Fred's 2375 Rebuild Thread Options

[technicalninja]

If/when you get around to ceracoating things, as technicalninja says, things need to be clean. And even new parts need to get a good "grip" on the parts. For example, mask off the piston (except for the crown) and hit it with a media (like aluminum oxide in a smaller grit). Then use a small spray gun or maybe an airbrush (use what you have) to apply the coating before you bake it.

About that lower oil scraper ring that is in the piston pin area. My above post has a photo of how it's pinned to prevent it from rotating into the piston pin area. However, maybe someone else knows if a gapless/total seal type ring can be used instead of the pin? Maybe give Keith Black a call about what to use in that lower ring groove?

(IMG:style_emoticons/default/sunglasses.gif) Sounds like "a clean" like what's needed for electroplating. I've done that. I spent 95% of my time cleaning and 5% actually plating.

Yep, clean, bake, clean again, bake and so on. Pretty quickly the "cleaning" is using acetone and doesn't look like it's doing anything. The baking "outgasses" the aluminum.
Most cylinder heads you're screwed on as they are not new, and they take a BUNCH of cleaning. Brand new stuff or ferrous is far easier to get clean.

Lots of videos on YouTube. "Air dry no bake" stuff is available. I don't fully trust it yet.

You probably want that oven "separate" from your house.

It will STINK and your wife will go Ballistic!

That 1200 sq ft shop would be ideal...
(IMG:style_emoticons/default/ninja.gif)

[VaccaRabite]

I've got some opinions here.

Remember that this is an aircooled engine, and compression = heat.
9.7:1 - 10:1 is going to be REALLY hard to keep cool, even with coatings. This is water cooled compression land, and that's a totally different ballgame. To run that kind of compression, you are going to need to spend money for the Nikkis pistons and cylinders, ARP studs, etc. At that point, you will be using only the case, crank and rods and pretty much replacing everything else including your heads.

KB pistons are good pistons. And you can absolutely build an engine using them and rehoning your cast iron cylinders that will easily make 150+ hp, and run cool doing it. But you are going to be looking for compression in the 8.6:1 - 9:1 range to do that (and 9:1 is going to be pushing it). COATING WILL HELP! Ceramic is damn near magic, and will go a long way to push heat out of your heads and into your exhaust. And the coating itself will give you a slight compression bump.

No matter what you build, you are going to require aux oil cooling to keep oil temps in line and protecting your bearings. With my 2258 I'm learning that the passive extra oil cooling isn't enough and will be adding fan packs to my aux cooler. I'm going to caveat this saying that I believe head temps are mor important then oil temps, and I'm comfortable driving with 250* oil temps in an air cooled engine. I'm not comfortable driving with 375* head temps. On very hot humid days and 4+ hour drives my oil temps were creeping towards where I was uncomfortable (260+) with only passive aux cooling, though my heads were fine.

Cams - I'd look at the LN9520 which is the cam that Jake designed for stroker engines running carbs or modern EFI. I'd note here that they recommend a 9.5:1 CR for this cam - which they get safely through use of Nikkies P&C, purpose built heads, ARP studs etc. The 9520 (IIRC - its been a while) was based on the 86 cam.
The 9530 is the web494 with extra exhaust duration. I have a lot of experience with this cam (and the 494 it was derived from) - and its a gem IMO. It performs WELL even at the more moderate compression required by steel P&C sets.

My advice (for a street/touring car) is ALWAYS to build an engine that favors drivability over peak HP. A wide powerband and a cool running engine are going to be more pleasurable in the long run then a peaky hot running motor that makes 15 more HP.

Zach

[friethmiller]

I've got some opinions here.

...

Zach

Zach, thanks for your input! I appreciate you insights. I'm not new to engine building but I'm not completely up-to-speed on this air-cooled stuff, yet. Strokers are another business, for sure. I've got a W-block in my shed that I'd like to get crazy with... but that's for another day (IMG:style_emoticons/default/biggrin.gif). For this engine, I'd like to reuse as much as I can and keep this motor a bit more on the street-able side. Adding an external oil cooler, coating heads/cylinders, picking out/purchasing a better cam is doable. Putting down thousands of $$$ for nickies/LN heads isn't going to happen. Certainly not while I've got an LE under construction in the backyard (IMG:style_emoticons/default/smile.gif).

Fred

[technicalninja]

I've got some opinions here.

Remember that this is an aircooled engine, and compression = heat.
9.7:1 - 10:1 is going to be REALLY hard to keep cool, even with coatings. This is water cooled compression land, and that's a totally different ballgame. To run that kind of compression, you are going to need to spend money for the Nikkis pistons and cylinders, ARP studs, etc. At that point, you will be using only the case, crank and rods and pretty much replacing everything else including your heads.

