There She Blows

[bob58o]

I'm no expert but that rod looks horrible. Piston not great either. Engine experts correct me if I'm wrong.

This is why I don’t take them apart once put together. Lol

 

[Denny]

Looks like something ran through that engine, like grit.

 

[bob58o]

Looks like something ran through that engine, like grit.

Would you recommend replacing the rod bearings?

 

[Denny]

Polish crank first with some crocus cloth and a shoe string.

 

[bob58o]

Polish crank first with some crocus cloth and a shoe string.

I was thinking I could polish the journal, get new bearing (ARC 6292), flex hone the cylinder, …

Do I need new rings? New Piston?

 

[Denny]

I would, God only knows how much grit is embedded in the piston, rings and all the other stuff. Use auto transmission fluid on a white cotton rag to make sure all is clean. Make sure all is flushed really well with hot soapy water first and then blown out really well with compressed air.

 

[bob58o]

Ok, I got some emery cloth, new rod bearings, rings, piston, some gaskets, 240 grit hone…

 

[BrownStainRacing]

I was thinking I could polish the journal, get new bearing (ARC 6292), flex hone the cylinder, …

Do I need new rings? New Piston?

Was this engine ran with an aftermarket air filter that comes with those stage 1 kits???

We have alot of gravel roads and red clay dirt around here, very dusty. I see the same piston, ring end gaps, cylinders, cranks, and rod bearings jus like yours, only after a few hrs of running those filters.

I think I had 11 bad blocks come in last year that was way too far gone because of those filters.

That piston and those compression ring end gaps, will cause alot of blow by and excessive crankcase pressures. You will be blowing gaskets and seals, especially with that blower.

IMHO, .005" ring end gap difference in the cylinder is too much for any decent mild build.
In a tiller, log splitter, or any other steady low rpm use would be a better place for it.

Jus my opinion,

 

[bob58o]

Was this engine ran with an aftermarket air filter that comes with those stage 1 kits???

We have alot of gravel roads and red clay dirt around here, very dusty. I see the same piston, ring end gaps, cylinders, cranks, and rod bearings jus like yours, only after a few hrs of running those filters.

I think I had 11 bad blocks come in last year that was way too far gone because of those filters.

That piston and those compression ring end gaps, will cause alot of blow by and excessive crankcase pressures. You will be blowing gaskets and seals, especially with that blower.

IMHO, .005" ring end gap difference in the cylinder is too much for any decent mild build.
In a tiller, log splitter, or any other steady low rpm use would be a better place for it.

Jus my opinion,

Maybe I wrote it wrong.

It was an estimated 0.0005” difference in ring gap between the top and bottom of the cylinder. Not 0.005”.

0.0175” top to 0.0170”.

So I think that means the bore is is less than 0.0002” wider at the top than the bottom.

The engine was only ran on a stand in my parking lot.

My air filter is a metal screen air filter from treatland. I quote here…

“

so nice screen air filter for limitless flow. fits on OKO 21mm, 24mm, 28mm and 30mm carburetors. OD of the chromey part = 65mm OD at the largest part = 75mm total length = 37mm ID = 48mm "OKO - new yuppie fashion trend"

With a dry charge pre-filter like this zipped tied tight.

 

[BrownStainRacing]

Maybe I wrote it wrong.

It was an estimated 0.0005” difference in ring gap between the top and bottom of the cylinder. Not 0.005”.

0.0175” top to 0.0170”.

So I think that means the bore is is less than 0.0002” wider at the top than the bottom.

The engine was only ran on a stand in my parking lot.

My air filter is a metal screen air filter from treatland. I quote here…

“

so nice screen air filter for limitless flow. fits on OKO 21mm, 24mm, 28mm and 30mm carburetors. OD of the chromey part = 65mm OD at the largest part = 75mm total length = 37mm ID = 48mm "OKO - new yuppie fashion trend"

With a dry charge pre-filter like this zipped tied tight.

OK, I gotcha. Yea, it's a good block to rebuild.

Pick up some magnetic oil drain plugs. They really help when breaking an engine in.

I've posted pics somewhere here about the magnetic oil drain plugs.

 

[bob58o]

Pick up some magnetic oil drain plugs. They really help when breaking an engine in.

I've posted pics somewhere here about the magnetic oil drain plugs.

should I get some file to fit rings? If so, what gap do you think I should run with ~10psi boost and hot intake air temps?

