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Author Topic:   ? for Steve
tim62
Member
posted June 03, 2003 11:34 PM
I have a 355 12.5/1 alcohol motor. Last weekend the water temp went up to 240 and the oil temp guage was pegged out. I tore the motor down and have found that the bearing were all good but found 2 pistons that looked a little dark. Number 3 and 5.
No. 3 top ring was stuck and No. 5 pistons was galled above the top ring land.
Any ideas waht could have caused the oil temp to go up so high?


sdhnc29
Member
posted June 04, 2003 12:27 AM
If the rod bearing's looked ok and were not pounded from detonation , then I'd say that you have a very lean condition going on . Since your ring land area on the piston's that your speaking about seam to be most affected , I'd say that the engine was too lean and there is a fuel system problem of some sort . If severe detonation had occurred , you should see damage in the center of the piston's (piston caved in ).

The oil temp went out of sight due to the extreme piston temperature . The oil that splashes onto the bottom of the piston's would be super heated , and your oil temp would skyrocket , as you can tell by the burned on oil that's on the bottom of your damaged piston's . The water temp would follow the oil temp , and you would see the 240 that you saw .

You were on the verge of Three Mile Island situation , so I would check your fuel system real close , make sure your pick up in the tank is not s+cking bottom , none of your fuel fitting's are loose , the fuel pump is ok , and you don't have a paper element fuel filter in the system anywhere .

Steve

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


tim62
Member
posted June 04, 2003 08:30 PM
The bottom of the pistons are clean except for 3 and 5. They are a little dark in the dome area. There are no signs of detonation and didnt run lean.Oil smellsburnt and when i pulled the pump off the oil was a different color than the oil in the pan.


sdhnc29
Member
posted June 05, 2003 08:17 AM
Once again , if 3 and 5 piston's are damaged and showing color on the bottom side , then they are running extremely hot for some reason . There are only a couple of reasons that the cylinder temp. would run hot enough to damage piston's , one would be too lean on 3&5 , the other would be pre ignition , or a combination of both . Of course cylinder temp will also rise dramatically from ignition timing being off or from an exhaust system with too much back pressure . But generally these two problems are seen on more than two cylinders . Depending on which intake your running , 3&5 could be the lean cylinder's in your engine . If you have a problem of any kind , it will show up there first . As an example , if your using a Victor JR 3&5 are extremely lean cylinder's on alky unless your using a 2" spacer under the carb.

Steve

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


sdhnc29
Member
posted June 05, 2003 08:20 AM
P.S. Be sure to check the #4 cam bearing . If your oil temp was pegged , then 9 times out of 10 the #4 cam bearing will be melted . It seems to almost always be the first bearing damaged in a high oil temp situation .

Steve

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


tim62
Member
posted June 05, 2003 06:33 PM
One more question. I am running a victor jr. 2999 that is an inch taller than the 2975. Will a 1 in. spacer work or will i still have to go with a 2 in.


sdhnc29
Member
posted June 05, 2003 07:00 PM
The 1" will work for you . The extra inch that Edelbrock added was there feeble attempt to fix the distribution problem that I mentioned above . If you get a chance , you might try the 2925 Super Victor . It's a very good intake , and much more modern in design .

Steve

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


Pickles
Member
posted June 05, 2003 11:48 PM
Similar situation, pegged oil temp and a sudden increase in smoke coming out of the breather. I did a compression test and found one cyl down 50 pounds. Pulled the piston and found a tiny crack in the top of the piston.


tim62
Member
posted June 06, 2003 12:10 AM
Thanks for everything Steve. I have it back together and will see what happens this weekend.


Flanndad
Member
posted June 06, 2003 06:14 AM
Steve, in your post above you mention that the Victor Jr will lean out #3 & 5 on alky, Does the Victor Jr usually run lean on gas also.
I'm just finishing rebuilding my motor, Pro Topline 220 heads with a Victor Jr, currently running a 1/2" spacer. Any problems known with this?????


sdhnc29
Member
posted June 09, 2003 02:01 PM
It does , but it is not quite as critical with gas , due to the fact that your moving half the liquid thought the intake .

I'd go to at least a 1" spacer with your combo . You might look at investing in a Super Victor . The Super Victor is far superior to V-JR . On average you should see an increase of at least 20-30 HP with the more modern intake .

Steve

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


tim62
Member
posted June 10, 2003 12:39 AM
Hmmm 200.00 = 20-30 H.P.

Sounds good to me.

Steve i put replaced number 3 and 5 pistons and went up on the jets. Raced it this past sat. night and everything went great. Again i appreciate your help.

sdhnc29
Member
posted June 10, 2003 12:51 AM
Yea it's cheap power ! With the extended plenum design , the mid range is picked up quite a bit . The lean cylinder on the Super Victor is #6 , which is at least on the bank you would want it on for a circle track car . But this is easily corrected with a small amount of grinding .

No problem with the advise !! I just hope that it saves someone a dollar or two . good luck !!

Steve

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


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