problem getting 350 started

[SirRobyn0]

Hopefully this will help. I removed the fan so I could get closer without the air noise.

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Well that is an interesting noise and the sounds is much clearer. I will think about some and get back to you but I'm no longer thing valve to tap or lifter.

 

[SirRobyn0]

I think your going to be stuck with investigation on this one. It's not want I'd call a common noise. I could see it having to do with a valve spring, or possible fire getting past a valve, but the thing is it doesnt seem to have a misfire. I'm not asking for a third video, but how does it sound underneath? On some engines I'd almost believe that one of the plugs wires was crossed but again it does seem to misfire. I will think more on it and write more but like I said it's not what I'd call a common noise at all.

 

[bucket]

That's an exhaust valve not opening and it causes the backfire/pop up through the intake. It's an ugly sound. I've had two wiped cams and a broken rocker that made the very same unpleasant noise. I bet it makes a lot more racket when you rev it up.

 

[curse]

Unfortunately my job is sending me to Pittsburg for a week so I will have to pull the valve covers after next week. I wondered if I bent a valve or 2 or a push rod when I blew the mufflers apart.

 

[curse]

but the thing is it doesnt seem to have a misfire. I'm not asking for a third video, but how does it sound underneath?

It seems to have a slight misfire, kinda intermittent??

 

[Rusty Nail]

You cant pinpoint which cylinder with a wooden stick or what?
I think it's an even number. I pick cylinder 6

 

[SirRobyn0]

It seems to have a slight misfire, kinda intermittent??

A valve not opening would / could cause a miss. Not to step into diagnostic advise to heavy, but Bucket seems pretty sure of what the noise is so at this point, I'd pop the valve covers fire it up and see if any of the rockers aren't moving. You can do that with the engine running, but I prefer to do it with a remote starter because it's less messy and I think it's easier to see the valves working. That would be a give away of a wiped cam lobe.

 

[Rusty Nail]

Hmmm..

Wiped cam lobe...all too common today.

I HATE to think about that.

What brand of engine oil do you choose?

 

[curse]

synthetic valvoline

 

[curse]

I think it's an even number. I pick cylinder 6

More noticeable on drivers side, I pick #5

 

[Rusty Nail]

I use conventional Valvoline....so that can't be it...

#5 vs. #6 !

Ready?

Fight!

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[SirRobyn0]

Hmmm..

Wiped cam lobe...all too common today.

I HATE to think about that.

What brand of engine oil do you choose?

I could have big discussion with you on this topic. The thing is I hear a lot about wiped cam lobes, but rarely see them in the shop and we do a fair amount of work on older rigs.

I'm curious what you think of as a good engine oil, and also do you think a zinc / ZDDP/ZDTP additive helps? I was just saying on another thread how much fuel formulation has changed since the 80's and the something goes for engine oil. The main concern is that zinc levels have been lowered in engine oil. The main job of zinc is to be cushion to prevent dry start ups. At the shop we have not been pushing zinc additives for flat tappet engines, but more and more are requesting it and we are thinking of adding to the oil change package for those engine.

So @curse if it is a wiped lobe perhaps the best oil in the world won't be enough protection without enough zinc. Something to think about anyway.

 

[idahovette]

OK, so what zinc additive are you going with?

 

[SirRobyn0]

@idahovette, At the shop we have been using the hyper lube brand zinc additive. https://www.hyperlube.com/product/zinc-replacement-additive/ Mostly because that's the brand most requested, and is readily available.

 

[Rusty Nail]

If this was MY thread, I would mostly just want it to involve getting my 350 started..maybe a different spot would be better.

I dont speak for OP, it's my opinion.