Manley 99.50A and 99.50B Pistons

[Waddlz]

Been running these in my car for 22k miles. So far, no oil consumption and no issues.

New case halves. BBBB
Manley B-graded drop ins with total seal
Eagle H-beam rods
King bearings
OEM 2012 STi crank

Car is making ~500 whp on high boost, and ~420 on normal boost. E85 mostly.

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[pcampbell]

Has anyone had any luck putting graded forgers into a used block that has just been honed?

[yamahaSHO]

I would not do that, they are noisy enough with a new block.

[Rideit636]

They make a 99.55, but most used blocks should really go to 99.75 off you want a nice square bore and run tighter PTW. You'll see this once torque plates are installed.

[motorbykemike]

Originally Posted by Rideit636

They make a 99.55, but most used blocks should really go to 99.75 off you want a nice square bore and run tighter PTW. You'll see this once torque plates are installed.

that's pretty much it in a nutshell

[nucci]

99.55 requires the bore to go from 3.9179 factory to 3.9192-3.9200 depending on desired piston to wall, they are NOT and could never be drop-ins.

Additionally they ship with 99.50 Total Seal rings which out of the box have first and second ring gaps in the .021-.026 range in the 3.9200 bore, which in my opinion is too loose for a non-race engine, and the oil rail gaps are huge if you care about those.

I just did this and I ended up getting them to work by buying a 99.75 set of the same rings and mix-n-matching to gap them to .018/.019 first and .025/.026 second.

Highly would not recommend, do drop-ins and wait to blow a head gasket or spin a rod bearing, or properly hone to 99.75 and buy those.

[pcampbell]

We are talking about grade A and B drop ins. Pretty sure these are made specifically to drop in without boring?

[nucci]

Originally Posted by pcampbell

We are talking about grade A and B drop ins. Pretty sure these are made specifically to drop in without boring?

Rideit636 brought up 99.55, and yes the rest of the thread is about the graded A/B pistons that fit stock bores.

[Rideit636]

Originally Posted by nucci

99.55 requires the bore to go from 3.9179 factory to 3.9192-3.9200 depending on desired piston to wall, they are NOT and could never be drop-ins.

Additionally they ship with 99.50 Total Seal rings which out of the box have first and second ring gaps in the .021-.026 range in the 3.9200 bore, which in my opinion is too loose for a non-race engine, and the oil rail gaps are huge if you care about those.

I just did this and I ended up getting them to work by buying a 99.75 set of the same rings and mix-n-matching to gap them to .018/.019 first and .025/.026 second.

Highly would not recommend, do drop-ins and wait to blow a head gasket or spin a rod bearing, or properly hone to 99.75 and buy those.

Rewind. I never said they could be dropped in. I'm saying they are the smallest useable size on a seasoned case. They'll obviosuly require honing. But that's the point. You can't just seat new rings on a worn crosshatching. Drop-in's are for a new case. And yeah. Those gaps put of the box do suck. Your second ring is still on the loose side IMO.

[pcampbell]

Does anyone else make A/B pistons?

[flyboynextdoor]

I’ve been running these pistons for two years now.. no issues. They chatter a bit on start, but my block has a lot of miles on it. Haven’t had it tuned since the rebuild. But it was dyno’d at 282whp and 295lb’ at the wheels with 11psi. I don’t regret getting these compared to getting the block machined for other pistons and still having cold start noise.. once they warm up it’s quiet and runs great.

[pcampbell]

If IAG puts drop in pistons in, I am sure they’re fine on a NEW block. They actually use JE I think.