Received my order and have a question… basically everything in my order had the factory seal on the box broken. Meaning I feel as if I may have someone else’s returns here. Not that that would mean the parts are bad, but I am inspecting them closely.

how perfect do you expect new pistons to be? I do see what is probably a casting or machining flaw. The below is an example that my phone struggled to capture. I can feel it with a finger nail but it goes inward, in other words I don’t think it would scrape against the cylinder walls. Is this acceptable? Normal even?




What I captured is probably the worst flaw that I saw on my first pass inspecting. I did also notice some of the pins feel like the bind just a hair or have a tight spot. I swapped the pins in 2 pistons and then they both felt relatively good. Is it normal to have to mix/match pins/pistons to find the best fits?

 

Also the pins are measuring 0.9265 - 0.927

And I think I’ve landed on the Scat Pro Stock I-Beam Connecting Rods 2-ICR5700P. Press fit, the need to have floating rods honed/fitted it just seems overkill when pressed is just fine.

 

Probably a handling mark or from one of the clamp fixtures when it was machined... that kind of stuff is to be expected from parts in that price range and use category. Those pistons were mass produced by the thousands and not treated with any real care from the moment the raw casting poped out of the mold, till when it was being weight and size sorted for boxing.... If it's just cosmetic live with it, if it's going to effect something, knock it down with a file until it's just cosmetic...

Were they mfgrd in India or Mexico? It's been a long time since I saw any of those Sealed Power hyper pistons but I heard that Federal Mougle was going to reopen one of the US mfgring plants, in addition to the newer plants in Mexico and India.....

Those pins should run in a bushed rod with minimal fitting... and 5 tenths of a thou across all 8 pins is pretty good tollerance for a Federal Mougle product.... but in all honesty the rods were mfgrd with the same level of care as the pistons (but in China) so they might still be tight.
Will

 

Thanks, that was the info I was looking for as it had already crossed my mind on how easy it would be to sand/file an imperfection.

I’m not sure where manufactured, can check later. Any thoughts on some of the pins feeling a hair tight in the piston bores? They all go into the pistons relatively easily and most spin freely but some not as much and feel like tight spots. I’m presuming it’s more of a casting issue with the piston than a problem with the pin. Does the steel pin just wear in and self clearance the piston in these cases? I went with press pin rods so the pistons are the only pivot point for the pin.

I presume the “F” cast into the pistons on one side indicates Front for orientation.

 

The clearance is in the pin bore of the pistons.... if it's tight something is wrong... a nick or something like a sharp edge in the pin bore that needs to be dressed would be my first thought. This needs to be addressed before assembly.... tight wrist pin will wipe out a new engine.

F could mean front... usually there is an arrow or dot on the top that signifies front.
Will

 

As mentioned, clean up of the pistons and pin bores is recommended. Sharp edges and burrs tool marks should be knocked off, small fine round jewlers works well, for the pin bores you can use one of these if you apply it evenly... for $11 on Amazon, assuming you may have a 1/8 rotary tool of some sort, pins need to rotate super smooth even if you're not measuring things with higher precision methods.


I've used a krytex wheel to clean up the edges also. Make sure the ring lands are perfect visually and rings fit without any bind (top two, just rotate the outside edges in the grooves, no need to install at this point). The machine shop will ask for the crank, flywheel, connecting rod, piston, set of rings, pin, bearing shells in order to determine bobweight and balance.

Also I usually inspect/polish the wrist pins carefully, must do if it has any scratches dings or burrs. Store them clean and separated as they can knock together and cause issues, light coat of oil.

 

This is all great advice - really want to thank you guys for hanging in there as I ask all these questions, it’s very much appreciated.

Not knowing how much the crank is to be ground leaves me with not knowing what bearings to get. I kind of presumed a set of rod bearing weighs what a bearing weighs and the outgoing (to be replaced) set could sub in for weight/balancing purposes. Maybe not the case?

