New 454 pinging [Archive] - Chevelle Tech

: New 454 pinging


LeLynn
Dec 31st, 07, 5:38 PM
Hello everyone, I have a problem with the 468 I just fired up for the first time last weekend. I have a 454 .060 over with .200 domed pistons, pistons .005 below deck, 049 heads milled to 119cc's, ROL head gaskets with 9.47c compressed volume and .039 thick (I get just under 9.6:1 compression ratio) Is this quench .044" aceptable? The engine also had a UDHarold cam 223/227 duration @.050 and .539/.550 lift on a 112 LSA ground with 4 advance and installed dot to dot for a 108 intake centerline. Ignition timing is set at 17 base 37 total timing in by 3000rpm. The engine runs like a dream, but has a problem with slight detonation inder hard acceleration, like when getting on the freeway. Should this combonation be pinging? I did not think the compression ratio would be high enough to worry about. I do run it on 91 octane. I have 3 options the way I see it. I can either resort to runnig octane boost in every tank of gas (Not my first choice since I drive 150 miles per week), I can retard the ignition timing but then I can hurt performance and run the risk of overheating or I can change the cam timing. The way I understand it, advancing the camshaft will bleed off a little more cylinder pressure and move the horsepower and torque up in the RPM range. Is this correct? Does this sound like the best way to solve my problem considering the fact that I don't want to pull the pistons. Are there any options I have not thought of? Thanks for the help.

SWHEATON
Dec 31st, 07, 6:09 PM
Your timing is right on with 17 base/37 total @ 3k rpm with the cam your running.

I am not surprised at all that it pings under load with only 223 deg dur @ .05 cam in a 468 with 9.6 comp.

The comp could be even a little higher if you didnt take into consideration a decked block and heads when you figured compression. In that case the compression could be closer to 9:8- to maybe even 10:0 comp if a thin head gasket was used and alot of material was removed from block/heads when decked for flatness.

If it doesnt ping when at part throttle cruise or when accell from a start it's not too much timing comming from the vac adv .

You say it pings under hard acelloration so the vac adv drops out when the intake vac goes away when throttle is opened hard so you only have a few choices without going into the motor to lower compression assuming your already running highest oct fuel avial which is 91 octain in CA.

You can retard the timing untill it stops the ping and loose power & use more fuel or you can buy some real lead kemco booster ,1qt kemco per 28-20 gals 93 fuel increases oct to 97-98 and that will stop the ping and give you some more power.

If the car is not a daily driver it will only cost you approx $100 yrly to retain the full power/perf of your 468 which is what i do with my mild 396 insted of retartding the timing loosing power/perf.

For a wk end cruiser only the kemco is the way to go in your case where the timing is dead on correct and all you need is a hit of kemco to boost the octane.
Search the Kemco site to find the "kemco supreme 130 octane booster" .

Other then doing the above you would have to install more cam to bleed of more cyl pressure,install thicker head gaskets, replace the pistons with lower comp units,or install heads with larger comb chambers to lower comp.

And for all you guys that are going to chime in (like last time ans a post like this one) to say my 540 run's on 91 or 87 fuel with a huge 260 deg @.05 cam & 10-11:0 comp thats compairing apples to oranges in this case,end of story.

I say this because large duration cams bleed off a lot of compression/cyl pressure allowing the use of lower octane fuel in thoses cases even with high comp ratio's which is not his case here. His motor has a farily short dur cam in almost 470 cubes with compression likely above 9:6 closer to 9:8 + on crappy 91 oct fuel used in CA . Keep in mind this is in a 35-40 yr old design motor not desinged to run on low oct fuel and or not built specifically to run on 91 fuel with larger cam to bleed of comp or using flatop pistons for lower comp or larger chambered heads. There motors were designed to run on 98+ oct fuel back in the day which = roughly 96 oct for todays fuel which is still 5 points short for his motor that is running on 91 fuel in CA.

It just confuses the issue in cases like this with a mild perf motor with ping issues being compaired to larger motors with tons of cam duration or even same size motor with a much larger cam bleeding of comp.

