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Ok, I have 15,000 miles on a set of Keith Black Forged Pistons. It looks like the ring has rolled and I have to replace them. I do NOT want to use these again! I see the threads about Ross, CP, and JE. Not a big deal. I have already bored .20 over, but hopefully I won't have to go further, Yet.
I am wondering "How Long is the Forged Piston going to last"? I talked to two machine shops and they both said that the forged piston ring will probably need to be replaced at 30,000 miles and then Piston and rings will need to be replaced at about 60,000. I am only making about 400rwhp and I don't see going any higher.
How long have your Forged Pistons Lasted???
Thanks
 

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damm i thought forged pistons meant not only will they take more power, but will last a lot longer than weaker pistons... :stickpoke
 

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desufnoC
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etdean2 said:
Ok, I have 15,000 miles on a set of Keith Black Forged Pistons. It looks like the ring has rolled and I have to replace them. I do NOT want to use these again! I see the threads about Ross, CP, and JE. Not a big deal. I have already bored .20 over, but hopefully I won't have to go further, Yet.
I am wondering "How Long is the Forged Piston going to last"? I talked to two machine shops and they both said that the forged piston ring will probably need to be replaced at 30,000 miles and then Piston and rings will need to be replaced at about 60,000. I am only making about 400rwhp and I don't see going any higher.
How long have your Forged Pistons Lasted???
Thanks
Kinda crap is this? I hope not! I didnt spend more to have them not last as long...
 

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Discussion Starter #4
When I talked to the shops, they were saying that there are some improvements in all of the pistons out there, but they say that they still don't last very long. I also talked to a Toyota Master Mechanic ans he said the same thing. HE did add that if some guys out here are using some newer Brands (CP), it may be beneficial, since they may want to be better and more price competitive. Each of the SHops and Mechanic felt that the harder piston, causes the piston to "slap" and this also cause the short life of the rings.
 

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I believe piston slap is caused by forged pistons being sized a bit smaller to compensate for a larger heat expansion coefficient. When you start up, they are smaller than when they heat up, so they "slap".


As for supras, I have no idea, but in stock 5.0 mustangs the stock pistons are lasting way longer than 60k miles (afaik)
 

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Buddy thought I had a NA
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yes they slap more cause htye hav eot have proper clearese


je and cp are junk in my mind they have dick all for skirt


ross pisotn as much better since they still ahve the skirt and will not slap as much and if you run good molly ring you should nto have top much turbo besides breaking them in
 

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wtf?? replacing piston rings isnt supposed to be on the "Every 30k miles" maintenance schedule
 

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someone on these boards said he had 210,000 on his ROSS pistons, maybe he will chime in. I absolutly can't believe that forged pistons only last 60,000. Sounds like a load of crap. I just got a set of ROSS pistons and Pauter rods and I am expecting longer than factory life out of this engine.
 

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b/s the turbo coupe comes stock with forged pistons and so do some mustangs and i can tell you they last alot longer.
 

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I have a set of factory pistons in excellent cond. after 70,000 so do you really think that forged are going to crap out after 30,000? It is the builder that caused the problem or unproper tuning most likely. There are also other things that may be wrong but pistons dont go to $hit after 30000 miles for no reason.
 

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I like wisco pistons they dont require as much clearance as JE and some of the others ..I've used wisco in most of the motors that I have built..If you are replacing the rings after 30k than somthing is wrong .. depending on the motor(race none race )

p.s
I'm a toyota master tech
 

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Discussion Starter #13
Thank You
Tun_x
 

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25psi = 14" brakes :)
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Ross calls for 6k clearance on the pistons, but if you setup more than 4k, your going to have piston slap like crazy. (Especially if your pistons are coated.)

The 7M does not like a short skirt piston from what I've seen. (Slap city.)

Go with coatings on the crown, and skirts, and if you can, get the thermal dispersant on the undersides as well. This will keep the forged piston from expanding as much from heat, and you can run closer tolerances so there is minimal/no piston slap while the engine is running. (If you don't coat them, I don't know how close to run, but I have read 4k is what uncoated guys are running ROSS pistons in the 7M with no problems.)

I did have an engine with excessive clearance, and it was slapping like crazy. (Sounded like a powerstroke diesel truck.)
 

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I Didn't Do It!
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if the stock pistons can withstand 200K+ miles how can stronger pistons not last just as long? I don't understand that?
 

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One thing that I think is being missed is that most forged pistons are designed for race applications. ... Extreme heat (egt) in wich case the piston is going to expand hence the need for wider tolerences . Most piston manufactures take this into account ..Some pistons expand more than others though...It is really important to have an experienced engine builder that will take into account your personal goals and setup..
 

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HKS T51R
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I would have thought forged pistons would last alot longer than 30,000miles. and ross pistons should last ALOT longer than that
 

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adjuster said:
Ross calls for 6k clearance on the pistons, but if you setup more than 4k, your going to have piston slap like crazy. (Especially if your pistons are coated.)

My ross are at .005 and very little slap when cold.
 

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adjuster said:
Ross calls for 6k clearance on the pistons, but if you setup more than 4k, your going to have piston slap like crazy. (Especially if your pistons are coated.)

The 7M does not like a short skirt piston from what I've seen. (Slap city.)

Go with coatings on the crown, and skirts, and if you can, get the thermal dispersant on the undersides as well. This will keep the forged piston from expanding as much from heat, and you can run closer tolerances so there is minimal/no piston slap while the engine is running. (If you don't coat them, I don't know how close to run, but I have read 4k is what uncoated guys are running ROSS pistons in the 7M with no problems.)

I did have an engine with excessive clearance, and it was slapping like crazy. (Sounded like a powerstroke diesel truck.)

hey greg your my buddy and all, i'm i'm going to have to disagreee with you on this. i got a .007 piston to wall with my ross pistons and the supra is running awesome. pulls like a motherfucker, and is very quiet. i'm very happy with this new motor
 

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Keith Black pistons do not have a good reputation, and from my own experience, they are not very good.
Now, Ive had good experiences with ROSS, Mahle and Wiseco. Never had a problem with them.

When confronted with piston problems, most of the time (in my experience) its the builder making mistakes with ring choice and ring installation.
 
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