After reading endless threads on "what fits where," I collected some numbers from many sources and then dug through the Mahle piston and bearing catalogs to create this table.

So you want to build a turbo 8v? Chuck B. turned us on to using Audi MC pistons as an easy way to get a quality forged piston and lower CR at the same time. These are not just a drop-in for most 1.8 motors, since although the bore is the same, they have lower wrist pins than almost all 1.8s (this is to move the top ring land down, making the piston much more robust in the presence of high heat and detonation).

You need to ditch your 144 mm rods and go with 136 so they don't pop above the deck. By looking at the table below, we can see that there are three 136 mm rods with 22 mm wrist pins. Two of them use small crank journals; the 1.7 rods are wimpy, the MC rods are strong like ox. G60 rods are the right length and have big journals (you can keep your original crankshaft), but may not be as strong as the MC rods. So get either MC rods and a 1.7 crank, or G60 rods and a 1.8 crank.

Another interesting combination would be to put a 95.5 mm diesel crank into a ABA tall block. Bore it to 83.5 mm and you have a 2092 cc thumper. Anyone got a good combination of rods and pistons that gets one of these cheaply?

E-mail me if you do. Otherwise, use 144 rods and have some custom pistons made with about 45 mm compression height.

Engine Key
Tag	Description
1.7	VW 8v EN (early '80s Rabbit, Scirocco)
1.8	VW 10:1 8v (about a million engine codes, use HT, RD or PF)
1.9	1.9 diesel (all VAG 1.9 diesels from all eras; CRs vary, but all critical dimensions remain the same)
16v	VW 1.8 16v (mid-late '80s GTi, Scirocco), engine code PL
20v	VW/Audi 1.8t 5-valves per cylinder, Audi A4, neue-Beetle &c (got codes?)
3A	Audi 2.0 8v "bubble block" (late '80s Audi 4k/80)
9A	VW 2.0 l 16v (early '90s GTi)
ABA	VW 2.0 "tall block" 8v crossflow head (mid '90s to present all models; common codes are ABA)
G60	VW Corrado G60 1.8 supercharged, engine code PG
MC	Audi 2.2 5 cyl turbo (mid-late '80s Audi 5kt and 5ktq; forged pistons)

Dimensions
Tag	Bore	Stroke	Disp	Rod Journal	Rod Length	Wrist Pin	Compression Height	Piston Dish	Block Height	CR
1.7	79.5	86.4	1715	46	136	22	37.5	21	220	8.2:1
G60	81.0	86.4	1781	48	136	22	39.5	25	220	8:1
MC	81.0	86.4	2226	46	136	22	41.5	26	220	7.8:1
1.8	81.0	86.4	1781	48	144	20	32.2	10	220	10:1
16v	81.0	86.4	1781	48	144	20	33.4	-5	220	10:1
20v	81.0	86.4	1781	48	144	20	32.8	0.0	220	9.15:1
Tag	Bore	Stroke	Disp	Rod Journal	Rod Length	Wrist Pin	Compression Height	Piston Dish	Block Height	CR
3A	82.5	92.8	1984	48	144	20	?	15.5	220	10.5:1
9A	82.5	92.8	1984	48	144	20	30.2	-4	220	10.8:1
ABA	82.5	92.8	1984	48	159	21	30.9	14.61	236	10:1
Tag	Bore	Stroke	Disp	Rod Journal	Rod Length	Wrist Pin	Compression Height	Piston Dish	Block Height	CR
1.9	79.5	95.5	1896	48	172	26	45.8	?	?	19.5:1

Yellow entries are not confirmed, but calculated from guesses. Block height for the ABA tall block was guessed to be 16 mm higher than the 1.8 block from the difference in connecting rod length. The dish volumes may be computed without actual knowledge about combustion chamber size or CR (I guessed that the 3A has the same 30 cc as all other 1.8 8v motors, and that the 9A has 45 cc like 16v motors).

Red entries are unknown. If you know one of these numbers, e-mail me, do it now before you forget.

Part Type	Part Number	Description
Head Gasket ABA 4-layer metal	037 103 383 N	This is the stock ABA replacement part from your local dealer, about US$25-30. Layers from top are 0.009", 0.040", 0.004" and 0.009". Total thickness is 0.062"; bore diameter is 83.5 mm.
ARP Rod Bolts	ARP-104-6004	Part number for the real VW ones, not the Ford 5.0/302 ones.
1.8t FPR	VAG 078 133 534 C Bosch 0 280 160 575	Number for the 4.0 bar FPR found on some 1.8t motors.

If you are making your own fuel rail, 16v fuel injectors are on 88 mm centers. 8v has 88 mm between 1 and 2, and 3 and 4, with 45 mm between 2 and 3. Audi 10v heads are just an 8v with 5 another 88 mm behind 4.

• Compression Height measured from crown of piston to wrist pin centerline (called CH in Mahle catalogs).
• Block Height measured from block face to crankshaft centerline.
• See some pretty drawings of piston dimensions at the Mahle website.
• It appears that all the '80s 5 cylinder motors used the small rod journals, both turbo and NA (from my Bentley for WU, KH, KZ, MC and NF motors).