I recently ran a post asking for what motor setups were running on what oct fuels and not detonating and in most every case there were large 255-260 deg + deg dur @.05 dur cams being run in 454-540s bbc with the higher comp ratios that were not detonating on 91 or 93 fuel which was no surprise to me.

But when someone has an older gen sbc/bbc built with stock type heads and higher comp above approx 9:5 & up with a short dur cam in his case here that's often a rcp for ping on todays fuels.

Running the kemco to avoid having to break a new engine appart to lower comp is a good solution to his problem not to mention the additonal octane will likely give the motor more power esp when retaining the full perf ign timing curve your currently running which is riught where it belongs.

Scott

HP Hunter
Dec 31st, 07, 6:38 PM
What piston are you using?

Did you measure the heads or is it a guess?

You may be closer to 10 to 1 on the comp ratio

And last, who picked the cam numbers, they look a bit small for 468 inch big block? It may have been picked with lower compression in mind!

Harry P.Hunter

71 chevy
Dec 31st, 07, 6:47 PM
maybe use a thicker head gasket???

mr 4 speed
Dec 31st, 07, 6:57 PM
first and only question: Are you running vaccum advance? If you are,disconnect it and go for another ride and report back.
If it still pings,your total timing is more than 37 and it is still advancing at higher rpms.
I am running Harold's grind: 223/231 @.050 .525/.550 112 LSA with 10.5 to 1 compression in my 454 and I have no issues running 25* initial/38* total with NO vacuum advance.I have been running this combo for 7 years and have been driving it for 17K+ miles and drag racing it as well.It runs fine on 92 or 93 octane.

kettbo
Dec 31st, 07, 8:23 PM
and what about the 4 deg adv in the cam....this would BOOST low end cyl pressure.
Mighta been OK if you had 9:1......probably not what you wanna have in a engine with 9.5, 9.75 or even 10:1 AND only 223/227* dur. In a 396 this would be a fairly large street cam and you'd do OK. A 454 sucks up a 223/227 cam like it was nothing, makes it a fairly mild grind.....

When my 454 eventually comes together, I'll have around 10:1 so I'm gonna run 238/248* dur

LeLynn
Dec 31st, 07, 9:16 PM
What piston are you using?

Did you measure the heads or is it a guess?

You may be closer to 10 to 1 on the comp ratio

And last, who picked the cam numbers, they look a bit small for 468 inch big block? It may have been picked with lower compression in mind!

Harry P.Hunter


I'm running Keith black forged pistons part number 9919-060 they are a .200 dome piston. The heads were CC'd, well one chamber in each head was CC'd at 119cc, the head gasket are ROL .039 thick, 4.345 bore. The block is decked so that the pistons are .005 down in the hole. I get a calculater compression ratio of 9.58:1 and a quench of .044 inches. Thanks for the replys but I'm still kind of stuck, I guess everyone is saying that unless I want to retard ignition timing, run octane boost in every tank (I drive the vehical about 110-130 miles per week) or pull the engine apart to lower compression I'm pretty much screwed. Do I have any other options? Can the cam's timing be altered to help (Retard or advance)? The detonation is slight, but any detonation is too much in my book. Thanks again for the help, I look forward to hearing your input.

mr 4 speed
Dec 31st, 07, 9:28 PM
What distributor are you using? What rpm are you at with 37* of timing ?

LeLynn
Dec 31st, 07, 9:33 PM
What distributor are you using? What rpm are you at with 37* of timing ?

I'm using a MSD pro billit. 37 deg is in at 2900-3000 or so.

mr 4 speed
Dec 31st, 07, 9:33 PM
Are you using vacuum advance?

LeLynn
Dec 31st, 07, 10:31 PM
Yes it has vacuum advance. I tried dis connecting the vacuum advance without changing the actual timing (Without moving the distributor) to see if perhaps it would cure the problem. It did not. The pinging is not under light acceloration, it is only inder hard romps, althought I have not really jumped on the engine too hard yet as it is only about a week or so old and I only have about 75 miles on it. When getting on the freeway I gave it about 1/2 - 3/4 throttle and it had SLIGHT detonation. When cruising at say 2500 rpm and I lightly press the throttle it will not detonate, if I press the throttle hard at those speeds I can hear a slight rattle. I pulled the plugs and they all looked good with no aluminum speck or anything, so the problem is not exreme. Tomorrow I will try to pull 1 or 2 degrees of total timing out and see if it helps. I am just aftraid that after the break in period (400-500 miles) when I'm able to I push the engine hard it will have a more serious problem. I'll give it a shot tomorrow and see how things go. Any other suggestions?

racecar100
Jan 1st, 08, 12:03 AM
What park Plugs are you using???? Wrong spark plug heat range will cause one to ping.

