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

Sat Mar 27 07:31:26 PDT 2010

My old 4ktq had a KH.  The head is different than a MC head.  Not all the
oil return ports line up.  It is also a smaller bore than the MC block as it
is slightly lower displacement.  It does have piston oil squirters and as I
recall the same stroke as an MC so likely the same crank etc.

I don't really remember the exact differences in the head interface, but
here is an old picture from when I built the motor that might help.

http://www.sofadog.net/4ktq/images/FreshBlock.JPG

The engine was strong, but didn't really get fun until I put an MC cam in
it.  That required some machining on the head because the second bearing
journal is slightly further forward on a KH head and interferes with the
adjacent cam lobe.  It is only about 0.02" that has to be removed.

Ben you gave me the cam years ago when I visited you.  I had the gray 4ktq
with the front mount IC and euro lights.

-Eric

On Sat, Mar 27, 2010 at 10:01 AM, Cody Forbes <cody at 5000tq.com> wrote:

> Yeah I forgot all about that! Damn.
>
> Anybody know anything about a KH block? If it's compatible (I'd bet
> yes) I've got one here you can have, but you'd have to pick it up as I
> have been having a bad life recently and there's no way I could make
> the trip and shipping would be too expensive. It's a complete KH
> engine in a car minus the CIS. I'd like to keep the turbo and the
> head, the rest is yours. You could get that 7a head and A/C condensor
> too ;-). If needed I could see about one of my customers/friends
> taking it to his house in Raleigh which should be a bunch closer.
>
> -Cody (mobile)
>
> On Mar 27, 2010, at 1:15 AM, "Ben Swann" <benswann at verizon.net> wrote:
>
> > Showstopper?  Etka shows NF piston as 82.5 vs. 3B/MC as 81 which I
> > take is diameter.
> >
> > So I'd need oversize pistons  - 7A uses 82.5 too and has the recess
> > for valves.
> >
> > Would have been nice to use this block.  Just threw away a couple JX/
> > KT that no one
> > wanted.
> >
> > Ben
> >
> > -----Original Message-----
> > From: Ben Swann [mailto:benswann at verizon.net]
> > Sent: Saturday, March 27, 2010 12:50 AM
> > To: 'Cody Forbes'
> > 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)
> >
> > 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 <Cole%3A%3Apcolegrps at comcast.net>
> >>
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