opinions on engine rebuild oem vs aftermarket pistons

[rfelker]

Had a cam chain falure tues. So now eveyrthing is being rebuilt. If everything checks out on bottom end would guys stick with stock pistons with upgraded rods or do aftermarket pistons. Really going to towards stock pistons but not set in stone. Will be running CTS k04-x if that matters.

thanks

[Jayz691]

I'm just doing drop in rifle drilled rods(IE), cuz only k04. No need for aftermarket at that power level. Just wanna take care of the weak point. If no piston damage, if leave em stock.

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[esandes]

It happened to me too. I kept the same pistons and just used a rebuilt head. The last time I checked ecstuning.com has good rebuilt heads. Check your cam follower. It was the root cause for my cam chain carnage.

[rfelker]

esandes- just checked my cam follower month ago so I dont think it was that but I havent pulled anything yet. I have the engine and tranny ready to pull for this weekend. hopefully all it is bent valves and the pistons are ok. Really wanted to keep the stock pistons BYG engine code and just change rods rings bearings and Oil Spray Jets. Will also refresh head with new valves springs and all new little crap on the engine. plan on having everthing up and running by oct hahahahaha

[Branzor]

How many miles was on your car when the Cam chain went?

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[rfelker]

110k and no signs or sounds. just popped lucky I was just pulling out after stop sign.

[esandes]

esandes- just checked my cam follower month ago so I dont think it was that but I havent pulled anything yet. I have the engine and tranny ready to pull for this weekend. hopefully all it is bent valves and the pistons are ok. Really wanted to keep the stock pistons BYG engine code and just change rods rings bearings and Oil Spray Jets. Will also refresh head with new valves springs and all new little crap on the engine. plan on having everthing up and running by oct hahahahaha

110k and no signs or sounds. just popped lucky I was just pulling out after stop sign.

That's when it happened to me too. The valves likely just kissed the piston like it did mine and those same pistons and whole bottom end are still going strong. Just look at the pistons and feel them for the depth of the damage. Should be fine.

Just watch the valve guides. If they're still good the rebuild should be easy. My cam chain housing grenaded so I needed a new one of those too.

[rfelker]

didnt get a chance to pull engine. Just got back the wifes TT from paint. So had to put everything together. hoepfully this weekend. think Im just going to rebuild everything. Planned on going with the CTS turbo but now looking into the EFRs.

[aluthman]

Use stock pistons on a k04 build. Aftermarket pistons are unnecessary unless you’re shooting for big power (~500 hp).

[Charles.waite]

I'm just doing drop in rifle drilled rods(IE), cuz only k04. No need for aftermarket at that power level. Just wanna take care of the weak point. If no piston damage, if leave em stock.

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Same here. Drop in rifled IE rods. Don't fuck with pistons unless you plan on shooting for the stars (aka over 400whp).

[rfelker]

I really havnt decided yet. Want something for daily but also want more out of the car. I do have other cars just like to driving my b7. Plus have way to much invested now to scrap it and go with something else. Whats a reasonable number for a FWD 6speed that can actually get out of its own way but daily driven?

[esandes]

Use stock pistons on a k04 build. Aftermarket pistons are unnecessary unless you’re shooting for big power (~500 hp).

100%. The golf r runs k04 and has the same piston and rod steel type as our 2.slo

[Charles.waite]

Golf R rods are definitely sturdier, and probably forged. Side by side they’re thicker (someone posted side by side comparison pics a few years back). The pistons are pretty much the same I think.

[rfelker]

So this is what I been thinking. Drop in rods if pistons look good. Refresh head all new valves etc. New clutch and tranny because 2nd gear grinding. All new parts outside engine lines tstat hoses. For turbo want to run the cts hybrid k04-x That way keep all the emissions stuff I live in upstate ny so they look at that stuff. goal is 400hp and with water/meth setup 425 anything after that would be a bonus. Also wanted to do a balance shaft delete and is it as easy as just cutting the gear off?

[Jayz691]

So this is what I been thinking. Drop in rods if pistons look good. Refresh head all new valves etc. New clutch and tranny because 2nd gear grinding. All new parts outside engine lines tstat hoses. For turbo want to run the cts hybrid k04-x That way keep all the emissions stuff I live in upstate ny so they look at that stuff. goal is 400hp and with water/meth setup 425 anything after that would be a bonus. Also wanted to do a balance shaft delete and is it as easy as just cutting the gear off?

Well, BD delete depends on condition of shafts. If theyre tight, personally, I got the WASA freewheel. If you cut the gear, you SHOULD still install a solid wheel. Cus the dampened sprocket can still fail. So easier and quicker to do freewheel, and reversable(if it matters). If you have play in your shafts, either get a used pump, or weld the oil feed closed, so they don't bleed oil pressure. I bought a used pump before pulling mine apart, to save time. But surprised mine was still tight after 210k miles. My issue of low idle pressure was strictly piston cooling jets.

