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One off piston pics

Here are some pics I figured I share of some one off Wiseco pistons I just had made for a 930 motor I am doing. .
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Christian Garibaldi
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Old 07-08-2004, 07:24 AM
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Nice ! Lets talk about your engine. Specs and pics if you got em.
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Aaron. F.S. 1965 Solex engine w carbs/cleaner
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Old 07-08-2004, 07:30 AM
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Hi,

I find it interesting to see there is no dome on the piston. What was the reason for designing the piston with a 'flat' top ?

Thanks,
Michael
Old 07-08-2004, 07:33 AM
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Its for a turbo so not too much dome, but the eyebrows make room for some more cam.
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Aaron. F.S. 1965 Solex engine w carbs/cleaner
Burnham Performance
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Old 07-08-2004, 07:51 AM
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The lack of dome is to drop compression. Actually on this motor, the target C/R was 8:1, and the Mahle 3.4 7.5:1 p/c set actually poured out to 7:1 give or take a few tenths of a point depending on which base gasket you ran. So instead of milling a ton off the heads, it was more efficient and cost effective to have the pistons made. This way I could tailor material, pin offset and location, ring package, material, skirt design, taper, dome and compression height, dome thickness, valve pocket depth, etc, to my need for this motor. Now it yields the clearances I want, no matter what cam the customer uses, piston to head is more than ample, and most importantly, the c/r is 8.05:1.

ANyone looking to buy a new, unused set of 3.4 pistons with rings and pins and clips? No cylinders though.
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Old 07-08-2004, 08:25 AM
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.
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Old 07-08-2004, 08:26 AM
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Thanks for the detailed explanation. In my first reading of the post I didn't notice it was for a 930.

Michael
Old 07-08-2004, 12:49 PM
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What is the purpose of the grooves above the top ring? And, if my eyes do not deceive, it appears you will be using an extra compression ring, correct? Looks fabulous to my untrained eye. Jürgen
Old 07-08-2004, 02:11 PM
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Actually the grroves obove the top ring are a wearable surface for lack of a better word. It is to reduce surface area in that area should the top area contact the wall when the piston rocks over center. That surface does not come into contact with the wall, but in old days, before there was skirt rigidity and geometry, they would cut grooves like that in the skirt as well as the top area of the ring lands to prevent galling. I suppose now its there just for tradition. All the Wisecos I get have that.

The groove between the two top compression rings is not for a third comp ring, it is there to give the oil on the walls a place to go as the top ring wipes down. It helps avoid a hyraulic lock between the top rings. The top ring actually controls the oil contrary to what you think, the oil control ring gets most of it out of the way, but the top ring is what really does the job since that is the one that seals tighest against the walls.
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Old 07-08-2004, 03:18 PM
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Mr. Garibaldi,

Why Wiseco pistons? Have you had better luck with theirs as opposed to J & E's?

Are they comparable in costs to J & E's?

Due you run barrier coatings in your turbo motors?

Tinker
Old 07-08-2004, 04:25 PM
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Nice pistons. Correct me if i'm wrong though, i thought using parts in the combustion chamber with sharp edges was generally not a good thing?
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Old 07-08-2004, 11:04 PM
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I have used JE before, if a customer brings them in. I use Wiseco becasue the guy That I apprenticed under used Wiseco, and he, and I through him have a great relationship with the aplications engineers at that company, and they will do pretty much any combination we ask. So when doing a motor, I can contact them and tell them the specifics on the engine, as well as what I am looking for in terms of an end result and we come up with a piston that fits our requirments. I have never had an issue with them, and I use them just because I have a realtionship with them and they are not opposed to doing a one off specific set for me, instead of only offereing mass produced production runs. Plus their quality is excellent.

In the past I have nto run any coatings on the turbo motors. In my opinion, the arenot the best for a street type car. For a balls out race motor, they may offer some merit. I think I will wait a bit longer for the technology to be proven before swearing by them. I would consider their use in a racing application where there are themal extremes, but for less severe use I dont think its needed. The only thing that holds me back is that if they fail, you could be in big trouble. I recently pulled apart a high performance motor that ran a caoting on the skirts of the pistons, and half of it was flaked off. This was a coating applied by the manufacturer, and it wasnt worn off, it was flaked off in chunks, now depending on the coating and where it is applied, if lets say a piston coating fails, that very hard and durable (by itself) coating can be imbedded into a cylinder wall, or pulled through a pump, etc. I have heard in the past there were issues with coated piston rings where the channel would dislodge its material and stuff it into the wall, thus hindereing the proper ring seal.

In closing, dont misunderstand me, I am not saying that coatings are not good, or dont work. I just dont use them right now, nor do I have that much experience with them.
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Old 07-09-2004, 06:13 AM
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I'm just used to hearing to old engine builders tale of sharp edges in combustion chamber = detonation prone motor. I'd like to know if that a bunch of bull or true that all. And for what it's worth, wiseco pistons are highly used in motorcycle racing, and take one hell of a beating.
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Old 07-25-2004, 06:19 PM
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Christian, thank you very much for posting those. What is your target maximum boost pressure for this motor?

Thank you,
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Old 07-25-2004, 07:54 PM
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Probably around 1 to 1.2 bar.
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Old 07-26-2004, 05:45 AM
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