87_TA

Last seaon figured out that my very old (12yrs+) cheater solenoid had become restrictive due to swollen seals and car began slowing - changed it to a big shot - that had proven it was a big restriction as the car picked up a lot from it.. All along I had run 34° timing, knowing whne the car picked up I should have backed off some now that it was getting full spray with same ratio of fuel - but plugs looked ok sooo..

This year get on Dyno, leaned out some to make more power to a less conservative 12.5-12.8 afr from 12.0 783HP at wheels/850 TQ - First day at track runs great but blew header gasket, replace and go back and does it again - still running well.. Second time back does it again on another tunbe, now suspecios I shut down and check plugs = Destroyed - I have no idea how car was even running.. Decide to tear down last night - destroyed plugs = scratched cylinder walls and dinged up pictons.

I think I can repair the pistons and may be ok with a hone and new rings - will see..

FSTFBDY

iTrader: (33)

clean and buff off the top of the pistons. Then thermal coat them while out.

DIGGLER

iTrader: (1)

34 degrees?!?!? i ran my car at 32 degrees n/a!! can't remember now, but i was probably somewhere around 24 degrees with the .082 jet.

sucks to hear, i hate having to fix stuff. nothing to be excited over like if you were putting a new go-fast part on. good luck with getting it straightened back out.

JesasaurusRex

iTrader: (3)

Wow

brandoz28

iTrader: (1)

Holy crap that's a lot of timing on that large of shot!!!!!!

Hope you get it sorted out

itsjustabird

iTrader: (1)

^^ exactly what I was thinking! kept waiting to read how much was being pulled! lol Sorry you hurt it. Really check the ring lands as they were likely affected. How you can get it back together cheap! Out of curiousity how was it running time wise?

3rdBird

iTrader: (1)

I run 24* on a 200 shot.

34* is just asking for it

87_TA

Told you all it was aggressive, lol.. I had run 34° all last year with 200 shot and year before even, plugs were always clean so I stayed with it and made the best power there.. I run 38 N/A, same as above, just makes the power there.. But leaning it out was the killer I think and the full 250 getting to it now, probably could have had same result with 30° and leaner.. Once back together I will start back at 30° and a little richer to be safe and work up from there. Just depends of the effeciency of the head and piston, On the dyno there was only a few HP change from 37 to 39 N/A but more power none the less.


Also to clarify - I did not just throw this together and spray the hell out of it - This combo has been running for years.. As stated I just recently end of last year realized my old cheater solenoid had been a restriction - but again however realizing the car was getting more spray now I was neglegent in reducing timing a little more.. Which was still ok, until I got greedy and began to lean on it.. I have not gotten the times I have by being conservative - this time though maybe a little to aggressive.

87_TA

Plan to, 1 piston may need rplaced as it is pretty bad IMO, do the thermal coatings need baked on?

Thanks

JesasaurusRex

iTrader: (3)

38* total makes best power NA? You either have the most inefficient sbc of all time (afr headed too), timing marks are off, or you're just doing it wrong.

DIGGLER

iTrader: (1)

mine made the most power on the dyno at 32 degrees. i normally try to pull plenty of timing and get the mixture right first then add timing until it stops gaining mph.

brandoz28

iTrader: (1)

This is my general philosophy as well. But I don't like letting the timing mark past the middle of the bend on the strap.

And any time you pull fuel I like to pull a little timing as well. This will help keep from making sets of really expensive ashtrays

On a side note what plugs do you run? I have found that the ngk plugs show heat sooner and are a little easier to read.

87_TA

Reeeeally dude?! Not my first engine build my friend.. I am not going to sit here and argue timing and effeciency.. My cars prove themselves.. We are not dealing with small bore engine with flat tops with aq good quench area... I give the engine what it wants.. If it makes power I use it..

