Building a Performance IH 345 - Part 2

I finished part 1 with, "The next installment - porting the heads myself, painting the new engine, fitting the various pieces together, and machining the intake for my new induction system.."

I was close to accurate.

I dropped the pistons, rings, rods, crank, harmonic balancer, and flywheel off at the second machinist with instructions to balance the assembly, and to resurface the flywheel.

Within a week, I was $232 poorer, with a pile of balanced engine parts. The bill was $25 to resurface the flywheel, $175 to balance the reciprocating assembly, and another $32 to install the pistons to the rods.

The 392 connecting rods are assembled to the hypereutectic .030 over pistons.

While everything was being balanced, I continued to port and port and port the heads. My air compressor is a bit under powered for the job (an old industrial 1HP compressor I bought for $100). I have plans to replace it with a larger unit, but those plans won't happen until after this engine is done.

I used the porting kit from Standard Abrasives in my 1/4" air powered die-grinder. I concentrated my efforts on the exhaust ports. IH heads have a large hump protruding from the top of the head in the middle of the exhaust ports. These are specifically to accomodate air-injection for smog engines. My engine wasn't a "smog" motor when it first started life in 1977, and it's not about to become one, either. My heads were not drilled for the air-injection tubes, but "smog" heads would be.

I used the large grinding stone to completely remove the "humps" from the exhaust ports. It took a good deal of grinding. I then moved on to the 40-grit and then 80-grit "cartridge rolls" and worked to smooth the entire exhaust port area - specifically where the humps had been removed. Once the worst was taken care of, I moved on to the 80-grit, then 120grit, and then the final polishing "flap wheels."

I then moved to the combustion chambers, and installed the rustiest pair of valves from my spare set of heads. I then proceeded to remove a little material - primarily cleaning up the chamber and removing the high spots, and then worked my way to the 80-grit, the 120-grit, and then the polishing attachments until the chambers were rather bright. I could have put forth additional effort to clean up the valve pocket area and to work a little at unshrouding the valves, but this is my first porting job, and I was leery of making anything worse than it was originally. I should also mention that it took an entire month of evenings to get the first head ported! I spent only 2 weeks doing the second head - it wasn't as nicely done, but adequate. The biggest speed benefit was that I now knew how long I needed to use the grinding stones before I moved on to the 40-grit cartridges.

The bare block, ready for assembly. It lives in a baggie most of the time. Notice the engine stand's legs are a "U" shape, not the typical "T" shape. The U shaped stand is rated to 1250lbs - the minimum for working on an IH. The T legged stands are generally considered too weak.

With the head porting finished, I took the disassembled heads, the old valves, and the new Big Block Chevy 454 LS6 valve springs and hardware to the machinist. I would have had the heads back within a week, but the machinist had to order 8 new exhaust valves - my stems had been worn .100 of an inch, which would be adequate for a while, but would fail well before my 300,000 mile target. The 345 exhaust valves were $15 each.

When I paid my $360 bill, I received back a set of IH 345 heads with fresh valve springs and valves, new Dana Perfect Circle valve stem seals, and a nice black paintjob. The valves were installed with 155lbs of seat pressure - this figure made the machinist cringe. On a "normal" engine 130lbs of seat pressure is enough to run a camshaft "flat" in short order. However, the stock specs for the IH heads is 125lbs, and the valves float around 4000rpm. John Comer suggested I ask the machinist to compare the weight of my valves to a small-Chevy (IH valves are heavier) and then to compare the lfiters used in an IH engine to a small-block Chevy - the IH lifters are 50% larger, with 50% more contact area on the camshaft. Because of this, the 155lbs of seat pressure is distributed across a larger surface area which means the camshaft shouldn't wearout and go "flat" in short order.

The machinist's bill was broken down as: Replace 8 valves - $120. 16 seals (Perfect Circle) $20, 16 cut (the valve guides) for seals - $20. The basic valve job was billed at $200. I also had the heads resurfaced and "squared" and while it was on the machine, the machinist removed an extra .010 from the heads to bump compression up slightly more. The valve job included magnafluxing of the heads and complete replacement of the valve guides and refacing of the valve seats.

Regarding the intake manifold modifications I mentioned - I had planned to place my 2bbl intake manifold into my drill press, and enlarge the two throttle bores from the tiny holes used for the Holley 2300 series 2bbl carb to the 2 1/16" or so size needed to accomodate the ProJectoin throttle-body unit, along with changing from a 4-bolt square mounting pattern to the 3 bolt triangle pattern of the ProJection. Unfortunately, a friend of mine is about to do the same thing to his own 2bbl intake, and mentioned that he was going to use a milling machine to do his. Naturally, once the machine is configured or 'set up" to machine a 2bbl intake for the TBI, the work is done and the time to do a second intake manifold is trivial compared to the setup involved for the first. He offered to machine my intake in exchange for a cold beverage. I like to do things myself when I can, but this offer was too appealing. The biggest advantage is it's one less thing I need to worry about doing before I can install and enjoy my new engine.

With all of that out of the way, let's take a look at how deep in the hole I am on this little project..

Source Parts Price
Friend Shortblock $80
Machinist Hot-tank $30
Machinist Cylinder Bore $88 ($11/slug)
Machinist Block Decked .040 $100
Machinist Purchase and Install Camshaft Bearings $50
Machinist Press Camshaft and Crank gears $25
Northern Auto Parts Re-ring kit $130
Northern Auto Parts Upgrade - Moly Rings $15
Northern Auto Parts H997CP Pistons $160 ($20per)
Northern Auto Parts Timing Gear Set $50
Northern Auto Parts Oil Pump Rebuild Kit $30
Gryphin Racing Iskendarian 262 duration camshaft & Lifters $225
Gryphin Racing Valve Springs, keepers, etc $125
Summit Racing Standard Abrasives Deluxe Head Porting Kit $40
Machinist Balance $175
Machinist Assemble Pistons to Rods $32
Machinist Resurface (Turn) Flywheel $25
Machinist Valve Job $240
Machinist 8 new exhaust valves $120
Total   $1,742