805moparkid
Slant and AFX Guy
i dont recall what plug and igntion system he was running.
Stopping the knock: Lower compression and ported heads...
- Thread starter Kern Dog
- Start date
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i dont recall what plug and igntion system he was running.
txstang84
Well-Known Member
Ehhh, Plugs, he said were a heat range cold, but I don't recall brand/type...ignition system was aftermarket if I recall correctly...
The plugs were Champion RC9YC set at .035. The Edelbrock instructions called for a RC12YC but with those, I had a problem with dieseling/run on. The colder plugs stopped that.
I am using a Mopar Performance electronic distributor with the stiffest springs included in the tuning kit. It was set to 16 degrees initial with 14 degrees in the curve for a total of 30 degrees. The curve began at about 200 rpms off of a 900 rpm idle and was fully advanced by 2300 rpms (approx). I have used a Wells Ecu, an orange ECU and currently have a chrome ECU. Performance seemed similar with those factory based boxes. I also ran a Rev-n-nator but the engine knocked even worse. I retarded the timing as-per their suggestion, (2-6 degrees) but that left my initial timing so far back, it felt soggy out of the hole. The engine idled best at around 19-20 degrees of initial.
In my other long winded threads, I mentioned that I was using a wideband EUGO guage to tune after the cam was broken in. I was thinking that I may have been running too lean, possibly making it knock as a result. I up-jetted, down-jetted, changed power valves, set it to best idle vacuum....I was able to get the numbers to mid 14s at idle in Park, mid 14s at idle in gear and as low as 11.0 at WOT. I understand that 12.5 to 13.0 is the goal for the A/F readings at WOT. Even when I had it jetted to get those numbers, I still heard the knock.
By the way, wouldn't piston slap make more noise when the engine is cold? Mine sounds pretty quiet cold, warm or at operating temperature.
**** The EUGO guage setup uses an oxygen sensor that I plumbed into the RH header collector. I never tried moving it to the LH header to see if the left bank gave different readings.
I am using a Mopar Performance electronic distributor with the stiffest springs included in the tuning kit. It was set to 16 degrees initial with 14 degrees in the curve for a total of 30 degrees. The curve began at about 200 rpms off of a 900 rpm idle and was fully advanced by 2300 rpms (approx). I have used a Wells Ecu, an orange ECU and currently have a chrome ECU. Performance seemed similar with those factory based boxes. I also ran a Rev-n-nator but the engine knocked even worse. I retarded the timing as-per their suggestion, (2-6 degrees) but that left my initial timing so far back, it felt soggy out of the hole. The engine idled best at around 19-20 degrees of initial.
In my other long winded threads, I mentioned that I was using a wideband EUGO guage to tune after the cam was broken in. I was thinking that I may have been running too lean, possibly making it knock as a result. I up-jetted, down-jetted, changed power valves, set it to best idle vacuum....I was able to get the numbers to mid 14s at idle in Park, mid 14s at idle in gear and as low as 11.0 at WOT. I understand that 12.5 to 13.0 is the goal for the A/F readings at WOT. Even when I had it jetted to get those numbers, I still heard the knock.
By the way, wouldn't piston slap make more noise when the engine is cold? Mine sounds pretty quiet cold, warm or at operating temperature.
**** The EUGO guage setup uses an oxygen sensor that I plumbed into the RH header collector. I never tried moving it to the LH header to see if the left bank gave different readings.
805moparkid
Slant and AFX Guy
well it looks like your AFR was good, just leaves EGT's.
I'm not very familiar with EGTs. I figure that means Exhaust Gas Temperature? Higher is leaner, lower is richer?
Is it possible to show a proper Air/Fuel number but somehow still get an unfavorable EGT reading?
Is it possible to show a proper Air/Fuel number but somehow still get an unfavorable EGT reading?
txstang84
Well-Known Member
12.5-13.0 A/F does sound fairly normal; did you ever run it any richer than that with differing effects on the detonation? I know we're hashing back through stuff that was already brought up, but I don't want to have to search back through another 6 page thread.
EDITED: misread other details...
