"Quiet" Stroker?

[69RTAlaska]

Hello FBBO,

I've been on various threads regarding piston slap (e.g., thread "440 knocking") where guys are sharing really great hard to come by knowledge. The mildly cammed, stroked 440 in my restored 69 RT street car seems to suffer from it, and I want to be very sure I understand how to minimize slap (and valve train noise as well) when I redo the engine. This may alarm some on these boards but I now realize that for this car, quiet (relatively) takes precedence over more than stock HP. I could put the 440 crank back in to help minimize slap but I'd still rather have the cubes if I can be sure no more slap.

I noticed Challenger340 mentioned short skirt pistons being more prone to slap, and the Comp XE/HL cams are noisy (I happen to have one as well - XE/HL 231/237).

A few questions:
So I need longer skirts (pistons, not on girls)?
I know piston to wall clearance is critical, apparently no one offers hypereutectic pistons for 440 strokers so I'm stuck with regular forged pistons?
Also, regarding valve train noise, are other comp series cams quieter, and are tappet hydraulic and roller hydraulic cams similar with respect to noise?

Many thanks for any replies.

 

[OSDart]

You'll need to do some research, but there are companies that still make an forged off-set pin piston. I'm not sure about the hypereutectic.
As for valve train issues, I've had the best luck with Hughes rockers, Manton pushrods and Erson cams.
I stopped installing/recommending Comp cams because of noise. Especially the High Energy series.

 

[33 IMP]

Id be willing to bet your cam is making lots more noise than your piston slap.
If you want it quieter, put a nice, slow ramp hydraulic in it, not an EXTREME energy (read: ragged edge aggressive/noisy).
If piston to wall is right, piston slap goes away as the pistons warm up. If your engine is noisy 100% of the time....its something else.

 

[69RTAlaska]

You'll need to do some research, but there are companies that still make an forged off-set pin piston. I'm not sure about the hypereutectic.
As for valve train issues, I've had the best luck with Hughes rockers, Manton pushrods and Erson cams.
I stopped installing/recommending Comp cams because of noise. Especially the High Energy series.

Very interesting, I'll do the research you suggest, thanks!

 

[diesel_lv]

I've got a 383/496 stroker that other than a bit higher exhaust noise under the hood due to headers is super quiet. Hydraulic roller Comp cam. If I had cast iron exhaust manifolds, I'd bet it'd be as quiet as stock.

 

[69RTAlaska]

Id be willing to bet your cam is making lots more noise than your piston slap.
If you want it quieter, put a nice, slow ramp hydraulic in it, not an EXTREME energy (read: ragged edge aggressive/noisy).
If piston to wall is right, piston slap goes away as the pistons warm up. If your engine is noisy 100% of the time....its something else.

Maybe it is the cam as you suggest, heck I think I have both, the knock came on over the summer, and what I believe to be valve train noise has been pretty constant since I had the motor built. I really should have done more homework before I had the engine redone, but also sometimes you don't know what you really want until you have some experience.

The noise is most noticeable when the engine is fully warmed up and at idle, and it fades as the engine rpm increases. I realize that's not typical piston slap, but maybe if the pistons are scuffed as well, the slap doesn't go away when the engine warms up. I will really listen to the valve train again with the scope. Thanks for the reply. I'll also do some cam research.

 

[69RTAlaska]

I've got a 383/496 stroker that other than a bit higher exhaust noise under the hood due to headers is super quiet. Hydraulic roller Comp cam. If I had cast iron exhaust manifolds, I'd bet it'd be as quiet as stock.

So I take it the roller is probably quieter that a standard flat tappet. Thanks for the reply.

 

[Curiousyellow71]

A 440 has a really, really tall deck and usually run long rods with a stroker. Piston slap would be rare. When piston slap does happen its the opposite of what your describing it happens when it's cold and the pistons haven't expanded. Once its warmed up the noise goes away. Some forged pistons grow more then others because of the skirt design and the old saying about noisy forged pistons is pretty much a myth. A extra .001 isn't going to make a piston slap.
The XE series from comp is a noisy cam. On the intake they close the valves very, very fast making a noise that almost sounds like a solid cam. The exhaust uses a magnum lobe I believe and isn't as aggressive. They are trying to make cylinder pressure by closing the intake valve quickly.

