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Author Topic:   Motor missing
Rusty93
Dirt Full Roller

Total posts: 44
posted June 22, 2003 09:31 AM  
Does anyone have any suggestions for this problem? My motor was popping at the end of the straight, tried a new carb and now it's worse. It runs out of power about 3/4 down the straight. Also it is over heating. I changed the fuel filter getting ready to change the pump. Someone mentioned the valve springs. Anyone? It's a chevy 350, turning about 6000 rpm. Thanks.

teamstertom
Dirt Maniac

Total posts: 149
posted June 22, 2003 09:54 AM  
Pull plugs and check for wetness and color.

Check wires for correct position to plug and that nothing is burned thru or damaged.

Look at the cap and coil,make sure everything look good inside the cap. One of the weakest parts of the HEI is the module,but when it goes,9 out of 10 times the car just quits running.

If everything above checks out,pull valve covers and give it the eye test. Meaning does something just doesn't look right.

Intake gaskets blown?

rico 08
Dirt Forum Champ
Total posts: 1139
posted June 22, 2003 11:05 AM  
Sounds like valve float.

Rusty93
Dirt Full Roller

Total posts: 44
posted June 22, 2003 01:26 PM  
Thanks guys. I checked the plugs last night. Looked ok. Plug wires are on right, but I did get one of the wires against the manifiold last week. It didn't look like it burned the wire just the cover, but I might switch them anyway. I probably smoked the rings last night. It was about 260 when I came in the pits.

teamstertom
Dirt Maniac

Total posts: 149
posted June 22, 2003 03:08 PM  
Race conditions this year has been very confusing to say the least. It is very funny how temps and dry to humid weather can affect a cooling system.

A proper working cooling system makes horsepower,people tend to say a junk yard radiator and stock water pump is all they need,and that is so wrong. Spend sometime on the cooling system and its parts,and with some of the low dollar tips you will find on this site,you will have your system working where it needs to be.

260 is a concern,but we all can atest to seeing hotter temps and had our hearts fall into our shoes hoping there would be no motor damage. Change the oil and filter,look into a oil additive or a racing type oil,get that cooling system flowing better,and with luck,all will be okay.

doubletrouble
Dirt Forum Racer

Total posts: 82
posted June 22, 2003 07:50 PM  
Sounds like the same thing we experienced earlier in the season.Old timer kept saying bad cam...I replaced timming chain,cause it would not hold advanced time.Didnt fix the problem.Finally run out of choices and tore it down...cam was flattend.....I THEN HAD TO TELL THE OLD TIMER HE WAS RIGHT(I hate when that happens)

Rusty93
Dirt Full Roller

Total posts: 44
posted June 22, 2003 08:13 PM  
Thanks. I have an aluminum racing radiator. The water pump is stock. I run Mobil One synthetic oil. It wasn't getting hot until last week when it started to skip more. This week was by far worse. It just ran out of power.

teamstertom
Dirt Maniac

Total posts: 149
posted June 22, 2003 08:46 PM  
I hate to see anyone have motor problems,but that is part of racing,and that part is where the dollars add up and are hard to find.
The cam theory is a good one,and with all other avenues looked into,that may be your next step. Cam and lifters are real cheap for the 350,but do some research into what will work for your operation. I seen alot of racers have those big cams with that big lope,just to go nowhere.

racer17j
Dirt Forum Champ
Total posts: 5390
posted June 22, 2003 10:44 PM  
You are probably running the carb out of fuel halfway down the straights. That, or the fuel pressure is falling as rpm's go up.
Then, when rpms come back down, it's masking the ultra-lean condition by coloring the plugs to lead you to believe it's not a lean condition.
What kind of carb, what jets, power valve, and fuel pressure are you running, and has the carb been modified?
Also, what total ignition advance are you running?

Let us know and I'm sure as a group we can solve it.

KP

eborcim
Dirt Freak

Total posts: 303
posted June 23, 2003 11:46 AM  
Check the resistance of your plug wires with a multimeter too. They should indicate 7500-35000 ohms of resistance depending on the length of wire. Over 35K or not giving a consistent reading, they should be replaced. Leave the wire on the dist. cap and remove from the spark plug to check.

hobby62
Dirt Full Roller

Total posts: 58
posted June 23, 2003 09:04 PM  
I'm with kp sounds like your running out of fuel. We had same problem last week in the heat. It would spit and sputter at the end of the striaght away. Let off in corner and it would come alive till end of the next straight. We reset the floats and the car ran great, to bad I blew a tire. Go figure. I also had a weak fuel pump do the same thing last year. You dont have an intake leak or under the carb do ya? Does it only do it under a load?

Rusty93
Dirt Full Roller

Total posts: 44
posted June 23, 2003 09:49 PM  
I think we found our problem. Took off the distributor cap and one of the brass connectors was laying in the bottom. We replaced cap and motor sounds good. Hope this fixed everything. I will let you guys know. Thanks for all of the advice. You guys are great!

jammin james
Dirt Maniac

Total posts: 118
posted July 08, 2003 07:23 PM  
rusty have you found the problem???

Rusty93
Dirt Full Roller

Total posts: 44
posted July 09, 2003 09:42 AM  
I think the distributor was the biggest problem. It still has a little hesitation in it, but not bad. It actually ran pretty good last week, I just couldn't get through the traffic like I needed to. Mostly my driving I think. I have another carb that I am going to try. I also am putting a fuel pressure gauge on it to make sure that I have enough psi.Thanks.

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