HM Headers Help Please

[vsdore]

Hi,

I've just bought the HM header set HM99SS for my VS ecotec, and would love to hear any tips from anyone here that has fitted these before.

Also, on mine I notice that one bank of the headers has 'splits' in the bolt holes, the other bank doesn't (see pic). Can anyone with these tell me if this is how they are meant to be - I'd hate to fit them then realise I have a dud set.

Thanks!!

 

[shaggerz]

Those splits look factory machined. I'd say they are supposed to be that way, but I couldn't explain why one set is split and the other is not.

I can see no problems fitting them as they are.

 

[vsdore]

thanks shaggerz. i contacted HM, they are quite helpful actually, apparently their flange supplier has changed the way they make them and some sets have one of each. makes no defference they say, so should be ok.

 

[Not_An_Abba_Fan]

I would have said different suppliers of flange plates too. No difference at all, the one with splits is the way the plasma cutter cuts them out, it does it in one continuous cut. You will need a welder to weld the flanges on in front of the cat but apart from that they should be a straight forward fit. Just be careful on the drivers side if you have ABS.

 

[Doggie]

I have them fitted to my VS, but had a loud shrudder noise when I braked. Turned out it was the right header that was rubbing on the steering rack. My mechanic placed some sort of packing under the engine mounts and problem is fixed. Appartently VS's are prone to sagging mounts.

 

[Boonz]

any v6 commodore up until vy onwards were bad for sagging engine mounts....

 

[vsdore]

hmmm, maybe sagging engine mounts explains why my cat is hanging low at the moment. i was hoping the HMs with the new Y piece would fix this.

 

[Boonz]

it only drops it a couple mm...was the sump close to the crossmember??? ive seen some sumps sitting on the crossmember and the driver knows no difference after ive replaced them

 

[vsdore]

thanks for that info - what sort of gap should there be between sump and crossmember if the mounts are OK? i'll check it out tomorrow...

 

[Boonz]

well anywhere between 10mm and about 4 or 5mm before they start getting to the point of needing replacing.