Hypereutectic or Silvolite Hypereutectic

[JTwthaXJ]

One of my friends and I are building a 4.7 stroker, since we hydro-locked the engine in his '91 a few months ago. I have checked out Dr. Dyno's page and several others, but what are the advantages or disadvantages to running hypereutectic pistons or silvolite hypereutectics? I wanted to check on his behalf as well as my own for later, for when we build mine. We are trying to build this thing right on the first go round. And also I read that the early 90s HO motors have a 270/270 cam can we reuse this with no worries? Thanks guys...

 

[Flash]

Hypereutectic is type or piston or should I say a type of material for a piston.....

What you need to do is talk with your machinist as to which piston will give you the right compression hight with what's been or will be, shaving or decking from you head and block.

Once you have the piston pin hight figured out(how hight you want the piston in the bore) then you can see with pistons are available for you requirments.......some time we can't be picky with what brand or design of piston is used.............unless your willing to spend the big bucks for a custom piston......then the sky is the limit!


Flash.

 

[seanyb505]

On Summit they list 4.0 pistons for two different prices. The sizes are metric and standard and the same size, but the standard measurements are more expensive. Same brand and material, different measuring scales. Does anyone know why this is?

 

[Flash]

One of my friends and I are building a 4.7 stroker, since we hydro-locked the engine in his '91 a few months ago. I have checked out Dr. Dyno's page and several others, but what are the advantages or disadvantages to running hypereutectic pistons or silvolite hypereutectics? I wanted to check on his behalf as well as my own for later, for when we build mine. We are trying to build this thing right on the first go round. And also I read that the early 90s HO motors have a 270/270 cam can we reuse this with no worries? Thanks guys...

YES.

The standard cam will be fine as long as you don't mix up the lifters.........and thay do not have a bad ware pattern(concaved)

I still want to put a after market cam in mine, when i get my stroker built, and by that time..........all the air should be let out of the reason why!(cam failers) How know i just might end up with stock stock cam.

Flash.

 

[JTwthaXJ]

Thanks, his cam should be pretty good about 3k miles after the initial drowning the #6 con rod went through the block, so we have that one. And also found an almost complete block from a '92 with the 270/270 cam. We are replacing the lifters and the push rods so those won't be a problem. It's just the his cam we need to worry about. My main concern is still is there a performance or durability difference betweent the hypereutectics and the silvolite hypereutectics? From what I have seen they are fairly similar in price, we are going .060 over...

 

[Flash]

Thanks, his cam should be pretty good about 3k miles after the initial drowning the #6 con rod went through the block, so we have that one. And also found an almost complete block from a '92 with the 270/270 cam. We are replacing the lifters and the push rods so those won't be a problem. It's just the his cam we need to worry about. My main concern is still is there a performance or durability difference betweent the hypereutectics and the silvolite hypereutectics? From what I have seen they are fairly similar in price, we are going .060 over...

How a about a couple pic's!!! I'M must not be getting your point:dunno:

Hypereutectics?...............silvolite?:dunno:

Flash.

 

[JTwthaXJ]

One is from Speed Pro (Federal Mogul) and the other is from Keith Black, just curious if there is a major difference that would make people choose one over the other....

 

[Flash]

One is from Speed Pro (Federal Mogul) and the other is from Keith Black, just curious if there is a major difference that would make people choose one over the other....

I have no idea but..... FYI Keith Black is who came up with the "Hypereutectics" piston.

Its a nice little piston that fills the gap between a Forged and a Cast Piston.

Tougher then a cast but don't expand as much as a Forged piston(kind of the best of both cast and forged pistons!)

I wouldn't be afraid of either piston!!!!!


Flash.

 

[jeepinwi]

Either piston will work fine for your application. Get the cheaper piston. Unless you're going with forced induction, You don't really have to worry about the type of piston. The Sealed Power H802CP piston have a larger dish volume than the Silvolites, so they will help keep your CR down.

Now, why are you boring it .060" over? No need to go that big unless you have to.

 

[tealcherokee]

more displacement????


im boring mine .125 over

as far as the 2 pistons for the 4.0, in 96 the switched from SAE to metric, as long as you get the coorosponding rings, it doesnt matter

 

[jeepinwi]

What's the point in boring it over so much? Generate more heat? Weaken the cylinder wall? You don't gain the power from an overbored cylinder, but rather from that longer stroke. A 4.7L stroker will have at most 5 more HP than a 4.6L stroker with bore being the only difference.

