Coloradoracer wrote:Ok guys, not trying to start another bash thread or anything like that. Just looking for some input. Over on Bracket talk, we've got a discussion going regarding a Merlin block, a Dart block, and Titan oil pumps. The issue is that the guy built a new motor with a Dart block, and ended up with no oil pressure. He was running a Titan oil pump. His previous combo was the same, only difference is he was running a Merlin block. I myself currently run an older Merlin Pro, a Titan oil pump, and have no issues with oil pressure like decribed, except for under hard braking after the stripe at speed, my pressure will drop, then come right back up. I know it's my flat bottom pan causing it, and I know of a bunch of other racers using similar setups that the same thing happens too. The guy in the thread however, appears to have a much bigger problem. Some of the other racers over there told him it's because of the pump, but I'm calling BS on that because it wasn't an issue with his previous combo, only the new one. Their fix is to replace the oil pump, but I'm saying its something else, and he needs to check his whole package and fix what's wrong, not just bandaid it with a different pump. Again, all I'm looking for is some input on this. Here's the link to the thread:
http://drr.infopop.cc/eve/forums/a/tpc/ ... 1017075416
540 RAT wrote: But he and those idiots over on the other Forum will all scream that the Titan oil pump was at fault. Unless you know the whole story about something, you cannot believe what a lot of people say.
Racing68 wrote:It's usually a pickup to pan distance problem, or some piss poor scraper that does not allow the oil to drain back to the pan. Example Milodon BB Chrysler scraper with 4.5 inch stroke. It will clear but will pump the pan down in about 8 seconds. Been proven on 3 different builds that had know-it-all customers, they did not.
Racing68 wrote:Yes not enough drainage for the Chrysler scraper. My opinion is that when the louvers are faced down they act more like a drain than a scraper and hold oil back. Every one of these we have used in 4.25-4.5 stroke applications have lost oil pressure after 8-12 seconds of use above 3500 rpm. Longer the stroke the quicker it lost oil pressure. Shut engine off for 20-30 seconds and then everything is fine, idle time does not seem to affect it. The first time we saw this was at the end of a dyno pull on a 572 wedge motor. We added a quart same result. Thought about cavitation so loaded engine at 4000 rpm and held it, after approximately same amount of time oil pressure dropped again. We called a Chrysler expert and after telling them about the oil pressure drop first thing he said was remove the Milodon scraper, funny thing was we never even mentioned it. Removed scraper and pressure problem disappeared.
http://drr.infopop.cc/eve/forums/a/tpc/ ... 1017075416Mopar Traitor wrote:Broke my merling block last year so went back with a Dart. This is a 565 with Big Chiefs. Got it running and took it out last night. Drove around the pits quite a bit getting the tranny fluid right.
I have Andy's favorite oil pump, a Titan and it always worked fine on the Merlin. Now it was holding 40 at idle and 60 with a little rpm, no restrictors.
First pass, I intended to leave then ease out and check things but it left good so I stayed in it, tires setting all winter and Friday night so was having to drive it some and did not notice the oil light was on until well pass the finish line and guage was showing zero and just before shutting it off I thought I heard the squeaking sound.
Today put the oil primer on it and it took a bit but then the oil pressure came up, dropped the pan and pulled number one rod cap and it looks like new money but looking at the oil in the sunlight I see a lot of silver film in it.
Here is my theory, tell me what you think. Maybe the Dart does not drain back as fast as the Merlin and the Titan pumped the pan dry and the pump lost prime. I had changed the filter and did not replace the oil lost in the filter before I ran it so was down what oil was in the filter. This is a Milidon oil pan 31187 and I run a 3 quart acumalator which actually holds a little over 2 so usually run 9 quarts which would leave me 7 in the pan. I have the old pump a Melling M77HV which I am thinking about putting back on it. Just not sure if I should take the motor out and strip it down and check everything again.
Also not sure what the vacuum might play into this, I have a small guage and also meant to look at it but did not do that either. Always stick to your game plan...
I had lowered the shift to 7000 and it still ran a 4.65 so think it is going to run if I can sort this out.
I think the main problem was not enough oil although I had gotten by with this little oil with the Merlin.
The Milidon pan calls for 8 quarts plus filter and I have the 3 quart accumalator. I started out with 9 quarts total and then lost almost a quart when I changed the filter.
Will definitely have more oil when I go back.