mark kibort

what was your oil pressure with the VR1? we got really bad pressure with mobll 1 and VR1 so went to redline and Amsoil and that fixed that issue. if you got low pressure in the turns, you will burn bearings. Ive raced HARD for 8 years and 130 or so hous on the same engine with no issues. pulled the engine out and everything was in spec and near perfect! no baffles no spaces, cooler, accusump, no mods at all. all stock stuff. still running all stock stuff today and this new engine has 3 race seasons under its belt too!
I woudl be curious to see if you had any oil pressure issues with the VR1. that could be the reason for any problems

d15b7

hi.

i don't run a 944; but i have two japanese racecars (ford probe *cough* Mazda and a honda), and a vintage Lotus Super Seven (Ford Kent 1600 xflow motor). both japanese motors have never been apart, and each have tens of thousands of race miles on them and untold numbers of hours, so no help there... BUT -- the Ford 1600 xflow motor has been rebuilt twice; it seems to go about 50 hrs between rebuilds; its got a fully baffled pan, and a huge remote oil filter, and an oil cooler, and a 3 qt accusump (the jap cars have nothing at all; completely stock engines oilwise). i think what really hurts the Lotus is that it corners ferociously - i've run cantilever slicks on it at times, and it feels like your head is about to separate from your body when decelerating and cornering! even with the Accusump, i think the motor is barely able to live with the slicks on it (it really needs to be dry sumped, but the cost is soooo much for those parts). anyway, on to the point of the post --- the Lotus always shows signs that it needs to be rebuilt -- i run an Autometer mechanical oil press gauge, and the pressure will gradually drop down as the bearings start to wear; for example, when brand new rebuilt, and hot (oil temp 230 degs) and at racing speeds (5000-7000 rpm) the oil press is usually about 55-60 psi. as the engine gets older, and more hours on it, the press will start gradually decreasing til its in the 40-45 psi range. thats when i really start getting worried and pull the motor and have it rebuilt. and the bearings typically show wear. i really keep an eye on the pressure gauge; just wondering if you see a correlation like that with the 944? or if its just 'everything is perfect and then suddenly kaboom'?

interesting discussion!

Todd
ReidSpeed

hp18racer

Mark, good question on the oil pressure. I asked the other drivers on my team, none of us saw less than 4. Doesn't mean for sure it didn't happen. Have to see if I can set up video so we can review it.

333pg333

Can you run totally modified sumps or even dry?

hp18racer

For my Chumpcar team's car, the mods have to be limited to stuff I could fab in my garage without any machine tools, parts have to be pretty much stock.

hp18racer

With 39 hours on our chumpcar motor, we decided to do rod bearings again. New motor has a cross drilled crank, otherwise same setup as before. Checked their wear with plastigage before replacing them. 1, 3 and 4 showed 0.0015", 2 showed about .003", very near the factory spec for max gap.

Going to switch to Amsoil and repeat the test if we make it to 40 hours again.

944meister

a recent thread that is a good read https://rennlist.com/forums/924-931-...ring-fail.html

91K-Man

We at Manissport, first solution is our twin baffle oil pan.Why, most tracks have more right turns than lefts. look at your oil pan, porsche has a baffle system on the left side. This baffling holds up the oil from returning to the center of the pan.our twin baffled oil pan stops this from happening. We also mod the pick up tube, only the late oil pan.
If building an engine use only forged rods or turbo rods.May sure they are resized! Next crankshaft, check rod journal sizes, either hardchrome journals back to "middle specs" crank guy will know what is meant. Or grind to 1st under "middle specs". Cross drill rod journals. Most are just looking at the journals and if they look good, you just throw in a set of bearings. pictures of ol pan are on the web page. www.mantissport.ca we do oil pans on exchange basis.

Sterling Doc

I'm with the others about being fussy about sizing the rods, checking clearnces carefully, and replacing the main bearings.

With my first, very fussy engine builer, I've never had a motor failure in 5 seasons of racing, plus 2 seasons of endurance racing, a 9 hour enduro.

For one season I was sponsored by a shop, and went through three motors. Fussiness matters.

txhokie4life

So does anyone know what the size of the particulates are floating in the oil stream prior to bearing failure,
but showing bearing wear?

I'm thinking about getting a drain plug based CDC unit, but I need to know what detection size to order.

thanks,

mike

M758

I don't believe you can use debris as a predictor of bearing failure. The bearings fail nearly instantly if there is an interuption of the supply of cool high quality oil. So all fixes I know about are designed to prevent or limit interuption of that flow. The contribution worn bearings have it simply that it takes more oil flow to support the loads with worn bearings.

gums

I've just read more than I care to know about this, you guys have really looked into this. I have over three seasons on my motor and am planning to do bearings just out of prevention. I use Mobil 1 5/50, always full, but my motor guy tells me that's junk and I will change to something with a higher zinc content. I always shift by 6,000 and change the oil every two events. The only gauge I check frequently is the mirror. I'll put a Lindsey three piece to make it easier next time. My motor seems fine so I hope I don't make it worse with this piece of prevention.

IcemanG17

Back in August my 928 had 52 racing hours on the engine....it now has 74 hours.....oil analysis came back perfect as always.....even after 21 hours oil change interval.... I run Amsoil racing 15-50 (RD50)....I use an early oil pan with 3/8th" pan spacer...thats it...not even an oil cooler....

I plan on running this engine until it dies......afterall I gotta get my $300 out of it!

gums

Who does this oil analysis?

jerome951

This is who I use:
http://www.blackstone-labs.com/

However, I rarely check the oil in the track car. With 125k on the clock I'd rather not know what's going on w/ my engine.