[Wyteboii86]

Doing drop in pistons in my 392 currently. Got it all disassembled, and ran a 320 grit ball hone thru it to knock the glaze off. Cleaned the deck up with 320 grit sandpaper. Everything looks good but I'm wondering if I should take it to a machine shop to get a real hone and the deck and bearing tolerances checked? Engine ran fine when pulled, good oil pressure. I bought hhp drop in pistons and rods with long mains and rod bearings. Am I good to go or should I take it to a shop to get honed and checked?

 

[baabootoo]

Did you check for taper at the top of the holes? Did you check the piston to bore clearance? Why did you get new pistons? Getting new rings?

 

[Wyteboii86]

Did you check for taper at the top of the holes? Did you check the piston to bore clearance? Why did you get new pistons? Getting new rings?

I haven't checked anything except ring gaps so far. I have stock bore drop in pistons. Only 42k miles on the block. Got all new forged internals cuz I put a whipple on and wanted to rebuild before something happens.

 

[baabootoo]

Again, the taper will kill you even with new rings. Ever watch Roadkill? They cover this many, many times and go into details. I'd really doubt it's that bad at 42K, BUT that's why you need to check everything yourself. Are the new pistons designed for the boost you'll be running?

 

[Wyteboii86]

Again, the taper will kill you even with new rings. Ever watch Roadkill? They cover this many, many times and go into details. I'd really doubt it's that bad at 42K, BUT that's why you need to check everything yourself. Are the new pistons designed for the boost you'll be running?

Yeah they're low compression boost pistons from hhp.

 

[Rockster]

Doing drop in pistons in my 392 currently. Got it all disassembled, and ran a 320 grit ball hone thru it to knock the glaze off. Cleaned the deck up with 320 grit sandpaper. Everything looks good but I'm wondering if I should take it to a machine shop to get a real hone and the deck and bearing tolerances checked? Engine ran fine when pulled, good oil pressure. I bought hhp drop in pistons and rods with long mains and rod bearings. Am I good to go or should I take it to a shop to get honed and checked?

My limited experience is when I rebuilt the 318CID engine in my D200 pickup I hand honed the cylinders but I used a very coarse set (45 grit?) of stones to leave a "rough" cross hatch pattern. This to help ensure the rings "seat" ASAP.

I had a dial bore gauge and honed the barrel shape out of the cylinders. I didn't take the bores over size though.

With a previous engine I had the block bored to the next size larger piston size (0.030" over?). The block came with the proper hone finish.

The piston/ring maker might offer a bore hone finish recommendation. You should go by this. I had access to a portable Sunnen hone setup that was driven by a 1/2" drill motor. (I used this at the machine shop I worked at and borrowed it.) And I used the hone to put the right finish on the bores.

Unless you are equipped to produce the hone finish required you probably should take the block to an automotive machine shop for the proper hone finish. Hopefully the bores can be finished without taking the bores oversize while at the time ensuring the bores have the correct geometry. No taper, barrel or (less likely) hourglass shape and have the correct size to ensure proper cylinder to piston clearance.

For checking flatness of the decks I used a Snap On precision straight edge and feeler gauge. Most likely you can have the block checked at the same time it is in for cylinder finishing. The heads should be checked to though.

For bearing clearances I measured the main and rod journals for any signs of wear. They were ok. I bought new bearings and used Plastigauge to confirm the bearing clearances were within spec. You can't (or shouldn't) leave this to chance.

 

[Wyteboii86]

Again, the taper will kill you even with new rings. Ever watch Roadkill? They cover this many, many times and go into details. I'd really doubt it's that bad at 42K, BUT that's why you need to check everything yourself. Are the new pistons designed for the boost you'll be running?

Do you know any specific episodes? Trying to find it now.

 

[saagz87]

Might want to take it to the machine shop and ask to watch them verify readings for block, heads, piston rings, and a couple of bearings so your comfortable doing the rest if this is your expedition into drop in pistons. You can slap it together at 42k miles on block if the hone is descent and there is such a slim chance anything else needs to be done in all honesty. Plastigauge for bearings is a must for me personally as said above.

what ring pack did you go with, and what did ring gap measure when you first pushed them down into bore with a piston? Getting before and after measurements in multiple spots before and after hone is a ******* way to verify you didn’t take too much material off, but again that’s hard to do with a hone. If you already file fit them for the boost you plan to run that then that verification won’t apply at this point. I’m assuming you don’t have a dial bore gauge?

