F 134

The refinished valve seats is good. Were your valves refaced too? Your photo on post #217 is too blurry to see. If they were refaced by the machine shop, you may need to lap them in to the seats if you wirebrushed the faces. A little tin of lapping compound (usually Clover brand) and a hand lapper with a suction cup are inexpensive, and will give a nice seat, provided the seats and valve faces were reground. You want only a narrow seat, around 0.080”(2.2mm), to 0.12”(2.6mm), and it needs to be centered on the valve face. A quick hand lapping will show the seat area on the valve face in a matted finish. -Donny

 

I got the intake valves out, cleaned and returned today with new o-rings. The seats on the valves were polished clean and even. The valves moved smoothly in their guides without and wobble I could detect.

They weren't quite as carbonized as the exhaust valves. I was a bit surprised to see any carbon at all... but this is my first rodeo.

I hadn't seen Donny's recommendation before working on this today. I'll need to look at the seats again before calling this finished.

 

I acquired this, abandoned by it's owner, in a newly leased building. It had a story attached as "recently rebuilt". The oversized pistons and oversized main bearings attest to it being rebuilt, but main bearing wear and a significantly clogged oil pick up suggest it wasn't recent.

The tapered crankshaft/flywheel dowels were replaced by bolts too small for the holes. There's no way that flywheel was centered. And with the connecting rods spanning over a 2 oz weight difference, I have to believe somebody was having a rough ride.

Now that I know about it, I can't ignore it. The machine shop wants to pitch the #4 connecting rod (@850 gm ...the rest are 900 gm).

I found a #2 but the seller said it's 950 gm... too heavy.

And I found about 35 NOS rods but their owner said they are all "odd" cylinder connecting rods (oil spray on wrong side).

Has anyone ever converted an odd rod into an even rod by drilling a new oil spray hole and plugging the old one?

 

I can find lots of odd NOS connecting rods, but no even ones. So I talked to the engine rebuilding machine shop today about drilling an oil spray hole in the opposite side of an odd connecting rod to turn it into an even rod (and plugging the old oil spray hole). He said sure, but the truth is there's so much oil flying inside an engine already, one more or less sprays from a connecting rod isn't worth the effort. He said a lot of old Ford engines used to do the same thing, but the replacement parts for them deleted the connecting rod spray holes. He said something about the bearings not having a hole for that either. (?)

I'll keep looking for an even rod but this guy's been building race engines forever...

 

I tried to turn mine around (nose out), but couldn't get it to start. I don't have a threading die that size so..

 

I disassembled my head, looked closely at the intake valve seats, and ordered a lapping tool and paste. It's arriving tomorrow.

It looks as if the lapping job itself is a really easy job (if not over done). But the clean up afterwards... Yikes!!! About 1/2 hr for lapping, and 2 hrs for decontaminating (hot soapy washing), heating (drying), oiling and shop clean up, etc.

I probably needed to do this cleaning anyway. Flipping it over several times shook our a bunch of trash, hopefully only from the coolant side. I had put my pressure washer away in the fall. I'll need a decent Western PA March day to pull it back out after the lap job.

 

The lapping tool and paste arrived yesterday but I was pulling the radiator out (it leaks) and couldn't get to the intake valves. I'll find out next week if it can be repaired. The radiator guy said all his core prices skyrocketed overnight (imported). He said he'd rather repair it than see me spend such a high price for a new core. So, we'll see.

So, I lapped my intake valves today, fairly gently since it was my first time. This is how the most questionable one appeared:





I say most questionable because
(1) The polished ring is just a bit wider than I expected
(2) I see a reoccurring discoloration running axially across the ring.

Thoughts, anyone?

 

I got a "PASS" from two other forums, so today I pressure washed, dried and lubricated my stripped down head.

My 4 new NOS M38a1 connecting rods came today, all odd cylinder... I need an even cylinder.



But I have a full set of used rods coming tomorrow (from a generous forum guy). I should be back on the train by next week.

