reading that solid lifters create a vibration that can be picked up by the knock sensor in EFI systems, causing problems.
I'm wondering if deleting the knock sensor is the solution to that problem?
Anyone tried it?
Any additional input on this topic appreciated as well.
Thanks

 

day 2... no replies...

 

I haven't done solid lifters in about 25 years. I'm considering them for the '57, but that's a strip-primary, driven-to-the-strip car.

It isn't that the solids create a vibration. They create a "knock" when the clearance is taken up on the ramp. The less clearance you run, the less noise they'll make and the less likely they are to set off the sensor.

Solids help get more revs out of the engine. With today's cams & hydraulics, you can put a rev kit on a roller hydraulic engine and easily run 7000 RPMs. I assume you're talking about the 327, though. Running the LG4 CC system? An cam that has enough duration to need solids isn't going to make the computer happy, anyway.

 

I'm looking at going with an LT1 induction system later on, and I was asking about the solids as being something that might work well with that in my 327, yes.

 

yes, if you disable the knock sensor, you can still run FI


the friend i got my solid roller lifters from ran FI with a geardrive and solid rollers.. he just bypassed the knock sensor with a resistor.

 

Dumbest thing I ever heard of............

 

Why's that?

 

The solid cam will make more power than a hydraulic, but the knock sensor is a very good thing to have when you run on the edge of detenation (as most FI motors do) You will need to play it conservative on timing and compression which will likely negate most of the benefits of the solid cam. I am sure with some tuning it can work though, although I don't think I would take it on. Look into a hydraulic roller setup and get the best of both worlds.
JMO,
Charlie

 

Last year I did some spectral analysis on another BB. A member was having rocker problems and posted the sound on the BB. I "dissected" the sound file and found this. The main sound energy is at about 140 Hertz. That correlates to every valve smacking at idle. The loud sounds are in red and the whispers are in blue.

I'm bringing this up because the engine sounded like it was a solid lifter engine, but was a hydraulic flavored one. The point is that most of the sound energy is at 140 Hz and knock sensors look for frequencies at the 4 to 6 kiloHz range.

And with this display I wonder if there is any sounds from a solid lifter engine in the knock detector range.

Caveat, the sound recording equipment sounds bandwidth limited, so frequencies in the 4-6 kHz range may have not been recorded.


***Sorry, I clipped the 4-6 kHz range, but there was NO sound energy there***

 

It's not that uncommon to get rid of the knock sensor in a race engine. Once you're tuned properly all it'll do is pull timing in the middle of a race, since it's a race engine if something is causing it to knock bad chances are knock sensor or not you're going to either break something want to pull it apart and fix the problem....
I wouldn't remove it on a street engine though due to the variances in the octane rating of "93" or "87" as sold by different stations. It's a good idea to have one but on a noisy race engine running 116 that's going to be rebuilt every season or every few months it's not going to help anything that much anyway.

 

Here is the sound file

C H E V Y

 

Thanks for all the replys, it looks like we're leaning in the direction of the hyd. roller here...
So with a hyd. roller and a rev kit and all the other matched parts, my valve train will be stable to 6500?

 

he said it for me.

 

also, note most carbed cars dont have them.



and look how fast they run.... the world didnt change because someone invented the knock sensor. same rules apply that always did.

 

So another way of looking at it might be; If my CR is high (10:1 or so) then I'd want to keep the knock sensor cause there's a good chance that detonation would be an issue. But with a lower CR and a lesser likelyhood of detonation
a knock sensor might never be used anyhow, and a solid lifter cam might be ok there. But if I'm pushing the envelope with compression then hydraulics with a knock sensor are a must.
Hmm.

 

He said this:

If you have it tuned properly then WHY would it "just pull timing out in the middle of the race"?

You CAN'T tune it properly if it's either really knocking or picking up false knock due to the solid lifters.....you have no way to tell.

Also carb cars do sometimes have a knock sensor.....it's there for a reason in both, to save your engine from any form of detonation weather it's from bad gas or poor tuning/engine building.

 

I dont think you should have problems with detination with only 10:1. I never had any knock with my iron headed 9.8:1 motor, and the only time I had it with 11:1 was when I used 92 octane instead of 94. Albiet I had AFRs on the 11:1, so the aluminum heads helped a little.

 

because if it had a knock sensor, it would have a totally agressive timing curve, and if it detected one snippet of it while on the edge (it happens) then it pulls timing (and power).

the car can run down the strip with detonation for all we care, we just want peak power.... that said, it works.... *shrug*

not to mention, if you kept the soild lifters, you have a high chance of getting false knock.... and that costs power. are you saying noone should run a solid lifter motor?


damn, i better warn everyone running a regular no knock sensor HEI... they CANT tune it properly! i mean, they have no knock sensor at all!
and thoes darn guys and their loud exhausts... how are they going to hear knocks over the ruckus of their exhaust?! or supercharger whine? ooooh thank you! THANK YOU! we've all been doing it wrong the past 100 years!

never said they were a bad idea... i just said they wernt NEEDED... the tune isnt set by any knock sensor on this car, and its tuned deciently as is... and i doubt any "bad gas" will ever go thru it.
think application. not "what you would use".


as for the carbed cars running them, yea, i know... that ASC setup... i helped put one on my uncles truck.... carbed 400 SBC in a early round headlight toyota pickup... nice little beach truck

 

You misunderstood me. I am only talking about tuning cars WITH knock sensors. I could care less how the cavemen do it.

