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Author Topic:   Running lean?
dirtracer14
Member
posted July 27, 2003 10:31 PM
Is it possible to run lean on 1 or 2 holes and the rest look perfect? Is it possible to loose a head gasket between 2 holes and have it lean them out to the point that they burn threw the piston? If it was lean were would it burn threw at...middle or sides of the piston? I lost a head gasket last weekend between 3 and 5 but the head and block looked fine so we put new gaskets on and tried to run it...got 2 heat races and it burnt the #5 piston and started to burn the #3. When we lost the first gasket the cylinder wall was pretty bad and the #3 were it meets the #5 hole. I plan on putting another motor together with same head...after they get back from the shop...and i dont want to put it back together on another shortblock if i have a lean condition somewere in the fuel system. I run a kse pump big filter that i just changed i have around 3 pnds at idle and around 7 to 9 at wot. What about fuel is there some allky that is not to be used for racing? I went to a out of town track and got fuel there right befor all of this stuff started....could the fuel have not been the right stuff? The barrel looked like the rest but it didnt say anything about racing fuel? Any help on this would be great. Thanks, Craig Moore


sdhnc29
Member
posted July 28, 2003 12:19 AM
Usually if your too lean the piston will burn on the intake side of the piston . You will see detonation when the piston burns in the center or toward the exhaust side . Unfortunately since you bought fuel at a track and not from a sealed drum , this could definitely be part of the cause . Who knows what could be cut into the fuel you bought ?? If you have never had this problem before now , I'd think it was bad fuel first , then I'd look toward your ignition and fuel system for problems .

Steve

------------------
Hendren Racing Engines
Rutherfordton , NC
(828)286-0780


dirtracer14
Member
posted July 28, 2003 12:37 AM
Thanks for the insight on this subject steve...i have only had this problem 1 time befor but it was a block that had been welded inbetween the #3 and #5 and had a low spot that lean out and burned up the pistons...but that happed in about 4 laps and was twice the hole size of this. Now when you say the fuel cut right i am assuming that there are many kinds of allky out there. I heard the guy say somthing about getting it from a gas station that would use it in the winter for the washing fluid. I also saw on the barrel it said on the sticker that it was for industial use only? And had Tarr on there if i remember right. I sure hope that it was not the fuel this was a pretty good motor...well for me anyway and i would hate to find out that it could have been avoided. The burn was right were the 2 cyclinders meet side by side. Is it possible if there was a low spot for it to lean from each side? There was dust all over the intake and the other valves. Could timing have played a part in this also? I just changed cap and rotor? I tried to double check my tdc mark on my balancer... i made the checker with the spark plug and i couldnt get it to touch the piston....had about 2" of the bolt in the hole and couldnt feel it touch when i rolled it over by hand....yes with all the plugs out anyway i will make sure i know were tdc is for sure on the new one just to rule that out!


Dustejr73
Member
posted July 28, 2003 06:55 PM
dirtracer14

Do you have a digital camera ?? If so , or if you can borrow one , email me some pictures of the burned pistons from several different angles and I can give you a much better idea of the cause . Without looking at them , all I can do is give you a long list of things to look for . Email me at sdhnc29@yahoo.com

Steve
P.S. I've seen alky cut with just about everything . This is why I always bought mine in sealed drums . If your forced to buy any at a track , I would invest in a hydrometer which is much cheaper than burned down engines .

------------------
Hendren Racing Engines
Rutherfordton , NC
(828)286-0780


dirtracer14
Member
posted July 28, 2003 11:05 PM
I was going to offer some pics for to help tell what happened... im going out right now to take em ....


dirtracer14
Member
posted July 30, 2003 11:20 PM
Well after realy looking to find the problem befor we put a new motor in....with the help from Steve i may have found the issue! The first night i got the super heat problem and the bad head gasket i had got a new fuel filter at the track(wich i never do) and it was a speedway paper one. Now i have run paper for 4 years with no problems what so ever but they were napa filters. I think the speedway ones says DO NOT USE WITH ALLKY!! it looks like the paper inside is diff. Now i took the filter out and it was very wavy in the paper part wich i think is from the swelling do to the water in the fuel. Now with a lean condition normaly the #3 and #5 now add the water and you get a very hot hole and i would guess that would cause the detonation.I still have to check the carb for the crushed floats but after seeing the fuel filter im pretty sure that was the problem combined with the water in the fuel....i plan to get a hyrometer and check the fuel that i pulled from the car. If anyone thinks i am way off please let me know...i need to make sure that it wont happen again(couldnt afford the first time)because i cant afford to do it again. Thanks Steve for taking the time to help me with this issue! Its wed and i still dont have a motor ready tried to put some stock bowties on a old 383 but the piston seems to hit the head .... every time i turn around im hitting a wall...just got a new set of heads tonight so should have it ready by fri....but want all the other problems fixed!!


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