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Rod Bolts a go-go

1345 Views 7 Replies 3 Participants Last post by  brownington_bomber
Greetings from a first time poster....

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:D), 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.
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Anyone had any issues with failure on the earlier small rod bolts? Opinions would be gratis. Thanks.
Why not shop around for another used engine? I've seen 4AC engines for less than $200. They were available in so many corollas, right up until 1987 or so.

Then you could overhaul your complete core instead of frankensteining something together.

Next best option would be to check and see if early 4AG crank and rods would work.
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
Rods/bolts were changed in 10/83, so any 4A-C before that had the smaller bolts. I've never seen any failures caused by rod bolts.

I'd suggest just getting the rod bolts you need, and using the already machined engine.

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.
There's definitely 1 rod bolt in the national warehouse in California, so you should have still been able to get one, but alas, as long as you got what you needed. :)

Here here! The ole man was chompin at the bit to get it together, so completion is paramount.
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