Forum » Webinar Questions » 214 Adjusting bearing Clearances

214 Adjusting bearing Clearances

Webinar Questions

Ask questions about webinar lessons here. To see the Previous Webinars for a complete list of archives tuning webinars. 


Page 1
Author
43 Views

Quick and simple question, has any one noted a correlation between tighter clearances and higher oil temps?

i have seen two similar engines (3sgte making 240kw) but the oil temps on the same track are about 30'c difference. about 95 vs 125'c.

both run oil coolers with thermostats (the engine with hotter oil has a larger cooler go figure) etc etc. the car with hotter oil temps has unknown clearances how ever the cooler engines has 0.0025" mains and 0.002" big ends. both cars measure oil temp in the sump.

just curious if any one else has come across this? i just cant explain such a large difference in temps.

Clearances can play with your oil pressure, having additional oil pressure then necessary can cause temps to rise due to the oil going through the oil pumps bypass valve to keep the pressure from blowing seals.

Monitor your oil pressure and see if there is a noticeable difference, assuming all things equal the car with the hotter temps I bet has tighter clearances so you can either change the oil pump if there are varients of your model or perhaps using a different viscosity oil to manipulate it a little.

My question to you Andre is if you are using different sized bearing shells to get the clearances you want - do you need to use different shells on every bearing?

Example - say a main bearing clearances measure up at 2 thou on 4 out of 5 journals and one measures up at 3 thou. Would it be ok to use the mixing journal shell method on the odd journal?

@booki89, yes you only need to mix shells where required to get your clearances correct. With a factory engine you would check the graded shell requirement for each journal and order them to suit. It's a little trickier in the aftermarket as you'll need at least two sets of bearings since they usually aren't sold individually.

Thanks Andre,

Have you had any experience doing this process for Subaru's? Specifically for the EJ25 platform? I can't find any products that have 0.001" bearings that will tighten up the clearance's, lots are for +.001" which will give me a larger clearance.

I'd suggest you take a look at the king Bearing range. They offer STD, STDX, 0.026, 0.25 and 0.5 options for the EJ25.