[s-cars] NF or 7A block substitution (and possibly MC)

Sat Mar 27 13:04:02 PDT 2010

I've only got two MC's both of which I need and that KH that you are  
welcome to. Wish I could help.

-Cody (mobile)

On Mar 27, 2010, at 3:28 PM, "Ben Swann" <benswann at verizon.net> wrote:

> Well after all the Q&A regarding trying to use an NF block I have  
> and even had possible
> solutions, it won't happen.  The NF block is NFG - except to use as  
> a counterweight on
> my boat tide compensation system (glorified boat anchor).
>
> So I'll have to find another engine or block to toy with.  A short  
> block from 3B, MC or
> AAN would be most straightforward.  I have rebuild parts for 7A as  
> well.
>
> Ben
>
> -----Original Message-----
> From: Cody Forbes [mailto:cody at 5000tq.com]
> Sent: Saturday, March 27, 2010 9:54 AM
> To: Ben Swann
> Cc: P Cole; <s-car-list at audifans.com>; Quattro List; <200q20v at audifans.com 
> >
> Subject: Re: [s-cars] NF or 7A block substitution (and possibly MC)
>
> No, 3B rods will not fit a MC crank. All 10v cranks are 46mm rod  
> journals, all 20v
> cranks are 48mm journals. All rods fit all pistons, but 10v rods  
> must be on a 10v crank
> and 20v rods on a 20v crank.
>
> I'll add that my direct experiance is with turbo engines of 20v and  
> 10v plus 7A, but I
> am very sure that the above applies to all Audi 5cyl before the new  
> ones of recent
> manufacture.
>
> -Cody (mobile)
>
> On Mar 27, 2010, at 12:50 AM, "Ben Swann" <benswann at verizon.net>  
> wrote:
>
>> OK - looks like I'm getting somewhere.
>>
>> NF block (have the NF crank, pistons and rods but probably won't
>> use) with some
>> combination of pistons and rods. AFAIK this block does come with
>> piston oil squirters installed.  If not I can install some - if I
>> recall it is not a difficult retrofit.  No problem machining oil
>> return into the boss on the block - I forget if there is a return in
>> the 3B pan like there is on the AAN.
>>
>> I might be able to use the 3B(20V) crank from wasted engine if it is
>> not shot peened by the flailing rod ***story below***
>>
>> If 3B crank shot then I have MC(10V) crank
>>
>> I have complete set of 3B rods and Pistons - not the ones in the
>> messed up engine.
>>
>> I also should have MC pistons and rods, but sounds like using 3B
>> internals is best.
>>
>> So in short, I think if the 3B crank is wasted then my best choice it
>> to install MC-1 crank with 3B rods and pistons.  There ought not be
>> any need to use special head gasket or anything like that.
>>
>> Hopefully I can do a quick teardown and build in order to get the car
>> on the road.  In the long run, I have the 3.7 aluminum V8 I'm  
>> building
>> to accommodate twin turbos!
>>
>> Ben
>>
>> Story *** I lent the Deerslayer http://www.gtquattro.com/
>> 200Q20V8.html to a friend - ig mistake.  He must have mashed the gas
>> pedal while merging.  Said he was not able to shut it down  
>> immediately
>> and engine bounced off the rev. limiter for about 15 sec.  He called
>> to report what he thought was noisy lifters.  The car went over 150
>> miles with the rod coming loose and eventually flapping about.  All
>> this time thinking it was noisy lifters!  Driver finally realized the
>> problem was not coming from the top of the engine when the car
>> stalled.  Upon restart, noticed the noise had gotten worse and saw
>> some oil leaking around the turbo - still thought problem was due to
>> losing oil pressure thru the
>> oil line.   And no I was not the driver!  The minute I started the
>> car up I winced at
>> the carnage! So much for no good deeds going unpunished.
>>
>> -----Original Message-----
>> From: Cody Forbes [mailto:cody at 5000tq.com]
