Engine Question/Opinions for Tii Purists

[PaulTWinterton]

Are the Ireland forged 9.5:1 pistons an upgrade to the tii engine or would they be considered an "un-original" modificaton? 

 

Everything else is stock, although Wes Ingram recommends adjusting the rebuilt KFish for the slightly higher displacement.

 

Thanks for reading and replying.

[jrkoupe]

not sure what u r asking...

 

if car was being sold u would say what the pistons were..

 

 

...correct?

 

 

is oe comp ratio equal?......I think so ..iiirc

[Conserv]

Paul,

 

Two absolutely identical round taillight tii's: equipment, color, condition.  Amazingly, they're only one VIN apart! One has four OEM Mahle pistons.  The other has four I.E. pistons of roughly the same compression.  Believe it or not, both even had the same engine builder, a well-known and respected shop!  ?

 

I believe the premium associated with the OEM pistons would be....give me a minute, I'm calculating...

 

$0

 

My opinion, so take it for what you paid for it!

 

Best regards,

 

Steve

 

 

Edited November 30, 2016 by Conserv

[Conserv]

1 hour ago, PaulTWinterton said:

 

Everything else is stock, although Wes Ingram recommends adjusting the rebuilt KFish for the slightly higher displacement....

 

Paul,

 

I'm guessing you mean "compression ratio" rather than displacement, the difference being 9.0 versus 9.5...

 

Best regards,

 

Steve

 

[PaulTWinterton]

3 minutes ago, Conserv said:

I believe the premium associated with the OEM pistons would be....give me a minute, I'm calculating...

 

$0

 

That's what I was hoping to hear. I had to ask.  Re-boring a block to fit the new 9.5:1 pistons is a major step and I didn't want to make a mistake.

 

9.5:1 is the euro tii spec, so it seems like an honest and substantial upgrade.

 

Thanks,

 

Paul

[Conserv]

8 minutes ago, PaulTWinterton said:

 

That's what I was hoping to hear. I had to ask.  Re-boring a block to fit the new 9.5:1 pistons is a major step and I didn't want to make a mistake.

 

9.5:1 is the euro tii spec, so it seems like an honest and substantial upgrade.

 

Thanks,

 

Paul

 

Paul,

 

Just to clarify, you would be re-boring the block to fit oversized pistons, without regard to the compression ratio of the new pistons.  Oversize boring would be mandated simply by wear or damage in the block's current bores.  Yes, indeed, re-boring to an oversize dimension does increase displacement, but not by much!

 

Did Wes Ingram say that oversize pistons mandated an adjustment to the Kugelfischer, or that the increased compression ratio mandated an adjustment to the Kugelfischer?

 

Regardless, I stand by original statement that the value difference is $0!

 

Best regards,

 

Steve

 

Edited November 30, 2016 by Conserv

[PaulTWinterton]

Compression Ratio.

7 minutes ago, Conserv said:

I'm guessing you mean "compression ratio" rather than displacement, the difference being 9.0 versus 9.5...

 

Actually it was Wes Ingram that used the word displacement when I asked him about the KFish adjustment requirement if I upped the CR to 9.5:1.

Wes is a master race engine builder as well as a MFI re-builder, so I let him use any terminology he wants.

 

 

[Conserv]

12 minutes ago, PaulTWinterton said:

Compression Ratio.

 

Actually it was Wes Ingram that used the word displacement when I asked him about the KFish adjustment requirement if I upped the CR to 9.5:1.

Wes is a master race engine builder as well as a MFI re-builder, so I let him use any terminology he wants.

 

 

 

Curious, Paul,

 

What oversize are the I.E. pistons?  When you go to 91 or 92mm, you're worrying about the proximity of the bores to the water jackets, and you're pretty much eliminating the possibility of any future overbores...

 

I would not be thrilled to know that a prospective tii purchase was already bored to 91mm!  ?

 

Steve

 

Edited November 30, 2016 by Conserv

[PaulTWinterton]

Following is the page for the E12 replacement pistons from Ireland.