 

[Flash]

the only advantage with the ..........way larger bore is the ex valve wouldn't be less shrouded with a 2.02/1.60 in the head.(might breath a little bit better!)

I will tell ya what guys i will run a stroker Dyno to night with the piston bore being the only diff between a stock 4.0 bore and a .125" bore and see what happens!

say with the the HO cam!, 91+ cam

 

[Flash]

the only advantage with the ..........way larger bore is the ex valve wouldn't be less shrouded with a 2.02/1.60 in the head.(might breath a little bit better!)

I will tell ya what guys i will run a stroker Dyno to night with the piston bore being the only diff between a stock 4.0 bore and a .125" bore and see what happens!

say with the the HO cam!, 91+ cam

sorrry, that should have said: The only advantage with the ..........way larger bore is the ex valve would be less shrouded with a 2.02/1.60 in the head.(might breath a little bit better!):twak:


Flash.

 

[Flash]

OK here is the base and the big bore!

Bore: 3.875 and 4.000
Stroke 3.895(258 crank)
Cylinder head 7120(no mods)
CR 9.40:1
Int/ ext 1.91/1.50(stock valves)
Small tube header with muffler
stock HO CAM UP TO 95

at 1500 RPM the big bore had 5 HP/ and 20 more fpt
at max HP there was only 2 more for the big Bore then the base, and at max torque there was still 15 more fpt


Flash.

 

[tealcherokee]

What's the point in boring it over so much? Generate more heat? Weaken the cylinder wall? You don't gain the power from an overbored cylinder, but rather from that longer stroke. A 4.7L stroker will have at most 5 more HP than a 4.6L stroker with bore being the only difference.

are you freaking retarded?

a 4.0, stock makes what 225lb/ft
a 4.5L stroker prolly makes in the vacinity of 310+lb/ft
now what do you think a 4.0, stock crank punched out .125 will be?

a 4.3L prolly making 285+ lb/ft

now combine them both, 4.8L, coming close to 350lb/ft
and offet grind the crank some more, 4" or up to 4.06" to get 301-306 ci, a full 5L putting down 375lb/ft

granted all of these need the supporting mods to go along w/ them

 

[JTwthaXJ]

One reason for the big bore, is that the block that we found had nearly 300k miles on it, so it had a pretty decent ridge at the top of the cylinder wall. We are aiming for the most bang for our buck, not really the HP but the low end torque. We are planning on porting and polishing the head and eventually going with something like the LS1 big valve idea. Thanks guys, you cleared up a lot of my questions.

 

[Flash]

are you freaking retarded?

a 4.0, stock makes what 225lb/ft
a 4.5L stroker prolly makes in the vacinity of 310+lb/ft
now what do you think a 4.0, stock crank punched out .125 will be?

a 4.3L prolly making 285+ lb/ft

now combine them both, 4.8L, coming close to 350lb/ft
and offet grind the crank some more, 4" or up to 4.06" to get 301-306 ci, a full 5L putting down 375lb/ft

granted all of these need the supporting mods to go along w/ them

I support that last statement 100%

Flash.

 

[MudDawg]

Big valves in a iron head will not do much good....the shrouding in the combustion chamber is too great....the valve simply come too close to the wall in the combustion chamber. If you are doing the Chevy valve substitute..because of excessive valve guide wear requireing guide replacement....the 1.94/1.50 valves work since the chevy stems are 11/32" the stock worn guides can be reamed to fit without replacement...better choice if the guides are in good shape are the mopar performance valves..nice pieces..

I run the Sealed Power/Zollner pistons in the mighty 2.5....and have had no trouble despite frequent trips to the 7K range...don't try that with a 4.0!

 

[JTwthaXJ]

So the main problem with the big valves is not the valve itself but the material that the head is made from. As long as the head doesn't have any excessive wear in the valve guides, clean valves are all we need? We pulled the head from the motor last night the only problem that we saw was that he was running really rich. Other than that everything looked really good. So off to port and polsih over the weekend, having it hot tanked and reassembly.

 

[Flash]

So the main problem with the big valves is not the valve itself but the material that the head is made from. As long as the head doesn't have any excessive wear in the valve guides, clean valves are all we need? We pulled the head from the motor last night the only problem that we saw was that he was running really rich. Other than that everything looked really good. So off to port and polsih over the weekend, having it hot tanked and reassembly.

Re read MudDawg post grate info!

the strength of the valve is not the problem.

Flash.