Yes 2 camshafts in the 186 XU-1 but the 1st one was set at zero and the next set retarded at the timing gear at one point and then the other camshaft came for a Bathurst version I believe.

There was a 186X the 1st pilot cars most likely and then came the 3100X 8/1970 TO 8/1970 and then the CK 9/1971 TO 1/1972

Edited by user Tuesday, 9 June 2020 2:22:28 PM(UTC)  | Reason: Not specified

No LC XU1 186 engine number was prefixed 186X, they were all 3100X until the CK prefix was introduced with HQ release. The 1st 20 XU1's did not have the camshaft set at zero. The same alloy cam gear was used for ALL LC XU1, from the very 1st LC XU1 built to the very last LC XU1 to roll off the assembly line. It was the position of the keyway in the cam gear that was retarded 6 degrees.

Edited by user Wednesday, 10 June 2020 10:30:24 AM(UTC)  | Reason: Not specified

They were a special run of 186. They did the CK engines and some NK service engines. It also looks like they built a number of probably block and piston sets to service pre-HK red engine 179/186 and these have NG prefix on them. GMH issued a bulletin basically stating as much, they say 202 is OK to service HK-HG but not earlier stuff. It wouldn’t have been hard for them to do it, just a mix of 173 and 202 patterns to make the sand mould.

GHM says that provision was made to have 186 stuff available for a period after 173/202 started, so that there were engines suitable to replace/repair 149/161 and 179/186 in EH-HR. They would have supplied ND or NE block and piston for 149/161 or NG prefix for 179/186. 202 were allowed to service HK-HG, and they even say that the 3300 XU1 engine was suitable for LC XU1.

The earlier 173 used the same crankshaft mains as earlier red. Later on they changed to 202 mains.

173 might be similar to 179 as it’s only about 60 thou difference, but it won’t be the same as 186 as it’s bore is the same as 202. They would have had specific patterns for both 173 and 202. Just used the 173 mains area patterns with 202 rest plus the 186 plate screwed to the side. Made enough moulds and blocks to suit those final LC XU1, some spare part XU1 engines and/or shorts plus the generic NG to supply spares for the early girls. It looks like some people even bought those NG blocks to repair HK-HG 186 and LC XU1, probably done by owners or the aftermarket industry though.

Yes, they must have kept some. Probably out of whatever stock they had for 2600S, 186S and 3100X engines after the nodular iron plant started producing crankshafts mid 1967-ish. From what I understand the 2850S engines had nodular iron crankshafts as would the planned 202S for the cancelled HQ GTS.

I am talking about the mains caps ? not the size of the journals.
The 202 mains caps will not fit into a 186 as the bolts are wider apart than the 186 and the rest, but I am not sure of the 173 mains caps, maybe they stayed the same as the 186 or they changed to the 202 type.

I believe later that the 173 changed to 202 mains, so the 202 and them 173 maybe the same casting, just with a 2.8L casting on the block, would it be worth making a block that's 60 tho less, that's f all. the 179 was playing it safe with extra thickness in the walls, but would an extra 60 tho be a problem with a 173 bore wall thickness.