Cylinder & Liner Tolerances.

**Dougal** · 29th December 2011, 08:04 AM

Here is the grading from the 4BD2 manual for liner fitment.
Measurements are averags of 4 measurements taken 115mm down from deck height.

Grade 1.
Cyl 105.001-105.010mm
Liner 105.011-105.020
Grade 2.
Cyl 105.011-105.020
Liner 105.021-105.030
Grade 3.
Cyl 105.021-105-030
Liner 105.031-105.040
Grade 4.
Cyl 105.031-105.040
Liner 105.041-105.050

The upshot of all that, liners should be interference fit 0.001-0.010mm. I haven't measured mine, but I know they are on the loose side.

**rick130** · 29th December 2011, 09:29 AM

So which liners do you already have ?

**Bush65** · 29th December 2011, 02:29 PM

Isuzu mark (near the front right from memory) on the deck of the block, the code for the liner to be used in each hole - the markings are all together in one place, not adjacent to the cylinder.

If the deck has been faced or given a severe clean the marking may have dissapeared.

**rick130** · 29th December 2011, 03:38 PM

Originally Posted by Bush65

Isuzu mark (near the front right from memory) on the deck of the block, the code for the liner to be used in each hole - the markings are all together in one place, not adjacent to the cylinder.

If the deck has been faced or given a severe clean the marking may have dissapeared.

According to the manual I have, liners are printed on the RHS, piston's on the LS front.

**Dougal** · 29th December 2011, 03:50 PM

Originally Posted by rick130

So which liners do you already have ?

Ones I swapped for beer about 6 years ago.

Pretty sure they're generic part liners at the loosest tolerance, they come in and out pretty easy. My bores were cast-iron sleeved and rebored so the factory tolerances are lost.

Back then Isuzu wanted $400 per hole for matched piston/liner/rings and I had a wedding coming up. My liners cost me some beer, pistons were generic (but apart from the Isuzu logo and wear were identical to the Isuzu pistons that came out). Rings genuine.

**c.h.i.e.f** · 30th December 2011, 10:19 AM

dougal out of curiousity would a rebuild kit for a 6bd1t suit a 4bd1t ? (same tolerance liners,rings pistons etc etc?

**Dougal** · 30th December 2011, 10:40 AM

Originally Posted by c.h.i.e.f

dougal out of curiousity would a rebuild kit for a 6bd1t suit a 4bd1t ? (same tolerance liners,rings pistons etc etc?

Yes, they use the same parts. My beer swapped rebuild kit was actually a 6BD1T rebuild kit that was missing a few pieces.

**c.h.i.e.f** · 30th December 2011, 11:13 PM

Mmm interesting....
with your findings on these tolerances have you discovered any differences between NA and turboed motors tolerances ?
Also what are your current piston skirt lengths out of interest ?

**Dougal** · 31st December 2011, 08:21 AM

One of the manuals I have covers NA and turbo engines with no distinction between them for cylinder tolerance.

From a solidworks model I created a few years ago my pistons are ~98mm overall height, ~60mm from the pin centre to the bottom of the skirt.

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