>> Sent: Saturday, March 27, 2010 12:15 AM
>> To: Ben Swann
>> Cc: P Cole; s-car-list at audifans.com; Quattro List;
>> 200q20v at audifans.com
>> Subject: Re: [s-cars] NF or 7A block substitution (and possibly MC)
>>
>> Nope, the 20v cars used different size rod journals on the  
>> crankshaft.
>> You'd need a 20v crank to match the 20v rods. Or you can use a 10v
>> crank (turbo and NA are the same) with MC rods and 3B pistons.
>>
>> IIRC the only difference in the bare block between post 1985 10v
>> blocks is the hole for the turbo oil return and I'm not sure if the
>> non-turbo blocks have the piston oil squirters. All other turbo
>> related parts (oil filter housing, turbo coolant return freeze plug,
>> head, etc) is all a matter of bolting it on.
>>
>> -Cody (mobile)
>>
>> On Mar 26, 2010, at 11:04 PM, "Ben Swann" <benswann at verizon.net>
>> wrote:
>>
>>> Thanks Paul, all!
>>>
>>> OK - How will the combination of NF block with 3B Pistons and Rods
>>> work?  This is a combination I have/can assemble with parts on hand.
>>>
>>> Is the NF block different than the MC blocks or is the difference
>>> crank and rods?
>>>
>>> Ben
>>>
>>> -----Original Message-----
>>> From: P Cole [mailto:pcolegrps at comcast.net]
>>> Sent: Friday, March 26, 2010 10:25 PM
>>> To: Ben Swann
>>> Subject: RE: NF or 7A block substitution (and possibly MC)
>>>
>>> On Fri, 26 Mar 2010 19:48:04 -0400, Ben Swann wrote:
>>>
>>>> Thanks all for the replies so far.  I just wanted to know if I  
>>>> could
>>>> use the NF block
>>> as a reasonable substitute for a blown 3B.   I have in my garage
>>> with all parts to
>>> rebuild the NF.  I may have an MC sitting here too.  I have  
>>> internals
>>> for both MC-1 and NF.
>>>>
>>>> Interesting that the NF which is high compression motor makes low
>>>> comp when putting on
>>> a 3B head - doesn't make sense.  When you put an NF head on an MC-1
>>> block - that is good combination.  MC-1 is a good substitute for the
>>> 3B.  So, what makes the compression go so low?
>>>>
>>>
>>> Combustion chamber SIZE- in the 10v heads it's 27cc in the 20v heads
>>> it's 44cc ( or something like that)
>>>
>>>> I thought that the NF and 7A were similar, if not the same block? I
>>>> don't have a 7A but
>>> can get one if that is a better alternative.
>>>>
>>>
>>> Piston size and dish depth are another BIG difference between the
>>> various I5 engines.
>>> The high compression 10v's have small dish pistons in the same
>>> combustion chamber as the 10 turbo cars do hence the higher CR.
>>>
>>>> Is there an ideal combination:  on hand - NF block, 3B pistons and
>>>> rods,  MC-1 pistons
>>> and rods,  NF pistons and rods.  Rings and bearings, seals for them.
>>>>
>>>> I would like to use what I have to put together a decent block to
>>>> install 3B head on -
>>> without getting into procuring odd and esoteric combinations.  Just
>>> want to use what I have on hand, possibly procuring head-gasket  
>>> and a
>>> few odd bits.  No problem machining oil return line - BTDT.
>>>>
>>>
>>> The bigger issue is the crank and pistons - I think all the I5's had
>>> forged cranks, all the turbo cars did for sure. The pistons in most
>>> NA cars are cast whereas the turbo cars all had forged pistons. I
>>> think Audi used forged rods in all the I5's but I'd have to check  
>>> the
>>> NA cars.
>>>
>>>> Ben
>>>>
>>>> S-car-list in copy because I thought I'd seen this done for AAN
>>>>
>>> --
>>> //************************
>>> Paul R. Cole::pcolegrps at comcast.net
>>>
>>> _______________________________________________
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>>> http://www.audifans.com/kb/List_information
>>
>