Tuesday question: marine exhaust manifold.

[arse_sidewards]

I'm not going to be using this engine far enough outside its OEM performance envelope for there to be a need for anything beyond a stock bottom end.

If I did anything it would be a welded aluminum insert but I'd need to re-bore and deck after doing that and this is a quick-n-dirty rebuild so that's not happening.

 

[Lbhsbz]

gonna concrete the block deck?

Heard of guys using devcon pourable aluminum epoxy to make open deck blocks a little more stiffer, you set the block down on wax paper upside down and then try and get it squirted in there somewhat evenly
drill some holes for water to pass through and you're golden

You can pack the water jacket with salt to about 1/2" below the deck and then pour epoxy...drill a bunch of holes and circulate water to get it out. I've done the same with those corn-starch based foam packing peanuts...they dissolve easier.

 

[[486]]

You can pack the water jacket with salt to about 1/2" below the deck and then pour epoxy...drill a bunch of holes and circulate water to get it out. I've done the same with those corn-starch based foam packing peanuts...they dissolve easier.

nice, that's a good one

 

[arse_sidewards]

Remember when I said:

I still have a ton of work to do making the transmission I want to use work

Well the crank doesn't have a hole for a pilot bearing.

And it uses this flywheel that's basically a Ford 157 tooth car flywheel but with this weird bore in the center for locating a marine coupling.

So naturally I decided to cut the center out of a GM flywheel that holds a pilot bearing and cut the center out of it.

I basically just roughed it by eye. The point was to have something small enough that it was easier to handle than a flywheel. The blocks I wanted to use for proper work holding were nowhere to be found so I stopped here for tonight.

I still need to clean out the flywheel bore, turn the pilot bearing holder down to appropriate height and then spend a bunch of time measuring a normal SBF crankshaft to figure out what depth I need to set the pilot bearing relative to the crank face which will determine how much gets cut off the backside of the spacer part.

just give it the "feel" with the snap gauge
measure once and then feel around with it to get an idea of the out of round and taper

because face it you aren't really gonna do anything to it anyways even if it is lumpy and shit

I wound up getting obscenely drunk and recording a consistent 4.361 for everywhere except the top inch or so of every cylinder where it was borderline 4.362. This includes the pitted cylinder. Obviously the pits were deeper.

I'll re-measure. Eventually.

 

[arse_sidewards]

Close enough for a pilot bearing?

This indicator is in .01mm

It'll probably pick up some from less than perfect machining of the OD but we'll cross that bridge when we get to it.

Edit: Fucking video compression. It's bouncing between 6 and 10 on the scale.

 

[[486]]

you expect too many concrete answers to subjective questions

so .01mm is 4 tenths
6-10 would be a swing of .04mm so that'd be... .0016"
math is hard

seems okay but you could do better if you just did better :fo2:

 

[guy in Idaho]

At the rate the OP is going with the engine rebuild......

DeSantis will be on his 2nd term as president when it's done.

 

[arse_sidewards]

you expect too many concrete answers to subjective questions

so .01mm is 4 tenths
6-10 would be a swing of .04mm so that'd be... .0016"
math is hard

seems okay but you could do better if you just did better :fo2:

I'm not expecting an answer. I'm expecting people to tell me they fully sent something that was way worse and tell me how it turned out.

I too can do math.

 

[ExWrench]

I'm not expecting an answer. I'm expecting people to tell me they fully sent something that was way worse and tell me how it turned out.

Shit's kosher, fuk'nrunnit

My buddy's gardener's baby-mama's goldfish's hairdresser's cousin ran a pilot bearing with 5 thou of runout and got 300k miles out of it.

PSA: random internet feedback may be unreliable

 

[arse_sidewards]

At the rate the OP is going with the engine rebuild......

DeSantis will be on his 2nd term as president when it's done. /https://data.irate4x4.com/assets/smilies/laughing2.gif

Shit runs on Sceep time around here.