And yes, EGT=Exhaust Gas Temperature...I don't think it's quite as simple as higher = leaner, lower = richer, but when you combine the readings with A/F or EGO info, you can better figure out what the engine needs.
EDITED: misread other details...
And yes, EGT=Exhaust Gas Temperature...I don't think it's quite as simple as higher = leaner, lower = richer, but when you combine the readings with A/F or EGO info, you can better figure out what the engine needs.
805moparkid
Slant and AFX Guy
exactly... EGT's are the "final product" if you will, they tell you what is going on which with other known variables can help watch other issues that may be coming up. Everything effects EGT's.
CPMotorworks
Well-Known Member
Was the block honed with a torque plate?
Looks like it may be sucking some oil thru the guides too.
Was the cam degreed and actually verified intake and exhaust lobes are what they are suppose to be?
With your numbers I also get 10.7:1 CR, but cranking should only be 177 lbs at most. Your dynamic is 9.08, not 8.0 with that cam in at 106.
If you had 1cc of carbon buildup in there it would be pretty bad looking. That's not changing your CR enough to matter.
I don't see 190 lbs on pump gas being a problem either. I can however see your ignition causing issues.
Personally I highly recommend putting it on a dyno with someone that has good tuning knowledge.
BigBlockMopar
BigBlockMember
Have you ever tried driving the car without a hood on it so the engine can ingest some cooler air?
What is the average running temp of the engine normally?
Does it also ping when you lean on the engine when cold (within 5 minutes orso from startup)?
What is the average running temp of the engine normally?
Does it also ping when you lean on the engine when cold (within 5 minutes orso from startup)?
*The block was bored and honed. Torque plate? I'll have to check on that. I think the machinist said the machine is a Sunnen CK10?
*I incorrectly ran the engine for awhile with the intake manifold bolts too loose. Somehow I had my torque numbers wrong and I had them in at 15 lbs insteads of 35. I used to occasionally see oil in the valley pan under the middle of the manifold. I replaced the valley pan and didn't see any more oil come back. This was one of many areas I thought may be contributing to the knocking. It does look to be responsible for the carbon buildup, at least in my opinion.
*This was my first time degreeing the cam. I used the intake centerline method written in the instructions included with the degree kit. I never checked the exhaust lobes.
*I was pretty diligent about checking compression #s after every change I made. Maybe my guage is AFU. I will certainly retest the engine after it is up and running again. I can compare the new readings against what I recorded before, THEN recheck the engine with a higher quality guage.
*My Dynamic compression readings were calculated from this site:
https://www.uempistons.com/index.ph...=comp2&zenid=5886b5a1e26a6addce30f95974e64ff7
I listed the stroke as 4.15, the CR at 10.73 and the rod length at 6.76. For the intake closing, I took the 56.5 degrees from the cam card and added 15 for a 71.5 total. This gave me a Dynamic of 8.09. I'm open to look at other formulas though....
*In 2005 I had it tuned at a shop with a dyno. It was there where the man recurved the distributor, added bigger jets and advised me to get a more modern cam. I've followed the advice of some very qualified people and still have run into trouble.
Interesting ideas, but no, I have never ran the car without the hood.
The guages are circa Dec 1969 and I'm sure that the temp guage isn't as accurate as it once was. It rarely ever runs hot and has never boiled over. The guage reads to the left of center.
The engine does run better in the first few minutes before it is totally warmed up. The detonation worsens as it gets warmer. In the winter out here, it gets into the 30s and 40s. It will detonate at that temperature but it is very slight. The 100 degree Summers are much worse. It may be an unfair comparison though because in California, the Winter blends of Gasoline are different that Summer. Not sure how that skews the whole thing.
Perhaps it's time to consider that both hydraulic and solid cam timing events are recorded on the cam card at .050" lift, but during the engine operation with a solid cam, those events will be altered buy the valve lash, and the valve will be opening later and closing earlier. With a hydraulic cam and solid cam having EXACTLY the same timing events at .050", the solid will build more cylinder pressure because of the valve lash, which is not included at .050" on the cam card. Oh-Oh. IT'S SIMPLE. Too much static compression and/or not a big enough cam! Get it right and you can lock the distributor and run 38 degrees advance and it won't detonate.