KB pistons are good pistons. And you can absolutely build an engine using them and rehoning your cast iron cylinders that will easily make 150+ hp, and run cool doing it. But you are going to be looking for compression in the 8.6:1 - 9:1 range to do that (and 9:1 is going to be pushing it). COATING WILL HELP! Ceramic is damn near magic, and will go a long way to push heat out of your heads and into your exhaust. And the coating itself will give you a slight compression bump.

No matter what you build, you are going to require aux oil cooling to keep oil temps in line and protecting your bearings. With my 2258 I'm learning that the passive extra oil cooling isn't enough and will be adding fan packs to my aux cooler. I'm going to caveat this saying that I believe head temps are mor important then oil temps, and I'm comfortable driving with 250* oil temps in an air cooled engine. I'm not comfortable driving with 375* head temps. On very hot humid days and 4+ hour drives my oil temps were creeping towards where I was uncomfortable (260+) with only passive aux cooling, though my heads were fine.

Cams - I'd look at the LN9520 which is the cam that Jake designed for stroker engines running carbs or modern EFI. I'd note here that they recommend a 9.5:1 CR for this cam - which they get safely through use of Nikkies P&C, purpose built heads, ARP studs etc. The 9520 (IIRC - its been a while) was based on the 86 cam.
The 9530 is the web494 with extra exhaust duration. I have a lot of experience with this cam (and the 494 it was derived from) - and its a gem IMO. It performs WELL even at the more moderate compression required by steel P&C sets.

My advice (for a street/touring car) is ALWAYS to build an engine that favors drivability over peak HP. A wide powerband and a cool running engine are going to be more pleasurable in the long run then a peaky hot running motor that makes 15 more HP.

Zach

(IMG:style_emoticons/default/agree.gif) He's right!

One of the things that is nice about this set up is the ability to change comp ratio with minor CC changes.
Add JE pistons with 3cc eyebrows and at .045 quench adds 4 cc to the clearance volume and you hit 9.22/1...
At this point I'd chose the smaller of the two cam profiles I mentioned.
This is SAFER to run but will make less HP.

I'd take a REAL HARD look at the LN stuff here, most likely "Bite the bullet and go LN on cam stuff.


I believe three things could allow additional compression to be added.
Digital FI. Ceramic coatings. Piston squirters.

On carbs and 123 dist 9.2 would be the better choice.

On big thing that I didn't mention is the failure progression on a cast hyper piston.
It's made out of 12.5-50% silica or GLASS! Works KICK ASS right up to the point it fails. This stuff CRACKS and SHATTERS.
Like a baby hand grenade!
Piston can DISSAPEAR and leave the rod swinging!

Forged stuff stays together so much better!

[cgnj]

Falcor75 2270 made 158 to the wheels with 10:1, 86b/86c, FI and heat exchangers.
https://www.youtube.com/shorts/QGGdYYHBmTo

[friethmiller]

Falcor75 2270 made 158 to the wheels with 10:1, 86b/86c, FI and heat exchangers.
https://www.youtube.com/shorts/QGGdYYHBmTo

That things sounds like a beast! (IMG:style_emoticons/default/aktion035.gif)

[friethmiller]

Ok, Cylinder test via antifreeze titration says 60cc. I'll get the engine/parts put together to test the cylinder stroke this evening.

[friethmiller]

@technicalninja - Initial look at deck height here.

#1 Cylinder at TDC without any shims:



#1 Cylinder at TDC with the two shim stack (installed by FAT). This gap is north of .085.

[friethmiller]

BTW. I’ll put the head stud back and tighten it down tomorrow. I’ve got some cut pvc pipes I ‘ve used before. I’ll get some better measurements too.

[technicalninja]

Normal quench, .040"thick,96mm bore is 7.2 ccs
.085" is close to 15 ccs
60+15+1 = 76

Swept of 593.5
Clearance 76.0
7.81
+ 1
Comp Ra 8.81

And ZERO quench at all.

Add bad cam choice.

There you go...
$$$$ and low power

You have pistons at reasonable heights for a build. Keeping the KBs might be possible.
I don't believe your heads have been fly cut. (valves are "deepest" now).
Both of these are good!

Next for me would be piston to bore measurements. Those KBs can be run tight.
I'd run loose in their suggested range. Just guessing I'd say "around 2 thou"

I'd take the valves out of the heads, clean them up, and hand lap the valves.

One of the things I e-mailed EMW was compression height of those. I have it somewhere. This is basically height from pin centerline to top of piston.
I need that and same info on the JEs too.

I sort of expect by the time quench is right and the proper (larger) profile cam is selected you are going to NEED the valve eyebrows in the piston tops.
You've GOT all of the BIG, big stroke, big valves, big compression.

