You know when you are actually starting to make progress with rebuilding your engine.

 

The first lot of parts start to come in. :D

 

 

 

 

Stuart

Pic 2

mmmm.. They look lurvly.

 

What make are they?

Wiseco.

 

They are more well known for making motorbike and powerboat pistons.

Originally posted by SRRAE

Wiseco.

 

They are more well known for making motorbike and powerboat pistons.

 

 

Good choice !

Very nice :) lets see how they perform, could very well be tempted to do these

Nice pistons, did you get them with the Polydyn coatings??

Nice one Stu,what size are they?

Originally posted by JayPSC

Nice pistons, did you get them with the Polydyn coatings??

 

Don't know. :confused: But they are shiney, :D

 

 

 

I just looked and yes they are.

 

What is that Polydyn?

Spoke to SE about these as I was gonna use them , even sent SE the specs and all the blurb on them and got told in not uncertain terms to stay well clear because of what it does to the compression ratios of the car , from my understanding it raises or lowers the compression , can't remember which :rolleyes: so you can't run big boost , :( If anyone has any info to the contrary , I would be interested to hear as these look fantastin value for money

Nice one mate, wiseco are exellent i had them in my old GSXR1260.

 

When you reckon she'll be done.

 

Rich

They look spot-on Stu, good luck with the rebuild ;)

More info on the Pistons

 

Wiseco has been producing racing pistons since 1941. We produce our own forgings in house which makes our parts lighter and stronger and built for specific engine models. Our competitors use one-size fits all forgings that require excessive internal milling which leads to stress risers and overly-heavy pistons. For turbo applications we use 2618 low silicon alloy-although we still recommend .003 piston to wall clearance in order to avoid piston slap. For extreme racing applications of over 23 pounds of boost, we recommend that clearance be opened up to .004. Wiseco is the sole distributor for Nippon rings in the US. These Heavy duty ring sets were designed specifically for the turbo applications. We also sell these same rings to our sister company JE, and others as well like Total Seal, Ross, and Arias. In particular, the vg30dett forging was built to accomodate a bore range of 87-88mm. The two part numbers we stock are the k549m875 and k549m88 for 87.5 and 88mm over bores respectively. Compression ratio is 8.55:1, but 8.9:1 can be achieved if .030 piston to head clearance is used by changing gaskets. A 1.6mm gasket would lower the final compression to 8.25:1. The pistons have a 9cc dish with a nice radius and valve pockets that accomodate 1mm bigger valves than stock and larger cams as well. Forged pistons contain no oil reservoir as the oe cast pistons do. We rely on the oil squirters to keep the crown cool. This does reduce the weight of the piston considerably to 338 grams-which takes quite a bit of stress off the rods, crank, and block and will also makethe engine rev quite a bit quicker. For those customers interested in heat barrier coatings and skirt coatings, many of our customers choose Polymer Dynamics in Houston. They can be reached at 713 694 3296. If you call them with the Wiseco part numbers, they will order the parts from us. Their prices are around $609 for the pistons, rings, standard coatings, and they charge the freight that it takes to send the pistons from Ohio to Texas to begin with. We keep these pistons in stock, but extreme spikes in sales might cause back orders. Call me, Brian Nutter, at 800-321-1364 ext. 3177 for availability.

 

Wiseco prides itself in meeting or exceeding our customer's expectations for each piston-every time. As the piston is the first line of defense against the extreme heat and pressures seen in the internal combustion engine. The old adage of measuring twice and cutting once is the most important rule when designing a proper piston. Due in part to advanced forging and CNC technology, your Wiseco pistons will have less variance than any other part in your engine. Many tolerances in a Wiseco piston are less than one-half-of-one-thousandths of and inch (.0005).

An engine builder has the first and last word when designing, machining, and assembling an engine project. It is their responsibility to measure and verify every measurement in the engine. We at Wiseco have compiled a list of frequently asked questions to aid the engine builder. As every engine is different from any other, these answers are not set in stone. If you have any doubts as to the specifications of your piston in relation to your specific engine combination, please call your Wiseco technical sales representative.

1. Why are my Wiseco pistons better than pistons made by the O.E.'s and aftermarket piston suppliers?

It all starts with the forging. Wiseco starts with certified extruded bar stock and forges our pistons in-house with the world's most advanced forging presses. Most aftermarket piston companies do not and therefore can't achieve the level of quality control that Wiseco demands. After thorough inspection, that part goes through an extensive heat-treat and finishing process. This makes for an excellent forging with maximum strength and minimum variance. The other benefit to doing our forgings in-house is making the finished piston design dedicated to your engine combination. Wiseco can forge a variety of advanced materials including S.A.E. 4032 and 2618 alloys. High silicon 4032 is a durable and lighter material usually used in naturally aspirated engines. 2618 Alloy is designed for the rigors of blown, marine, and nitrous applications.

2. What kind of piston to wall clearance can I run?

The usual rule of thumb is .001 for every inch of bore size. The factors that affect this are cylinder wall thickness (including filled blocks), overall compression height of the piston, piston material and thickness, and whether a marine engine is to see fresh-water cooling. Most small blocks get .004 piston to wall clearance and most big blocks get .005 due to the use of our 2618 high-strength alloy. For heavy blower and nitrous applications, Wiseco recommends adding .001 to the standard clearance. Special note: Clearance numbers are taken 1.300 down from the oil ring land-Not 90 degrees from pin centerline.

 

3. What are the most important factors in deciding what piston fits my engine combination?

There are many important factors, which we will explain in depth, but the first two are bore and compression height. Bore size is important for obvious reasons. With the different block, stroke, and rod combinations, Wiseco has designed a large number of pistons with varying Compression Heights. This number is the distance from the center of the wrist pin to the deck of the piston (not dome). When adding 1/2 the stroke + rod center to center length + Compression height, our goal is to have the piston adequate piston to head clearance without being excessive (which causes a loss of compression and quench).

