Off pace tonight....and damage

[my66coupe]

Well im tired as hell and i bet my writing will look all funny when i read this tommorow....but anyways went to the track tonight.....First pass, 100 shot slicks, Pulled a 1.9 60ft......bogged hard near the 1/8th marker. Second pass, my overflow bottle cap popped off and laid a nice slick down the full 1/4. But same results 1.9 60ft, bogged. I was low on gas, put some 108 race in there and fixed the bog.....3rd pass I gun it....all is well no bog, about 1/8 marker i get a loud snap, (sounded like a carb backfire) and my cockpit immediatley got filled with a poof of white smoke. The smoke came up through the hole under my megashifter. Pull around and get my slip.....1.9 60ft again......Engine is running real rough. Pulled the plug wires one at a time each made it worse except for 2 and 3. Not sure if I melted a plug or not....Didnt have any required tools (doesnt that always happen). Soo ya taking off at a stop it boggs hard...sounds like its real bad on timing...gradually there is a light tick that dies away, and the car gets up to speed. On the highway it holds its own.....(yes i did limp home). Oil pressure and temp all fine. Tair down time tommorow. Any thoughts? best run i did was a 13.1 at 99 with a 1.9 60ft....and with this i cut off right at the 1/8th.....Thanks fellas

Mike

seemed everyone was off pace tonight.....humidity could have been an issue.

 

[bnickel]

my bet is the nitrous shot fried a couple plugs and that's where your miss and ticking are coming from, but it could also be a wiped cam lobe or broken rocker or spring. i still put my money on the plugs though, it's actually fairly common on the giggle gas.

 

[12sec67]

are you running a colder spark plugs then stock when using the bottle. 10secgoal i think had to use 2 heat ranges of a colder spark plug to prevent the plugs from melting and back off the timming a little.

you may also running lean at the launch with the edelbrock carb due to the secondarys running off partial vacuum before opening. i know when i had my set up for the edelbrock 750 i had to use .119 jets drilled in front and regular .119 in the rear with the smallest metering rod and the largest squirter plus a bigger squiter when at the track...man would it suck gas at the track!

but i got it to run 12.67 at 108 with 1.89 60' with that set up and ran 12.9's 106 when i came in off the street with reg 119 in front and 113 in the rear with a larger 7347 metering rod to help the gas miliage on the 1hour trip up to track.

 

[my66coupe]

Stock ebrok carb..........Did not have problems previously with leaning out. The only difference last night was that i ran with my air cleaner. The carb back fire ripped holes through the cotton, and the metal screen is burnt to look white. I thought only holleys suffered after carb backfires?? What could have went wrong with the ebrock during the backfire? I puled most of the plugs and they all look normal. I will get back to you under further tair down.

Mike

 

[10secgoal]

. DO NOT leave the line one the bottle with an Edelbrock. If you are lucky, it will only be a HG seeing as the plugs are ok. But the only problem is you drove home on it. You'll never know what the plugs looked like right after the fact. The were probably blistered as hell. What were your fuel PSI's when this happened ? The white smoke was more than likely coolant being burned in your cylinders. And this is good cause for the leaking from the over flow. the gas build up in the system will over power your cap.
. Keep the plugs out. Turn the motor over by hand with a wrench before you do it with the starter. If you did pop a HG, you don't want to bend a connecting rod because of coolant in the cylinder.
. I know it sucks to dump more money it it, but please buy a holley. PM Hueythepilot and ask him the performance difference between a vacuum secondary and a DP. Unfortunately an Edelbog is neither. It is a half ass DP, that has no secondary squirters. so you floor it, and you have instant LEAN. On just motor, no big deal. It is just an annoying performance killer. But with the nitrous going, and the added heat internally, you have detonation.
. I suspect the 1/8 bog was because of a lack of fuel, but everything else, who knows. The damage may have already been done.


PS, do not use Edelbog off the line, if you don't buy a Holley. I used to use a edelbog, but never from the line for this very reason. Sorry to hear the bad news. Welcome to the addiction. Get her fixed quick.

 

[my66coupe]

10secgoal you are in fact the nitrous god......I know you did warn me prior my install about the edel bog....but after numerous talks with edelbrock, they told me it was not an issue. I have yet to detonate off the line.... Im running 6 psi of fuel pressure. Tonight i got side tracked in the tair down...tommorow i will continue.. Sooo is there anything that could have gone wrong with the ebrock on the backfire??? thanks

Mike

 

[brianj5600]

Did any of your plugs look very clean? Coolant in the cylinder will steam clean the plug. How long is the drive home? What does the oil look like? Not over heating is a good sign, but it may have pushed the gasket between cylinders. Can you do a compression check? What head gaskets do you have? I think 10sec is on the money with the lack of fuel at the 1/8 mile.

 

[my66coupe]

Felpro head gaskets....most of the plugs so far look normal....the drive is about 1 hour....40-45 miles. I had my timing retarded to 8* initial.....The oil is fresh....Im going to drain it and see if there are any shavings....I have a compression guage soo ya....more delays.

later

 

[10secgoal]

10secgoal you are in fact the nitrous god......

Dunno if I'd go that far, but I have been know to spit out a nugget of truth now and again.

....but after numerous talks with edelbrock, they told me it was not an issue.

If you were trying to sell a product, would you say the item you were hocking had a design flaw ?

Sooo is there anything that could have gone wrong with the ebrock on the backfire??? thanks

Mike

A backfire out the intake is a sign of bad timing, or a lean spot. It could happen with an ill tune on any carb. It could have just been the low fuel in the tank, and had nothing to do with the carb. Don't get me wrong. Edelbrock is a good carb, but not when you are looking for great performance. I ran one for 2-3 years. Bolted it on and didn't touch a thing. I also used it with the bottle, but not from the line. I think Brian is right though. The gasket is probably blown between the 2 and 3 cylinder. And makes sure all the plugs are out when you do the compression check, you don't want any false readings.

 

[my66coupe]

Finally got around to tearing it down, blown head gasket between the #3 and #4 cylinders.....the metal rings were twisted where the blow occured. New gaskets are in....just got done wrestling the headers in....tommorow awaits the rest of the top end..
thanks guys

Mike

 

[thehueypilot]

I blew many a head gasket (Ford Racing Type) on NOS and I can tell you a stock gasket is pretty weak for NOS. I switched to a Mr. Gasket "high compression" head gasket that was originally designed for diesel engines and they have not failed me yet. I beleive Fel Pro makes a special "high compression" head gasket as well but very $$$$$.

 

[10secgoal]

Eh, was close.
Huey man. I gotta wonder why you kept blowing headgaskets. Had to have been the tune. And that is prolly what caused the expensive failure to lead you to give up on nitrous. I have been running stock felpros the whoel time. Haven't blown one.

 

[10secgoal]

I was thinking about something today. When I used the 100 pills, I used 93 octane, stock plugs heat range, and 38 deg of timing. Point is, the most power will be made just before the point of detonation. If you knocked your timing back to 32 deg or so, you may be shooting yourself in the foot by running 108 on top of that. You are making the combustion reall hard to happen at the right point when retarding timing on top of high octane race gas. Understand ? Try one or the other. I never used race gas, but try the pump stuff first, it's cheaper. Go with your intial timing you had with the race gas, and slowly bump it between runs. Take a 2 deg jump at first, but bump up slower the closer you get to 36-38 deg. Then if your max is 38, try 39 with race gas then 40 and so on.