496blaze
Jan 1st, 08, 12:52 AM
Yes it has vacuum advance. I tried dis connecting the vacuum advance without changing the actual timing (Without moving the distributor) to see if perhaps it would cure the problem. It did not. The pinging is not under light acceloration, it is only inder hard romps, althought I have not really jumped on the engine too hard yet as it is only about a week or so old and I only have about 75 miles on it. When getting on the freeway I gave it about 1/2 - 3/4 throttle and it had SLIGHT detonation. When cruising at say 2500 rpm and I lightly press the throttle it will not detonate, if I press the throttle hard at those speeds I can hear a slight rattle. I pulled the plugs and they all looked good with no aluminum speck or anything, so the problem is not exreme. Tomorrow I will try to pull 1 or 2 degrees of total timing out and see if it helps. I am just aftraid that after the break in period (400-500 miles) when I'm able to I push the engine hard it will have a more serious problem. I'll give it a shot tomorrow and see how things go. Any other suggestions?

What type of carb are you running? If its a Holley you might be getting a lean condition form a slow opening power valve. You can help this problem by replacing the existing p.v with a higher than stock number like a 8.5 or a 9.5. With your cam, I would almost bet your engines vacuum is really high when rolling into the throttle as you described. If you do a short wide open blast (like getting on the freeway) and it doesn't ping, I would look at the power valve.

Todd

Tom Mobley
Jan 1st, 08, 2:36 AM
Take 3 or 4 degrees timing out of it. You're noticing detonation under WOT, this will not involve the vac advance since there is no noticeable vacuum under these conditions. Your timing is aggressive enough so you can drop a few degrees with out killing the engine. It would be good to reduce the amount of mechanical advance since since it's at WOT and above your full advance RPM.

You've built an engine with too much compression ratio for iron heads and a short cam. I've harped on this for years and I'm getting tired of typing it. Plus, I'm in a bad mood. :)

mr 4 speed
Jan 1st, 08, 8:13 AM
Since you have all ready tried it w/o the vacuum advance...what Tom said.
I am actually suprised it pings with 37* total and no vacuum advance. I get away with a small cam and too much compression w/iron heads myself. I have .100 tall domes and 101 cc chamber heads (piston .008 below deck and .039 head gasket)
The small dome/tight chamber deal is probably less detonation prone than the large dome/large chamber maybe.

69-CHVL
Jan 1st, 08, 9:56 AM
Try heavier springs in the dizzy. Usually MSD's come with the heaviest springs installed to prevent what's happening to you. I think they let the curve in 4500. I ran mine than way for a while and couldnt tell the difference between all my timing in being in by 2500 vs 4500.

sleeper
Jan 1st, 08, 10:08 AM
Try taking 2 degrees out at a time until it does not ping. I had this exact issue with an HEI I was running. I switched distributors about a year later to the MSD distributor and was able to increase the timing to where it should have been. I tried every curve possible but could not get the HEI to run without pinging when running the amount of timing that the engine should have had. Since you already have the MSD play with the springs and see if that has any effect.

If you are running a Holley try raising the fuel level in the primary bowl a little. Set the fuel level to just where it dribbles out. Install the sight plug and raise the float about 3 more flats. That will richen the carb slightly, maybe enough.

If it does not ping at light throttle I agree it is not the vacuum advance. I would still get a Crane adjustable advance and play with it. Can't hurt.

How much pumping compression does the engine have? I am guessing somewhere in the 180-190 range if you are pinging. All the books say you can run up to 200 but I have never been able to. Anytime I get over 180 I have pinging issues, even with conservative timing. If you have less than 180 and pinging you have a distributor/timing issue.