 

If you're still there... What sort of cam were you running in the 9.8:1 motor you described above?
Some #'s as well as type of lifters, if you're able to remember all that.

 

Another question as long as I'm here:
With a typical vaccum/centrifugal advance dist, the spark curve normally flattens out around 3000 rpm, and it has been my observation that most of the knock that takes place in a street motor happens below that range. It seems to me like if that's so, it ought to be possible to fudge the timing enough to arrive at a "workable compromise" that would permit acceptable fuel economy and performance in that lower range. Though probably not as optimal as it would be using a knock sensor. And above 3000 rpm, just leave it set at a flat 34 or 36 deg. or whatever your motor seems to be happiest with, for the times when foot is actually pushed down.
It's always seemed to me like a major part of optimizing the spark curve for a street motor is about getting it so it will cruise efficiently at low speed, without knocking when you get to a hill or some similar situation.
I guess the real question here is:
Does the knock sensor even have any effect above 3000rpm anyway, on a motor that's correctly tuned?

Feel free to contribute to, or shoot this theory down in flames.
...I'm just a rookie

 

If your A/F ratios and timing tables are correct for your application, you can just limit the knock sensor in the PROM to only be able to pull 2* timing MAX under any circumstance and you should be ok at that point. Then you can run solid roller / fuel injection / and a knock sensor with-out power being robbed by the KS when you got your foot in it.

Just a thought!

 

Thanks, that's good to know.
I think it would be worth my while to study up on some of the prom burning programs.
Isn't there some program that records ping counts? It seems like that might be awfully useful.
I know practically nothing about EFI tuning programs, point me in the right direction.

 

I have found that sometimes a knock sensor picks up knock perfectly accuratelly, and sometimes its full of crap.

for instance, the other day i used my laptop with the car running and threw in 40* of timing at idle. the knock sensor apparently picked up something because i watched the timing drop to 28* at idle and the computer kept adding in 2* then pulling it back out because it was too much for idle.


Then i noticed that during WOT apparently my knock sensor sees nothing BUT knock and drops my timing back to 25~*. I suspect its either my headers hitting the X-member or my exhaust, or maybe my valvetrain, but its not knocking, no way. i limit max retard to 1* at the track and it runs like a champ.

and sometimes on the highway my engine will knock or "kickback" because of too much timing and the knock sensor wont even flinch!!!!

the point is, sometimes it works, sometimes its full of crap. its not a bad idea to run one, but its obviouselly about as reliable as a narrowband O2 sensor; that is, not very, but it has its usses.

 

Why not just put 32-36degrees of timing in by 3000rpm, find a good idle spark, and ramp it up to the total at 3000rpm.

Assuming you don't have a huge quench, too high compression, or VERY bad gas (And anyone playing with knock should invest in some decent 92octane pump gas), or forgot to give the engine fuel at WOT, then you aren't going to knock unless there is a problem.

And I agree with the people up there speaking of carbs, they don't have knock sensors but run the same kind of WOT timing we do, just as I said above. Audible knock is when you can have problems, and that's a pretty darn agressive timing curve.

But I wont leave out the fact that some motors just wont take alot of timing, which you should already know how the engine reacts to some degree with timing for a given rpm and load.... BEFORE you put in the cam.

I'm going Solid Tappet, and am not worried about the knock sensor one bit.

Another thing to consider is that this CHANCE of false knock, will be random, if it's so random and unrepeatable but you aren't knocking in other places constantly, turn the damn thing off.

 

That's pretty much what I had in mind.
After gaining a little bit of experience fiddling with timing curves, and finding out what does what, I'm coming to the conclusion that factory timing curves along with the KS are put there to squeeze the most out of an engine as far as emissions and MPG are concerned. Which is what it took at the time to put our cars into production.
It seems to me that a solid lifter cam is something that's at least worth keeping in mind as an option.
I like too that there are an abundance of used solid rollers out there to be found at a pretty good price.

Thanks

 

Just in case you still care, I was Mechanical roller with 248@.050 and .575 lift on a 112...

 

...Still here...
That cam seems like it would be good for about 7 thou in my 327, a bit bigger than what i had in mind. But still, it's good to hear about what other guys are doing.
I'm looking for the largest cam that would give me clean tailpipe #s. A solid roller might not be nessecary, but with a 327 it doesn't take a lot of cam to put your motor into the "valve float zone". I'm thinking ahead to what my options might be, should I feel a need for greater valve train stability.
I probably won't find too many guys on the boards that are running smog legal 327 EFIs, will I?
Mine's about 9.7:1 with 64cc iron heads, +.030, zero deck. If that ended up being too much CR for the cam, I'll go with alum, and that should fix that.