350 Main Bearing Caps Identification

[Rich1972C20]

My machinist did label the main bearing caps after he bored my 1972 350 block .030 over. There are no factory marks on caps. One does have two dimples that match one journal but I don't trust it. They are all unique in that the sides have different foot appearances (not sure of the terminology). See photos attached.

Any chance that these footings always match a certain journal location?

I did have the crank polished and I'm putting in new bearings but I don't think that matters in that I still need to put the caps back to where they were originally. I hate to spend money align honing which my machinist should\will pay for.

Any help is appreciated.

[RustyPile]

In the past, when caps got mixed up, I've been able to determine their proper position by carefully bolting them in place. The arrow points to the front.. No need to bolt all three caps in place to begin with.. Just snug the cap with 2 bolts.. Carefully inspect the hone marks.. When you have the correct cap in place, the original hone marks will all line up perfectly.. Choose one cap, pick a location and make the trial fit.. Once you find it's location, leave it in place and do the next one, it will fit in only one of two places.. The third one's location will now be obvious.

[kwmech]

Inspect the caps carefully for a number. Majority of the caps were stamped at the factory. Actually you only need to stamp 2 of them. I can almost see them myself from the pic you posted. Look closely by the NF casting

[Rich1972C20]

I saw those marks but it wasn't helpful. I'll try the honing mark suggestion tomorrow. What a drag. I kick myself in the ass not making a permanent mark and trusting the machinist. Lesson learned.

[Rich1972C20]

Checking the hone marks didn't help. Thanks anyway.

[RustyPile]

Originally Posted by Rich1972C20

Checking the hone marks didn't help. Thanks anyway.

I sent you a PM...

[Rich1972C20]

OK. I will try again probably tonight. I did use a magnifying glass and found what looks like a number 2 on one cap. What's confusing about that is its on the only cap that has two dimples stamped on it but the corresponding two dimples on the block is on the third journal. I haven't' spoke to my machinist yet.

I'll let you know what I find.

Thanks

[MS66]

Originally Posted by Rich1972C20

My machinist did label the main bearing caps after he bored my 1972 350 block .030 over. There are no factory marks on caps. One does have two dimples that match one journal but I don't trust it. They are all unique in that the sides have different foot appearances (not sure of the terminology). See photos attached.

Any chance that these footings always match a certain journal location?

I did have the crank polished and I'm putting in new bearings but I don't think that matters in that I still need to put the caps back to where they were originally. I hate to spend money align honing which my machinist should\will pay for.

Any help is appreciated.

I'm guessing you meant to say "didn't" mark your main caps.
Unless your caps have been run across a surface plate, it shouldn't be that difficult to match them up by witness markings on the caps and block. Just remember the caps do need to register snugly in the block with no slop.
If you can't seem to locate them properly, why don't you let your machinist locate them for you? It's not that difficult.
I do see factory markings on the caps, try using chalk on them to highlight the marks.
EDIT: From what I can see is; 3 2 4 the way they sit in the pic.

[dmb]

you should have talked to the machinist first. And I am using the term machinist very loosely.

[MS66]

Originally Posted by dmb

you should have talked to the machinist first. And I am using the term machinist very loosely.

Oh boy, you have him on his way now!!

[Rust_never_sleeps]

Nice of them to stamp 2 and 3 on those but not have them mean anything.
I'm guessing some other shlub ignored those when they rebuilt previously :shrug:

[MikeB]

That's a critical part of engine assembly. It's totally inexcusable for a machine shop not to stamp them with dots on the caps.

I tired a few photo editing tools to make the marks stand out, but I still couldn't read them. Good luck.

If you can get a combo that lets the crank turn easily by hand when the caps are torqued, then you're probably OK. It's been a while for me, but I want to say it should take no more than a couple lb/ft torque.

I'd probably start with the front and rear caps in place and torqued. Check for rotational resistance, and then try all three of the remaining caps in the center location. Keep the best one torqued down, and then do the same for the remaining two caps.

Worst case, have the main bores align honed by another shop.

Don't forget to check thrust.

[Rich1972C20]

Tonight I tried everything permutation of cap orientation. I took photos and zoomed in to inspect honing grooves on both sides of caps and did the finger nail test. None of this proved an "ah ha" moment I think a more experienced engine builder than myself might be able to tell but to me the differences are virtually imperceivable and possible contradictory in that one cap might feel right the best but the honing marks do line up as good as another cap.

At this point I'm calling my machinist and take one of your advices and see if he can convince me which cap goes where by bringing it too him.

As a side note for beginner builders like me, its true that even though this block was cleaned, you still need make sure its completely clean. I found a super fine wire thread and small loose bits of casting by the camshaft bearings (which I didn't notice before).

I have a feeling I'm going to end up align honing it for peace of mind. I'll let you know.

BTW, its impressive the knowledge base you guys have.

[Rust_never_sleeps]

I wasn't sure from your posts if you had seen these numbers. Please ignore if you have.

I've desaturated these areas from your original pic, so they're kindasorta in black+white.
I'm seeing a 3 on the left and a 2 in the middle.
Hope this helps

[MS66]

Originally Posted by Rust_never_sleeps

I wasn't sure from your posts if you had seen these numbers. Please ignore if you have.

I've desaturated these areas from your original pic, so they're kindasorta in black+white.
I'm seeing a 3 on the left and a 2 in the middle.
Hope this helps

Good work. That's exactly what I posted this morning. 3 2 4
Most likely wouldn't take 10 minutes to have this all sorted out with the crank spinning freely in the bearings if everything else was in spec.

[Rust_never_sleeps]

Originally Posted by MS66

Good work. That's exactly what I posted this morning. 3 2 4
Most likely wouldn't take 10 minutes to have this all sorted out with the crank spinning freely in the bearings if everything else was in spec.

LOL, Yeah, I knew you saw them, but wasn't sure Rich had, based on what I read

[MikeB]

Originally Posted by MS66

I've desaturated these areas from your original pic, so they're kindasorta in black+white.
I'm seeing a 3 on the left and a 2 in the middle.
Hope this helps

Originally Posted by Rust_never_sleeps

LOL, Yeah, I knew you saw them, but wasn't sure Rich had, based on what I read

Good detective work guys!

If the crank spins freely using the above sequence, then I don't see why line honing even needs to be considered. Because unless it's done properly, a shorter timing chain might be required. And we're talking about a shop that didn't mark the caps and left debris in the block!

The OP probably should wash out the block with soap and hot water. Or at least spray any suspect areas with solvent or brake cleaner followed by compressed air. And don't forget to wipe down the cylinder bores with something like WD40 and white paper towels until the towels remain white.

[Rich1972C20]

I did see them. The number 2 is very clear. However it's the caps that has two dimples in it to match the two dimples on the block right next to the journal. But it does seem to feel better (smoother) in the number 2 journal. Lst night the "3" stamping didn't look as convincing as it does now. And the last cap can be interpreted as a four. The stamps are all in the same place location on the caps.

With all that said I rearranged them and will bring back the block to my machinist to measure the bore diameters. I intend to hide the marks to avoid him being influenced where they go.

I thought I would include photos of what I'm working on. THe red truch is a 72 that is rotting away which is where the 350 comes from. I'm the motor in the 67. Getting burned by the one year only frame differences in the 67 from 68 through 72. Learning to do body work. Hopefully will have a rust free C-10.

I'll let you guys know how I make out and thanks again.

[Rich1972C20]

You were right Rust Never Sleeps . I brought it back and that what it was.

THanks guys

[Rust_never_sleeps]

MS66 had it nailed. I never saw the 4 at all until I had re-read his post and went looking.
Glad it all fits back together