Here’s my situation. I just had my 340 completely rebuilt. When I took it to the Dyno we notice the frost plugs where missing. No big deal we didn’t start the water yet. Installed frost plugs. We started the 15 minute break in. The Dyno guy noticed the oil filter temperature was only at about 80 degrees and not following the engine temp up. After the break in time was up we determined the plug under the 90 degree filter housing was never installed. So during the break in time the filter wasn’t doing much of anything. The oil was bypassing the filter. After we put the plug in the block, the oil filter temp followed the engine temp up.

My concern is the damage that might have been done to the bearings etc. Should I have a third party take a look at the oil filter (for debris), bearings and pan? The engine builder hasn’t gotten back to me yet, not sure if he will.

Yes I would cut open the filter/check the bearings and post what you find

I would clearify any warrantiy with the builder or who ever left the plug out first and foremost.

then you could have the 3rd party that is agreed upon by the first 2 partys to cut open the filter and have a looky see at it and move on to a tear down if need be.

good luck

post back results

Scratchn's idea of third party sounds good. Did you happen to have a magnetic drain plug in it? If I had to bet on it I would bet you didn't do any damage.

Didn't you have the oil pressure hooked up when it was on the dyno?

I was thinking the same thing about having a third party look at the bearings as well. I did contact another engine builder and he would look at it in about a week at about $180.00. But, I just heard from the original engine builder and he's willing to look at the bearings. I told him I wanted to be there when it happens. I guess we will start from there. If I'm there I figure I have a better chance and catching anything before anything gets covered up (not to say that would happen but might). He was telling me that filters do have a built in bypass for cold weather starts? Never heard of that? There was good oil pressure during the breaking at about 61 PSI.

the oil pump has a by-pass plunger and spring for that reason

filters may have an anti-drain back valve but never seen a pressure by-pass on one.

on a good note,it may not have hurt anything,but its a good idea to recheck everything before hand ..just in case

good luck

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....but never seen a pressure by-pass on one.

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Most, if not all filters have a by-pass valve.

Update. Well the engine was brought back and they pulled off a couple bearing caps. There was some damage to the bearings. He's planning on replacing the bearings. We will see where we go from there.