I'd also try to get down to a single shim at the base.
I don't like stacking those.


Did FAT supply those pistons?

[friethmiller]

Did FAT supply those pistons?

Yes, crank, cam, pistons, rod, etc

[technicalninja]

I don't remember what gauges you had...

Minimum for your engine is

Oil pressure and temperature. Verified accurate with mechanical.

CHT an accurate one. I purchased a 4-channel display as I thought I was going this way.
Most good displays can run EGT sensors as well which might be useful.

WB02 easy to read one.
That exhaust system gives you a nice single tube before the muffler to mount one.

Tach.

I wouldn't run it without those.
I'd start it but no load without the above.

Hard to believe they missed the oil control ring mod.
That's "baby" steps...

[Jack Standz]

VaccaRabite made several good points about the CR. Kinda forgot that you were running cast iron cylinders not nickies. Jake Raby said he likes his larger motors in the 2.7 liter range at 9.6 CR. Or something like that.

Well, he's using several "tricks" to keep those motors alive besides the nickies, like ceramic coatings, etc. Some we know about and there's probably some we don't.

So, use caution and take VaccaRabite's comments into account. If you keep the cast iron cylinders, you'll probably need to back off on the CR. But, you'll still want a tight deck height too. So, the combination of all the factors is the game we all play. Adding an external oil cooler is a good idea.

[friethmiller]

Thanks guys! My head is starting to spin here. Trying to figure out the best course of action.

Option #1: Target 9.2 CR and get JE pistons
Concern: CR is still too high. How can we lower it? Deck Height at .045?

Option #2: Target 9.5+ and get Nickies
Concern: Not made of money!!

Option #3: Get a different sized crank?
Concern: Cost as much as, or more than, JE pistons.

Thoughts?

[technicalninja]

I'd go option 1.

JE does offer coatings done by them.

Maybe biral jugs, look at chemical coatings for jugs. Some are supposed to increase cooling ability. Not sure how much I trust that. All Raby's stuff had all of the coatings!

9.2-1

Add ceramic coatings on heads/valves

9:5-1

Add digital FI
9.7-1

Add squirters

10-1

Add Nickies 10+/1

I want the old pistons and jugs you are removing if you don't re-use them.

I lean heavier towards 10-1 than Vacca does.

At the 10-1 level I'd probably be on "Heavy Fuel"...
100LL av-gas or E/85.

I wouldn't expect this to last forever. I would expect at least 30K...

And the deck height at .045 is BECAUSE they're forged, have a lot more side clearance, and can wiggle MORE in the bore. You NEED more deck clearance on forged.

We could cheat that height around (little bit) to give lower compression if we wanted.

[technicalninja]

I'd want the cam and its stuff to map out valve clearance to pistons.

If you get flustered (head spinning) take a break!

Make logical choices. Go weld on the other car, clear your head.

I believe Nickies are NOT a requirement for the level of engine you have.
I do believe you're pushing steel-based jugs to their upper limit.

I'd love to be able to build that on the KBs but think you will have clearance trouble.

Did you verify total stroke?

Need to compare CD on both the KBs and JEs.

This might alter choices.

[friethmiller]

Did you verify total stroke?

Need to compare CD on both the KBs and JEs.

This might alter choices.

Cool (IMG:style_emoticons/default/sunglasses.gif) How exactly do I verify stroke? Am I just checking piston travel in the bore for 82mm of stroke? I thought I saw a diagram of the CD for the KBs yesterday online. I'll see if I can find it.

[technicalninja]

Yep, how far down +/- deck height.

Dial caliper works fine. Don't have to get fancy here.

I could get this reading with a ruler!


The KBs and the JEs will have significantly different P-W clearance.

You would have to machine .002" bigger or more for the forged pistons.

I'm not sure of the limit of honing VS boring a jug.
Honing can only take so much...
Boring (and then honing) is more expensive.

[technicalninja]

At this "level" of engine I'd expect shimmed rocker arms (no springs) and elephant feet on the adjusters.

What's you got?

[friethmiller]

At this "level" of engine I'd expect shimmed rocker arms (no springs) and elephant feet on the adjusters.

What's you got?

(IMG:style_emoticons/default/ninja.gif)

I'm still trying to find 96mm JE pistons with eyebrows! Their website sucks for finding anything. I put in Porsche and I go down a 911-style rabbit hole (IMG:style_emoticons/default/headbang.gif) I do see the custom coatings you referenced.

I have rockers from a 1.7L engine. I'm assuming they're the elephant feet adjusters. I already have the spacers for the rocker assemblies and I recently purchased extra shims so I can make adjustments as needed.

I'm going to verify stoke today and then get ready to send this crankcase out to get serviced. Don't know where yet.