2 Quick Questions On Oil Surge

[matthewm 1]

I know this subject is constantly banded around and probably does everyones tits in, but:

 

1. Have a MI16 205 road rally car (baffled sump, mech oil gauge and big orange light at 15psi). Just had my 3rd death ratttle. Although all 3 times the rattle has started, its been when I've been pootling the car around between events.

On events I've had the oil pressure light come on (mostly whilst handbraking the car right) although the bottom end has never let go under the stresses of an event, only under normal road use afterwards.

Why?

 

2. Have watched my mechanical oil pressure gauge whilst going around a long roundabout, and can see the gauge dropping, straighten up to turn off and it goes back up. Am I correct in thinking that as soon as the gauge starts to drop, I'm experiencing oil starvation. As if the pump is spinning and theres oil at the scavenger then there should be no drop in pressure?

 

Incidentally I'm planning to get a dry sump and never look back, but would be interested on your theorys to my questions.

Cheers guys.

[welshpug 1,657]

is this the 3rd rattled bearing in the same engine?

 

have you had the crank checked and the conrod checked?

 

light coming on is low pressure, also if the needled drops, certainly a drop in pressure there, if there was enough oil there you wouldn't see this.

 

 

often it takes a while for the damage to worsen to a knock/rattle, I only saw my gauge drop once, was about 50 miles later it started knocking.

[matthewm 1]

First one to go was the bottom end the engine came with afetr 2 rallys

Replaced that with a 8v crank and rods - which did 4 events before spinning a shell (Just after I'd messed about sealing the sump so thought it may of been loose sealant)

Replaced that with a new 8v crank and replaced the damaged rod - went after doing one event.

 

I've definatly been experiencing drops in pressure quite frequently, although always thought it would die there and then.

 

Time to wince, take the financial kick in the nuts from the dry-sump, then live happily every after. Are pace stil doing the forum discount?

[welshpug 1,657]

got the correct dipstick fitted?

 

re-discount, dont know, ask them !

[matthewm 1]

Yeah, fill it to max line then give it another litre for luck (6 total usually)

[welshpug 1,657]

yeah but is it the right stick?

 

and do you really run 6 litres in there?!

[petert 587]

Why not fit an Accusump or Moroso equivalent? The 1.5L Moroso accumulator is currently on special at Summit Racing. Comes with free mounting brackets.

[matthewm 1]

yeah but is it the right stick?

 

and do you really run 6 litres in there?!

 

Yes and yes, checked the stick length agaisnt measurements on here.

[matthewm 1]

Why not fit an Accusump or Moroso equivalent? The 1.5L Moroso accumulator is currently on special at Summit Racing. Comes with free mounting brackets.

 

Read mixed reviews on here about them, despite being recommended them by owners of other vehicles. Judging by how often my 25psi light came on when i had that fitted, could see it being constantly in use.

[welshpug 1,657]

I always wondered whether the accusumps etc were a bit horse+stable door situation, granted they do save the outright damage that zero oil pressure causes, but if you lose enough pressure for the accumulator to kick in there's got to be aerated oil already being pushed through which will still damage the bearings.

 

why not sling your XU9 pistons + rods + crank in an XU7? given the head is a big part of the problem, use an XU10 head if you can't stretch to a worked head.

Edited April 14, 2012 by welshpug

[jonny6 8]

is it just me or do these constant horror stories of engines failing worry anyone . :/

[welshpug 1,657]

doesnt worry me, but I run an 8 valve, a 2.0 Mi, and a gti6 lump !

[Green Machine 3]

Mi16's in rally cars will get the death rattle, the amount of times ive seen them retiring due to big ends isnt fun anymore, a dry sump is the only good solution in my books. I fitted 1 to the rally engine i built for a friend and the engine has never missed a beat.

 

The car has rolled gone on its side and the engine is still sweet. It won 1st in class & 3rd overall in the 2009 regional championship and has been used regular since, upto and including Cadwell last sunday.

 

Once you get the sump fitted you find more time to consentrate driving that looking at oil pressure.