Turbo M20 2.8L Stroker w/ 135mm rods

[digger]

The piston guy what you want they can mod as required, 9.5 is just what you get with Oe dome as is with standard valve reliefs.

[SLEEPYDUB]

Sometimes I wonder if you guys are serious about what you post.
9.5:1 CR for a boosted engine? Most N/A strokers go with similar CR and aftermarket cams.
Unless M/Ethanol or special racing fuel is used there is no way that decent boost is inducted into this thing.
No one mentioned about boost limits on this "build", but it is apparent that it is a fantastic project for a discussion.

Well if you would have read early, you would see that I mentioned this car will be strictly rsn on Ethanol only, as it is available at the pump here. I would like to stick with 9:1, though I dont think 9:5:1 would cause any problems.

As for boost limits, I'd like to know that as well, the stock engines have already seen 30psi and the car was a rocket, so I'd like to run 30-35psi on a 6266 when I need it. I am debating Oringing the block OR sticking with OE gasket and ARPs, just in case we have a problem with detonating during tuning. MLS has been brought up, which is an option. Power goal is ~600whp

[digger]

It's not high less than stock b25 euro engine

[apostate]

Gapless top will be fine for you, topend can do an OEM 8.8:1 dome style for 885 head on a piston for a 84mm crank should net 9.5:1 CR give or take.

Sometimes I wonder if you guys are serious about what you post.
9.5:1 CR for a boosted engine? Most N/A strokers go with similar CR and aftermarket cams.
Unless M/Ethanol or special racing fuel is used there is no way that decent boost is inducted into this thing.
No one mentioned about boost limits on this "build", but it is apparent that it is a fantastic project for a discussion.

[digger]

This car will be full time E85, so what should I do?

Gapless top will be fine for you ( conventional also good I'd still get total seal brand rather the Std ones from Je) , topend can do an OEM 8.8:1 dome style for 885 head on a piston for a 84mm crank should net 9.5:1 CR give or take.

[apostate]

prostate stfu

you're not contributing anything at all here. I'm surprised you haven't been banned yet. Not for being a retard, but for being an asshole.

I don't give a FUCK if I am banned from this forum.
And you are wrong, I am contributing. A lot.
Digger and EngineBuildingBird will confirm.
I have instructed them so since they are my inferiors and therefore slaves.

[MrBurgundy]

prostate stfu

you're not contributing anything at all here. I'm surprised you haven't been banned yet. Not for being a retard, but for being an asshole.

[apostate]

..
That is a lot of options...i dont even know what I do or dont need as piston options...

Then you can't build that engine.
The variant is that someone is building it for you and you just seek for an advice here.
Better ask the guy who is building the engine on the options.
And also the guy who is going to tune the motor.
Otherwise, all the answers shall be provided by the EngineBuildingBird in remote mode and you'll be very happy to be advised by one of the Guru's on this forum and show off to everyone.

[SLEEPYDUB]

Who do you guys recommend to order pistons through? VAC Seems to be the only place I've found. I've seen some bad reviews on the Ross pistons through Ireland Engineering. So who do I go with? I've seen digger mention TopEnd as a good supplier for JE.

From their site:

Total-Seal Gapless Rings - NOTE: You use Gapless Top OR Gapless 2nd. You do not do both Gapless.
None
Total Seal Gapless Top Rings (Endurance Road Race, Extreme Turbo and NOS Use) - $38 each + $152 +$228.00
Total Seal Gapless 2nd Rings (Street and mild Race use) - $25 each +$100 +$150.00
Other Piston Options
High Heat Ceramic Coated crowns and Moly coated skirts - $43 each +$258.00
Moly or Tuff coated skirts only - $23 each +$138.00
Heavy Duty Wrist Pins - $15 each +$90.00
FSR Forgings (Limited to certain bore sizes and applications only.) - $20 each +$120.00
Vertical or Lateral Gas Ports (For Drag Race and High Compression engines, also good for NOS use.) - $22 each +$132.00
Contact Reduction Grooves - $8 each +$48.00
Accumulator Grooves - $6 each +$36.00
Milled Side Relief Lightening - $6 each +$36.00
Brushed and Milled Dome Crowns - $4 each +$24.00

That is a lot of options...i dont even know what I do or dont need as piston options...

[SLEEPYDUB]

The intermediate shaft isn't quite the quite the same. Most machinists think it's similar to cam bearings from a push rod engine, but those type bearings just press in and done - they will have to be burnished to size - but it's not rocket science for a machinist.

When you purchase pistons, they will come with a pamphlet and specify how much piston to wall clearance is needed depending on coating and such - yes they will expand more the stock castings.

When upgrading rods and going forged pistons, it's a good idea to rotate the balance assembly. If you weigh parts from a BMW engine that has all of it's factory parts, they are extremely close. +/-2gm (4gm total variance).

When I bring him the bearings for the Intermediate shaft, ill be sure to give him some literature on the process so there is no mistake. Ok so no worries on the pistons then since it will come with what tolerances are needed.

He is definitely balancing the rotating assembly, that has already been discussed

[ForcedFirebird]

The intermediate shaft isn't quite the quite the same. Most machinists think it's similar to cam bearings from a push rod engine, but those type bearings just press in and done - they will have to be burnished to size - but it's not rocket science for a machinist.

When you purchase pistons, they will come with a pamphlet and specify how much piston to wall clearance is needed depending on coating and such - yes they will expand more the stock castings.

When upgrading rods and going forged pistons, it's a good idea to rotate the balance assembly. If you weigh parts from a BMW engine that has all of it's factory parts, they are extremely close. +/-2gm (4gm total variance).

[SLEEPYDUB]

I have seen quite a few blocks like that, was discussed in the piston thread a few days ago. You can trust him if he carries a warranty. As I mentioned earlier, forgings are going to need more wiggle room. The BMW piston clearances are very tight in stock configuration, much tighter than domestic builders are used to. Did he understand the intermediate shaft bearings?

Do the forgings need more wiggle room because they expand? I think I remember that being mentioned when I was running Wiseco. In that case, he must bore it out a few mm to make room? As far as the intermediate shaft bearings, he said that the process to do that isn't much different from what he is used to on other engines. Same concept applies to both. I still haven't had a chance to go by there and discuss everything in person, I plan to do that tomorrow

[ForcedFirebird]

I have seen quite a few blocks like that, was discussed in the piston thread a few days ago. You can trust him if he carries a warranty. As I mentioned earlier, forgings are going to need more wiggle room. The BMW piston clearances are very tight in stock configuration, much tighter than domestic builders are used to. Did he understand the intermediate shaft bearings?

[SLEEPYDUB]

Without question bore it at least .25mm, but .5 is more common, +1 gives you matching gasket size to bore, which is great to avoid edges and hot spots. I have had blocks measure out for reuse of stock replacement pistons after deglaze, but no quality machinist will hone a used block the extra few thousandths for forged replacements. The bores will not be round. Don't forget to rent a torque plate, your local v8 shop probably won't have an m20 setup. These long siamese engines will move when the head is bolted.

Just talked to my machinist, he said the bores measured out perfect for stock replacement, he couldn't believe how good it came out. He said to order stock sized pistons for it. He also mentioned the intermediate shaft bearings and said its not problem for him to replace them, as he was planning on doing that regardless. At this point a torque plate will not be needed.

Should I be weary of this? Or trust my machinist?

[SLEEPYDUB]

Gapless is good for reducing oil contamination so e85 and methanol it's helpful

This car will be full time E85, so what should I do?