SOLVED - New engine with DOD delete and Cam Motion cam - valvetrain noise normal?

[iamdub]

... your 'sewing machine' comment is almost dead-on to how it sounds. If that's normal, I am fine with it.

LSs are known to have the sewing machine sound, but it's usually just on larger and/or aggressive cam profiles. I wouldn't consider yours large or aggressive.

Would they have put in some sort of break-in or lower viscosity oil? He did tell me to change the oil at 500 miles.

Possibly. A short cycle oil change after a rebuild is necessary to get the break-in metals out.

According to the work order, the block was 'line-honed, .020 in.' block and heads milling, factory stock head gasket. Nothing about pushrod length, though. The builder seemed very familiar with DOD deletes but did say he had never installed a Cam Motion camshaft before. I hope that is not a red flag.

So, the deck AND the heads had .020" taken off? I can't speak for Cam Motion, but it's common for larger aftermarket cams to have a smaller base circle on the lobe, often .050". This means you'd need a .025" longer rod (half of that .050" diameter). Stock is 7.380", so you'd need a 7.405". Aftermarket rods are commonly available in .025" increments, so you'd use 7.400". BUT, if the deck and head both had .020" shaved, then you'd need to subtract .040" from the push rod length, yielding a 7.360". I'd go with 7.350" or 7.375". LS lifters have a wide acceptable preload range.

You really do need to know your cam's and engine's specs. I have a hard time believing they took .020" off the deck. Unless they used shorter rods or pistons. I can see .020" taken off the heads. That would put you back at 7.380" push rods, meaning stock length.

 

[randeez]

Doesn't have much to do with the type of cam, unless it's ground on a smaller base circle or some weird shit but cammotion is using new blanks so no reason to.
like @iamdub said above most dod kits will come with 7.400s or reuse stock...but it should be checked or verified during installation. There's a pretty narrow window. You don't necessarily "set" the valve lash you get the correct push rods that give you .050 past zero lash when the rocker arm bolts torque gets to 28ftlbs iirc, which corresponds to 1.25-1.5 turns past zero lash.

Also yes, the extra noise could just be from the increase spring/seat pressure compared to the stockers

 

[Geotrash]

Greetings everyone!

My #6 lifter collapsed (see this thread), so I went ahead with a full rebuild: refreshed aluminum short block, DOD delete kit from Texas Speed, a Cam Motion Stage 2 truck cam with their beehive valve springs, and a Blackbear tune to make it all run right. Now that it is back together, I swear I can hear the entire valvetrain spinning, chain and everything. It sounds a little like a modern diesel or maybe like it is low on oil (oil level is fine, though). The engine is very 'staccato' now, if that makes any sense. Almost like I can feel every valve event and rotation of the cam. The valvetrain noise very pronounced when the engine is cold and lessens a bit when it warms up. The engine builder asked me to drive 500 miles, then change the oil and see if the noise is still there.

The Cam Motion camshaft I chose has a 115 LSA with .553 of lift, so it should feel just like a stock engine, right? Everything is actually perfect, save for the noise. Tons of low end power and pulls strong in the midrange. It just sounds odd and sort of drives/runs funny. For those of you that have an aftermarket cam, do you have any kind of valvetrain noise or experience any of the issues I mentioned here?

I have that same cam and it’s quiet. Standard pushrod length also. I suspect that if the heads were milled, your lifter preload is off and you’ll need to make adjustments to pushrod length. More when I have more time…

 

[Foggy]

did the "refesh aluminum shortblock" include decking the the block and/or heads? may need to revisit pushrod length and make sure preload is correct.

Very Good Point !!!!!!!!!!!!!!!!

 

[bcbickers]

So, the deck AND the heads had .020" taken off? I can't speak for Cam Motion, but it's common for larger aftermarket cams to have a smaller base circle on the lobe, often .050". This means you'd need a .025" longer rod (half of that .050" diameter). Stock is 7.380", so you'd need a 7.405". Aftermarket rods are commonly available in .025" increments, so you'd use 7.400". BUT, if the deck and head both had .020" shaved, then you'd need to subtract .040" from the push rod length, yielding a 7.360". I'd go with 7.350" or 7.375". LS lifters have a wide acceptable preload range.

You really do need to know your cam's and engine's specs. I have a hard time believing they took .020" off the deck. Unless they used shorter rods or pistons. I can see .020" taken off the heads. That would put you back at 7.380" push rods, meaning stock length.

I may have left a comma off. The block honing and milling are separate line items on the work order. I take it to mean the block was honed .020 in. over, while the heads and block were simply milled to ensure a good fit. It doesn't say how much was milled off the heads and block. I'll check with the engine builder for more details.

I have that same cam and it’s quiet. Standard pushrod length also. I suspect that if the heads were milled, your lifter preload is off and you’ll need to make adjustments to pushrod length. More when I have more time…

That's great to hear. Everything I read about this cam said it is quiet, has good manners like stock, and didn't move the powerband really high in the rev range like some of the others do.

I think I will give it 500 miles then change the oil and see how things are. Blackbear's tune update may help as well.

 

[iamdub]

I may have left a comma off. The block honing and milling are separate line items on the work order. I take it to mean the block was honed .020 in. over, while the heads and block were simply milled to ensure a good fit. It doesn't say how much was milled off the heads and block. I'll check with the engine builder for more details.

Definitely see if the builder documented specifically what they did. If even just a cleaning pass to true the deck and heads, it's still something to account for. You can get a push rod checker tool for about $25. It's tedious work, but knowing is worth it.

Having said that, I checked every one of mine about a year ago and replaced the rods accordingly to tighten the variance range between them all. I have three different length rods throughout mine. But it's an original 200,000+ mile block and these engines are often "bowed" from the factory, making the corners lower by a few thousandths.

 

[Dustin Jackson]

@bcbickers Does your engine sound like the one in this video?

 

[Geotrash]

Here's what my L94 sounds like with the same cam. That was right after the swap and it's gotten a bit quieter since:

 

[bcbickers]

Thanks for the video and sound clip. Yours seems a little quieter than mine, but it could be me just being OCD or something. I'll try to get a quick video of mine when the rain lets up.

 

[bcbickers]

@bcbickers Does your engine sound like the one in this video?

Not really. Mine sounds more like it is low on oil, albeit very faint. Oil level and oil pressure are good. I'll try to grab a sound clip when the weather lets up.