I really think the pumping compression is a more accurate indicator of how much timing/octane is required than DCR. DCR is very helpful getting you in the correct range on a new combination. I feel a poll comparing cam timing/compression/DCR/ and distributor timing would be helpful. All these folks that can run 11.5-12 with 91-93 octane have some sort of combo that I have never found, especially if they really run them hard both on the street and strip with the same gas.

496blaze
Jan 1st, 08, 2:54 PM
Take 3 or 4 degrees timing out of it. You're noticing detonation under WOT, this will not involve the vac advance since there is no noticeable vacuum under these conditions. Your timing is aggressive enough so you can drop a few degrees with out killing the engine. It would be good to reduce the amount of mechanical advance since since it's at WOT and above your full advance RPM.

You've built an engine with too much compression ratio for iron heads and a short cam. I've harped on this for years and I'm getting tired of typing it. Plus, I'm in a bad mood. :)


Actually Tom if you read post 11 he says it pings at 1/2 to 3/4 throttle, not wide open because he hasn't gone there yet.. I agree he could back some timing out and not hurt performance at all, but I think it could also be carb related.

I respectfully disagree that 9.6/1 compression is too much for his cam combo. I have ran the same compression in a 496 with a similar cam on 91 with no pinging issues. Oh, and this engine was in a truck.

SWHEATON
Jan 1st, 08, 7:03 PM
Chris,he stated righ up front it pinged when under hard accelloration like getting up to speed onto an interstate so its not the vac adv,that goes away when throttle is opend up far and intake vac drops off,it just the total timing at that point.

I did restate he said it pinged under hard load and not light throttle cruise hoping others would no mis that fact but i guess we all mis the little details from time to time.

Scott

SWHEATON
Jan 1st, 08, 7:47 PM
Sleeper,i just ran a post asking for people to list their full engine combos & fuel they run on with no detonation.

And it was no surprise to me that guys running higher comp 10-11:0 + ratios with no ping were running very lrg 255-260 deg + @.05 dur cams bleeding off a lot of compression in hot motors that didnt ping.

But its the guys with as low as 9:5-9:8 comp in some cases & 9:8-10.5 + comp in mild street perf sbc/bbc motors with mostly stock head/piston design along with mild / fairly short duration cams that get into trouble with detonation on todays crappy lower octane 91-93 fuel .

I keep stating this over and over again which i am sure many are tired of which is these motors with 10:0 comp & higher were designed 30-40 yrs ago to run on 98+ oct fuel not todays unleaded/oxygenated/ethenol added /lower octane 91-93 oct fuel. From what i read todays unleaded 91 & 93 fuel would roughly = leaded 92-93 & 95-96 oct fuel of 40 yrs ago due to difference in figuring leaded fuel octane vs figuring octane for todays unleaded fuel.

I grew up with these motors/cars and i can tell you when you ran less then 98 oct fuel back then they would ping when running the correct timing so it doesnt surprise me that they ping on todays totally reformulated fuel being 2-4 points lower on avg for octane. That's even taking into account the difference in the octane ratings 40 yrs ago to today when talking mild cam'd 10:0 comp & up motors that have higher cyl pressures,not motors that were built to run on 91-93 oct fuel with very lrg cams with a lot of duration (255-260 deg + dur @.05) that bleeds off cyl pressure (that motors with mild cams & 10:0 + can't do) which helps avoid detonation.

It's easy and inespensive to run the kemco booster @ approx $100 yrly if its not a daily use car which is the case for most of our chevelles .

With Kemco he can run his full perf ign curve without having to retard the timing loosing power/perf/throttle resp,and lower fuel economy. But how much perf he looses in these areas totally depends on just how much the timing needs to be retartded to stop the ping.

Compaired to what we have tied up in our rides/motors spending $100 + - yrly to run real lead Kemco to inc octane and retain full power is a small price to pay IMHO rather then jumping thorugh hoops to detune the motor to stop ping loosing perf or worse yet take appart a good running freshly rblt motor to lower compression with thicker had gaskets,or lrg chamber heads,replacing pistons,or just caming it up more rto bleed off some more cyl pressure resulting in a less street friendly ride with more cam duration.

