[QUOTE=Weav's Vet;1572364769]The operator dropped it down in passing gear on the first try. There was some slight smoke then but just looked normal to me. It was black in color.There was very little smoke on the the next try and it sounded good to start with then as the rpm got up the engine just seemed to bog down. No stumbling or any like that just boggy or sluggish sounding. It has sounded this way before down at the track when it shifts from 2nd to 3rd but that didn't seem as pronounced as on the dyno. I haven't been back to the track since the cam swap. Saw no need in it.

There is one thing I had forgotten about on the last track trip. The guys with me saw a puff of smoke out the right hand side on the first run. I fluffed it off as carbon burn off. It didn't seem to effect the next two runs at all. All three were about the same.[/QUOTE

Black tells me fuel. Engine, at least on that side, went rich for a few. Question is why just one side and not both?

Assuming (there I go again) all injectors are the same and that all of them - especially on the rich side - are flowing the same, are we looking at PCM programming?

If one (or more) is flowing more fuel than the others, then we're getting to the cause of the black smoke.

How do all the plugs look? Actually, to get an accurate plug reading, the engine has to be CUT CLEAN from a WOT blast, coast to a stop and pull them. Gradual slow down and/or idle time can clean them giving unreliable results.

Another option that can be addressed later is to have the injectors flowed to see what's what with them. Which one's are you running BTW? Did I miss that? Well-used ones and some after-market models have bad records.

What plugs and gaps are you using? You may have already mentioned this stuff, but going back to find it, well need I say more . . .

Steve says to have the knock retard function tuned out. I go along with that if for no other reason to see if THAT'S the cause. In fact, we got along very well for decades without that little feature. I believe it was only gone to in order to allow pushing the envelop in ignition timing for CAFE, bad gas, etc. Good tuning in the PCM will eliminate the need for that little 'constantly causing problems' feature.

Jake

West Point ROCK! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

 

I think you mis-understood what I was trying to say. I ONLY meant that JUST returning things to how they were before isn't much of a plan. I didn't intend to imply that's what you're doing, because you're not. You're making changes.

I was just trying to get your agreement that putting things back exactly as they were isn't a good idea, that's all.

Sorry for any confusion I caused.

Seat pressure is a little higher than I like to see by 15#, but I really don't believe that's a major issue here. Open pressure looks good though.

Just as a point of reference, you can take a look as the pressures GM is using in their 505 HP LS engines (and other builders too); just to give an idea on how they're approaching the issue. HR lifters become more sensitive to spring pressures as more spring is installed.

TPIS and AFR can tell you what their test results show. And since we're trying to eliminate possibilities, that's one worth considering.

Just to get an idea for myself, I looked up what GM used on the 96 LT1 81-89 # on the seat and even on the LT4 seat only went to 96-107# range. Opens are in the 265-273# range. Now I know these numbers are for a stock cam, but, for me, it gives a little insight. Like 150# on the seat is close to a 90% increase in seat pressure over the low end stock spring range for the LT1.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

 

I see your point Jake but I'm sure he was speaking in terms of the valve opening and closing correctly when he said that and I took it that way.

Actually I had seen that in the FSM so lets look at it a bit. I didn't have this problem before the cam swap. So that may eliminate a few of these.

Low oil pressure It was good before the swap and better after because I replaced the oil pump drive gear and the shaft with a harden steel solid piece unit. I also installed a GM White spring to increase oil pressure.
Loose valve rocker arm attachments I guess this is the stud, brand new 7/16
Worn valve rocker arm and/or pushrod Both new and the pushrods are hardened steel
Broken valve spring This I would have to check by removing each one but they are double springs and I seriously doubt these heavy dudes are broken anywhere.
Sticking valves Not sure here but doesn't seem likely with the low end torque it has
Lifters worn, dirty or faulty Once again, brand new GMPP lifters.(bad batch, rebuilt and resold maybe. Should I replace them?) How do you check a lifter?
Camshaft lobes worn Lord, I hope not! I may have to just quit!
Worn valve guides I guess this is possible because I have no idea of what condition the valves are in. If I run the compression test again it will tell a lot here.
Worn or damaged valve keys (re: the broken one you have)
Bent pushrods See above on push rods. Also, to add to this I wonder if the rods possibly rubbing on the bottom of the U on the guide plates would send enough vibration to set off the sensors. I'm not sure they are rubbing there but it's really close and perhaps during high RPM's the move enough to rub......... I will check it out. Out of all of these this one is a possibility.