I simply posted my failure - Been tuning this combo many of years and know it inside and out.. Running deep 10s N/A, in a pump gas in a 6 speed, 23° sbc 3400lb streer clutch car takes a little more than not knowing what you are doing or not being effecient. Easy with the stone throwing

FSTFBDY

iTrader: (33)

You can get air dry if needed. I use both air dry and oven cure. Both are nice products.
This is what I use http://cerakotehightemp.com/finishes/

87_TA

I hear you, I do not put any stock in Dyno's and never used to even use until I saw a little help from... My MPH is always my HP indicator..

These heads always have made best power at 38° for me with my long rod, dished 406. With my flat top 350 it liked 34°.. Last trip on dyno I worked AFR close to 12.9 NA making best HP at 6200 and best TQ at 12.4 at 4800.. I also start by fueling right, then working timing up from there 32 to 38.

Maybe its a result of me running low head temps, I race my cars with oil hot, but keep coolant near 140... Always seems to make best power for me, on street I run 32 degrees with car running around 170 or so.

87_TA

Thanks, have you ever torn apart after to see how the hold up? I have never played with coatings, but maybe I should try while..

JesasaurusRex

iTrader: (3)

Really

I'm not trying to bust your *****, I'm saying something is off. You may feel your engine is special but it is not. There is NO reason for it to need 38* total timing to make max power. That or somebody messed up your combustion chambers pretty good.

FSTFBDY

iTrader: (33)

I have not. I have asked a few customers how their stuff is holding up (turbos , hot side piping , headers , etc) and have had good results.

Id deff. be interested in seeing how well it hold up being flogged with 250shot for a season or two.

maybe when I get a few miles on my boosted lt1 I'll have to rip a head off and check it out. I did my pistons , valves , and comb. chambers. All bearings are coated , etc..

Orr89RocZ

iTrader: (20)

I dont see a problem with the timing. Alot of the older heads make best power in the 36-38 deg range. Older AFR's are like that. I've run the 190's on a 360" motor that ran best at 38 deg as well


Sucks to hear about your issues. Thats alot of timing for a 250 shot IMO lol I ran 150 shot and 32 deg with a 12.0 air fuel. I wouldnt have leaned it that much lol.

Be careful on the thermal coating thickness if you do the skirts/sides of piston. Piston to wall clearance is reduced, but since you need a hone you may need to hone it alittle more loose to account for the coating.

FSTFBDY

iTrader: (33)

micro-slick goes on at .25 mills thick.

87_TA

Sure it is I am the most modest guy you will ever meet, ask anyone who knows me.. I don't talk about my cars or compare shaft size with other "racers".. I just do my thing - but.... not many doing what I do, that makes me feel kinda special.. Just look at the LS1 fastest T56 list..

You realize we are talking about a 1% difference between 34 and 38° - that could be my method of finding TDC, Or we are also talking about an ECM generated advance - No 2 engines are alike - so to say there is something wrong with 38° vs 34° is assanine.

We are not talking about an LS motor that makes good power with 28° due to efficiency.. Give the engine what it wants.

87_TA

I have been running bosch platinums for the last couple years - This will be first plug change actually in 2 years..

87_TA

That may be a good thing though, I am a little loose in the holes now and a honing on top of that may make it worse, I will have to see how I measure after..

But on a good note - pistons are perfect other than where plugs dinged them up.. No real signs of detonation other than my last bout here...

xpndbl3

iTrader: (5)

platinum and nitrous....wow. another big no no there.

GTA matt

iTrader: (1)

X2 on the NGK's. The strap will melt before the piston or anything else is damaged. Spark plugs are cheaper then pistons.

JesasaurusRex

iTrader: (3)

A sbc is a sbc. No two engines are like you're right, but at the end of the day they're pretty similar.

Give the engine what it wants...not more

brandoz28

iTrader: (1)

Platinum plugs retain a lot of heat. Going to a copper plug will give you a little more room for error.

Orr89RocZ

iTrader: (20)

Obviously its been working.... several years of spraying this motor and no failures other than cracked factory 400 block, and now this little tune mishap. So what does that show about platinums in a n2o motor?