 

4. What is minimum piston to head clearance?

Generally the factors that decide this are: Piston Speed, Piston Mass, and Rod Material (Steel or Aluminum). Aluminum Rods generally require .010 more clearance than steel rods. Steel rods in a big block usually require .045. Steel rods in small blocks require at least .036. Most imports can get by with as little as .030 depending on piston mass. *Remember, a compressed gasket thickness can vary from .025 in steel shim applications to .040 for composite and up to .100 for some copper gaskets.

5. Why do you use piston speed versus rpm to determine the loading in tension of the block, crank, rods, and pins?

For example a 434 C.I. stroker small block turning 7000 Rpm has the same average piston speed as a 350 turning 8045 rpm, a 327 turning 8615, or a 302 turning 9330 rpm. It is important to note that average piston speed is only about 2/3rds of what peak piston speeds can be due to the accelerations seen when the crank is between 45 and 90 degrees away from TDC or BDC. Rod length is a major factor in maximum velocities.

6. Now the part physically fits in my engine, what factors determine the part I choose?

The most important issue is to have a piston that is built for the right application. Material, thickness and pin choice are the major factors. While a super light piston rated at 500hp may have a .150 crown thickness, a Nitrous/blower/Marine application needs between .220 and .250. Skirt thickness can vary from .110 to .150 depending on the application and rod angle severity at BDC.

7. In order of magnitude, what are the hardest conditions that a piston can be used in?

Street and drag race applications are fairly easy on pistons if ignition and fuel curves are correct. Circle tra

I had Wiseco in my jet-ski, a 2 stroke 750cc. They were the only pistons to get! My ski was seriously revvy and the Wiseco's stood up to the abuse! MSD total loss ignition, swirled head, ported........oops, going off topic here.

 

They look very nice! :D

They are really light too.

 

The piston pin is heavier than the piston.

Originally posted by Baggins

Spoke to SE about these as I was gonna use them , even sent SE the specs and all the blurb on them and got told in not uncertain terms to stay well clear because of what it does to the compression ratios of the car , from my understanding it raises or lowers the compression , can't remember which :rolleyes: so you can't run big boost , :( If anyone has any info to the contrary , I would be interested to hear as these look fantastin value for money

 

Errr, but putting a metal head gasket decreases the compression ratio.

 

Anything you do to the cylinders effect the compression. So it will be no different if I used JUN or HKS pistons.

 

Stuart

They look kinda familiar. Dunno, what do you reckon?..

 

Forged / busted

 

Mine were shiney and new once :)

 

Baggins - you wanna drop the compression so you can run more boost, which is what the blurb seems to be saying.

Dont know.

 

Pistons look like, Pistons to me ;)

 

But they only to have 2 gaps for the rings.

 

There seems to be a large gap and then the oil ring gap below.

 

These have the oil ring at the bottom, then the 2nd ring above it, then a small empty space and then the top ring.

 

Also the gap between the top ring and the top of the cylinder have grooves on, those in the ohter picture do not.

 

Also the cut out for the valves seem to go all the way to the edge of the cylinder. There is at least a 1mm maybe 2mm gap from the cut out and the edge of the piston.

 

Stuart

Just thought it was kinda strange SE saying "don't go there" when they look virtually identical to mine... which are SE's. Dunno, maybe they measure up differently. Still, they look fantastic... freshly plucked virgin-pistons :)

When you look at them side by side, there are quite a few differences.

 

 

 

So when you look there are more differences than simalarities. Lets take into account that all pistons have to be shaped that way too, so the parts of the piston which can be different are nothing like each other, if you get what I mean.

:confused:

 

Stuart.

Originally posted by SRRAE

if you get what I mean

Yeah, I s'pose. Bit easier to see side by side like that. Don't s'pose anyone's got a similar pic of a standard one? Sorry I h'aint got any pics of non-busted ones (forged or standard).

Originally posted by 51x

Yeah, I s'pose. Bit easier to see side by side like that. Don't s'pose anyone's got a similar pic of a standard one? Sorry I h'aint got any pics of non-busted ones (forged or standard).

 

Yea;)

 

Stuart, still really interested in getting these myself as they were my first choice for replacements, what thickness gasket are you gonna use ??

Originally posted by SRRAE

Errr, but putting a metal head gasket decreases the compression ratio.

 

 

Stu Metal head gaskets fail when used on a 300zx,ask PeterR;)

I am using standard gaskets for that reason MAC said.

 

Plus did any one read the write up on TT.net? Some mechanic wrote about the 300ZX engine and said that you should always use the Nissan stock gaskets. Others just dont work.

 

The pistons I got from the US. They are not Wiseco's ones for the 300ZX, even though they do a set for them. The place I got them from sent off the spec they wanted for a piston to Wiseco and these pistons are the result.

 

However they only do 87.5 and 88mm. 88mm is 3.1 litre :eek:

I got the 87.5mm so it will be larger than stock but not 3.1. Cant be that far off though can it? How can I work it out?

 

Anyway. I got the Pistons from Z1. http://www.300ZX.com.

Pistons are $540 and shipping was $55. With the exchange rate as it is, its less then £350 for the set, which includes rings. Lets consider when I was looking at options for my car, I was looking at £150 for a set of rinds a lone from Europe.

 

I actually got my pistons for cheaper, as they put stuff on Ebay every now and then. I am sure they would have put some stuff up yesterday considering it was a free day.

 

Stuart

does any one have any info on where each ring goes? There are a lot of rings and all seem to be different/made of different stuff. :S