I'm thinking maybe the valve lock was probably broken when I ran the 7.1 pushrods.

Once again this LT4 knock module and how much desensitizing Ion did on the PCM comes into play with this knock retard. I'm also going to remove the knock sensors and Teflon tape them in hopes of making them less sensitive.

 

[quote=JAKE;1572365904]The engine not acting the same on both sides is what the guy at RPM Motorsports said. He didn't have an answer though. He said it acts like a vaccun leak but they searched the engine up and down looking and found none. Even sprayed it down several times with Either.

I'm running these injectors from Jon
http://www.fuelinjectorconnection.co...od&productId=4

Plugs are Autolite 104's gaped at .048. I haven't checked them like you suggested doing after a WOPT run. When I do take them out they have always been wet looking. Like they aren't firing good.

To address the programming......... I'm seriously thinking of getting a totally different tune from another tuner. Maybe Mseven might like to take a shot at it. I haven't contacted him about it yet though. Just kind of hoping it's the opti or the knock retard issue.

Sorry about the length of this thread. It does kind of get the information spread out all over the place. Wasn't intentional and believe me when I say, I want it end sooooooooon!

I've been in contact with the company I have the data logging equipment with. I'm hoping I have this software issue fixed so when I do get it running again I'm sure a datalog will show a better picture of what's happening.

 

This is a little embarrassing so no flaming please....... :o

I was reading on another forum about LS7 lifters. A question came up about the oil holes. This is tuff........are the lifters supposed to face a certain way to line up the oil holes? I just dropped mine in paying no attention to the oil hole.

If they are in wrong could they be damaged?

 

Wet plugs and those injectors, interesting. Do you know if they are rated at the same psi as ours at 43.5 psi?

Even though they're listed as 24 #ers, they may be rated for that at a different PSI. That's somethng the tuner would need to know when re-programming the PCM so he could crunch the number difference.

Let's say they're rated at 20 psi and at THAT psi they're rated as 24#. Now the programmer uses the rating psi we use - 43.5 If you kick injectors rated at 20 psi up to 43.5 they'll actually be flowing a LOT more than 24#. I don't have a conversion chart readily available -maybe someone here does - but they could be flowing closer to 30 #ers at 43.5. Just one more thing to check into and verify in the quest of eliminating possibilities.

Another possible side effect is in Closed Loop the PCM/02s would try to correct for (within the PCM's ability) the extra fuel by lessening injector on-time. However at WOT, all bets are off; no correction occurs since 02 feed-back is ignored by the PCM.

So, factoring in the injector rating psi, the wet plugs and the black smoke, could we be on to something? Even if addressing this doesn't result in the power increase you're expecting or even level out the graph, it's still something that should be checked out.

I didn't know about the possibility of a vacuum leak; didn't even know it was in the mix. Wonder what a vacuum gauge would show; steady reading/bouncing needle/low reading? I do know these suckas are really sensitive to a vacum leak. I've had a couple of really tiny ones (one intake and one exhaust) over the years but the engine sure let me know in no uncertain terms that something wasn't right - and mine were REALLY tiny.

The only way I know of to check valve stem to guide clearance (checking for guide wear) is pretty work intensive. Springs have to be removed and a dial indicator mounted to the valve stem. The amount of movement of the valve stem is read on the indicator. I don't feel we're there yet, though. I'd put that on the back-burner for now.

Jake

Wet Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

 

Vacuum is 16 and steady

 

I've wondered exactly the same thing and spent a LOT of time trying to find out if it made a difference or not. I've even scoured my FSM for anything on that and nothng's even mentioned.

In my experience, GM makes mention of things that have to be installed in a certain direction, like the water pump drive gear tube, but, NO, nothing on the lifters.

Nothing found in all my efforts, so my conclusion is, NO, it doesn't matter.

If someone has info to the contrary, take me/us to school.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

 

I looked thru the FSM too and saw nothing. The thread I read wasn't really about my type lifters it just got me thinking about it. Evidently some have had oiling issues with the LS7 lifters. It was mentioned the oil hole had to face to the rear of the engine and the ones having issues had not done that. I have no idea, once again it's hear say I guess......