Shit's kosher, fuk'nrunnit

My buddy's gardener's baby-mama's goldfish's hairdresser's cousin ran a pilot bearing with 5 thou of runout and got 300k miles out of it.

PSA: random internet feedback may be unreliable

Yeah that's why I didn't want to just come out and say it.

 

[D Nelly]

I'm not expecting an answer. I'm expecting people to tell me they fully sent something that was way worse and tell me how it turned out.

I too can do math.

Those Pakistani guys on YouTube would mic it with a tape measure. You'll be fine

 

[Lbhsbz]

I'm not expecting an answer. I'm expecting people to tell me they fully sent something that was way worse and tell me how it turned out.

I too can do math.

Back in my day we had pilot bushings...which when worn had way more slop than that.

Send it, since you're too lazy to do better....and since it's a Ford, it'll likely blow up for some other reason anyway.


Maybe if you'd use a lathe for round shit, you'd do better.

 

[arse_sidewards]

OD came out absolutely dead nuts on, within 6.500"+0.01mm/-0.0 all the way around (yes I'm mixing units, deal with it). It's a tight fit. IDK why because the hole in the flywheel mics at 6.503.

Here it is sitting in the flywheel. Height still needs to be knocked down so it sits lower but I need to make progress on other parts of the build first.

Maybe if you'd use a lathe for round shit, you'd do better.

I wish it were that easy. My 100yo lathe has nowhere near the accuracy this rotary table sitting on a clapped out Bridgeport does so rotary table it is.

 

[arse_sidewards]

Oh and I freed up stuck piston rings on my stove because I'm not whipped like some of you.

 

[arse_sidewards]

Before....

My sanding device. Yes that's a surface plate glued to a trowel.

Oh and whoever says that you should wet sand this stuff is full of shit. Worked great dry. Very lght oil cut progress by a ton because the paper just filled up and stayed full whereas it was falling out before.

Cleaning the surface plate and waiting for the adhesive on the next paper to dry takes the longer than each stage of sanding. Oh and the surface was comically fucked, like perimeter of deck ~1thou higher than bores and bores and a thou of random variation across any given 6" or so. I used a 0.02mm feeler gauge and once it was clear how fucked it was I stopped taking serious measurements.

Edit: 220 was too fine to start. Took three sheets to get ready for the next step. Should have started with 100ish grit.

 

[arse_sidewards]

Got it pretty flat. The deck is perfectly flat left to right and banana shaped fore to aft. The middle is lower. If I span the middle two cylinders with a surface plate there's a more than .03mm but less than .04mm gap in the middle.

I'm thinking this is theoretically fine to run since it's less than a thou per hole (and a big hole at that) but I'm worried that as I continue to work my way up through the finer grits for appropriate surface finish it will exacerbate the bananna shape since clearly it wants to take that shape.

 

[Dethmachinefab]

Got it pretty flat. The deck is perfectly flat left to right and banana shaped fore to aft. The middle is lower. If I span the middle two cylinders with a surface plate there's a more than .03mm but less than .04mm gap in the middle.

I'm thinking this is theoretically fine to run since it's less than a thou per hole (and a big hole at that) but I'm worried that as I continue to work my way up through the finer grits for appropriate surface finish it will exacerbate the bananna shape since clearly it wants to take that shape.

Why not work the high ends more and straighten it out?

 

[Lbhsbz]

Machine shop will deck that block for less than $100....why are you wasting your time?

Surprised you didn't make an R8 adapter out of an old hub to mount a brake rotor in the bridgeport with sandpaper glued to it to do this on the mill. If you're worried about the table rocking...just lock the table down and slide the block along the table

Edit: or use the flywheel. You'd be the first one to deck an engine with it's own flywheel

 

[arse_sidewards]

Machine shop will deck that block for less than $100....why are you wasting your time?

Surprised you didn't make an R8 adapter out of an old hub to mount a brake rotor in the bridgeport with sandpaper glued to it to do this on the mill. If you're worried about the table rocking...just lock the table down and slide the block along the table

Edit: or use the flywheel. You'd be the first one to deck an engine with it's own flywheel

Those are 2004 prices grandpa. $200 and a 2wk wait would be more like it. I'm $20 into sanding supplies.

