Case 450B starts great while cold but won’t while hot

Hi all, First time on here so bear with me. Bought my first dozer back in February (Case 450B). Had it out using it a couple of weeks back clearing land (trees). While operating it started overheating and then died. We couldn't get it started after that and thought the injection pump just went out, so we removed it to have it rebuilt. After taking it to the shop the gentlemen said he just built that pump two years ago but would check it anyhow. Got the pump back and said there was nothing wrong with it that he could find, he put some new gaskets in it but that was it. So we thought the key/pin had sheared. Took that apart and find nothing wrong there. Put it all back together and got it running and back to the house. I cleaned and straightened radiator fins and gave it a good flush. I got the over heating problem fixed. I drained the tank flushed the lines put new filters on and cleaned the filter in the pump. Even installed new shutoff valves on the tank. The machine will fire right up cold with no problem but once you get it to operating temp and run it for a little bit and shut it off it will not start until it cools off. When you are trying to start it while hot there is no smoke from the stack. Would this be bad injectors, valves too tight or worse case bad compression? I'm not leaning on the compression because I don't think it would fire up as good as it does cold. I've even heard that if the nut on the injectors is too tight it can cause poor starting issues? Any and all info is greatly appreciated Thanks.