I may push out bringing it all to the machine shop until week of July 3 when I’ll have the rods in hand too. Otherwise it’s just another trip I have to find the time to make. Time is my biggest challenge here. It would unfortunately push the whole deal out another week but what’s the difference with 6+ weeks of time in queue at the machine shop.

 

Revisited the piston wrist pins. The ones that felt tight I took apart, cleaned pin and piston bore, drop of oil and now they rotate butter smooth - I think with the tolerances so small that they were just a little dirt/dry. Believe I’m all good on that front.

I confirmed pistons are made in India. They do also have a dimple on the front face and that corresponds to the “F” in the casting.

This weekend I will thoroughly inspect them and knock down any imperfections, test fit rings as suggested above and give it all a good cleaning. Rods should arrive on the 3rd and then I should be able to get this whole lot over to the machine shop on the 5th.

 

This a great thread. Tons of good info here.

If I am reading this correctly this will be your first LTx engine build. If so please consider this book. I used it when assembling my LT4. I loved building my engine and want to build some more. I went through just about everything your going through and more. Mine dropped a valve and destroyed the block and really chewed up the passenger aluminum head on cyl 2. A new to me block, that had been in the hot tank, and the head welded up it was time for the rebuild. I had them do a valve job too since they were off the car and it had gone through a catastrophic event. Yes New pistons and rods. Crank turned. New ARP head bolts as the originals are a one and done dial indicator bolt not designed for reuse. That is very important. New bearings all around. New cam lifters and push rods along with the roller rockers. And a new timing chain. I put on a new distributor cap and wires but leaving the original sensor. It was time for assembly. The book came in very handy as there are some steps in there concerning the Opti spark and the proper placement. If not set correctly you'll be 180 out and it wont start and resetting it in the car is a nightmare. It also has all of the correct toque specs you will need. You really only need the assembly part of the book. The rest is just good interesting info but most home mechanics dont have machine shops.



Hope this helps. Have fun!

 

Thanks, I do have the book. Block and crank are at the machine shop presently. Planning to reuse many components (pushrods, rockers, double roller timing set, etc … they are practically new, just a few thou miles and came out unscathed. They do all need a good cleaning I’m sure.

I was considering changing out the cam (also practically new). It’s a Comp cc502. Back when I cammed it I went with this one because it would keep the need to shift at/below 6k. That was my foolhardy logic of keeping the original bottom end together! Considering a more robust cam to move the power up a bit more which I think would be a lot more fitting for my 4.11 gears, but what on earth happened to cam prices?! ~$500 for what’s essentially an sbc cam! Inflation I know, but they seem to have practically doubled from just a few years back.

 

While I’m waiting on the machine shop, I’ve started cleaning parts that will be reused. I have an ultrasonic cleaner, did all the main caps and bolts yesterday and they’re looking like new.

The Oil Pump is a Melling M155 with 3/4” tube and has maybe 3k miles on it. As expected the pickup has bearing gunk in it (I had spot welded pickup to pump too) and the gears have witness marks of junk going through the pump. Obviously none of this will get reused, that was never the intent. Just the curiosity of taking it apart. I did put a hardened steel oil pump drive shaft that eliminates the nylon bush. That will be cleaned and reused.

Thoughts on pump? The M155 is standard volume standard pressure.

Will using a +10% vol pump really suck the pan dry? Any case for a high pressure unit? Or is standard still the way to go?

hoping to build this motor a little looser than factory tolerances.

 

Put another M155 in it... it pumps more than enough oil for whatever bearing clearance you want to run.

Will a HV pump empty the pan. No, not on a SBC which has an excellent oil drain back design... it will however bypass more oil and if you look at that pump and where the bypass exits, you'll notice that it exits right above and dumps right back ontop of the pickup..... this can cause excessive aeration of the oil in the sump.... this is why people see a drop in oil pressure as RPM rises or is held steady for a long time and think a HV pump has sucked the pan dry.....