 

[Cranky]

The hypereutectics are just a better grade of cast aluminum pistons. Me....I'll go with the 'regular' forged piston any day! Usually you need more piston clearance with a forged slug but if things are straight and true and you make sure you don't overheat the engine, the forged pistons can be run tighter than what most run them at.....and I'm also thinking you're hearing valve train noise vs piston slap unless you are running clearances that should be used for forged pistons.

 

[69RTAlaska]

A 440 has a really, really tall deck and usually run long rods with a stroker. Piston slap would be rare. When piston slap does happen its the opposite of what your describing it happens when it's cold and the pistons haven't expanded. Once its warmed up the noise goes away. Some forged pistons grow more then others because of the skirt design and the old saying about noisy forged pistons is pretty much a myth. A extra .001 isn't going to make a piston slap.
The XE series from comp is a noisy cam. On the intake they close the valves very, very fast making a noise that almost sounds like a solid cam. The exhaust uses a magnum lobe I believe and isn't as aggressive. They are trying to make cylinder pressure by closing the intake valve quickly.

Interesting, I understood the same about piston slap (basically only when engine is cold). I thought it was the fuel pump/rod (I listened to it with a scope and it was knocking very loud) but changed both and still have the noise. I'm really going make sure I get the right cam next time. Thanks for the reply.

 

[69RTAlaska]

The hypereutectics are just a better grade of cast aluminum pistons. Me....I'll go with the 'regular' forged piston any day! Usually you need more piston clearance with a forged slug but if things are straight and true and you make sure you don't overheat the engine, the forged pistons can be run tighter than what most run them at.....and I'm also thinking you're hearing valve train noise vs piston slap unless you are running clearances that should be used for forged pistons.

The pistons in the engine are KB840s, "premium forged," sorry if my post wasn't clear. I sure wish I was smart enough to have confirmed what clearance my builder used. KB says 0.0045-0.0055 for a stroker.

 

[Curiousyellow71]

The noise is most noticeable when the engine is fully warmed up and at idle, and it fades as the engine rpm increases. .

Sounds like Comp XE. If you have comp lifters that is likely not helping making it worse.

 

[Challenger340]

Piston Slap has NOTHING to do with Block Deck height nor Rod length.....

Piston SLAP is entirely a product of Piston to Cylinder Wall CLEARANCE..... while in operation
or,
how much of that "clearance" is spread over the length of the Piston Skirt as determined by the Compression Distance of the Piston.... the "clearance" required being relative to the Piston ALLOY (4032 variants / 2618 variants).... and Piston construction DESIGN (ie: Cam & Barrel / Slipper Skirt / Full Round etc., etc design internal of the Piston itself)... and Pin location for thrust... etc., etc.

Piston slap is just that.... an audible noise from the Pistons slapping around in the Bores caused by too much Piston to Wall clearance.
Contributing factors:
* Short Piston Skirts relative to the Piston to Wall "clearance" present
* WRONG Piston Alloy for the application
* WRONG Piston Design/Construction for the application
* WRONG Piston to Wall Clearance Honed by Shops doing the Boring and Honing without a BB Mopar Torque Plate wherein they always ADD EXTRA Piston to Wall clearance to the Rec'd Piston to Wall clearance as a "safety factor" to cover their arse because they don't have a BB Mopar T/Plate and their Bores are .001" all over the map anyways.

 

[Challenger340]

The pistons in the engine are KB840s, "premium forged," sorry if my post wasn't clear. I sure wish I was smart enough to have confirmed what clearance my builder used. KB says 0.0045-0.0055 for a stroker.

I dunno what a "KB840" is.... but from the clearance Rec (.0045" to .0055") you provided they sound like a 2618 Alloy Cam & Barrel design structure.... and if Bored/Honed without a T/Plate because the Shop didn't have or use one ?
.... then undoubtedly the Shop probably ADDED a "safety" clearance factor which is very common ? So "if" they are installed around .006+" or better.... and relative to "IF" they are also a shorter skirt Stroker Piston.... and "IF" you are also using relatively thin Oil.... MUFFLERED STREET CAR.... SLAP... SLAP... SLAP...

