Accusump fitment on MI16 engine.

[mollisk 2 1 Cars]

 

I have a MI16 engined rally car which I have competed with over the past few years. The engine was built about 10 years ago and hasnt had any major work done on it since.

During a recent rally, towards the end of one of the stages the engine oil pressure warning light came on then recovered. This occurred several times, as we were about 1 mile from the end of the stage we continued to the end of the stage.

Once thought the flying finish I checked the oil level which was found to be OK.  However engine oil had been coming out of the breather tank vent. The engine hydraulic tappets were also noisy.

I feared that the engine was on the point failing, however I couldn't work out why the oil pressure was dropping, then recovering.

I checked the crankshaft pulley securing bolt and found it to be slack. On tightening the bolt and restarting the engine the oil pressure recovered to normal and the hydraulic tappets quietened as they filled with oil.

We didnt lose any time and continued the rally with no further problems with the engine oil pressure. The engine breather vent had no further signs of oil.

As the crankshaft pulley assembly is used to secure the oil pump drive sprocket to the crank, the sprocket was slipping and causing the loss in pressure. I assume that the sprocket was driving the pump occasionally before slipping, hence the increase and decrease in pressure.

The engine has an Accusump fitted, and although its difficult be certain, I think that it has helped save the engine on this occasion.

I will strip the engine to check the crank bearings etc, before any further events. I will also Locktie the crank pulley bolt and lock wire it. The lock wire probably wont stop the bolt loosening, however it will make it easy to see if the bolt has loosened.

 

Mollisk

 

 

[Andy 105 1 Cars]

If you fit a later oil pump sprocket ( 26 tooth) and 52 link chain, you will find it is woodruff keyed onto the crankshaft , thus  avoiding this ( frankly terrible ) way of securing the oil pump drive to the crank . As for Accusump, I  am a big fan, not least as, with an electric valve and a delay timer, it is possible to pre oil the crank before starting . Always nice. And I agree that if you lost some pump drive and therefore pressure ,the Accusump would rescue you  for a few seconds .

[petert 586]

The 26T sprocket from the XU10J4 is retained the same way as 1.9L, clamping force. I wouldn't recommend it though, as they are soft and will fail before the 22T sprocket does. The retaining bolt should be torqued to 110Nm.

Accusumps are a good step before dry sumping. I ran one for a long time and logged oil pressure. You can definitely see when the accusump makes up the difference. I found the electric valve was a restriction however, and best results were obtained just by using the manual valve. This means all the contents of the accusump enters the sump on shut down, but it quickly refills on start up.

[Andy 105 1 Cars]

Hi.Odd that. The sprocket I mean. The one I got from Peugeot had a spacer built in so that the front cover oil seal  bears onto the spacer and is definitely keyed onto the crankshaft . 

[petert 586]

Perhaps you have the R/RS version of the sprocket?

[Andy 105 1 Cars]

Ah. Yes. That is it. I think it is the only one available from Peugeot . Anyway, oil pump drive security is guaranteed. On the dry sump question, I have never given one much thought until I was offered a complete kit, used but in good condition for about a third the cost of a new one last week. Sleeping on that one .

[wicked 103 3 Cars]

10 hours ago, petert said:

 This means all the contents of the accusump enters the sump on shut down, but it quickly refills on start up.

Will this work with a 4 pint accusump? Or would 4 pint (1.9l extra oil) be too much?

Edited December 18, 2019 by wicked

[petert 586]

I ran a 1.5 quart Moroso accumulatorand it wasn't an issue.

[andy0075 9 1 Cars]

I fitted an Accusump to my MI16 engine last month after my race saison has ended.

 

I always had 1-4 seconds during racing (sprint race) where the oilpressure drops to below 15PSI,

sometimes for half a second or so to near zero !

 

I use the electric valve version. I set the pressure switch to about 35PSI and i have added a second switch in line which

is controlled by the ECU. this relais is only closed if rpm of the engine is over 3000.

So the oil should stay in the Accusump when idling.

 

And i installed the pressure switch in front of the check valve! I hope this prevents that the electric valve toggles

because it meassures the pressure on oilpump side and not on the Accusump/engine side!

 

I hope this will prevent me in future for changing my rod bearings every year :-)

 

Andi

 

Edited December 21, 2019 by andy0075