Blown 408 Oil pressure issue

[Aussie408]

Hi everyone, as you will probably notice I am new to this forum.. I am desperately seeking some advice/input on a current issue with my engine..Mopar specialists are hard to come by here in Australia..
I have a 408 Mopar, brief engine specs as follows - R3 block, Mopar 4340 4.00" crank, Titan billet oilpump,Custom oilpan and pickup,Systems 1 remote filter,GRP ally rods, diamond blower pistons, modified Brodix B1 BA heads, BDS 671 Supercharger w/ Enderle mechanical alky injection. Crane cusom roller and followers, T&D rockers, Isky springs etc.. Clearances are at .0028" -.003" on both Main and conrods.
My problem is with oil pressure. At cold idle the engine has 50lb at idle (1600rpm), increasing to 60lb with rpm(4500+). Once the temp is up to 180deg, the oilpressure drops to 20-30lb and does'nt increase with rpm.. I am using Lucas 20W50 oil and we have checked all the usual oil gallery plugs that can be missing as far as we know.. We're now pulling our hair out!!
Hoping someone may have encountered this problem before and can offer some advice.
Cheers, Cass

 

[daryl h]

You need to modify the hell out of the oiling system to keep it together with a constant high rpm. run a dry sump system on mine an even had to go as far as feeding it oil from the front too to keep the bottem end from starving. One secret that has helped me is fully grooved bearings. You have to buy two sets of bearings an use half from each. also have restricted oil to the topend. there are books that will help. Lost mine 3 times before finally figured it out. Run mine in a sprintboat so its a little different application but the oiling mods will be similar. Came over an raced boats over there a few years back. Where are you at in Western Australia

 

[C130 Chief]

If your oil pressure levels off at a certain point warm, I would say that is where your bypass opens. If you switched to a 10w30 and got similar results, that would tend to confirm.

It requires a pan drop to shim the relief spring, but that would be a good way to know for sure.

 

[Aussie408]

Thanks for your reply. From what I understand, Bob @ Titan engineering setup the oilpump based on the engine specs I gave him. I'm pretty sure the relief spring is externally adjustable, but will run it past Bob anyway.
Cheers, Cass

 

[Aussie408]

You need to modify the hell out of the oiling system to keep it together with a constant high rpm. run a dry sump system on mine an even had to go as far as feeding it oil from the front too to keep the bottem end from starving. One secret that has helped me is fully grooved bearings. You have to buy two sets of bearings an use half from each. also have restricted oil to the topend. there are books that will help. Lost mine 3 times before finally figured it out. Run mine in a sprintboat so its a little different application but the oiling mods will be similar. Came over an raced boats over there a few years back. Where are you at in Western Australia

Hi Daryl,
Thanks for your advice. We're not doing big heaps of rpm with this engine, no more than 7200rpm, generally drag and occasional street use.. Excuse my ignorance, but would'nt full groove bearings not help oil pressure either?? We're currently using clevite tri armours - have you had much experience with these? We're running pushrod oiling also and have drilled extra holes to help with oil drainback..Can you let me know the names of the books you mentioned too please. I've just spent a heap of money setting up the titan oil pump, don't scare me with the dry sump idea!
We ran the engine with a mellings HV pump previously with the same problem, suprisingly the bearings and everything were as new, there didnt appear to be any damage to components due to lack of oil pressure but it's still a worry. Thought the titan pump might fix the problem, unfortunately not!
We're just south of Perth in a suburb named Canningvale. I assume you would have raced your boat at Burswood?

 

[daryl h]

Just read you have the r3block so dilling is good. If you are running a roller set up one of the lifter galleys need to be blocked to keep oil on the bottom of the moter. Any constant rpm over about 5500 will starve the bottom end has been my experience. Turn mine right at 7000 an have had no problems since I started feeding oil to the front. Full groove Is my preferance an I use them on all race moters I build. Look on ebay for the small block mopar books. There are 2 or 3. Deffenantly have a problem. THe books were cheap, parts are not. Try a different gauge to. Have raced there an hope to come back again if they ever put world series back together