Whew....I think I'm in the clear on this one. Thanks Jake

 

In my situation, I wasn't being faced with a LS7 lifter question but, knowing how GM just LOVES to change things, MAYBE LS7s are somehow different in that area. But still, I never found anything even on those. Even as recently as a few months ago when I was in the process of changing the cam and heads on my son's 96, I researched that lifter direction question. NADA!

How about asking on a board where the LS guys hang out and see what they say. But I caution you, make them site their SOURCE, because there's a LOT of bad information flowing around out there. Like the guy who posted that it doesn't matter about the water pump drive tube, saying it doesn't matter which way it goes on.

Some guys will say just about anything and many times it's DEAD WRONG - so I suggest have him site his source.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

 

[QUOTE=Weav's Vet;1572367250]I have had problems on high performance engines with high cylinder pressures not firing the plugs at WOT with spark plug gaps of .045. The problem goes away with gaps of .035, try a tighter gap and see if the car works better?

 

[quote=bjankuski;1572373139]Thanks for the suggestion bjankuski and thanks for chiming in.

Actually, the first run was with NGK plugs. LE suggested the Autolite's. They are about a 2 degree range cooler. I tried a tight gap first but the idle the car had was aweful. When I opened the gap back up the idle was better. I never ran WOT with a tight gap though. Maybe a hotter spark would help with a wider gap at WOT.

 

[QUOTE=Weav's Vet;1572375021]the cylinder pressure at no load idle is minimal...you should be able to run smoothly with a wide range of gaps and temps.. something else is bad.

the only thing you are doing with weird heat ranges is to make the exhaust emissions a little dirtier/cleaner at idle.

 

 

Stayed up late last night doing some more research on LS7 lifters. I GOOGLED and found posts going back several years on those. Seems views are all over the MAP as to the depth of the pushrod cup and the preload.

Some were recommending preload as much as +.100 and MORE, as compared to what I usually see (.030-.040) for LT1s.

In addition to that, I saw posts saying the depth of the pushrod cup is like .060" lower than on LT1 lifters. Before reading that, the number I'd seen was .020 lower, not .060". One guy posted that he had measured his LS7s and his stock LT1s and the .060"is what he found.

Well, if any of this is applies to your application I can see how it would directly impact the pushrod length, so:

Numbers aside for the moment, did you actually measure/check when determining what length pushrod to run?

I'll post links to a few sites I found.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

 

http://www.ls1tech.com/forums/genera...ifference.html

There're more and I'll try posting them as I come across them.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

 

Hold on Jake.
I appreciate all of your digging and I have bookmarked those links for future reference. But.......

I am not running LS7 lifters. I'm running GMPP replacement lifters for the LT1. I did check PR length and there is a picture a few pages back. It's dead in the center of the valve stem with 7.2 pr's. I questioned whether the lifters were holding their pressure is how all of this came up, I think.

I got a lot back together this afternoon so It's getting there. I am going to remove the guide plates and enlarge the bottom of the "U" just a tad. Bank #2 is definitely rubbing at the bottom of the "U".

 

Hey, Are you using aftermarket or OEM guide plates? I am not sure, but supposedly there are some minor issues with aftermarket and OEM. I originally used Comp Cams, then reverted back to OEM. You could actually see the difference in angle of your rocker arm on the valve stem as they werent straight with the Comp Cams.
I figured you needed to hear this, so as to not be really concerned per sey as many issues are common with push rod/guide plate interference etc.

 

[QUOTE=Weav's Vet;1572367250][quote=JAKE;1572365904]

The engine not acting the same on both sides is what the guy at RPM Motorsports said. He didn't have an answer though. He said it acts like a vaccun leak but they searched the engine up and down looking and found none. Even sprayed it down several times with Either.

Maybe if there is a possible vacuum leak & none are found,maybe casting screw(s) that screw in bottom of intake leaking.Just thought I would throw this out there.This can cause a vacuum leak that will not be found unless intake is removed & they are screwed out & reinstalled with thread sealant.Just thought I would add my 2 cents on possible intake leak

 

Thanks Steve
At this point though I have to check it all just to make sure any little minor thing isn't the issue. When you say the rockers weren't straight do you mean like not parallel to each other? Mine aren't parallel and some are worse than others. I have a pic somewhere if needed.

Here are the plates I'm using.

http://www.trickflow.com/partdetail....098+150&orig=1