11:1 Engine Rebuild

[Cam]

Originally Posted by NeedForSpeed

Why only the left side piston pins offset, and not the right?
Are the pins offset for performance or for quiet operation?
EDIT: Should have reread more cafefully, for piston slap.
EDIT: NOT NEEDED ON RIGHT BANK BECAUSE THRUST IS ON UPPER WALL AND SLAP NOT AN ISSUE??
How did you know the difference between pistons, .020" is hard to see?
Aren't you happy you didn't have to swap #3 and #4
Keep up the great work

If you look on the straight ahead shots, you can see the access holes are not lined up perfectly straight. The driver side is slightly closer to the intake manifold. I am not sure why they offset them but they definitely did. However, if you misinstall it will cause the piston to travel out of center of the cyliner ( = BAD). The difference in the pistons were not that hard to see when comparing them to each other.

And I had to take all 6 out anyways, so it would have been the same no matter which ones I switched. I could not use the rear access holes because the misalignment made them not clear the threads of the hole. I had to get the circlip off the forward side of the piston and use a dowel to knock the pin far enough into the middle cylinder (hence why I removed all 6 pistons) and caught the pin before it fell and hurt anything.

[NeedForSpeed]

Originally Posted by Cam

If you look on the straight ahead shots, you can see the access holes are not lined up perfectly straight. The driver side is slightly closer to the intake manifold. I am not sure why they offset them but they definitely did. However, if you misinstall it will cause the piston to travel out of center of the cyliner ( = BAD). The difference in the pistons were not that hard to see when comparing them to each other.

And I had to take all 6 out anyways, so it would have been the same no matter which ones I switched. I could not use the rear access holes because the misalignment made them not clear the threads of the hole. I had to get the circlip off the forward side of the piston and use a dowel to knock the pin far enough into the middle cylinder (hence why I removed all 6 pistons) and caught the pin before it fell and hurt anything.

Interesting subject,

How did you install the rear pins when you assembled the block the first time, if the pins didn't clear the rear access hole threads? You inserted the rear pin through the center cylinder, then installed the center piston and then installed pistons 1/2?

The factory pistons are marked R/L, are the factory pistons offset only on the left bank like your aftermarket set?

Are the access hole threads in your block offset on the left bank and not on the right bank??

[Cam]

Originally Posted by NeedForSpeed

Interesting subject,

How did you install the rear pins when you assembled the block the first time, if the pins didn't clear the rear access hole threads? You inserted the rear pin through the center cylinder, then installed the center piston and then installed pistons 1/2?

The factory pistons are marked R/L, are the factory pistons offset only on the left bank like your aftermarket set?

Are the access hole threads in your block offset on the left bank and not on the right bank??

The rear pins went in pretty easily even with the offset. Before the pin was fully installed the piston would shift to clear enough for them to go in and once started, tapping in with a dowel was performed. This was needed on a couple of them (VERY GENTLY). The tapping in was not needed because of the offset, but the close tolerance wrist pins. I had to have the holes in the pistons honed for the pins to fit in because of the coating on the skirts.

The factory pistons are indeed marked, but the new ones are not. Both sets have 3 pistons with offset pin holes, however. The access holes and pin holes are only offset on the LH side (DRIVER SIDE).

[NeedForSpeed]

Originally Posted by Cam

The rear pins went in pretty easily even with the offset. Before the pin was fully installed the piston would shift to clear enough for them to go in and once started, tapping in with a dowel was performed. This was needed on a couple of them (VERY GENTLY). The tapping in was not needed because of the offset, but the close tolerance wrist pins. I had to have the holes in the pistons honed for the pins to fit in because of the coating on the skirts.

The factory pistons are indeed marked, but the new ones are not. Both sets have 3 pistons with offset pin holes, however. The access holes and pin holes are only offset on the LH side (DRIVER SIDE).

Cam,

I just found a OEM SVX piston spec, states that both R/L pistons are offset 2.0mm/ .080".
That makes more sense, but is not consistant with your findings.

[Cam]

Originally Posted by NeedForSpeed

Cam,

I just found a OEM SVX piston spec, states that both R/L pistons are offset 2.0mm/ .080".
That makes more sense, but is not consistant with your findings.

I don't remember listing the offset measurement. I remember looking with my ruler and seeing almost .100" difference though.

[NeedForSpeed]

Originally Posted by Cam

I don't remember listing the offset measurement. I remember looking with my ruler and seeing almost .100" difference though.

The OEM specs I saw listed all six OEM SVX pistons as off-set.
Only three of your pistons are offset?
Only the driver [left] bank?

[longassname]

The pins are offset on all of my pistons.

[Boxersix]

The stock slugs are offset-pin on both banks, done so to reduce stress on the rotating assembly. Keeps rod angle low during power stroke, reduces piston slap, "softens" the reciprocating transfer, etc, etc.

The choice as to whether use an offset pin is solely based on the motor build, where calculating piston velocity and primary/secondary piston accelerations are taken into account. Lots of math, most best left to the engineers

[Cam]

Originally Posted by longassname

The pins are offset on all of my pistons.

I am sorry for the misinformation. I assumed that one set of them were centered.

[Cam]

Re-read the original E-mail LAN sent me about the wrist pins. He very clearly stated that both sides were offset, but in different directions (towards manifold or towards oil pan). How the hell did I score so high in reading comprehension in high school .

Anyways, got the Oil Pump gutted, cleaned, lubed and re-installed today. She is coming together slowly but surely. Tomorrows agenda, clean and install water pump. Sooner or later I will get those lash adjusters and then I will be able to complete the long block.

[NeedForSpeed]

Originally Posted by Cam

Re-read the original E-mail LAN sent me about the wrist pins. He very clearly stated that both sides were offset, but in different directions (towards manifold or towards oil pan). How the hell did I score so high in reading comprehension in high school .

Anyways, got the Oil Pump gutted, cleaned, lubed and re-installed today. She is coming together slowly but surely. Tomorrows agenda, clean and install water pump. Sooner or later I will get those lash adjusters and then I will be able to complete the long block.

Obviously, your patience for reading has declined since high school

[Cam]

Slow and steady progress. Still need to buy new lash adjusters, silicone lines, etc...

[sowise]

Very sweet looking! I see you did the full block in black! I like the look and new hardware to boot. Wrinkle coat on the alt. and A/c compressor mount is nice touch too as are the clean water and oil pumps. Nice job. I used the copper spray on my gaskets as well

[Cam]

Thanks. The water pump is brand new, and the oil pump was rebuilt. I like what you did with your alternator and ac compressor. I may do the same thing on my compressor and paint it, but the alternator will be left bare for some contrast I think.

[sowise]

Yeh I had the similar idea for contrast in mind too, if you want to keep the contrast look but want it clean you could check out the alumiblast paint to make the alternator look new. Either way I think having a nice mix of black and aluminum on our engines looks awesome. What color of car is this going in Cam?