oil accumulator

[joeltjen]

I've never ran one of these till the last season . thought it would be a good idea but looking at my bearings it seems as though my bearings look worse with it on. I ran 50 or more nights with my first go round and my bearings looked great. the next season right at the end I got into a big pile-up and my car was pushed halfway down the backstretch backwards before I could get it out of gear ( had smoke coming out of the air cleaner) this was the last night so during the winter I pulled the bottom end and you could see oil starvation on the bearings . I pulled it all down, turned crank .010 and put it all back together. I at this time installed a 2 quart accusump thinking it couldn't hurt. I only ran 6 nights the next year and was chasing "warm" problems all year and found a leaky head in the fall so mi decided to tear it all down again and my bearings looked like junk. is my accusump taking the oil away and starving it when I need the oil at the engine? I also put in a BB pump when I installed the accusump to help with volume. thanks, john

[Hurst390]

Its a great pre-luber. And can help to save an engine if it loses oil pressure..It gives you a few seconds of insurance to get the engine shut down...But when you lose and regain pressure it has to refill the accumulator. At rpm that's not a good thing. at idle its ok

[Brian Gray]

Procedure. Sounds like your not starting and shutting off properly.

With an accusump first you need to install the shutoff. Always shut valve before you shut down. You can prelube engine by opening the valve before cranking engine but remember to close it before you start. After the engine is running reopen the valve slowly to allow the vessel to pressurize but do it in a manner as to not cause any pressure drop in the main system.

Cold starts are the worst on your bearings and an empty accumulator can starve the bearings while it is filling.

Also don't forget the additional amount of oil that needs to be added to the system.

[Hurst390]

That's correct but it doesn't change the fact that under racing conditions if you lose pressure and regain pressure it has to fill the tank. Unless you see a pressure drop and pull in its not a good scenario at rpm. An accumulator is only insurance when you get it shut down quick..

[joeltjen]

kinda what I was getting at was the accumulator is taking the oil from the engine while refilling and starving the engine.

brian : maybe I was doing it wrong as I would open the valve , start to crank the engine then turn on the ignition. before I had the accumulator I would always crank the engine with the switch off till I saw the oil gauge move to atleast 20 psi. you say to close the valve BEFORE I start it then reopen after it starts? on initial filling I always just cracked the valve and let it fill slowly as not to starve the motor (I get it that you don't want to slam it open and give the oil someplace to go besides the bearings)

[Brian Gray]

Yes if you use it to prelube always close it before you start the motor.

If you are seeing pressure drop while using the accumulater you have another problem.

Are you using the piston style accusump?

[Brian Gray]

Your oil pump should have the volume capability t o supply enough residual volume for you to not have any pressure drop while it is filling at speed.

[Profile]

I've use the accumulater's since the early 60's when we made our own out of WW2 surplus landing gear struts. Never had one problem on both circle and road race tracks. Worked for me.

[Lizardracing]

How many engines are out in the world that get cold started several times per day for years and years and years and they don't have problem wiping bearing out. Umm....sound like an accumulator is band aid for a problem that doesn't really exist.

When you changed the bearings do you check the bearing bores? They may have been out of round and/or fretting which is hard on bearings. A bad polish job on the crank can destroy them pretty quick too.

[joeltjen]

well a little update, found a cracked cylinder wall so I got a new block for this season, so new splayed caps and a line bore and everything should be good to go there. I guess i'll try the accumulator one more time with a bearing check after 4 or 5 nights. fingers crossed! thanks everyone!

[dereksehi]

A bearing check after 4 or 5 nights shouldn't be necessary or should the accumulator. Make sure the rods and mains have clearance like to see between .002 and .003 on both and if the journals and housing bores are straight round and within tolerance there should not be any issues there providing the crank was polished properly. Another thing is you should have a good circle track pan that holds 7 quarts and a racing quality pump with the pickup tube 1/4-3/8 inch from the bottom of the pan.

[Hurst390]

A bearing check should be made every time you change the oil when you cut the filter open..