4MG Rebuild

Don’t get nervous when you don’t see the oil pressure you’re used to. It’s not terrible uncommon to be at 25psi idle on a good hot day when stopping at red light or first parking. It will usually come up 5 psi or so after idling just a minute. Running down the road close to 50 or so. The B looses oil pressure through the pump and advance that the E doesn’t have. So there is a little lose with the dual squirt nozzles even with the high pressure spring guide. I always put some washers under my spring too.

It’s really honest to goodness nothing to be worried about. I’ve never had a minutes trouble out of the rotating assembly or seen sign’s during a bearing roll to say this isn’t ideal. I know alot of people that think oil pressure is king and worry to death over not having 40 psi at idle. It helps to get past the thought of it with a little pre warning

 

Yes to all that. Some think shimming the spring raises oil pressure when all it does is keep the bypass closed. Now I will say the bypass starts opening gradually so you delay that you do gain some pressure. The sealing surface of the bypass being smooth matters etc. With new cam bearings that should help. Rocker shafts being in good shape with the bottoms of bases flat filed will help. Flat file the oil pump outlet that bolts to block. No gasket no sealer of any type. That all helps. Pressure goes up flow goes down. So every small internal leak lets pressure go down. Flow is increased but out the leak does that make sense? So a big enough leak in the right spot can rob flow from the end of the line. I always make sure my top is oiling regardless of my pressure. The added squirter is gonna drop your pressure because it’s increased the flow of oil. The single squirts are a bigger hole but the double flow more oil. It’s a give to get deal

 

A 855 Cummins is within spec with 5 psi at hot idle. Even the new DD16 is at 20 psi hot idle. I don’t remember what my 7fb ran at, but I believe it was around 20-25 idle and 50 ish going down the road.

 

CAT spec is 18 at idle and 38 at high idle.

 

Almost looks like #1 was burning a little oil. Fair bit of carbon.

 

Good looking build! I've done a few with IPD stuff, including a 3ZJ with that same enhanced durability kit you are using. No complaints at all, about 170k miles so far. With the B pump and 14.6 pistons will you use 3421 nozzles? or something different. I would consider changing the oil pump spring retainer now while its apart, not exactly an easy clean job to drop the pan and reinstall IMO. Looking forward to the finished product!