DIGGLER

iTrader: (1)

it was my understanding the platinum tends to come off the plugs. main thing is to have a non-projected tip plug in there. the ngk's may melt the strap a little sooner than some other plugs, but by the time you melt a strap you may very well have damaged other stuff in that cylinder.
it is good practice to run as little timing as you can without dropping mph. too much timing can cover up an incorrect n/f ratio, if you are looking at the plugs each pass and tuning off of that.
just adding some tidbits to the convo.... this car has deffinately run well the past couple of years.

87_TA

Thanks Orr and Diggler.. Yeah I sorto thought the same about the Platinum - being this is the first and only issue I have had in years.. this is surely new news to me - and after a quick search it seems a lot of people say not to use - but every reason was different.. Platinum does melt higher than copper, so in that sense failure could occur to late.. But my pistons do look perfect aside from the brand new damage from porcelain.. I chose them because of the grond straps not being very projected, seems I was wrong in this case.

I would certainly agree timing was added with spray due to being very rich as I have always run it.. I did check a few plugs often as well, this failure was 100% my fault due to greed as mentioned - I knew spray had increased, I then leaned mixture some and got bit..

As for N/A, as mentioned that was running almost 13:1 for best power then timing was added.

Shagwell

This. Pull extra timing to base-line, clean up the fuel FIRST, then add timing back according to the MPH on the time slips.

Throw the whole "timing mark at X point on the strap" out the window. A plug change + or - one heat range will shift that heat mark with the same total timing. - The motor wants what it wants for timing, as the MPH will tell you.

87_TA

Exactly what I do when dialing in mine..

DIGGLER

iTrader: (1)

makes you wonder how many people are running -11 plugs with a 200 shot adding more and more timing trying to get a heat mark to show on the strap....
bet there has been alot of carnage done that way.

a better way of doing it might be to start with a -7 plug. if there is heat at the bend but the car has still been going faster each time you add timing, go to a -8 and continue adding timing. if heat shows on the -8 and car never stopped picking up, go to a -9.

alot of nitrous tuning involves just sitting down and thinking about ideas sometimes. i have come up with so much stuff since i ran my car last... i wish i could try some things out, but cant now that its apart.

Orr89RocZ

iTrader: (20)

Thats what I did with my 150 shot. I pulled a good 5-6 deg at first and it was pig rich. Dialed in the jets to get it showing high 11's to 1 and then started adding timing back. Ended up with 32 deg of timing and it picked up the most mph. I ran 34 all motor. After I parked the car for the winter and did my turbo build, I found 1 plug with ground strap missing. no marks on piston, and the motor ran as fine as ever last few times I drove it. NGK plugs -7 heat range i believe but it was a projected tip. Perhaps had a lean spot there but the pistons had heavy carbon/fuel burn patterns compared to the front and the rear plenum was coated wet like it was fuel spray. Not sure.

brandoz28

iTrader: (1)

what hole was it that was kinda hurt? or do you remember?


I ended up at 34 degrees from 36 on a 100 shot on my TPI 305. never nipped a plug or anything. that 100 shot sure did wake up that little motor.


I'm doing a 9.7:1 vortec headed 350 in that car now and putting a plate on it. I can't wait until I start making passes in it.

87_TA

One thing I did notice that may have been the demise - while on dyno earlier, when I sprayed with my NOS Mini Progressive timer, car had went very lean when toggling the solenoids.. And the start of this year I dial back the progression to 50% initial hit instead of 75% and also slowed progression to 100%.. So if this was causing a lean condition I only enhanced that by utilizing the coltroller more..

Any thoughts? Maybe I should shorten fuel line from noid and increase N20 line some to soften N20 hit? Or start 2 staging and stop the progressive control. ANyone else seen this with a controller? Maybe was not totally my fault thinking back now..

ZONES89RS

iTrader: (2)

Think I was running 30 on a 150. Afr was 12.0:1.

DIGGLER

iTrader: (1)

i think it was just too much timing, myself. pulling more timing, i doubt you'll have any issues.

87_TA

What do you think about about the lean condition thought? not saying it was the cause, but I would spike high 14s on the dyno when it was activating.. Have you run into this before with controllers? Figure you have 1000psi vs 50 psi, so when a solenoid is toggling nitrous is going to win that race.. There is no adjustment for that.. I will be reducing timing, but that lean condition bothered me... Have you seen this before?