 

[Wyteboii86]

Might want to take it to the machine shop and ask to watch them verify readings for block, heads, piston rings, and a couple of bearings so your comfortable doing the rest if this is your expedition into drop in pistons. You can slap it together at 42k miles on block if the hone is descent and there is such a slim chance anything else needs to be done in all honesty. Plastigauge for bearings is a must for me personally as said above.

what ring pack did you go with, and what did ring gap measure when you first pushed them down into bore with a piston? Getting before and after measurements in multiple spots before and after hone is a *** way to verify you didn’t take too much material off, but again that’s hard to do with a hone. If you already file fit them for the boost you plan to run that then that verification won’t apply at this point. I’m assuming you don’t have a dial bore gauge?

They came with total seal rings. I gapped the first ring to .026, second to .028 and oil rails around .040. Initially they had no gap at all or even touched. I 3d printed a ring depth tool. I don't have a dial bore gauge. Is plastigauge really accurate. I was told bearing clearances should be .0027-.0032

 

[SickToo]

Good engine builders hone block in ck10 or the like remove taper and measure so they know exactly where they are at before ordering pistons and rings

8 round straight holes (all the same diameter) is a great place to start when trying to make good reliable power

 

[saagz87]

They came with total seal rings. I gapped the first ring to .026, second to .028 and oil rails around .040. Initially they had no gap at all or even touched. I 3d printed a ring depth tool. I don't have a dial bore gauge. Is plastigauge really accurate. I was told bearing clearances should be .0027-.0032

Gotcha. Yes plastigauge is quite accurate in my experience

Good engine builders hone block in ck10 or the like remove taper and measure so they know exactly where they are at before ordering pistons and rings

8 round straight holes (all the same diameter) is a great place to start when trying to make good reliable power

No doubt! But we are talking a drop in kit here…

 

[SickToo]

PG is not as accurate as measuring everything but it doesn’t require expensive tools

It will tell a back yard builder if whoever ground the crank or resized the rods screwed up and she is tight (save ya from disaster)

It’s not blueprinting tho

 

[SickToo]

But we are talking a drop in kit here…

Rings have best chance sealing in a round straight hole

Piston rock knocks edge off and effects longevity

You already set end gap, kinda late to consider hone or oversize. Never too late to measure and know whatcha got tho

 

[Dyno]

The new 392 blocks are very good. At the miles you have, make sure the bores are clean and put it together. It will run great.

 

[Wyteboii86]

So just to see about where the clearances are I did plastiguage and the mains are all around .0015"-.0017". I was told by hhp that I should have .0027"-.0032" unless they meant mm instead of inches? I think stock clearances are .0009"-.002"

 

[SickToo]

New bearings? Take em out n scotchbright em if yer worried about it

Doesn’t really matter. I think you will be fine…

It’s got a hydraulic roller…

Not like yer gonna spin it to 8500

Where are the rods?

 

[Wyteboii86]

New bearings? Take em out n scotchbright em if yer worried about it

Doesn’t really matter. I think you will be fine…

It’s got a hydraulic roller…

Not like yer gonna spin it to 8500

Where are the rods?

Didn't check the rods yet. What about the deck of the block and heads? I would think they're fine if I never had a head gasket issue or over heated

 

[SickToo]

Did you check them with a flat edge?

I’m not big on doing what ya did w the 320 grit but I’m anal and have ocd. Prefer to clean em up on a mill. Some gasket material works better with a smoother finish than others

I always o-ring for boosted applications. Wanna give it the best chance I can. If there is a ring within the composite gasket you will prolly be fine

At least get a flat edge if you don’t have one so you can see what’s up

 

[Wyteboii86]

The local Napa is supposed to do really good work. They told me 6-800 bucks to hone, check clearances and deck and install rotating assembly. Only problem is I gotta wait 3 the 4 weeks. But this is too overwhelming second guessing all of it.

 

[SickToo]

Yup. If ya have all the equipment it doesn’t take very long to do

I would ask them how much more it would be to check the mains. See how straight and how round the main bore is. How much crunch is there

Are you using brand new rods? I check everything but like I said I’m anal. I was a aircraft mechanic. Ya gotta check everything in that industry. Race motor same thing to me. Not like you will fall outta the sky if it breaks but engines are expensive and not making it to the stripe under power sucks