My father is trying to get the 4AC back together for his 86 hatch and has had several issues, due to the rebuilder core we used being from an 83 or 84 model (can't remember exactly). He ordered the kit for an 86, as externally both engines appeared identical. The indentations on the rod bearings were reversed on the later motors, so he had to buy earlier bearings and now, due to a faulty torque wrench stretching one of the rod bolts (recently returned), we've discovered that the bolts from the later motors (of which we have two extra) are larger.
My question regards the use of these earlier, smaller rod bolts. I understand that generally engineers tend to change things only when neccessary, so were there reliability issues with these earlier bolts. This will not be a track car of any sort, so if in general use they tend to be adequate, I would be interested if there is anyone out there who may have a few of the smaller bolts around they'd be willing to part with reasonably.
Let me know your opinion on this, as I'd like to see the ole man get his SR back on the road. Thanks.
The problem is that he's already had the early rods resized and block machined. The difference between the size is fairly small, but enough that machining to fit them would be neccessary. We've got two of the later motors between us. I do appreciate the reply and advice though.
On a side note, it may come down to stepping up to some ARPs
Just an update, we ended up finding a stock rod bolt. Toyota no longer makes the part, but by ordering a reman rod, we were able to get two. It will replace the stretched bolt and not force us to remove and ream the rods for the larger later model bolts or ARPs. Thanks to all who replied.