R
robbie
Guest
Hello and goodday:
I found my problem and why my I lost oil pressure. I have never replace a oil pressure relief spring in my long years rebuilding engines and will now do it until I can get a spring tester. I have for a long time seen my pressure drop when I hit 3500-3800 and with my old engine had hooked up a mechanical oil pressure guage and found that the guage was at fault. Well with the new engine (assembled with different parts from stuff I had aquired) I did not pay real close attention to it when I saw this problem. Mistake number one.
after working the engine hard (jsut like before, for close to 3 years), I saw the oil pressure guage drop with high RPM's and did not think any thing of it until driveing around town the pressure was staying low. Mistake # 2. that is when I found bits in the oil filter and parked my truck until I tear in to it.
Well when I tore in to it I found #4 main real messed up and not much damage done to the crank. The down stream rod bearing did not get any of the bearing material, so it was fine. The bearing material went side ways and fell into the pan and made its way back to the oil filter. No futher damage to any bearing. But I did replace all bearing when I had the pans down.
I got it all back together and and drove it with a after market guage installed and found that oil pressure droped off after 3000 rpm. I should of listened to the little bells long ago. So after shiming the relief valve and getting better pressure and shifting the pressure drop to higher rpms with the shims. I tried another spring from a wrecked 97 and found the relief worked fine no drop off of pressure at high rpm's. I had found the problem, a weak oil pressure relief spring. So I ordered one and will have a new one soon.
So if you see oil pressure build and then fall off at higher RPM's I would suggest either just replacing the spring or getting a external guage and plumbing it in to see what is up or it could cost you the same it cost me (or more). A ten dollar part cost me well over 200 in parts and lots of labor.
Observation I have seen on the stock oil pressure guage is that the first slash from the bottom mark is aoubt 25 PSI the second mark is about 50 psi, the last mark is 75 psi. oil pressure at idle is at or above 4 psi, the oil pressure at 3000 rpm is 34-71 psi.
I am busy the rest of the day and want to get this posted so other if they have the same problem could catch it before it cost you. I do not have time to answer any question till I look at the list. This will happen tomorrow I believe. learning all the time, some lessons cost more than others. later Robbie
I found my problem and why my I lost oil pressure. I have never replace a oil pressure relief spring in my long years rebuilding engines and will now do it until I can get a spring tester. I have for a long time seen my pressure drop when I hit 3500-3800 and with my old engine had hooked up a mechanical oil pressure guage and found that the guage was at fault. Well with the new engine (assembled with different parts from stuff I had aquired) I did not pay real close attention to it when I saw this problem. Mistake number one.
after working the engine hard (jsut like before, for close to 3 years), I saw the oil pressure guage drop with high RPM's and did not think any thing of it until driveing around town the pressure was staying low. Mistake # 2. that is when I found bits in the oil filter and parked my truck until I tear in to it.
Well when I tore in to it I found #4 main real messed up and not much damage done to the crank. The down stream rod bearing did not get any of the bearing material, so it was fine. The bearing material went side ways and fell into the pan and made its way back to the oil filter. No futher damage to any bearing. But I did replace all bearing when I had the pans down.
I got it all back together and and drove it with a after market guage installed and found that oil pressure droped off after 3000 rpm. I should of listened to the little bells long ago. So after shiming the relief valve and getting better pressure and shifting the pressure drop to higher rpms with the shims. I tried another spring from a wrecked 97 and found the relief worked fine no drop off of pressure at high rpm's. I had found the problem, a weak oil pressure relief spring. So I ordered one and will have a new one soon.
So if you see oil pressure build and then fall off at higher RPM's I would suggest either just replacing the spring or getting a external guage and plumbing it in to see what is up or it could cost you the same it cost me (or more). A ten dollar part cost me well over 200 in parts and lots of labor.
Observation I have seen on the stock oil pressure guage is that the first slash from the bottom mark is aoubt 25 PSI the second mark is about 50 psi, the last mark is 75 psi. oil pressure at idle is at or above 4 psi, the oil pressure at 3000 rpm is 34-71 psi.
I am busy the rest of the day and want to get this posted so other if they have the same problem could catch it before it cost you. I do not have time to answer any question till I look at the list. This will happen tomorrow I believe. learning all the time, some lessons cost more than others. later Robbie
