[atari4x4]

Just about to do a plug change on my blagon & was having a quick suss of the various FSM's & noticed that they list a different plug gap for the 2 motors. H20a = 0.8mm & the H25a = 1.1mm

SV


SQ


Wondering if there is any real reason behind the different specs? I know a larger spark plug gap will produce a bigger spark but it also requires more voltage to do so, would it be the earlier H20a SV's running an external igniter on the firewall & the later SV's & SQ's running an internal igniter in the coil packs?


ok go

[alexvitara]

Interesting. So what would you run in a 2.5 swapped into a SV620?

[atari4x4]

NFI, hence my questions

do you have 2 or 3 wire coil packs?

[alexvitara]

2 wire

[atari4x4]

so you have the separate igniter on the firewall, i'd be going with the H20a plug gap.

[littleSuzicar]

From the SV620 service manual H20A motor .7 t .8 mm, I all ways set the small gap and as there wear the gap will get bigger and stay in the recommend range well that is my theory.

[atari4x4]

i've gapped this set at 1.1mm, as my SV620 is one of the later ones with the inbuilt igniters, the ones that came out have done 16,000kms & have very little viable wear on the electrode... my theory is bigger gap as per the H25a should produce a bigger spark.