29 NOV 2001 - Joe Doty sent some 9A numbers.

02 DEC 2001 - Lugnuts pointed out a typo on 16v wrist pin dia, should be 20 mm.

08 MAR 2002 - John Baas reports that he measured an ABA piston to have 14.6 cc dish.

24 JUL 2002 - ¹I CCed an ABA head at 30 cc, which means that the ABA piston must be 16.5 cc to give 10:1 CR.

13 AUG 2002 - Jim angusmf@gbp... is running 1.8 rods in a 3A, although the original 3A rods look different (rod bolts?), they are the same in dimension.

21 AUG 2002 - Patrick Ray says to use 3A and 9A pistons for 82.5x95.5 tall-block strokers in an ABA block, as they have 1.4 mm lower compression height than the ABA pistons countering the 1.35 mm longer half-stroke. You will need to bush the rods to 20 mm to make the 9A/3A wrist pins fit the ABA rods.

25 OCT 2002 - Jim angusmf@gbp... Has measured 3A rods and they have 20 mm pins, incorrectly listed as 22 mm in the table.

05 AUG 2003 - Killa points out that 16v exhaust valves probably are sodium filled, too, so you can ignore my comments down with the 3B motor.

28 MAR 2004 - Killa finds a big misteak in the 20v specs, the wrist pin was 22 but should have been 20 mm. Oops.

20 APR 2004 - Brian McGarvey found where Bentley indicates the 16v exhausts are in fact sodium filled.

05 OCT 2005 - Bobqzzi info regarding 95.5 stroke diesel cranks: Long nose is for later cars that have the chain driven oil pump (mark IVs). Uses a 16mm bolt. Short nose is for earlier cars (MarkIII) with the oil pump driven by the intermediate shaft. (14mm). You want the short nose one.

This first bit is from the Bentley 5k manual, 1984-'88. It is very non-specific about what goes where and has two non-unique ways of identifying what goes where; sometimes it refers to engines by code (KH, MC) sometimes by injection type (table headed CIS-E III or something). It doesn't make sense in a lot of places.

         Year Code  Type   HP        Tq        Bore  Stroke  CR     FI         CH1  RL2
         WP
         1982 DE    TDies   83/4500  127/2800  76.5  86.4    23.0
         1984 WU    NA     100/5500  120/3000  79.5  86.4     8.2   CIS        27.5
         1984 KH    Turbo  135/5500  150/2500  79.5  86.4     8.3   CIS-E III  30.8
         1984 KZ    NA     110/5500  122/3000  81.0  86.4     8.5   CIS-E      32.2 144
         20
         1985 MC    Turbo  162/5500  177/3000  81.0  86.4     7.8   CIS Turbo  31.5
         1986 NF    NA     130/5600  140/4000  82.5  86.4    10.0   CIS-E III  33.3
         

All have crank main journals 58 mm, rod journals 46 mm. Gas motors on p.13.4a; diesel given on p.13.26. Do I believe this? No, I think the KZ and NF have 48 mm rod ends, like all the VW with 144 mm rods.

All ex valves 33 mm (p.15.7), intakes 38.0 on WU,KZ,MC; 40.0 on KH(!),NF. I don't believe this either, I think KH has 38 intakes. On p15.9, it states that only "CIS Turbo" ex valves are sodium filled. This book would make more sense if the KH were tagged "CIS Turbo." (10 JUN 2004 - Eric Sanborn has a KH and confirms that it has 38 mm intakes and oil squirters like the other turbo motors.)

         CH1 - top of pin, so CH-wristpin/2, p.13.10
         RL2 - rod length only given for "CIS-E" as 144, p13.11a, wrist pin also
         

Piston squirters stated to be installed on "CIS-E III" and "CIS Turbo", p.13.12, but no distinction made between KH and NF. Picture shows a cutout on piston skirts, too. Diesels have these, too. They have a pressure regulator valve to maintain pressure at idle and to eliminate squirting when pressure is low, different pressures for different models. (KH has squirters, see above comment on valve sizes.)

---

The following is from the Bentley 100/200, 1989-1991 book, very much better detail. It has a 30-entry table giving every model designation and what engine was installed (even though there are only three engine options).

         Year Code  Type   HP        Tq        Bore  Stroke  CR     FI
         1989 MC    Turbo  157/5500  166/3000  81.0  86.4    7.8    CIS
         1989 MC    Turbo  157/5500  177/3000  81.0  86.4    8.4    CIS
         1989 NF    NA     130/5600  140/4000  82.5  86.4   10.0    CIS-E III
         1991 3B    Turbo  217/5700  228/1950  81.0  86.4    9.3    CIS-E Motronic
         

Aha, this is much better: MC crank as expected 58/46; NF 58/48 p.13.12a; 3B 58/48 p13.33.

Valve sizes MC 38x91/33x90.8, NF 40x91/33x90.8 p.15.11; 3B 32x95.5/28x98.2 p.15.28. 3B valves are sodium filled, p15.30, put them in 16v turbos? Don't bother, they are probably the same part number (see Brian McGarvey comments, above).