Scott

SWHEATON
Jan 1st, 08, 8:03 PM
Todd,you 496 may have not had as much comp as you thought,or maybe you werent running a full 18 deg initial timing & 38 total with a vac adv ,and to top that off most trucks run more gear numerically (373) placing a little less load on motor so its less liable to ping then a car with lets say 308 gear.

There are many variable that can lead to ping,thas for sure.

I have been working on sbc/bbc street perf motors for 36+ yrs and i can tell you from all those yr's of 1st hand exp dialing in/working on mild cam'd V8 motors of 30-40 yrs ago with comp approx 10:0 comp will often ping on 93 fuel when running full perf ign timing curve and vac adv on the street.

But again i am talking about motors running mostly stock setup with stock cam or mild perf cam that are short on cam duration,NOT MOTORS WITH AFTERMAKERT HEADS/LARGE DURATION CAMS/OR THAT WERE BUILT SPECIFCALLY TO RUN ON LOWER OCT FUEL.

I see it very often here in t/chevelle where guys post issues with mostly stock or stock type setups with mild cams detonating and there is a reason for that,the 91-93 fuel of today can handle it in those situations and thats where 1qt kemco to a full tank of fuel will bump the oct from base 93 to approx 98 fixing the problem.

I am pushing this kemco booster because its such an easy inexpensive way to avoid having to detune motors in this situation to run on 91-93 fuel loosing perf when $100 yrly will fix it by adding 1qt kemco with each fillup.

Some of you guys should try it,it gave my mild 396 a little more kick when i tried it,i will never go back to using just 93 fuel when i can get full perf all the time with kemco.

Scott

mr 4 speed
Jan 1st, 08, 8:04 PM
:) I would still play with the advance curve no matter what.
How come my combo doesn't ping? I have more compression and basically the same cam.
I do have a feeling it is the closed chamber head/small dome piston combo that is less prone to detonation with the same timing vs. open chamber/large dome.
Any thoughts on that Scott? My cranking compression is 200-205 lbs.

SWHEATON
Jan 1st, 08, 8:43 PM
Hi Chris,my cranking comp is also 200psi too and my mild 396(now 402) has 063's too like your 454 has.

You may have somethng on the closed chamber design being less likjely toping then other setups in certain situations.

My motor doesn't ping when at cruise or lightly accelllorating from part throttle cruise even with vac adv hooked up,it will only ping under hard throttle when vac adv drops off with 36-37 total.

I even tried unhooking vac adv just for a test and it will still pinged under hard throttle with 93 sunoco fuel running 18-19 initial & 36-37 total.

But i figured it waslikely o edge of ping under normal part throttle situations where i maybe could neot hear it. I kept a close eye on my plugs which were already running 1 step colder then stock for my motor and i thought i saw some early signs of detonation. This was when i installed a net set of plugs 1 colder heat range and didnt get on it to force it to ping,i wanted to see how it was doing under low load normal driving and even then i saw early signs of detonation.

I could get ping to stop dropping back the timing approx 4-5 deg but that really hurt the perf over the complete range of operation which i didnt like,it just felt soggy esp from a stop getteing the car moving and going through the gears in a normal manner while getting up to cruising speed with the retartded timing even with the vac adv hooked up to full vac alll the time,guess i was just spoiled and didnt want to accept anything less then fullpotential from my already cubically challenged 396/402 which you dont experience near as much with your larger 454 motor esp with ported heads ,headers,etc which i dont have either of that would definately wake up my little rat some more if i had them. but i wont install headers for a few reasons the most of which is i would likely get on it more with the better perf the headers would bring out and i can't affort to break/blow up the #'s matching drivetrain pushing it harder more often with a little more power/trq which may be just enough more to break something,just cant afford to break it.

I have to admit o do have an extra complete 396 motor,non #'s match m20 is currently in car(original #'s matching m20 trans was totally restored/rblt in 2006 and is stored in corner of garage),and havs an nos set of 3:31's lying around just in case i did break something.

