I am waiting info from Wiseco on a replacement piston. Sent email, and left message at Customer Service today. Can't get them on the phone. Is this going to take hours, or days? Meanwhile, maybe someone in the buick community, familiar with Wiseco pistons, can give the answer. Currently, there here are only two 455 pistons available from Wiseco....... a flat top and dish top. In 2012 I purchased/installed Wiseco PTS 5055H4 pistons, Buick 455, bore 4.350, -22cc dish top. After only 600 miles, a blown cylinder (that's another story!) So, I need a single replacement piston. Wiseco distributors tell me PTS 5055H4 is no longer availiable.....what? Wiseco catalog no longer lists PTS 5055H4, but shows PTS 544A4. This piston appears to be identical in specs to my 2012 Wiseco dish top. Is this my piston with a revised catalog number? Anybody in the community have info, or a good path into Wiseco? Thanks, Don
The 544a4 is a 4.350 bore piston with 22cc dish. The 544as is 4.313 bore with 22cc dish. 543a4 is a 4.350 flat top,
Thanks Ben. Yes, the current 544a4 seems to have the same specs as the old 5055h4 and appears to be the same. But, piston weight is not listed. There could be other differences. That's why I'm asking, are the two pistons the same in all respects including weight, which is not listed. My question was: Is the current #544a4 identical , and therefore, can it be used as a replacement for one of the old #5055h4 pistons? This is really a question for Wiseco, or someone who has dealt with the problem of matching to an older Wiseco piston. Where is that expert? Thanks for your input. Don
Update on my Wiseco piston search: Wiseco called today, props to Wiseco for getting back to me in 24 hours. Rep. Mike, was not able to provide any info on my "old" pistons(purchased 2013). He had no info on whether the current catalog # PTS 544A4 is a re-numbered version of my "old" # PT 5055H4 pistons. Mike was anxious to help, but in the end was no help. I find it hard to believe Wiseco cannot answer a question about engineering/development of a current catalog listing. I think I was just talking to the wrong Wiseco person. Wiseco did confirm, for anyone interested, that Wiseco has plenty of shelf stock for PTS 544A4, A forged 22cc dish top with valve reliefs (nominal 10/10.5 :1). This is their most popular Buick 455 piston, and available in std bore and .40 over bore. Sticker price about $570, but discounted online as low as $440. Wiseco also has stock on shelf for the other Buick 455 piston they make(only two 455 pistons available from Wiseco). PTS 543A4 is a 8cc flat top with valve reliefs (nominal 11/12 :1). Still looking for answer to this Wiseco puzzle. Don
My suggestion is to either buy Joe's used set, and save the rest, or buy just one one piston, regardless of the part number, from Wiseco. Take that new piston to your machinist and have him evaluate it compared to the other seven, odds are he can match the weight if it is different, and then can check all the other dimensions to insure they match the original pistons. I used 2 sets of those Wiseco pistons when they first came out, the first set was installed at the Wiseco spec for the application, and they ratttled so bad when the engine was cold, I eventually replaced them with a set of TA pistons. The second set, we tightened up the clearance, and they were acceptable. I called Wiseco to give them my feedback, and got their head engineer, I don't recall his name, he said those pistons were on a list of ones to be re-engineered. I suspect the new part number reflects that engineering change. They needed to redesign the skirts, to lessen cold engine noise. This redesign will have no effect in matching it up with your other pistons, unless they changed the piston to wall requirements. lf they did tighten it up, then you can send the new piston for coating to take up the space.. the outfit I recommend is Line2Line coating in MI.. read all about their coatings, they are unique, and work well, I have used them in the past. JW
Final on Wiseco piston replacement. Thanks to Joe for the offer, and JW for the always valuable expert advice. Regarding old Wiseco# vs new Wiseco #, after a number of dead-end phone calls, I eventually learned that Wiseco redesigned/re-engineered the piston. I came to believe(as suggested by JW) that I could probably use the new version, counting on machinist to "match" it to my old pistons. But, I decided to buy a complete engine set of the new design Wiseco forged piston. As is frequently the case (always the case?) the decision came down to $$. A new complete engine Wiseco forged piston set(with rings/pins) can be had for best internet price of $441, free shipping. (Holy cow, this is substantially less than $675 paid Summit in 2013 for the old set). Made in Mentor, Ohio! However, the single piston kit" is not quite the same deal at approx $115......and as JW said it has to be re-balanced to the old set. I figured, what the hell I don't have a money tree, but for an extra $300+ over a single, i can get a complete set of the new version piston(at less than 1/2 what I paid for the old set). The new set will have to be balanced as an assembly, but the extra $ gives me the latest design pistons. Thanks again to those who offered comments/suggestions. Don
Might not have to be balanced, have then weighed first. It is possable that even if heavier or lightly slightly it might not really effect the end outcome. Be curious to see what your scale in compared to the old. My set of flat tops if I recall were right around 660 grams. Had 4 right on, 2 were 1 gram under, was 1 over, 1 was 2 gram over which we brought down into range. I thought that was a pretty reasonable outo me from a 450 dollar set of pistons, pins, and rings
Ben, My brand new set of PTS543A4 flat-top forged pistons was apparently weighed/marked as part of Wiseco production & packaging. Each piston weight is clearly marked by hand with a "sharpie" ink pen. My piston weight is either 664g or 663g. Since you had at least 1 piston at 559g, that means as much as 5g difference between your flat-tops and mine. I'm guessing that little difference is meaningless in terms of engine performance/dynamics. The important point is that Wiseco apparently provides a piston set that is matched within 2g. This is the only buick 455 I've built. Certainly, I'm not happy with having to rebuild a 600 mile engine which ran beautifully until an allen screw went into #2 cylinder. Figuring out what to do with this Wiseco old piston # vs. Wiseco new piston # has been a PIA. However, I have received good help/advice here, and I am not unhappy with either my old or new set my Wiseco pistons. I especially like that the Wiseco"new" design set cost substantially less than the old Wiseco set ($441 vs $675). End, Don.
Mine were marked too, but we double checked each piston to totally verify. I hate to assume anything. My weight from theirs were on on some and off slightly on a few.
