While I've been here tonight (OZ time) I've been googling and found a bunch of second hand Sunnen (and other brands) rod machines for sale. $400-$1000 AUD second hand. So that's how they do it...
Its definitely a proper set up.
 

Have finally got around to prepping my spare 390GT motor parts, into a complete kit, ready to be built into a 68' OEM spec Mustang GT engine (spare for my car, which has a warmer one fitted).

While cleaning and inspecting the rods (matched set of C7AE-B's) I found one with a damaged wrist pin bush (one end had a wee bit broken out). The rest are great; look nice, no marks, pins run butter smooth and within spec. So no problem, sourced one new Clevite bush and am now ready to fit it.

However I live in the country and don't really want to wait months in line for my trusted machinist in the city to get around to honing this one bush (if required). With COVID it seems every man and his dog has got around to their projects and he's swamped. So as I'm a careful general engineer and trust myself not to be stupid, so I'm thinking I'll do this small job myself.

So my question is this. Has anyone used a flex hone to fit a pin bush? I don't like the idea of using a little stone type brake hone, as most are too coarse (made for doing ferrous cylinders) and perhaps too violent on bronze. Its easy enough to get a 1" aluminum oxide flex / ball hone (brake / lifter size) of a nice grit (240/320?), and I can't see why if carefully done, I can't carefully take off a thou or 2 as required.

In al these years building motors, I have never had to ream/hone a pin bush before, (lucky me). But it seems easy enough as long as you take it easy, check your measurements often, and maintain alignment & lubrication etc.

I seen videos of engine shops sizing rod eyes using a chucking reamer and lots of lube. Just running the rod eye in and out (by hand) until its at spec. So can a well lubricated, nice new flex / ball hone be any worse? Or was that "shop" a bit amateurish?

Happy for any views...

Thanks

Yes I remember you saying some time ago you weren't a fan. IN 282/ EX 288 & 110 LSA = 65 degrees of overlap. Not a huge amount I suppose.

I have seen a fresh mildly worked 390 (+30) with a XE262H (a lot less overlap) that only gives 14"Hg at 850-900 RPM. So will mine really do 15”? But of course who knows if everything is sorted on that motor. Maybe it will give more vacuum when its run in etc. Anyway I'm hoping you're right, as 15" should be enough for my factory Midlands brake booster. I asked as some web folks are saying they were barely getting 10" using this cam. But who knows what the other specs were (or leaks etc.). COMP Cams own dyno sheet for the XR282HR (same specs as the 280HR) on a Chev 350 with Victor Intake etc, only showed 9-11", and that is not enough, although a high single plane intake possibly hurts vacuum a bit.

In the end I'll eventually run it on my test stand and the truth will be revealed!

Thanks for the reply Brent.

Mungus,
When buying a pump from Doug, he normally sends a new plug and a large shim.  You *can* install it for High pressure, but honestly, his HV pump is darn near perfect as is.
On my car it's 80psi cold idle
25psi hot idle
and pressure jumps the second you hit the throttle right up to 65psi.  Works like it should, I wouldn't really want any more pressure for a street car.

Thanks Drew, if mine does those figures I'll be a happy man. No need for anything more.
I can't recall seeing any spare parts in the pumps box, although there is a lot of packing paper scrunched up in there, I'll have another look tomorrow. Can't hurt to have a spare plug...

OK, so are most staying with the OEM hot air system?
Seems you can do a reasonably tidy job pipe wise anyway.
I dud see someone selling complete hose kits just recently, maybe Mansfields?

Yes the pump you get from POP will have an integral pressure relief.  You should be good to go on that 390!

- Bill

Thanks Bill. Yes I had a look at the Melling HV pump today, and I can see a plug on the end of a gallery, maybe 1/2" diameter.
From the pump drawings I've seen I'm guessing the relief valve is hiding inside there...

1969. So do they just use the pump for relief function? Is the relief valve part of it?
I saw one in a 427 is all, and I think I've never built an engine that didn't have one (first FE).
So I just assumed they must have one somewhere...

Ahhh OK, thanks Barry. That explains it well.