Engine Failure

[olddog]

Originally Posted by Jerry Clayton

the MOST important factor was because it took oil away from the engine when it needed it MOST, refilling the sump after a long hard braking/corner portion of the track---3 quarts of oil--how long does it take to pump 3 quarts of oil???? how far does your car travel in that time frame?????its like a huge leak in your oil system, taking the oil away from your bearings (and those wonderful roller rockers)

Interesting point. So after the accusump saves the engine from a total loss of oil pressure, it causes a low oil flow to the engine as oil is diverted into the accusump to refill it.

Wouldn't a flow restrictor in the direction of filling the accusump slow this to a negligable rate and still allow full flow to the engine? I know there is directional flow restrictors for compressed air and would assume they are made for oil as well.

Certainly a dry sump oil system is better.

[DAVID GAGNARD]

For a price their are labs that can analize that bolt, and they can tell how many cracks started at exactly what points. I don't think it would be worth the price tag to analize it that far.

Where it broke is just above the joint line of the cap. Perhaps it was nicked when pulling the cap on a bind or something along those lines. The imperfection could have been when the bolt was manufactured.

Zacctly,and in the end,whichever occured first,(rod bolt backing out or rod bolt breaking), the results are the results, I can't un-do them...Live and learn.....I've certainly learned from this "event" and the advise received here, mainly I screwed up by not changing the rod bolts.... That will not happen again because I didn't change rod bolts.... Seems that's the way I learn a lot of lessons, the hard way.....

I've seen other broken bolts over the years and this one seemed very similar to a lot of bolt failures I've seen..... too many torque cycles,too much stress, whatever, something failed and I've got the results to prove it..... In the final analaysis,I'm pleased with the service the motor gave me and really can't complain about it and I'm not complaining about it, just showing what happened.......

I'll build another one, race another day, and if I can get almost four years of racing/use out of the next one like I got out of this one, I'll be one happy racer!!!!!!!!!!!!!!!

David

[olddog]

I'm no expert, but I will share some experiance. I have worked with some top engineers and metalergests (sp?) in industry. In particular we were working on gear pumps used to pump molten polymers (plastic) at pressures over 4000 psi. We had shafts that were breaking.

The bolt that you pictured, show signs of a classic failure. The outer ring of the bolt has what they call beach marks. Then the center is where a brittle failure occurred. What causes the beach marks in the outer ring is a slow process. A crack initiates, usually from a scratch or some type of a stress riser such as a sharp machined corner without a radious. The crack slowly grows. As the bolt flexes under load, the two sides of the crack rub on each other, causing the beach marks. As the crack grows, the bolt has less and less cross sectional area, weakening the bolt. At some point the strength of the bolt becomes less than the load put on it and it fails.

If I were to guess - as I am not an expert - the crack has been growing for a long time. Obviously a heavier load on the bolt will make it fail sooner rather than later. Once the crack was started, even if you had never reved it above an idle, the bolt would have eventually failed. It would just have taken longer to continue to crack, until the meat left in the bolt was too small to hold the load at an idle. It usually does take enough load to cause some flexing of the bolt for the crack to start, but not necessarily a higher load than it was designed for.

For a price their are labs that can analize that bolt, and they can tell how many cracks started at exactly what points. I don't think it would be worth the price tag to analize it that far.

Where it broke is just above the joint line of the cap. Perhaps it was nicked when pulling the cap on a bind or something along those lines. The imperfection could have been when the bolt was manufactured.

[Jerry Clayton]

try working some numbers---90 gallon/hour--3 quarts would take 30 seconds to refill--how far around the track would you go????remember--the oil comes out of the accusump faster than it goes back in because coming out only the engine gets oil but while refilling both the engine and accusump get it----accusumps present more places for failure and increase the risks involved--also adding more weight to the front of the car---WHY???????? do you see any on real race cars??????

[Doug I]

I thought an accusump kept a volume of oil that it fed back into the engine before you started it. Once the pressure gets over ~25psi it "collects" the volume and then isolates it. When you go 'key-on' it feeds that oil back into the engine to boost the pressure before you hit the starter.

[RICK LAKE]

Jerry Clayton I am unsure of your rants with some silly things you have said
You think ALL motors are the same except for the valve covers?? All oiling systems preform the same way for all motors? You think a center oiler motor is just as good as a side oiler ?? You think a Ford motor has a better oiling system than the LS series?? Until the last 5 years, anyone could beat Pat Musi, lets not go there. I have seen enough poorly built motors break from that garage. Top Fuel and Funny cars, look at Rampage rail and funny, worked the bottom end in the 70's, so what, You don't see accusumps on road race cars because they are DRY SUMP in most CLASSES. There are classes where DRY SUMPS are not allowed, I have seen guys running the accusumps on those motors.
You have a ton of QUALIFICATIONS and that's nice. Most people on this forum looking for info on how to extend the life span of there motors and still beat the balls of them. You don't like accusumps, OK but to some people here this is a cheap way that may save a motor if setup right. Do you think that 80% of wear and tear is done on startups? I have run the same bottom end for 8 years, no bearing problems or failures. Cheap eagle rods for an FE motor, started with .0021" ended with .0023" after 8 years of racing. The broken rocker shafts took my oil pressure from 75 psi down to 25 psi. A FE will not live long on this kind of pressure. I am sure with your engineering mind it should not be hard for you to figure out that there was little to no oil pressure to the rockers. If not for the extra 3 quarts, rod or main bearings would have been burnt or welded to the crank or worse. I run a HVHP oil pump with 100 psi spring, It takes my motor 20 seconds to fully recharge the accussump after racing. I vary the air pressure in the bladder side of the tank. I run #12 lines. We build 2 different motors, yours are screamers and high rpm, mine are endurance motors that run for years with minimum maintainance. IMO and just trying to help and suggest a cheaper way of helping a person who at this time doesn't want to add a drysump system to his car. Have a nice evening Rick L.

[Jerry Clayton]

so Rick---how far do you go on the track in that 20 seconds for the accusump to refill??? or do you pull over after every high g corner for 20 seconds while it fills up????

[vector1]

Originally Posted by Jerry Clayton

so Rick---how far do you go on the track in that 20 seconds for the accusump to refill??? or do you pull over after every high g corner for 20 seconds while it fills up????

it's usually half way down the straight at heartland park at 25 psi, waiting for the pressure to come up so you can hammer it. from a guy who uses one, not myself, i drysump.

sorry, that was my outloud voice, didn't mean to hijack.

[Jerry Clayton]

I'll bet you also kart---road race tracks??

[vector1]

Originally Posted by Jerry Clayton

I'll bet you also kart---road race tracks??

if you're talking to me, i like to say i do but haven't in about a year or so.

[Jerry Clayton]

we haven't since about 2002--youngest son joined air force