Im looking at getting a IHI 45J with blown motor cheap but to purchase a running motor is about 5000 NZD Is there any reason not to use a car motor as i can get these in about the same Hp for 500 dollars and parts are at every town and they are cheap as mud also compare to the yanmar motor (4TNE88) Cheers Brett
Yair . . . Buzzliteyear . Any thing is possible but there are lots of reasons not even consider an automotive petrol engine for this application. By the time you get the adaptors/mounts/brackets made and an adequate cooling system fabricated you may find four or five grand for the proper engine is looking pretty good . . . and have you ever checked the torque/HP/revolutions curve of your hypothetical engine to see where it makes its beans? HP figures can be misleading when it comes to doing work. If this type conversion was practical half the clapped out little diggers out there would be running Camry or Subaru engines or whatever. If you are going to fit a non standard engine at least make it an industrial diesel with similar characteristics to the original and save yourself some grief. Them's just my just my thoughts . . . some of the petrol-heads on here may tell you different. (big grin) Cheers.
Don't go the cheap way out you will pay for it down the road with all fabrication and will have the long life like the diesel engine.
For sure should be diesel, and it has to have a constant speed governor (most do, but check it) and as Scrub said you need to make sure the torque rating is as much or more than the old one, and it's at or below the rpm of the original torque peak. Max rpm's should be the same, or able to be adjusted down, they don't adjust up usually. You spin the pumps too fast, you'll burn them up. Around the US we can find surplus Yannies usually that can be shoehorned in.