Most mills are simply not going to get the surface finish required for an MLS gasket so I'd be sanding regardless.

Why not work the high ends more and straighten it out?

Yeah that's my plan. I was leaving it kind of open ended in case anyone had anything productive to say.

 

[Lbhsbz]

Those are 2004 prices grandpa. $200 and a 2wk wait would be more like it. I'm $20 into sanding supplies.

Most mills are simply not going to get the surface finish required for an MLS gasket so I'd be sanding regardless.


Yeah that's my plan. I was leaving it kind of open ended in case anyone had anything productive to say.

It won't get the finish, but it will get the deck straight...then sand it to get the finish...or use a composite gasket. MLS gaskets don't like much variation from dead straight.

Do you have have granite countertops in the kitchen?....those work as a bigger surface plate than you've got now. lol.

 

[arse_sidewards]

It won't get the finish, but it will get the deck straight...then sand it to get the finish...or use a composite gasket. MLS gaskets don't like much variation from dead straight.

I'm out two thou. I can sand that. Will just take me an hour or so. And I think the experience is worth a lot (this is my first time doing an object where the sanding plate is substantially smaller than the surface).

Do you have have granite countertops in the kitchen?....those work as a bigger surface plate than you've got now. lol.

Best I can do is beat to shit formica.

Next time I'm at the sawmill I'll put my .001" over 24" straight edge on his countertop and see what I get. Based on how much force it takes to bow my 12" long 1" thick plate by a thou I'm not expecting much.

 

[Lbhsbz]

I'm out two thou. I can sand that. Will just take me an hour or so. And I think the experience is worth a lot (this is my first time doing an object where the sanding plate is substantially smaller than the surface).


Best I can do is beat to shit formica.

Next time I'm at the sawmill I'll put my .001" over 24" straight edge on his countertop and see what I get. Based on how much force it takes to bow my 12" long 1" thick plate by a thou I'm not expecting much.

Just throw the head on there with some lapping compound between the deck and the had and slide back and forth some....GTG.

Edit...actually not a bad idea, but blue up the block, head back and forth, remove material from shiny spots...just like hand scraping ways on a lathe. lol.

 

[arse_sidewards]

Just throw the head on there with some lapping compound between the deck and the had and slide back and forth some....GTG.

Bolt a sawzall blade to the rocker pedestals

Edit...actually not a bad idea, but blue up the block, head back and forth, remove material from shiny spots...just like hand scraping ways on a lathe. lol.

I was actually planning on doing this since I already have to sand the head for the MLS gasket.

I was gonna use sharpie because I have a ton of sharpies and no marking compound.

 

[arse_sidewards]

Got the block done. Under 0.02mm everywhere. Head needed a fair bit of work to meet the same standard. Both the block and the head were cupped low in the middle and high on the ends.

Next steps are to step up to finer grits for the surface finish and fit the parts together with "marking compound". Would be nice to get the cumulative warpage down to below a thou but I might just wind up sending it as is depending on how the next sanding steps go.

Head sanding "fixture"

This gap is less than .02mm with a flashlight behind it.

 

[arse_sidewards]

100 grit:

 

[arse_sidewards]

220 grit:

Wound up having to spend a lot of time on 220 to get below those milling marks while keeping under a thou of flatness.

 

[arse_sidewards]

400 grit

 

[arse_sidewards]

600 grit

You can kind of see it on the last pic but this is starting to be somewhat reflective.

Not sure how I feel about those marks from stray abrasive earlier in the process. I guess we're gonna find out how well the sealant works.

 

[[486]]

you've been wasting your time since before the 100 grit picture
srs, it don't gotta be shiny, just reasonably flat
get you one of them fel-pro permatorque MLS gaskets they're making for 460s nowadays

 

[ExWrench]

You're gonna' blow through a hunner't bucks of abrasive & $200 of elbow grease to avoid having that mu'fugger decked