Question:
Does your "Builder"..... MACHINE his own stuff ?
or,
is this one of those where one guy ASSEMBLES.... what some other guy he trusts "Machines" ?

Just say'in....
seen LOTS of so-called Engine "Builders" that if I brought them into my Machine Shop and stood them right in front of any Machine in there ?
They wouldn't know how to START a fawking thing in my Shop !
So....
just how the hell are they supposedly to know or check what's right or wrong in what they get back ?

 

[69RTAlaska]

I dunno what a "KB840" is.... but from the clearance Rec (.0045" to .0055") you provided they sound like a 2618 Alloy Cam & Barrel design structure.... and if Bored/Honed without a T/Plate because the Shop didn't have or use one ?
.... then undoubtedly the Shop probably ADDED a "safety" clearance factor which is very common ? So "if" they are installed around .006+" or better.... and relative to "IF" they are also a shorter skirt Stroker Piston.... and "IF" you are also using relatively thin Oil.... MUFFLERED STREET CAR.... SLAP... SLAP... SLAP...

Question:
Does your "Builder"..... MACHINE his own stuff ?
or,
is this one of those where one guy ASSEMBLES.... what some other guy he trusts "Machines" ?

Just say'in....
seen LOTS of so-called Engine "Builders" that if I brought them into my Machine Shop and stood them right in front of any Machine in there ?
They wouldn't know how to START a fawking thing in my Shop !
So....
just how the hell are they supposedly to know or check what's right or wrong in what they get back ?

Challenger340,

Thanks for the reply, I was hoping you'd chime in.

The pistons are listed on page 25 of this older KB catalog:
https://issuu.com/tmeyerinc/docs/new_combo_premium___fhr_forged_catalog_2008

You are correct, they are 2618 alloy. I'm curious if they are also "short skirt" pistons?

Your questions regarding by engine build are spot on, and due to my lack of experience at the time, I did not ask the proper questions of my "assembler."

Water (and money) under the bridge, and now I want to be sure I do it right this time. I want a Mopar oriented shop that machines its own stuff and has a dyno (per your previous suggestions). This means shipping the motor out of Alaska. Can you recommend a good shop? From the few posts I've read from you I can't tell if you are still working.

 

[Challenger340]

Challenger340,

Thanks for the reply, I was hoping you'd chime in.

The pistons are listed on page 25 of this older KB catalog:
https://issuu.com/tmeyerinc/docs/new_combo_premium___fhr_forged_catalog_2008

You are correct, they are 2618 alloy. I'm curious if they are also "short skirt" pistons?

Your questions regarding by engine build are spot on, and due to my lack of experience at the time, I did not ask the proper questions of my "assembler."

Water (and money) under the bridge, and now I want to be sure I do it right this time. I want a Mopar oriented shop that machines its own stuff and has a dyno (per your previous suggestions). This means shipping the motor out of Alaska. Can you recommend a good shop? From the few posts I've read from you I can't tell if you are still working.

OK those are a 2618 Alloy but on a 1.867" CD so 'should' be able to run decently quiet once warmed(you shouldn't hear them).... varying opinions being what they are for many people, but what I mean is they will never be 'dead nuts' quiet to a knowing ear in a very quietly mufflered street car running a 10W Oil ? but they shouldn't sound anywhere even remotely close to a diesel either ?

Best utilization for that Piston is as mentioned before...
USE a T/Plate and fit at .0045" clearance maintaining Bores within .0002-3" straight & round(lotsa cool down) Pin-Fit and Clearance the rest of the Engine for a 10-40 or 15-40 at .0025" Vertical Rods and .0030" Vertical Mains using H Bearing Eccentricities.... it will Idle HOT @ 40 psi and 70 psi HOT cruising.

My apologies here... but just not accepting any customer work.

I still Machine/Build/Dyno here.... but only as time, and these days "parts" permit.... and only do what I WANT to build these days ? ... which I then sell later if someone wants it(pretty much spoken for as soon as I start)
Lotsa .030" over 440's.... nothing fancy, just really solid well running 440's that depending upon Flat Tappet Hydraulic Camshaft used kick between 500-550 HP on the Dyno with 550 Ft/Lbs on Pump Premium....low Intakes/Lotsa Hood Clearance.... they don't over heat in traffic... they don't leak... they fire first crank.... and as long as they have Oil & Water a guy can beat on 'em like a Red-Headed Step Child for decades and never lift the Hood !
People should ENJOY their rides by driving them without worry.