And for anyone who has not used a nitrous controller - they toggle the solenoids to restrict HP to engine.. So it may open and close 20 times per second... Or the fact that my N20 solenoid is brand new and the fuel Solenoid is probably 12 years old may/may not be the issue.

JesasaurusRex

iTrader: (3)

why are you using a controller for such a small amount of nitrous?

Orr89RocZ

iTrader: (20)

My guess is its a stick car with a non twin disk clutch but with the short torque arm, its hitting tires very hard and hard to hook up even with the slicks. Spray compounds that problem. Gotta ramp it in to hold traction, especially at PRP. Somedays its prepped well somedays its alittle off.

mw66nova

iTrader: (13)

87_TA is a cool guy, and JesasuarusRex is a cool guy, both of which have given an awful lot to this community...

NOW QUIT TROLLING EACH OTHER AND LETS FIX THE DAMN PROBLEM!

JesasaurusRex

iTrader: (3)

Didn't see it was a stick car, carry on

DIGGLER

iTrader: (1)

i was progressing mine for awhile, and didnt have any troubles. i never watched it on a wideband, though. i eventually got it to leave with no progressive, so i no longer use it. i was using a cheater plate that was around 17 years old. i put new plungers in the noids.

i don't think i would worry about what the wideband is saying at the initial hit. maybe log with it or check it going through the traps, but i wouldnt put a huge amount of faith in it. watch your trap speeds and keep an eye on your plugs to do the tuning.

87_TA

Thanks for the help..

DIGGLER

iTrader: (1)

now hurry up and put it back together. lol

Orr89RocZ

iTrader: (20)

Yeah get it running... Are you interested in the 275 radial class that I posted about? Some guys are trying to start one here

87_TA

I am trying, having machinist issues right now - Need to get the crank snout cleaned up and maybe a head surfacing - next to the worlds most inefficient combustion chambers there are some dings from the porcelain, and want his opinion on the cylinder scratch depth.. Drove an hour to Monday after work becuase he told me earlier he would be there.. Arrive there, it was pouring down raining and he was not there..

Orr, I don't think I could do anything in a radial class - Stick cars just don't like stiff sidewalls, I am not willing to run a slipper clutch yet.. I would not rule it out totally, I have a set of mickeys I could try and see what happens. Little harder than hooking a glide but I have 4 additional gears to play with!

I did not see the post, I will check it out.. A local class for PRP you mean?

Can't seem to hook at all so far this year now - I may have ruined the brand new slicks from driving home from Maryland end of last season due to my trailer wheel breaking.. Or my slight first gear reduction was a terrible move - I know it's more TQ, but thought it would help slowing the tire speed, first day I pulled a 1.42 with spray coming in late and launching at only 4900, since it has been horrible.

Orr89RocZ

iTrader: (20)

It was on unitedgearheads.com. I thought I linked it to you on facebook but maybe it didnt post? New iphone i havent figured it all out yet

Guys are trying to make it a 275 radial but they expanded rules to allow stick cars a DOT approved bias ply of some sort. Not sure full slick or not but there are some interesting rules. I think its a 378" limit for power adders and 427" limit for n/a cars. You'd have to run n/a and it will be at PRP 1/8 mile only. Right now based on the few ppl interested, its looking like a mid to high 6 second ET range so you'd fit well and it be very competitive. Its gonna be heads up, .400 pro tree racing

I dont know if it will take off or not. There is interest but most guys are either too slow or dont fit the rules. I need new tires and was considering going 275 radial, but they excluded my big twin setup so now i'm free to do whatever i guess.

Shagwell

x2 - anyone who tunes soley via a wideband would absolutely crap themselves to see my LC1 logs during a good pass from back when were were running gas/gas. Between being a leaded race fuel(118NOS fuel) and the n2o itself 15:1 @ WOT was rather normal on a clean tune, seen it as high as 15.6 w/o any issues.