 

[BrownStainRacing]

should I get some file to fit rings? If so, what gap do you think I should run with ~10psi boost and hot intake air temps?

I would go by that ring end gap chart you had for boosted engines.

I usally have bigger problems with the piston to cylinder clearance after a hone. It's some thing that's gonna need checked. It might take 1 or 3 or 4 pistons to find the right fit.

That's me, I'm picky about the piston to cylinder and end gaps. I like to seal that cylinder the best I can.

I start a fresh build with no less then 3 pistons, and 3 ring sets. Usually from different suppliers.

You will only find "file to fit" top rings. They oversized. 005"- .010".

Again, it's gonna be 1 of those things that takes time and measurements.

You MIGHT NOT need file to fit rings,

 

[65ShelbyClone]

Some of this comes down to what your expectations are an how unacceptable a possible engine failure would be. You could put it back together and it would probably work alright for a while. All the parts that show abnormal wear will continue to wear at an abnormal rate and it may lead to some bigger failure later, but there will be minimal investment in the short term. At the end of the day it still has a cast piston as well.

I was only half joking when I said send it with a little castor oil in the case.

 

[bob58o]

I would go by that ring end gap chart you had for boosted engines.

I usally have bigger problems with the piston to cylinder clearance after a hone. It's some thing that's gonna need checked. It might take 1 or 3 or 4 pistons to find the right fit.

That's me, I'm picky about the piston to cylinder and end gaps. I like to seal that cylinder the best I can.

I start a fresh build with no less then 3 pistons, and 3 ring sets. Usually from different suppliers.

You will only find "file to fit" top rings. They oversized. 005"- .010".

Again, it's gonna be 1 of those things that takes time and measurements.

You MIGHT NOT need file to fit rings,

I looked quickly and saw that I could only find file fit for the top ring like you say.

0.0055” per inch of bore =
2.75 x 0.0055
would make the top ring gap about 0.015”

I’ll see what the new piston / ring gap combo is when it gets deliver.

Im not sure how much material the 240 grit flex hone will remove. The walls “feel” smooth to my finger.

 

[BrownStainRacing]

I looked quickly and saw that I could only find file fit for the top ring like you say.

0.0055” per inch of bore =
2.75 x 0.0055
would make the top ring gap about 0.015”

I’ll see what the new piston / ring gap combo is when it gets deliver.

Im not sure how much material the 240 grit flex hone will remove. The walls “feel” smooth to my finger.

Yea, I think that would be best. You might get lucky and the "new" be perfect.......don't count on it, but you never know til you check.

The 240 will be fine. Jus clean it up and put cross hatch back in.
Make sure its SUPER clean before final assembly.

Check the valves and seats, while you have it apart.

I jus done a hemi head a couple weeks ago that was leaking on both intake and exhaust. The engine started and ran fine, before I pulled it off.
I had to lap the intake 5 times til it finally stopped leaking.
I was gonna throw it out the freaking door, but the hemi headed hero (owner) jus had to have a hemi head.

 

[Denny]

And that’s why the inside of your engine looks like it does. Put a real paper element back on there! Maybe I wrote it wrong.

It was an estimated 0.0005” difference in ring gap between the top and bottom of the cylinder. Not 0.005”.

0.0175” top to 0.0170”.

So I think that means the bore is is less than 0.0002” wider at the top than the bottom.

The engine was only ran on a stand in my parking lot.

My air filter is a metal screen air filter from treatland. I quote here…

“

so nice screen air filter for limitless flow. fits on OKO 21mm, 24mm, 28mm and 30mm carburetors. OD of the chromey part = 65mm OD at the largest part = 75mm total length = 37mm ID = 48mm "OKO - new yuppie fashion trend"

With a dry charge pre-filter like this zipped tied tight.

 

[bob58o]

Ok. Here’s a chance for everyone to post your favorite filter.

The OD of the carb air horn is 48mm but I think I can stretch 1.75” filter on there. I think people like UNI filters, correct?

 

[65ShelbyClone]

UNI are among the best oiled foam filters available for offroad motorcycles. I have a UNI in each of mine.

 

[bob58o]

Never saw lash cap marks like that, but never used a roller tip rocker arm.
One was a standard Hemi head rocker arm, other was 1.2 ratio roller tip. I didn’t pay attention taking them off. I’m guessing the one with circles is the roller top one.

 

[bob58o]

Valves and valve seats.