I have a reputable shop that has rebuilt my motor 4 times and it never lasts more than 1-1/2 hours and it goes down losing rod and crank bearings We have checked clearances .002 toatlly cleaned the block and all components cleaned oil lines, and replaced the oil cooler, They have used Joe Gilbbbs BR oil to break in and after a Hour or so we loose oild pressure then it iwll knock. I think the only thing left that is original in the whole assembly is my timing chain cover. They are good about it but it is getting old. I found out researching that they may have not installed the correct oil bypass valves in the block example, intalled 2 11 lbs instead of one 30 lbs and one removed. I also am questioning the joe gibbs oil as the Br is a 15w-30 oil and it may be too light and not able to handle the temperature especially with the wrong bypass valve. It is a gen 5 flat tappet motoer 454 with magnum heads, kieth black pistons and a comp marine cam.
Please if anyone has any thought on this I would appreciate hearing. Fisrt rebuild i set of rings did not seat, final result was blowing smoke and then the crank went out of it, second build the cam went down oil pressure drop and 4 rod bearings and crank bearings lost. Next rebuild, new cam, c;eaned all out again 1 hours runniing oil pressure droped and rod bearings out of it again. this one different block, lasted 1-1/2 nours and knocking, have not taken it apart yet, but same symptoms again, low oil pressure, alarm (oil Pressure0 knocking. Same oil was used everytime and I believe after the first rebuild the 11 lbs bypass valves were used. Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!

You don't mention replacing the oil pump nor the oil pump driveshaft......

everything was replaced including oil pump and shaft, my distributor my carb, my timing chain cover and rockers were reused

Oil line delamination on the inside? new crank each time or the same one?

2 cranks redone once each, also one new oil line as one caught the fan belt on an earlier install

Well,

If everything has been changed except the mechanic..................Just sayin' ya may want to look there.

Isn't that a little tight??? It think I have mine around 0.0029"-0.0032" (I am no engine expert but I think that is where my engine guy told me to put them) Any chance these are Eagle cranks???

I plugged my gen 5 block. My friend had a ZZ502 that was supposedly marinized and someone had the 11lb in there and he destroyed the engine in a couple weekends. He went through distributor gears the first weekend.

check your oil system, make sure your not running thru the filter backwards.

anyone have a flow diagram for the gen 5 oil line cooler and adapter for this motor I want one with arrows lol as all ican find is parts diagrams without direction of flow

http://teaguecustommarine.com//media...oij_piping.pdf