 

[lewtot184]

i seriously doubt you will find a "quiet" performance piston. i doubt you'll find a long skirt stroker piston. several factors on piston noise, straight pins in performance pistons vs offset pins in stockers, drilled oil ring groove performance pistons need more clearance than slotted ring grooves, some piston alloys need more clearance, short pistons can use a tighter clearance but will still be noisey cold. there simply isn't any free lunches here. i have two cars both 440's. one has icon pistons, solid cam and it's fairly noisey cold; ok real noisey cold, but shuts up when warmed up. another is a basic stock 440 with hypers; noisey when cold but shuts up when warm. i understand the noise and deal with it. unfortunately some folks think cold piston noise is the end of the world; it isn't.

 

[69RTAlaska]

i seriously doubt you will find a "quiet" performance piston. i doubt you'll find a long skirt stroker piston. several factors on piston noise, straight pins in performance pistons vs offset pins in stockers, drilled oil ring groove performance pistons need more clearance than slotted ring grooves, some piston alloys need more clearance, short pistons can use a tighter clearance but will still be noisey cold. there simply isn't any free lunches here. i have two cars both 440's. one has icon pistons, solid cam and it's fairly noisey cold; ok real noisey cold, but shuts up when warmed up. another is a basic stock 440 with hypers; noisey when cold but shuts up when warm. i understand the noise and deal with it. unfortunately some folks think cold piston noise is the end of the world; it isn't.

I agree on the "no free lunch," and I'm slowly figuring out exactly what's important to me. Just to be clear, my motor has slap at idle when hot. I'd rather not have slap when cold, but if that were all it was, I would not worry about it at all. Thanks for the info above regarding piston design, I'll do some research.

 

[69RTAlaska]

OK those are a 2618 Alloy but on a 1.867" CD so 'should' be able to run decently quiet once warmed(you shouldn't hear them).... varying opinions being what they are for many people, but what I mean is they will never be 'dead nuts' quiet to a knowing ear in a very quietly mufflered street car running a 10W Oil ? but they shouldn't sound anywhere even remotely close to a diesel either ?

Best utilization for that Piston is as mentioned before...
USE a T/Plate and fit at .0045" clearance maintaining Bores within .0002-3" straight & round(lotsa cool down) Pin-Fit and Clearance the rest of the Engine for a 10-40 or 15-40 at .0025" Vertical Rods and .0030" Vertical Mains using H Bearing Eccentricities.... it will Idle HOT @ 40 psi and 70 psi HOT cruising.

My apologies here... but just not accepting any customer work.

I still Machine/Build/Dyno here.... but only as time, and these days "parts" permit.... and only do what I WANT to build these days ? ... which I then sell later if someone wants it(pretty much spoken for as soon as I start)
Lotsa .030" over 440's.... nothing fancy, just really solid well running 440's that depending upon Flat Tappet Hydraulic Camshaft used kick between 500-550 HP on the Dyno with 550 Ft/Lbs on Pump Premium....low Intakes/Lotsa Hood Clearance.... they don't over heat in traffic... they don't leak... they fire first crank.... and as long as they have Oil & Water a guy can beat on 'em like a Red-Headed Step Child for decades and never lift the Hood !
People should ENJOY their rides by driving them without worry.

Too bad to hear you're not accepting work but I understand. If you're comfortable suggesting a machine shop/builder I'd love to hear it.

Many thanks for the recommendations regarding how to best utilize the piston, I'll make sure I understand everything you are suggesting and discuss with the machine shop I end up using.

 

[lewtot184]

I agree on the "no free lunch," and I'm slowly figuring out exactly what's important to me. Just to be clear, my motor has slap at idle when hot. I'd rather not have slap when cold, but if that were all it was, I would not worry about it at all. Thanks for the info above regarding piston design, I'll do some research.

slap hot means the pistons were set-up too loose. i bet the bore is too big. some years ago some folks were using the trw clone stock replacement 400 pistons with a 4.15 crank in a 440 block. if you could find those pistons they would be quiet due to offset pins and slotted oil ring groove.