Forget about running the compression on the edge. My 451 runs 9.5:1 compression and makes 694 HP with 906 heads.
Cylinder heads, cylinder heads, cylinder heads make horsepower on a pump gas street engine, not compression!
Curses, I broke my rule about not getting involved.
Forget about running the compression on the edge. My 451 runs 9.5:1 compression and makes 694 HP with 906 heads.
Cylinder heads, cylinder heads, cylinder heads make horsepower on a pump gas street engine, not compression!
Curses, I broke my rule about not getting involved.
805moparkid
Slant and AFX Guy
damn your right they are at .050...
Jim I really appreciate that you chimed in.
The issue where this Lunati made things worse has really confused me given the "bigger" numbers it has. I wanted to stay hydraulic, maybe going with the Comp 294, but as I was grasping for help, only Rusty Rat Rod came through with a suggestion for a specific cam. Since it made things worse, I can see why so few people stick their necks out to suggest a cam for someone else! I do not blame his or hold any ill will. He thought he was helping. Who knew that I was so close to the detonation monster that going with even this bigger solid cam still wouldn't be enough!
Comp Cam 294:
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=710&sb=2
RAMM
Well-Known Member
Wish I could get my hands on this one. Something is being missed (data) or not relayed accurately. Everything sounds like it has been addressed but something clearly is out of whack. That big solid may not be nearly as big as you think. I bet the intake valve is closing too early for the combination. You could easily crutch this combo with an MSD 6al-2 and program the spark curve accordingly. Hint: It won't look anything like the ramps we are used to seeing. It even comes with a plug in for a MAP sensor so you can design a cruise ignition curve tailored to manifold vaccuum.
Now that it's apart--Tighten the quench.
Use a head gasket as close to bore size as possible
Make sure exhaust is not restrictive
Keep intake manifold and fuel lines cool
Get that **** on an engine dyno with someone who know Mopars!!!! J.Rob
Now that it's apart--Tighten the quench.
Use a head gasket as close to bore size as possible
Make sure exhaust is not restrictive
Keep intake manifold and fuel lines cool
Get that **** on an engine dyno with someone who know Mopars!!!! J.Rob
moper
Well-Known Member
Would you elaborate on that? What dynamics would affect a solid lifter movement at .050 if valve lash is anywhere from .010-.030"? How is solid lifter motion any different in a running vs. not running engine? Is the effect different at different rpms?
BigBlockMopar
BigBlockMember
Reason for me mentioning this is that I'm experiencing pretty much the same problem as you have.
Once the engine warms up (180-190 deg) it starts pinging when leaning on the throttle.
I've mentioned it earlier in one of your topics but it never got picked up.
I went from a stockish hydr.cam with 1.6 rockers, to a solid XR274 roller cam w/ 1.5rockers and the engine started pinging when pushed (Besides/because the higher cylinderpressure ofcourse).
In my case I'm pretty sure it's the underhood heat and hot air that is causing the engine to ping, compared to the fuel-octane.
For testing winter/summer blends, you could fuel up a few canisters with summer-fuel and save them for test use in wintertime.
It's the way the opening and closing of the valve is effected by the lash in conjunction with the lobe. Of course the lobe never changes but lash greatly effects the valve timing. Give it 1.000" lash or remove the pushrod and the valve never opens.
What opened my eyes was the day that I began to play with the valve lash on a solid lifter cam and test the cranking compression. The tighter the valve lash, the less cranking compression, increasing the lash gave me more cranking compression. The hydraulic cam runs zero lash, put solid lifters on a hydraulic cam and give it .020" lash and you've shortened the duration and the valve will open later and CLOSE earlier, bingo, greater cranking compression, higher dynamic compression. (And with that much lash on a hydraulic cam you'll probably destroy the cam, this was for illustration purposes only.)
It's the reason less lash will give you more top end and more lash will make the engine pull harder on the bottom.
