ZD30 oil pressure readings

[GeeYouCRD]

Hi all, could those that have an aftermarket oil pressure gauge let me know what their readings are at idle and 2000 rpm, both at cold start up and then at operating temp. At idle Im getting as high as 70psi at cold startup, 32psi after idling warmup (factory temp gauage at about 1/4), and 18psi after a run (temp gauge at about half) . The big difference between cold and hot is concerning me after I just rebuilt the engine due to lack of oil pressure caused be loose oil pump cover bolts.
Workshop manual for CRD says should be more than 28psi at idle, more than 57psi at 2000rpm at normal operating temp. However what is normal operating temp? as this seems to have a huge bearing on pressure.
trying to work out if this is normal or I have a problem.

[basil]

Hi all, could those that have an aftermarket oil pressure gauge let me know what their readings are at idle and 2000 rpm, both at cold start up and then at operating temp. At idle Im getting as high as 70psi at cold startup, 32psi after idling warmup (factory temp gauage at about 1/4), and 18psi after a run (temp gauge at about half) . The big difference between cold and hot is concerning me after I just rebuilt the engine due to lack of oil pressure caused be loose oil pump cover bolts.
Workshop manual for CRD says should be more than 28psi at idle, more than 57psi at 2000rpm at normal operating temp. However what is normal operating temp? as this seems to have a huge bearing on pressure.
trying to work out if this is normal or I have a problem.

Is your aftermarket oil pressure gauge giving you accurate readings?? Double check them with a mechanical oil pressure test gauge to confirm whats going on first. I am in the process of ordering a oil pressure gauge for mine. Do you know what the thread size is for the oil pressure light sender unit ?? so I can order a T-Piece adaptor to suit.

[GeeYouCRD]

Yeah, I've allready checked against a mechanical test gauge and also measured the output voltage of the factory sensor and both confirm the same. I used a 1/8" NPT , T piece (all female) as this is what the aftermarket gauge is and had read that this was what the factory sensor is , however it is actually 1/8" BSPT. Only one thread per inch difference. Used a 1/8 BSPT male/male nipple between the engine block and t piece. Works fine, no leaks.

[basil]

I got a t-piece 1/8 NPT and couldn't get it started in the thread. Not sure if the wrong thread or maybee I can't get it square on to the hole. The starter motor bolt seems to be in the way. I am over it. I am thinking I will fit it to the other sender near the oil filter, easier to get to and more room too, to fit that t-piece and 2 sender units. I already pulled out the sender unit and its got a different thread, its more coarse.grrrrr So I will have to take it out again and try to figure out what thread this one is. I will get it finished, one day.

[basil]

Finally got my pyro and oil pressure gauges setup, VDO. Had to get a t-piece made up in hydrolic shop but they looked after me. Fitted the oil sender near the starter motor, very hard to get to but it can be done from underneath. Just have to take out the top starter motor bolt and get rid of the bracket holding the wire harness. Anyway my reading were about the same as yours. Cold start 55psi then up to 70 with a light throttle and then idle again. At 1/4 temp went for a drive and it was about 40 psi at 100 km/ph. Then after about 15 km noticed it was about 25psi at 100km/ph. (motor warm now). Back at home it was about 18 psi at idle (warm). Then rev to 2500rpm up to 70 psi. The oil psi readings did move around a bit more than I expected. My zd30 has only 25000km and has had plenty of services and have not had any trouble with it at all. I am running 5w40 synthetic oil which is a light oil. If running a heavier oil the reading may be a bit higher but i am not too sure. As the engine warms the oil becomes thinner then that would explain why the oil pressure would tend to drop off a bit, compared to when it is cold. So long as I see the oil psi go up to 60 or 70 psi when I am pulling a few revs I am happy. Your readings look very similar to mine so I wouldn't stress too much about it.

[GeeYouCRD]

Haven't been on for a while, glad to see your readings are similar to mine, with your engine only having done 25000kms it's a good comparison for me. Workshop manual figures are quoted at "normal operating temp" but what is normal operating temp. As you see readings Change a lot with temp. Good to see you managed to fit your sender, like you say it's not easy but can be done, By the way I've been using 0w-40 semi synthetic.

[GeeYouCRD]

Correction make that 10w40