AMGSC

Are my old pistons suppose to look like that?

AMGSC

Do you see any major damage here?

hooleyboy

IT looks like the stock pistons were scorched a bit. Maybe you were running a bit rich at some point or got some bad gas. I've seen worse.

hooleyboy

Its hard to tell with this picture (its small). the other picture of you head looks to me in great shape. I've seen people with blown head gaskets melt away the metal in between valve/piston chambers.

Are you going to put the heads on a flow bench? If you are going this far, I would think its a must after porting. Your sleeving the block right?

AMGSC

Good suggestion. I'll ask Vadim to do that. As for the sleeving of the block, I don't know why Vadim insists that it's not necessary. He also firmly believes that the AMG forged rods are strong enough for 7-800hp. I asked him to do both and bore it out to 6.1liters and sleeving it but he still refuses at this point. I even budgeted for Titanium rods. Vadim is a very practical tuner and does not want us to waste our money on mods that don't provide meaningful return on investment.

He did agree to use my larger fuel injectors and fuel pump controller to increase the fuel flow while exploring what intake mods make the most sense.

He keeps telling me this build can support 800bhp without any problems but I still worry. Especially if I go the Turbo Garrett GT55s route down the road.

hooleyboy

I dont want to step on anyones toes here. IMO, most race motors that put down those kinds of numbers have sleeved blocks for added protection and strength. I hear there is only a few people in the country that have the CNC mill that is able to machine out the coating that is on the cylinder walls. ( I could be wrong??)

The piston rods are strong sure but with that kind of power weak spots will be found. I've heard that the block will become the weak spot.

When the SL65 Brabus S was on Top Gear, Clackson talked about how the block was modded to handle the power it was putting down.

I just dont know if that kind of boost and power would be safe on a 91oct map.
Also a thing to think about is the stock oil cooler on the C55 might have problems handling the gobbs of heat with your new set up. Might want to switch to an E55 remote oil cooler with fan and radiator.

Motor protection is going to be paramount. I dont want to scare you but some questions to ask is, Can the Crank, bearings, and fasteners handle what you are throwing at it? Getting your heads ported and new pistons is one things... High HP cars always seem to find the weakness in the motor and driveline.

AMGSC

Thanks for some good feedback. I doubt this car can go 800hp without additional inforcements of the block. I think going 18psi should be enough. As far as I know the bearings will be upgraded. The crank shaft and the axles remain weak points. Vadim is also polishing and smoothing out the rods and crank journals to prevent any cracks from developing. So far my build is costing me a lot less than I budgeted but I don't want to go overboard to the point where it doesn't make sense anymore.

btw...I was just checking prices online and name brand (CP, Ross, Wiseco, JE, Diamond, Manley,etc) Racing V8 pistons average around $800, rods $900 (Crower,Carrillo, Pauter, Mahle, Oliver, Eagle ), valves $600 (Ferrea, REV, Milodon) ,so why are they so expensive for MBs? For example pistons cost me $4,000 while valves cost me $3000. I suppose that includes labor but I'm paying separately for 30hrs of engine installation. The tranny cost me $5000 alone.

Does this price sound about right?

FrankW

was that piston from one of the rear bank that was fried? it's not normal of course. lol

Biscuit

This might help give you some comparison prices... Building out my Saab engine right now and picked up a set of JE forged 91mm pistons with top & skirt coatings for $750. That's for four pistons.

I looked at getting a set of Crower forged rods as well which were going to run another $750. I ended up passing on that since stock Saab rods are crack forged and can handle the power without issue.

I realize it's a totally different engine, etc... But that should give you something to go by anyways. To me, $4k would be about double what I'd expect to pay for forged coated pistons.

Hope that helps.
Rich

spr

The reason for removing the casting flash on the rods aka polishing the beams is to strengthen them a bit. Polishing and rounding the crank journals is for oil flow and of course bearing performance. I would assume he is going to blueprint the tolerances as well. You may also put in a crank scraper and windage tray in the pan if non existent. This picks up a good 10hp at top end Still down to sell me the SC when you get your turbo?

AMGSC

Thanks for some more good advice! I hope Vadim does not forget to perform these steps and I will remind him to check if its been done.

Vadim told me the turbos will cost me another $8K but if I can recoup $6K from the sale of my unique SC which only has 1K miles on it then I'm down for it unless Vadim is unwilling to bore and sleeve for the turbo app which would cost me a few grand more I guess but no problem.