On the dyno, we open and close the lash on the intake and exhaust as a cheap way to see if the engine wants a bigger or smaller cam, without having to buy a $130-$330 cam. Increase the lash on the exhaust and see what happens. Power increase? You might be able to use a smaller exhaust lobe. Power loss? Tighten the lash and see if it wants a bigger exhaust lobe. And blah, blah, blah, opening and closing the lash on the intake and exhaust to see how it effects the power curve Then make your best guess and re-order the cam you want for the engine's purpose.
CPMotorworks
Well-Known Member
That calculator is making an assumption on seat timing IMO and is giving false numbers. Take out the +15° and Dynamic is just over 9.0.
Considering this is your first time degreeing a cam and given the cranking compression of 190lbs, the one possible solutiuon is the cam is advanced roughly 10°. That also puts your Dynamic at 9.5.
Something to check.
The hydraulic is a .000" lash design, and the lobes are designed that way, and the numbers will reflect that.
Lash on the other hand will alter the numbers as stated, however, not all manufactures list duration numbers the same way. For example Jones Cams are listed with actual hot lash numbers.
moper
Well-Known Member
"but during the engine operation with a solid cam, those events will be altered buy the valve lash, and the valve will be opening later and closing earlier."
I think that particular sentence phrasing was confusing me...
By decreasing lash you open the valve earlier and close it later. Increasing lash will open the valve later and close it earlier.
Increasing lash means a slight delay before the valve begins to move (as opposed to where the manufacturer intended for it to begin moving). That also means the valve will hit the seat earlier and seal the cylinder when the piston is earlier in the compression stroke (closer to bottom dead center) so there's more volume to compress and cranking pressures go up.
To me the mention of the valve timing changing inferred that valve timing was affected - it is, but it's a finite linear change on the opening and closing ramps once the lash distance is taken up.
I think that particular sentence phrasing was confusing me...
By decreasing lash you open the valve earlier and close it later. Increasing lash will open the valve later and close it earlier.
Increasing lash means a slight delay before the valve begins to move (as opposed to where the manufacturer intended for it to begin moving). That also means the valve will hit the seat earlier and seal the cylinder when the piston is earlier in the compression stroke (closer to bottom dead center) so there's more volume to compress and cranking pressures go up.
To me the mention of the valve timing changing inferred that valve timing was affected - it is, but it's a finite linear change on the opening and closing ramps once the lash distance is taken up.
The issue of tightening the valve lash is an interesting one. A guy from racer Brown Cams spoke about it 2 months back, but I didn't quite get it.
The way I understand it now is that by closing up the lash clearance, it makes the lifter/pushrod/rocker arm and valve more accurately follow the lobes. The valve actually "sees" more of the lobe. The key factor here is that a tighter lash makes the intake close LATER, which should reduce cranking compression.
The way I understand it now is that by closing up the lash clearance, it makes the lifter/pushrod/rocker arm and valve more accurately follow the lobes. The valve actually "sees" more of the lobe. The key factor here is that a tighter lash makes the intake close LATER, which should reduce cranking compression.
Great point. Since I am in it this far already, I should recheck the cam timing to be sure.
txstang84
Well-Known Member
For some reason I thought you mentioned in one of the previous replies how you had the cam degreed...probably mixing up more threads again
He did degree it. But from what I remember, he was not 100% sure where it ended up.
Along those lines, you need to remember, most cam manufacturers grind 4* INTO the camshaft. So, even if you install and degree it "straight up" it is likely advanced 4* already. SO, if you installed it advanced, you can probably add 4* to wherever you installed it, which would raise cylinder pressure even more. I am sure you can call Lunasty and they will tell you whether that particular cam is ground with advance or not. I bet a dollar it is.
Along those lines, you need to remember, most cam manufacturers grind 4* INTO the camshaft. So, even if you install and degree it "straight up" it is likely advanced 4* already. SO, if you installed it advanced, you can probably add 4* to wherever you installed it, which would raise cylinder pressure even more. I am sure you can call Lunasty and they will tell you whether that particular cam is ground with advance or not. I bet a dollar it is.
CPMotorworks
Well-Known Member
It clearly says 106° ICL is 2° degrees advanced, not 4°. The IVO and IVC points at the 106° ICL are on the card. Don't add another 4° just because:banghead:
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