Which pistons????

[TRYMYSIX]

Ordered a 3.625 crank and 5.967 rods. I'm having trouble finding the correct pistons. I found a Weisco part# 5109A2, but Summit only has 3! Carrillo has the ZR231 piston I'm researching now.

ZR231 specs:
Buick Grand National 3.8L, 3.820 Bore, 3.400 Stroke, 5.960 rod, 1.835 Compression Height, -27.2cc Dish, Advertised Weight 494

 

[TRYMYSIX]

CP says it will stick out of the hole about 80 thousandths. Is there not anything off the shelf? I know folks are running this crank and rods.

 

[thadeal4real]

Did u measure the deck ?

 

[TRYMYSIX]

Did u measure the deck ?

Went by the std deck height listed in their book of 9.535". But no I have not measured it.

 

[thadeal4real]

Well just sayn (I dont know what your plans are ) but you gotta start somewhere deck height ie block is usually the determining foctor for the "custom" parts

 

[thadeal4real]

I guess what im asking is what block you using and what has been done to it ? Then it might be possible to just play with gaskets and or milling vs piston/rod combo

 

[TRYMYSIX]

Stock 109 block that's never been decked. Original motor that was in the car.

 

[bison]

The math shows they will be about .100" out with the deck height around 9.510" which is common after squaring. If you can get me the exact deck height and want a specific set of pistons then message me. I will spec the design, dish, ring locations, ring sizes, ring type, etc. If you are worried about cost then please don't message me.


Sent from my iPhone using Tapatalk

 

[TRYMYSIX]

I'm just gonna order the complete stroker kit from TR Custom while it's on sale and be done with it.

 

[earlbrown]

If you're going to change the stroke and any other stuff like rod length or deck height my slugs are the only 'shelf' options short of full customs.

Your math will have to be altered as i use a 22CC inverted dome though

 

[turbo89]

Went by the std deck height listed in their book of 9.535". But no I have not measured it.

If you need a JE Job # let me know .. I have done a set of pistons from them that if you deck the block to 9.520 .. you would be .010 in the hole with the exact rod / stroke config you listed

 

[TURBOELKY]

Even buying a stroker kit doesn't guarantee a perfect fit. A piston made to spec is your best option.

 

[TRYMYSIX]

If you need a JE Job # let me know .. I have done a set of pistons from them that if you deck the block to 9.520 .. you would be .010 in the hole with the exact rod / stroke config you listed

Yes plz

 

[TRYMYSIX]

Even buying a stroker kit doesn't guarantee a perfect fit. A piston made to spec is your best option.

So is that to say the Stroker kits from Buick vendors do not fit perfect? One would think, the JE or Diamond pistons that come in the Stroker kit, with the 3.625" crank and the 5.967" rod have been developed to take into consideration the varying deck heights as Bison eluded too, to be a prefect fit.

 

[TURBOELKY]

I'm sure the kits get you pretty close. Perfect?

 

[turbo89]

So is that to say the Stroker kits from Buick vendors do not fit perfect? One would think, the JE or Diamond pistons that come in the Stroker kit, with the 3.625" crank and the 5.967" rod have been developed to take into consideration the varying deck heights as Bison eluded too, to be a prefect fit.

Whats a perfect fit? And for whom?
Most slam a kit in and call it good.. 15 minutes of measurement and you know everything you need to.
To some extent the machinist will bail
You out of a "compromise" in the stroker kit but you need to know what you want at the end of the build

 

[TURBOELKY]

The machinist bailout ends up costing what you would have spent on a piston that fits right, which needs to be purchased AFTER the block is squared and measured.

 

[turbo89]

The machinist bailout ends up costing what you would have spent on a piston that fits right, which needs to be purchased AFTER the block is squared and measured.

NO.. The cost is the same..
And again it depends on what you want the final outcome to be .. What im getting at is the out of the box pistons will get you a certain configuration that in most cases will work just fine.. Is it perfect??

Whats perfect??

Ultimately only the builder knows EXACTLY what they want

Is a custom piston really going to net you a measurable increase in performance or reliability over a out of the box kit designed piston ..I dont think so.. I cant tell you how many GN's have run low 10's on old school , heavy , out of the box TRW pistons

 

[TURBOELKY]

NO.. The cost is the same..
And again it depends on what you want the final outcome to be .. What im getting at is the out of the box pistons will get you a certain configuration that in most cases will work just fine.. Is it perfect??

Whats perfect??

Ultimately only the builder knows EXACTLY what they want

Is a custom piston really going to net you a measurable increase in performance or reliability over a out of the box kit designed piston ..I dont think so.. I cant tell you how many GN's have run low 10's on old school , heavy , out of the box TRW pistons

the cost is the same if the piston needs material taken off the dome? Damn, guess we've been ripping people off for charging for the extra work

 

[turbo89]

the cost is the same if the piston needs material taken off the dome? Damn, guess we've been ripping people off for charging for the extra work

You dont take material off the dome.. Thats a NO NO

The stroker kits ive seen dont set the piston above the deck but below the deck.. What he is trying to do is take a piston not designed in the kit and make it work... Dont ask me why???

What i suggested was that the pistons used in the kits will get you close enough where they will suffice for 90% of us

I also offered up a JE job number to take all the math out as that setup has been done.. Again this will be also dependant on if the OPs requirements are the same as what mine were .

Final point is there is no MAGIC piston that will unlock some hidden performance barrier .. you still have to work with somewhat fixed dimensions and can only alter so much