 

https://www.iemotorsport.com/bmw/2002-engine/M10cast-E12.html

 

Wes Ingram did say he "will adjust the pump for the slightly greater displacement."

 

[mac]

EVERY time I show up at an engine builder with a set of MAHLE's, to paraphrase their responses, they say, "Nice pistons".  If I show up with something else, their response is something like, "What are these?  Who's the manufacturer?  Get 'em off the internet"? 

 

Just my experiences, yours may vary.

 

mac.

[Conserv]

On 11/30/2016 at 5:17 PM, PaulTWinterton said:

Following is the page for the E12 replacement pistons from Ireland.

 

https://www.iemotorsport.com/bmw/2002-engine/M10cast-E12.html

 

Wes Ingram did say he "will adjust the pump for the slightly greater displacement."

 

 

Got it, Paul!

 

OK.  90mm isn't bad, but any future re-bore is probably going to require custom pistons or sleeving.

 

Question One.  There are other 9.5 CR pistons around, OEM and aftermarket.  Many of these are less than 90mm, e.g., 89.47-ish ("second oversize").  Have you considered them?  They would likely cost more than the I.E. pistons, maybe $600-ish, possibly more if OEM.  I ask you this question because I think you and I have some similar feelings about keeping our cars original and, if I wanted to move to a 9.5 CR in my tii, AND MY BLOCK'S CONDITION DID NOT MANDATE A 90MM BORE, I would not re-bore an original block beyond what was absolutely needed to get good clean bores.

 

Question Two.  Are you talking about your spare tii engine?  If so, I would be much less concerned than I would be about a numbers-matching block.

 

Best regards,

 

Steve

 

[PaulTWinterton]

23 minutes ago, Conserv said:

I would not be thrilled to know that a prospective tii purchase was already bored to 91mm!  ?

 

 

IE pistons require a bore of only 90mm.

 

But now I'm getting the responses that I thought I might get.

[Conserv]

10 minutes ago, PaulTWinterton said:

 

IE pistons require a bore of only 90mm.

 

But now I'm getting the responses that I thought I might get.

 

It's not the compression ratio, or even the "non-Mahle" brand, that brings on my real concern, it's the boring of a numbers-matching block -- especially beyond 90mm -- that brings on my real concern...

 

Edited November 30, 2016 by Conserv

[PaulTWinterton]

3 minutes ago, Conserv said:

Question One.  There are other 9.5 CR pistons around, OEM and aftermarket.  Many of these are less than 90mm, e.g., 89.45-ish (is that "first oversize"?).  Have you considered them?  They would likely cost more than the I.E. pistons, maybe $600-ish, possibly more if OEM.  I ask you this question because I think you and I have some similar feelings about keeping our cars original and I, if I wanted to move to a 9.5 CR in my tii, AND MY BLOCK'S CONDITION DID NOT MANDATE A 90MM BORE, would not re-bore an original block beyond the minimum needed.

 

I have only considered the 'first oversize" Mahles @ $271ea in Canada.  Yikes!  I looked to I.E.  because they have a great reputation and each piston is $153ea.  About half.   Hence my conundrum.

 

6 minutes ago, Conserv said:

Question Two.  Are you talking about your spare tii engine?  If so, I would be much less concerned than I would be about a numbers-matching block.

 

You are correct.  But I don't want to build a block that nobody wants if I chose to sell it.

[Conserv]

6 hours ago, PaulTWinterton said:

 

I have only considered the 'first oversize" Mahles @ $271ea in Canada.  Yikes!  I looked to I.E.  because they have a great reputation and each piston is $153ea.  About half.   Hence my conundrum.

 

 

You are correct.  But I don't want to build a block that nobody wants if I chose to sell it.

 

Paul,

 

Someone purchasing a standalone engine will buy a block over-bored to 90mm, or even 91mm, assuming it was done by a reputable machine shop.  They're probably not concerned about the next overhaul, 100,000 miles down the road -- they'll just buy another engine!

 

Best regards,

 

Steve

 

Edited December 1, 2016 by Conserv