And I got a quote for fixing my radiator leaks, $80. "Good for around town, but don't drive to California", he said. I told him to go ahead. Core prices have gone through the roof, it seems.

 

Still no rods, so I installed the intake valves:



Then I moved on to the rocker arms but quickly realized that would block access to the head bolts, so full stop on that.



Back to waiting for connecting rods.

 

All my connecting rods are in, both the 4x NOS odd cylinder pieces,



and the complete set of used rods donated by a guy on another forum (without cap nuts).



All the used rods weigh exactly the same (873 gm) on my postal scale.

I spent two days looking for appropriate new 3/8-24 connecting rod nuts. ARP has them but with a flange base only. (The originals don't have a flange base).

CROWN and Dorman have them but they don't offer ANY specifications. Who knows what is in their products...

GRADE 8 nuts are available lots of places but that's not an acceptable specification.

I'll likely take them from the set I remove.

 

I took my gifted set of used rods to my engine machine shop for an examination to find and fix any issues.

They had to be bored, and were balanced to 0.5 gm, and got new nuts. (March 2025, $20 each, Pittsburgh, PA). So all the hurdles are clear to assemble the pistons, and install them in the block, and attach and torque them to the crankshaft.

Whew. I wondered if I'd ever get here.

 

Ok, maybe not ALL the hurdles are clear...

While laying out all the piston/rod assembly and installation parts and tools., I examined the hardware closely. Good thing I did. The four(4) piston wrist pin cap screws (3/8-24x3/4 +/-) were all from different manufacturers (no big deal) but three(3) were Grade 8 and one(1) was Grade 5 (maybe a big deal?) All three Grade 8 cap screws had a shank, the Grade 5 did not. (Maybe a big deal?). All of them showed a lot of thread wear.



I've looked everywhere for a 3/8-24x3/4 hex head cap screw with a shank... Nope. All are full thread. But the 3/8-24x1-1/4 have a shank about equal to the originals. So I bought four(4) and cut them to equal lengths to match the originals. Problem solved... agreed?

 

I assembled the pistons today. Plenty of assembly lube (I need a second bottle!!) T-slot opposite oil spray holes. Locking screw torqued to 38 ft-lb (spec: 35-41 ft-lb). My torque wrench wouldn't fit inside the piston base so I attached it to a 9/16's crows foot.



But that extends the lever arm 3/4" to 1" further.



Which is less than 10% more torque than I'm reading on my torque wrench. So at 35 ft-lb indicated, I'm still in spec at about 38 ft-lb actual.

 

I installed my pistons today. All went smoothly until I checked the side play...



0.022 is over 2x the spec (0.004-0.010). How big a deal is this?

 

This is a fun build to watch. Lots of attention to detail.

If your piston has too much play, won't it rattle around in and explode into a million pieces or badly score the cylinder wall?

 

The clearance measurement in the pic above is on the rods on the crank, not the side clearance of the pee stones.

 

It has been fun for me, too... most days.

This issue is honestly disheartening, though.

The machine shop had the crankshaft and polished the journals but didn't have the rods (before I knew about balancing them). So they couldn't have checked the end play.

I see on line a way for the machine shop to Silicon Bronze braze the rod face and machine it to spec, but then it would need re-bored... AGAIN.

It feels like I'm back to square one... Pull the pistons, disassemble, take the engine (crankshaft really) to the machine shop.

Pay the bill.

Sigh.

 

An engine machine shop on YouTube had this approach for resolving connecting rod side play at the cap:



Silicon Bronze braze was applied via TIG on three spots on just one side of the rod cap face and then milled off to reduce the side play gap to spec dimensions. Apparently the braze material selected is an excellent bearing material. TIG, and just three spots, were used to minimize heating (limit distortion, material property changes).

I'd need 0.012 to 0.018 of added material (after milling), and then re-boring and rebalancing the connecting rods.

I'll talk to my machine shop on Monday and see what he thinks.

 

Oh man, what a drag. This really sucks. Slows you down and costs more money! I hope it can be resolved easily and cheaply. Would your original rods fit better and work?