14 replies to this topic

[hanra]

Does anyone know how GMH came up with its various engine codes? L16, L20, L32, L31, L34 ??

What’s the L mean? And what’s the correlation with the codes and engines types or sizes?

Did they just pick these codes out of a hat at the work Xmas party whilst sloshed?

[S pack]

Does anyone know how GMH came up with its various engine codes? L16, L20, L32, L31, L34 ??

What’s the L mean? And what’s the correlation with the codes and engines types or sizes?

Did they just pick these codes out of a hat at the work Xmas party whilst sloshed?

The L means Longitudinal ie: the engine is oriented North-South in the chassis. The actual code numbers chosen may remain one of those xmas party secrets.

[yel327]

When you put all the codes together in a list they do make some sense, but it is a GM system so was adopted by GMH at I believe the start of HK design. Remember the engines would be given codes when put into planning hence why they count up. Example:

 

L30 - 307

L31 - 308

L32 - 253HC

L33 - 253LC

L34 - 327

 

When engines ceased being used the codes were re-used so L30 became 350 for HQ and L34 became the higher output 308 in LH.

 

Some engines never got codes as they were standard engines for certain models or special vehicle packages, like the 350HC and 350LC engines in HT-HG and the XU1 engines. The L32 code wasn't used in HT or HG as the engine was originally intended to be standard fitment on most V8 models. However in HK it would be optional hence has the L32 code assigned.

 

I think the 6cyl engines were all L2x codes initially too in Holden and LDx in Torana but LJ used the L20 and L23 codes from Holden in LJ:

 

- - - - 161HC (standard engine, no code). 138HC was similar for LC Torana as was 161S.

L20 - 186HC (later re-used for 202HC)

L21 - 161LC

L22 - 130HC

L23 - 186LC (later re-used for 202LC)

LD1 - 173HC. Not used for Holden where standard but given LD1 for LC and when codes used across the board adopted for Holden.

LD2 - 161LC Torana.

LD3 - 136LC Torana.

LD6 - used in HJ at least for export 138HC but I expect it came from LH.

 

Not sure why the 186S got L66 but possibly the improved performance engines got L6x as the higher output 70hp 4cyl in LC was L60, but the low comp L4 1300 was L59 so not sure. 

Edited by yel327, 17 May 2020 - 10:48 AM.

[Shiney005]

When you look through the whole list of GM (America) RPO codes, there are thousands of them. Too many to have any real reason. I reckon they started at A01 and went from there.  Currently, the code L34 is for a 2 litre 4 cyl, but in 1970 it was the code for the 396 V8, so GM are re-using old codes for different applications.

I tried to copy the list of this webpage but computer says no.  http://www.rpocodes.com/

 

Edit. Byron beat me too it

Edited by Shiney005, 17 May 2020 - 10:52 AM.

[S pack]

LD1 was originally 161HC in LC which then became 173HC when the 161 was discontinued.

LD2 was originally 161LC in LC which then became 173LC when the 161 was discontinued

[Dr Terry]

The L means Longitudinal ie: the engine is oriented North-South in the chassis. The actual code numbers chosen may remain one of those xmas party secrets.

I don't believe that the "L" stood for longitudinal orientation, Camira engines (east-west FWD) use the codes L16, LV6, LV9 & LE4 for their engines.

 

Dr Terry

[yel327]

LD1 was originally 161HC in LC which then became 173HC when the 161 was discontinued.
LD2 was originally 161LC in LC which then became 173LC when the 161 was discontinued

Ah yes, I forgot they would be the same as L20 and L23 simply transferring to 173 and 202 when they replaced 161 and 186.

I wonder what LD4 and LD5 were?

Edited by yel327, 17 May 2020 - 03:35 PM.

[S pack]

I don't believe that the "L" stood for longitudinal orientation, Camira engines (east-west FWD) use the codes L16, LV6, LV9 & LE4 for their engines.

 

Dr Terry

I remember reading the meaning of the L in some GMH literature or documentation. I was sure my memory of what I had read was correct but perhaps I have joined two dots that don't belong together.

[grumpy xu1]

The "L" stands for Leaks from, sump, rear main, timing case seal, rocker cover(s) side plates. For it's entire life.

[Dr Terry]

I wonder what LD4 and LD5 were?

AFAIK LD4 was the 250ci Chev 6-cyl fitted to Sth African HK to AJ Holden/Chev models.

 

LD5 was the smaller 230ci Chev 6-cyl seen in HK-AJ Holdens & Chevs in SA. LD9 was the 250ci (Hi-Output - 180bhp) 6-cyl used in HT to AJ SA models.

 

Dr Terry 

[yel327]

Ah yes, I remember seeing them now. Will check in the HJ POA document.

[Shiney005]

Is there a comprehensive list anywhere? What is L36 in a VH?

[yel327]

L36 is the 4.2L V8 XT5.

[Shiney005]

I thought XT5 was 202. What were the major differences between 4.2 XT5 and the previous version? Is it high compression? Did the 308 come in XT5? If so, what was the code for that engine?

[yel327]

XT4 is pollution red engines. XT5 was blue engines. I think XT6 was the blue 6 with air pump maybe?

XT5 4.2 got 4BBL manifold, Quadrajet, HEI ignition and compression drop from 9.4 to 9.2:1. I don’t think there was any low comp 4.2 outside of Bedford by that stage. The head exhaust crossover port changed to square rather than U and had two centre bolts rather than one.

There was no 308 by then, it was called 5.0L and as it was only really the HEI dizzy and compression drop also from 9.4 to 9.2, it was still a 4BBL 5.0L so retained L31. The low comp version was Bedford only also, but had another code as it was a Rochester 2BBL carby like the low comp 4.2.

Here is the XT5 service manual:
https://www.ebay.com...u8AAOSwMyteAGoS

Edited by yel327, 22 July 2021 - 11:42 AM.