Shreddr's Excellent Big Bore Adventure, aka HP2S big bore install thread

[shreddr]

Originally Posted by AZ-Twin

Someone from Wossner is going to get their security clearance revoked.

not really, if you had one of their pistons in hand you could measure all this stuff up for yourself, if you are good with that kind of stuff. And evidently this drawing is flawed anyway, I guess that is the kind of info you want to leak to your competitors.

[DonB]

Interesting.
Could be just a mistake or could be on purpose.
I know when we give out drawings to cusotmers they are LDD-Limited Dimension Drawings. For reference only.

[fralind]

The pistons and connecting rods are manufactured reinforced exclusive to us. I would be surprised if anyone could get these drawings.

The first set had a piston deck height of 27.90 mm ​​for 12.5:1 compression.
The pistons have a current deck height of 28.00 mm to 12.7: 1 compression

[shreddr]

Originally Posted by fralind

The pistons and connecting rods are manufactured reinforced exclusive to us. I would be surprised if anyone could get these drawings.

The first set had a piston deck height of 27.90 mm ​​for 12.5:1 compression.
The pistons have a current deck height of 28.00 mm to 12.7: 1 compression

Thanks Frank.

[AZ-Twin]

Shred, what is measurement of the pistons you had made? What is the measurement of your stock pistons?

[shreddr]

the pistons I had made have a 31mm deck height, the stockers are 28mm. I will mention again that if I would have disassembled the motor first and then order the rods and pistons, I would be done by now. I was trying to get in a few late season rides so what I gained on the front end I lost on the back end....

I am still unsure why the piston spec i worked from has the deck height for the shorter rod. If in fact the GS, RT and R all use the short rods, then I have a nice set of pistons for sale to a lucky buyer!

Also, in defense of Carrillo, they did make what I wanted, and the only measurements they took from the print was the wrist pin and valve pocket locations, they then use their own X braced forged blanks. This would have been easy to measure from a stock piston, so nothing proprietary has been borrowed from Wossner.

[boxercup]

Originally Posted by shreddr

I got the remachined rods back, and I have the day off, so today is rebuild day!

NICE!!

you cant tell from this picture but the rod bolts are all coded, this says SM9 and Carrillo


the accompanying data sheet that gives tightening torques and stretch measurements. I just used the torque method as I didn't have the proper measuring device for the stretch method.


OUCH! Not suggested!

Greetings shreddr,

The bolts MUST be measured for stretch. I emphasize this!

The suggested torque specified is a arbitrary figure. The stretch of the bolt is the indicator.

Suggestion:

1. Use the supplied moly lube on the bolts and nuts as directed.
Tighten the bolts to 10 ft lbs - a little more than hand tight.
2. Measure the length of the bolt.
3. Tighten each bolt to 20 ft lbs
4. Tighten each bolt to 30 ft lbs - measure the bolt stretch
5. Continue to tighten the bolts in a sequence of + 5 ft lbs until you get the suggested bolt stretch.

The final torque reading might be 52 or 58 ft lbs - however it is the stretch measurement that is important here. Stretch the bolts now. Don't let your engine do it for you.

Enjoy your day off Jeff - You are doing a great job!

[AZ-Twin]

Shred, I was not asking to be smart (hard to believe, I know) I was just curious. This stuff happens when doing things for the first time. All part of the adventure.

[Guest24]

Originally Posted by shreddr

the pistons I had made have a 31mm deck height, the stockers are 28mm. I will mention again that if I would have disassembled the motor first and then order the rods and pistons, I would be done by now. I was trying to get in a few late season rides so what I gained on the front end I lost on the back end....

I am still unsure why the piston spec i worked from has the deck height for the shorter rod. If in fact the GS, RT and R all use the short rods, then I have a nice set of pistons for sale to a lucky buyer!

Also, in defense of Carrillo, they did make what I wanted, and the only measurements they took from the print was the wrist pin and valve pocket locations, they then use their own X braced forged blanks. This would have been easy to measure from a stock piston, so nothing proprietary has been borrowed from Wossner.

What would i have to punch out my DOHC GS to, Jeff?

[shreddr]

Originally Posted by Nail24

What would i have to punch out my DOHC GS to, Jeff?

4.1271" finished hone, it would take the RT from 1170 to 1258cc

[tm1100s]

Originally Posted by boxercup

The bolts MUST be measured for stretch. I emphasize this!

ARP has nice tools for this:

[shreddr]

New pistons in the house! With the correct deck height

they are on their way to Swain for the high tech coating, and then rebuild time!

[SergioK]

Oh those look nice.

[Bigred455]

Shreddr, looks great! I do follow this thread with great interest as I might follow your lead for my 30k service. But I just wanted to correct some terminology that may have gotten lost in translation from the German literature. Deck Height is the distance from the crank centerline to the head gasket surface and Piston Pin Height is the distance from the Piston Pin Centerline to the Top of the piston.

[kpolito99]

Originally Posted by shreddr

New pistons in the house! With the correct deck height

they are on their way to Swain for the high tech coating, and then rebuild time!

Is it just me or does that bottom ring land look ultra thin?

I have always heard great things about CP products and have installed a set of custom turbo pistons in my turbo 2002 engine. I am sure their engineers know what they are doing but that looks freakishly thin to me.

[PFFOG]

Originally Posted by shreddr

they are on their way to Swain for the high tech coating,[/img]

They are just a few miles from me, in a small village.

[Guest24]

It's almost a shame to get carbon deposits on those, Jeff. They look like fine jewelry.

[shreddr]

Originally Posted by Bigred455

But I just wanted to correct some terminology that may have gotten lost in translation from the German literature. Deck Height is the distance from the crank centerline to the head gasket surface and Piston Pin Height is the distance from the Piston Pin Centerline to the Top of the piston.

you are correct that I am incorrect. the better name is compression height

[Bigred455]

Originally Posted by shreddr

you are correct that I am incorrect. the better name is compression height

TRUE!

When are you getting the Pistons back and be able to return to the project?

[shreddr]

I sent them to Swain last Friday, I am hoping for a 2 week turnaround. So, the answer is soon!