What's on your bench?

[oddsaws]

Something different today…

 

[farminkarman]

Pontiac 400 ready for it’s date with the machine shop.

 

[Jusgunn3]

What’s the plan for the build? Stroker? Sleeves?

Pontiac 400 ready for it’s date with the machine shop.View attachment 470176

 

[farminkarman]

What’s the plan for the build? Stroker? Sleeves?

I’m not 100% decided yet, but most likely will bump the stroke up to 4.25” from 3.75”. The crank already had been turned 0.020 on the mains and 0.030 on the rod journals. The crank can’t be turned again. The bores look great at 4.150 (0.030” over), so should be easy to re-hone to 4.155 or 4.160”. The front main cap is missing a chunk of material, so I will have to find a new cap and have the mains line bored.

 

[farminkarman]

What originally was planned to be a simple oil pump swap (cuz everyone online said that is what my problem was gonna be), turned into a full rebuild. Doing tear down this afternoon, I found evidence of majorly shoddy work.

 

[Jusgunn3]

I’m not 100% decided yet, but most likely will bump the stroke up to 4.25” from 3.75”. The crank already had been turned 0.020 on the mains and 0.030 on the rod journals. The crank can’t be turned again. The bores look great at 4.150 (0.030” over), so should be easy to re-hone to 4.155 or 4.160”. The front main cap is missing a chunk of material, so I will have to find a new cap and have the mains line bored.

That’s going to be a runner once you get it all back together!

 

[Wilhelm]

Bread, fresh bread - and they know it, awaiting it to come flying out the shop doors all crumbled up.

 

[singinwoodwackr]

Hmm...

 

[jacktheripper]

Going out hunting tomorrow night for opener on Saturday. Just got done packing. The camper’s battery flipped on its side and was sitting for months. Battery acid all inside of the battery compartment.

 

[Partner]

Hmm...View attachment 470190

This looks like bad porting

 

[Wilhelm]

Hmm...View attachment 470190

Lightweight piston & crankcase with cleaning granulate.

It'll still run if You ad more oil into the fuel mix.

 

[Wilhelm]

Going out hunting tomorrow night for opener on Saturday. Just got done packing. The camper’s battery flipped on its side and was sitting for months. Battery acid all inside of the battery compartment.

Shouldn't the battery be strapped down somehow to prevent that from happening?

 

[Partner]

I once had a battery explode while starting it, good thing it was in a metal box

 

[Partner]

I always ask when I see a broken piston and the answer is one - excessive idling, often without a guide and chain

 

[Da dog man]

How would idling without a bar an chain cause a piston to check out?

 

[jacktheripper]

Going out hunting tomorrow night for opener on Saturday. Just got done packing. The camper’s battery flipped on its side and was sitting for months. Battery acid all inside of the battery compartment.

This shows how late it was. I thought I was on the NSP thread when I posted that lol

 

[Partner]

How would idling without a bar an chain cause a piston damege ?


I meant WOT without load. Sometimes, if the saw does not work properly, the user thinks that if he overgases it, it will be fixed

 

[Junk Meister]

Hmm...View attachment 470190

How would idling without a bar an chain cause a piston to check out?

I don't how to apply this odd thought but an old saying "Idle hands are the devils tools"
(or is that just something else that doesn't belong in my head?)
Idling saws and no work to be done (the no blade/bar or chain) will see all hell BREAK loose.
Looking at the nibbling's in the case This piston had the intake side chomped/ pacmanned. Would the intake temperature be cooler and slightly starved for oil at low rpms? Then the rebound from bottom dead center skew the intake side of skirt ever so slightly going back into the cylinder and start this demise/disintegration?
I think I have had enough coffee for the moment.

 

[Junk Meister]

Now it is
Wide
Open
Throttle
UH OH My train of thought is getting "DERAILED"

 

[singinwoodwackr]

Brad thinks it was submerged in water at wot. Hydro locked saw? There is no rust I can see, anywhere.
P&c show very little wear, no damage to anything external. The clutch was so tight I almost couldn’t crack it loose. Bearings are visually fine but crunchy. The crank seems fine. I’m thinking it went from WOT to zero in a split second.