But back to subject at hand,when 94 sunoco was still avail in NY back approx 4-5 yrs ago the motor didnt ping on it,it was just when Sunoco was forced to drop the 94 ultra back to 93 octane and reformulated it 4-5 yrs ago at the time due to new EPA regs for NY state that my motor said ,ok now you really went & did it and i wont take it anymore and started to ping with the newly reformulated Sunoco unleaded 93 ultra fuel.

so with all this said i just decided to spend the additional $100 yrly to run the full ign curve for max power/perf at all times and not worry about damaging my motor from detonation.

I have seen 2 people i know fall prey to detonation damage to their motors becasue they didnt want to spend the additonal $100 yrly for kemco as a precausionary step eeven though they didnt normally hear any detonation.

They both broke/cracked 3-4 pistons , bent some valves & a few con rods,and beat up the bearing in bottom end but luckily didnt destroy the blocks on low mileage motors.

But they had to dissassemble the motors and re-hone,re-ring & beraing it,replace some rods,and replace some pistons valves with some other head work,was farily expensive and very time consuming to say the least .

They were both running approx 10:1 comp and one had a 292 comp cam/244 deg int dur @.05 bleeding off some compression but i forgot what the other cam was in the other motor that had detonation damage.

The kemco will keep me safe from ever experiencing what they did for only $100 yrly,thats for sure.

Scott

LeLynn
Jan 1st, 08, 9:25 PM
Update. Ok so I went out this morning to pull 2 degrees of timing out and see if it would fix the problem. Well, when I just checked the timing it read 15 deg at idle and not 17 degrees. I checked the distributor hold down and it was tight and the distributor would not move by hand. I rechecked timing and it read 17 degrees like it did yesterday. I went out and borrowed another timing light (Non adjustable cheapo) and rechecked timing. Timing was now reading 20 degrees with the "Known good timing light" I then drove to Sears and got a brand new light and checked timing in the Sears parking lot. 20 degrees again. It looks like the timing light I used origenally (Old beat up adjustable Snap on light) is faulty. I got readings all over the place with it, and got a constant reading with the 2 other lights I tried. Well I Re-re-set timing using the new Sears Craftsman timing light to 17 degrees and drove it home, accelerating as hard if not harder then before with no ping (I guess 20 degrees of base timng is too much LOL). I REALLY apreciate everyones help. I can't explain to you guys how thankful I am to you for trying to figure out my "Problem" going just on my word. Turns out my timing light was just acting up. I have learned to be positive your tools are in working order. If anyone has any more questions I'd be happy to answer them. Thanks again for everyones time and your help.

mr 4 speed
Jan 1st, 08, 9:30 PM
Nice!!! :thumbsup:
Always good to hear a happy ending :beers:

496blaze
Jan 1st, 08, 9:31 PM
Good for you man!! Good thing you didn't start rippin the pistons out of that thing..

Tom Mobley
Jan 2nd, 08, 2:39 AM
excellent results. thanks for posting up your findings. Now things make a little more sense.

Sandy
Jan 2nd, 08, 3:49 AM
Glad to hear you got a good result from your efforts.

Something I have been doing now is to use a felt marker pen to mark the distributor and intake manifold when my timing is set where I want it. Then you know if it moved and have a reference mark if you change it.

Also, comes in handy if you have to pull the distributor for some reason, can get it back pretty close to where it was.

69-CHVL
Jan 2nd, 08, 8:10 AM
Glad to hear you got a good result from your efforts.

Something I have been doing now is to use a felt marker pen to mark the distributor and intake manifold when my timing is set where I want it. Then you know if it moved and have a reference mark if you change it.

Also, comes in handy if you have to pull the distributor for some reason, can get it back pretty close to where it was.

I just though about this myself...mark where the distibutor is with a line on the dizzy itself to the intake. maybe even make a mark for +2* and -2* for experimentation at the track. They actually sold a piece that had degrees etched on it just for this purpose, but I'm too cheap.

GRN69CHV
Jan 2nd, 08, 9:02 AM
I run 10/1 to 10.4/1 CR (never CC'd the heads but have found out they can range from 110CC to 114CC). Cam is 283/287 at seat, 233/236 @ .050 installed at 108ICL. Have ran it on as low as 89 octane without pinging (at least nothing I could hear).

My alum head motor does run cooler though, think that has a lot to do with it.