Pressure is a measure of restriction in the oil system... there's no advantage and some disadvantages to having a bunch of oil pressure. 10psi per 1000rpm is a very good general standard to follow. Most good engines will better that by a little.

Like I said you'll be good with another M155.
Will

 

Thanks - works out, I have a new M155 in the shelf. Just needs a pickup.

 

Stoped at the machine shop yesterday to bring them all of my rotating assembly parts so they could weigh to balance… they just so happened to be cutting my crankshaft at that moment so I got to watch that happen which was pretty cool. And the crank is salvageable. I believe they had to cut 30 on the rods and 10 on the mains.

Block needs to be decked as well. And at this point I’m going to bring them the heads too to renew. I’m this far in, may as well go all the way! He said he will be able to determine if it needs an align bore.

Thinking about a bigger cam again… the rest of the motor is going to be able to handle it. Just not sure about my wallet. I’m still in cam sticker shock and how much the $ has gone up in a few years time

 

Cleaning stuff and collecting parts… block and crank should be ready for me to pick up next week.

And speaking of picking things up, oil. I’ve long used Mobil1 5w30 and will likely stick with that, but what about break in?

Would non synthetic Mobil 5w30 be a good choice? Any other considerations? Hydraulic roller so I’m figuring a no frills 5w30 should be just fine.

how much? I was planning on an initial run of 30 min, never leaving the garage. Drain + filter. Then allow a complete cool down. Then run non synthetic for 500 or so miles. I think the most extreme thing it will see in those 500 miles will be some rpm to seat the rings. Then onto my normal interval on syn.

This is 100 steps down the road and it’s only crossing my mind now because I need to go to Walmart anyway and it usually a big selection of oils at a good price.

also… Moroso makes a pre-filter screen that sandwiches between filter and adapter. Any good/bad? Snake oil? In theory seems good. I’ll mention, my oil filter adapter bypass is no longer, 3/8 pipe plug. 100% of my oil will be filtered. I know there are mixed feelings about that mod. I do run top of the line filters and my change interval is maybe 2000 miles a season.

 

There's no real break in with a roller cam. If the cylinders are honed properly, moly rings will be seated good enough from just turning it over to adjust the valves, if they don't, they were never going to seat properly and thats no BS. The factory LTx engines were filled with synthetic from GM infact all modern cars have been for nearly the past 30yrs if that tells you anything.... I personally give my engine customers this recommendation - You can run conventional oil for the startup and initial run in if you want... its more economical to do so but there's no performance advantage to it.

The important thing is to change the oil and filter after 500-1500 miles to get the contamination from the assembly lube out. A regular oil filter is more than enough filtration.... don't over complicate things.

Don't be afraid of short burst of WOT during the initial run in, I encourage it as short duration of heavy loading followed by normal driving at intervals will fully seat the rings in this initial run in period and then your ready to run it as hard as you want after.
Will

 

Great advice, thank you. I’ll probably do just that.

 

Back from the machine shop…
Bored 30 over
decked
freeze plugs
cam bearings
I had the machinist take the measurements for and over rod/main bearings
crank ground and polished

It looks like the paint on the block is all but gone after the hot tank. So I think first will be masking it off and giving it a fresh coat of black. Then I’m sure the real questions will begin during assembly. Time is my biggest challenge.

 

I'm glad you still have a machine shop nearby to do the work. Many of them near where I live have just flat out closed due to lack of skilled machinist workers.

 

I had several within about 30 min. I didn’t use them. Between spotty online reviews and their complete unwillingness to talk to me on the phone about my engine I ruled them out. I ended up about an hours drive away. But, I am very happy with them. The owner/operator spent time speaking with me in detail when I called and in person. Customer service goes a long way! Plus they were very reputable.

I left them the heads when I picked up the block. They’ll need to be flattened for certain but they will also check seats/guides and likely make everything new again.

Turns out I had both engine primer and engine black in the basement so I got 2 coats of each on the block today and that’ll be it till next weekend. It needs to cure.