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[rfelker]

good to know about the pump. I have the WASA on my parts list but didnt think I needed it if I cut the gear. Cooling jets where also on my list. Ill make that decision after I break down the engine this weekend. If I get to it. Still doing crap on wifes car. Been in paint shop for 2 months waiting body parts. and after all said and done now the rear powersteering return line is leaking not fun at all to replace on a TT. Ddi tell the wife that I put a rod though the block so now she thinks I need to rebuild the whole damn car hahahhaa

[Jayz691]

good to know about the pump. I have the WASA on my parts list but didnt think I needed it if I cut the gear. Cooling jets where also on my list. Ill make that decision after I break down the engine this weekend. If I get to it. Still doing crap on wifes car. Been in paint shop for 2 months waiting body parts. and after all said and done now the rear powersteering return line is leaking not fun at all to replace on a TT. Ddi tell the wife that I put a rod though the block so now she thinks I need to rebuild the whole damn car hahahhaa

Well, ya don't "need" anything if ya cut the gear. But your still leaving a weak point, if ya leave the sprocket in there. Not AS likely to fail, if the BS's are disengaged, cuz less stress on it, but can still happen. Its still spinning the big gear. So thats up to you if the extra $150(or whatever) is worth the peace of mind and insurance.

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[Charles.waite]

And keep in mind you can’t just rip the balance shafts either as they will leave gaping holes straight off the oil pump and will kill your oil pressure (and quickly kill your engine).

[Theiceman]

I don't want to sidetrack you on this but I have helped many people put a new chain on and time it and it was fine. I hope you are not just assuming valves are bent.
That's a lot of work when you consider a new chain and tensioner " might" fix it
My son did exactly the same. Broke the chain and tensioner. At relatively low speed. Fixed it with chain and tensioner about 4 years ago and she still lives.
Just food for thought before you tear it all down.

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[Theiceman]

I would suggest at least glancing at the " that's all she wrote" thread before commencing in tear down if you are interested in fixing it as oppose to complete rebuild on a 15 year old car.

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[rfelker]

Theiceman-I wanted to go new turbo anyway so its a rebuild. Now just trying to figure out what turbo.Been looking at ATP package(450hp) 0r the CTS hydrid k04(400hp) but issue is I cannot run with Test pipe. will need cat or modify my 034 cat. Goal is at least 425 with 93oct and 450 hp with watermeth 4 nozzle setup with IE intake manifold.

[Theiceman]

got it !!! this is a performance build , not a repair .
carry on :)

[Charles.waite]

You’re going to really need to focus on fueling for any build bigger than a plain k04. Our low ends freaking suck even on a tuned k03.

[Jayz691]

You’re going to really need to focus on fueling for any build bigger than a plain k04. Our low ends freaking suck even on a tuned k03.

I have the CTS k04, stock lpfp, and r8 controller, and my low side never dips at all. The r8 controller made a big difference.

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[Charles.waite]

Yea the R8/Q7 controller is probably the best bet. Not sure if it could handle a small frame GT (the ATP Kit) but you don’t know until you try! If it’s too puny then the PM4 is the best step up.

The best part about the pm4 is that it uses a dedicated battery connection with much thicker than stock wires. It’s not cheap though. And not necessarily plug and play, though pretty damn close.

[Jayz691]

Yeah, the PM4 is a big step up in price. $750 compared to $150, lol. If ya need a little more, ya could get a 340lph pump(or similar), for a lot less. Which should be pkenty for a smaller BT setup, or a hybrid, ect. Haven't seen too many people running the torqbyte, prob cuz of the price. But its def a higher end choice.

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[rfelker]

already have the supporting mods for step up to the bigger turbos except the rods injectors and clutch. So its a no brainer to go bigger. My real issue is running the ATP kit with the test pipe and fueling. Ive run test pipes in the past and its a hit or miss on getting a go on the emissons clearing. had good luck with the Audi TT running the 52 designs spacer but not with my b6 running a spacer. Plus shops in upstate ny are cracking down now. Good thing is I can have 1 fail out of the 5. So maybe I will be ok.
Talked to a hot rod shop few hours away last night. Guy is 70 and does head work. From what I have been told he is a wizard at port matchng etc. Is there any gains to be had on port matching polishing the intakes on our heads or should I just replace everything valves springs and have the head decked?
Purchased a engine hoist last night. So shes going to be pulled with tranny this weekend or middle of next week. Plan is going to be have the whole car done in 4-5 months but depends on money. Really dont want to take out a loan. Created my parts list last night and Im hitting 8k.

[rfelker]

forgot to ask I have the bpg engine didnt that come with forged pistons?

[Jayz691]

forgot to ask I have the bpg engine didnt that come with forged pistons?

Yes, crowned forged pistons. Not as good as aftermarket forged pistons, but better than BWT pistons. Plenty good for what your planning.

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[Charles.waite]

Why do you have to run a test pipe with the ATP kit?

[rfelker]

from what Uro tuning is telling me only ATPs test pipe will fit that does come with the kit. either way going with one of the ATP kits still deciding on either the GTX2871R or the GTX2867R either will be .64 a/r. hopefully the 52 draft designs spacer will help. or I can have my local welder chop up the 034 HFC or my stock cat. looked into the PM4 and also will be purchasing that. Im building a custom housing for Snow performances large 5 gallon W/M tank where the spare tire goes so I will mount the PM4 there. My fuel pump is in the trunk of car being that I am FWD.

[Jayz691]

Looks like the ATP kits run a V-band test pipe, with an adapter to the turbo. So you could use a HFC, and have someone cut the flange off, and weld a v-band flange on it.

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[Charles.waite]

ATP’s manifold probably is not be stock location though so that’s unlikely to work. You’re better off having someone weld in a cat to the ATP test pipe.

They also make a stock location kit: https://www.atpturbo.com/mm5/merchan...egory_Code=AB7

Though everything is sold out and while that particular kit is an old gt2861rs, the sizing is the same in the gtx series so it would work for those too. Though, supply chain issues being what they are, you might be waiting a long while for something more specific like that vs. something that a tuner has on the shelf right now.