I will check my PM history but I believe you were one of the first to contact me about your interest.

btw.. Can you elaborate on the crank scraper and windage tray for us ignoramousses? Also what do you mean by blueprint the tolerances?

Thanks in advance for educating your fellow forum members.

AMGSC

Thanks Rich for the comparo...I hope Vadim can explain the difference and I think he can but I still like to know...

edit: I believe custom pistons cost more..plus piston rings, stops, etc.. will cost another $400 and special Alusil coating so maybe that's why they are so expensive?

Vadim @ FD

Let me clear couple of things:

1. Sleeving an aluminum block on a street car is a 50/50 proposition. I have seen some motors last 10K plus and some less than 1K, as sleeves shift and cause coolant leaks. Yes it works on the race motors, but not very well on the street. Since we are running boost, I would rather make the motor accept more boost in the factory configuration, than risk overheting the motor and making it junk.

2. Since we are keeping stock redline, going tatinium is a waste of resources. It is a street car driven 7 miles a day, with occasional strip duty.

3. Adding untested crank scrapper or windage tary can actually lead to oiling problems. Factory design is very adequate. How many AMG motors have failed from lack of oiling? Again, we are not building IMSA or drag racing engine.

3. Robert please look carefuly at your invoice, the prices are for complete short block and heads, plus a discount below.

Vadim @ FD

As far as stock piston. For those who never took their engine apart, this is how they normaly look. All of them have a layer of burned hydrocarbons. Two that damaged rings were slightly darker.

AMGSC

As usual that is why I chose Vadim for my build. Knowledgable and trustworthy with NO BS and NO HYPE.

Thanks again and sorry I appear to be doubting you. I should bite my lip before I ever question you but your input sure is good sensible advice for me and these forum members who are doing extreme mods like Blackbenzz, Hooley, mb_c55_guy, Alumnar and a few others...

splinter

There’s nothing improper about wanting to be an informed and prudent tuner customer.
I'm darn sure you’re in good stead relying on Vadim’s vast experience and know-how.

Some light reading on blocks and pistons - from a trusted OE M-B supplier - to better understand the nuances confronting your engine builder:

http://www.kolbenschmidt.com.tr/pdf/...804-02_WEB.pdf
http://www.kolbenschmidt.com.tr/pdf/...-02_en_web.pdf

AMGSC

Excellent stuff again! I guess I'll be smarter in the next hour...

Edit: This stuff is pretty deep so instead of one hour I think it's going to take me 1 year to fully understand. I guess I'm not that smart after all!

C32_Underdog

um, stupid question here but...

what is wrong with the pistons on the right?? you can probably clean that up good with some seafoam. the ones on the left seem to have plastic on the bottom...wtf? Isn't the single forged pistons way better?

Vadim @ FD

The piston on the right is stock at 11:1 Compression Ratio. The piston on the left is custom made, forged 9.0:1 Compression Ratio. It is coated with special coating so it can be used in Alusil coated cylinder.

I was thinking about recycling some old Rubbermaid garbage cans to cut out some pistons, but my kid's scissors broke.

Havoc

AMGSC- Can you please remind me why we went with this guy???

C32_Underdog

Yes but if something is "forged" then shouldn't it be formed from a single piece of metal and shaped with a mechanical or hydraulic press?

How do you figure the pistons on the left are "forged" if it is clear from the picture the lower section is a completely different material than the head of the piston?

AMGSC

The material is just a special coating so it can slide inside the Alusil cylinder walls. This coating is not in the original forged metal I believe.

hooleyboy

When something is forged like those pistons its done from a solid piece of metal... In this case aluminum. This types of forged pistons start out a a chunk of aluminum and are CNC milled into pistons.

edited...

hooleyboy

whats the weight of the new pistons vs the stockers.

MRAMG1

I have one IMPORTANT question for you:

1. The NEW psiton has the oil ring located in the wrist pin cut out area. On stroker mustangs, this has lead to premature failure of the oil ring, usually around 10,000 miles. Vadium, have you addressed this issue?

I know sonetimes this IS the only way to go, so I understand the engineering behind it. Just keep an eye on your tail pipes a few thousand miles down the road.

GOOD luck, and truly a GREAT build up

See yeah

PS: For LOW reving engines, aka below 7000, Titanium is a WASTE of money as was stated above. You will see NO gain, due to decreased mass below this.