need help on dirt track engine

[300ex mxracer]

on our dirt track B-mod, the last two races we have dnf'd because of engine trouble. the first race we pulled off because it started bogging and as we rolled off it quit and wouldnt re-fire. pulled it apart to find loose rockers and bent pushrods.. redid all the heads and was told be the engine builder that it happened because it ran to lean and got hot causing some of the valves to stick in the guides. it also lost all the water out of the radiator.we jetted up even though the plugs looked good hoping to run a little rich. ran on sat and had to pull off b/c the temp light came on and died on way off the track. it boiled all the water out of the radiator. got towed back and when we tryed to fire it, it sounded like the engine is seized on a couple cylinders. pulled the valve covers off to find it swallowed a couple pushrods. we cannot figure out what is causing this. the only thing i can think of is the cam is somehow messed up. we pulled the cam after the first time and it looked good. o and its a 355 w/ mech. lifters. its highest rpm was 6200, which is not high the way this engine was built.

[tat900]

1. gas or alky
2. what kind of cam and is it 4-7 swap
3. domes or flat tops and what crank is in it
4. sounds like its way to lean and what do the plugs look like

[red2004 TRX450R]

What kind of engine is it? fords are hard to get the air out of the colling system.

what kind of water pump are you running? should not run high volume one. to fast water flow will cause poor colling.

is the water pump belt slipping?

are you running a thermostat? should run one or run a restrictor in the housing - to fast water flow will cause poor colling.

what size pullies? to fast- slow water flow will cause poor colling.

are you using just water or are you running coolant to. Coolant has a higher bolling point.

are you running Gatorback belts? they are junk at high RPMS

you are running a good after marked rad?

what are you cam specs , springs specs, compression and heads?

what carb are you running and what is the jetting?

What oil do you run? with w/ mech. lifters you have to run oil with zinc or the lifters and cam will eat it self.

[300ex mxracer]

we running a gas holley 2-barrel w/ 78 jets. its a chevy 350 bored out. i dont know what the specs are for the cam but it is not a 4-7 swap. i will check with the engine builder about the cam and crank. plugs looked good after first time. we jetted up after 1st race. is not a high volume water pump. we are not running gatorback belts, they are something from napa since they are one of our sponsors. and it runs water w/ engine ice. we are running a thermostat. after the first race we had a cam to swap in to see if it would help but to set the timing you had to start the engine with 6 degrees retarded and then once it fired you moved to up to 20 degrees advanced. we spent alot of time on this but couldnt get it right so we put the old cam back in.

[vpofthedrc]

Do yourself a favor in the future and get a oil temperature gauge. A water temperature gauge does no good if there is no water in the system.

We run a 740+ hp engine in a UMP modified, and have no cooling problems. Good 1:1 pulleys, good water pump, GM 4 blade fan, with a shroud, NO restrictor or thermostat and a plain jane, single pass radiator. This is on gas as well.

The 5 blade fans are easily put on backwards, stick a piece of paper in front of the radiator and see if it sticks. Also, reduction pulleys could be a major problem.

[tat900]

do you have a shroud on the radiator?
to me it sounds like the timing has this motor all messed up never had to change timing from start to run. Are the heads votec and what car b are you running

[1FST/R]

check your ignition system and timming too.
Are you sure the cam is degreed correctly?
Also you running timing chain, belt or gears?

[vpofthedrc]

The problem you described with having to retard the timing with the other cam, almost sounds like you have something 180* out to me.

[tat900]

that would explain the timing issue on the cam .

[300ex mxracer]

we have a 4 blade fan w/ shroud and 1:1 pulleys and a single pass rad. as well. we only have a water temp. gauge, oil pressure gauge, and a tach. the driver said that on the last lap or two that he was out there, the oil pressure would drop when he let off to set up for the corner. he said the temp light came on and then went off and the temp gauge went down to zero. this must have been when it lost water. we checked the timing twice before the last race. if the timing would have been off, wouldnt we had noticed anything in practice or heats? this happened both times in the final laps of the feature. what would we check that could be 180 degrees off?

[vpofthedrc]

I can't really think of why it would lose pressure at the corner entry. If your gauge read 0 then you may have some internal problems, lord only knows how hot she got. What kind of oil pump/pickup are you running.

Check your distributor gear. Maybe its messed up, could cause all your problems in one deal there, jumping time, not pumping oil, etc.

[tat900]

you oilpupm is to close to your screen if its a 7qt pan