10 replies to this topic

[KevrevSLR]

Hi all, has anyone any recommendations on alloy valve covers (tall) that would suit a Holden 308? there doesn't seem to be a lot out there, has anyone had experience with KC type? and if so any Venting / PCW issues,.. or would you just go catch can? many thanks Kevin

[Heath]

On my car I have late model (VN/EFI) type heads (COME 600 series) with the KC alloy rocker covers. These are different to the HQ-type head's rocker covers.

 

My ones have a very basic baffle at the front, the outlet of which runs to a catch can I fabricated, which is baffled and has a breather. No PCV.

 

The Holden 6 KC rocker cover I had years ago didn't have any baffling at all. I had to add that. Very lousy piece. The casting was rough as, also.

 

The frustrating thing about KC rocker covers is they are very attractive, even though they are kind of shit.

[76lxhatch]

The KC covers are well enough made and I reckon they look good, but Heath's comments certainly apply to the poor baffle situation. They seal better at the gasket face than the pressed tin style because they are much more rigid. I fitted extra baffles as well as a proper oil cap, larger/relocated breather and an oil separator for the PCV:

 

http://www.gmh-toran...-14#entry963169

http://www.gmh-toran...17#entry1076069

(note there have been some baffle revisions since, not shown - but you get the idea)

 

I wouldn't remove the PCV unless you absolutely have to, the breathers have to be very large to make up for it and you still lose some benefits.

[Heath]

I fitted extra baffles as well as a proper oil cap, larger/relocated breather and an oil separator for the PCV:

Ahhh, good point. Yeah my cap leaked like a sieve and I had to weld on a threaded neck to take a proper cap, also.

[RallyRed]

Don't know about V8 ones, but recently fitted a KC to a 202. 

It was a whacky casting in as much as it sat up on the drivers side rear head bolt, by a mile.  Leaked like a you know what.

Had to keep taking bits out with a grinder until it sat down flat.

 

Once that was sorted, they do bolt down nice and firm compared to a pressed metal one.

 

Maybe just test fit yours a few times without a gasket to see if it sits down square?

[Lima31]

KC ones are fine, Aussie made too.

 

Edited by Lima31, 23 August 2022 - 09:25 PM.

[KevrevSLR]

On my car I have late model (VN/EFI) type heads (COME 600 series) with the KC alloy rocker covers. These are different to the HQ-type head's rocker covers.

 

My ones have a very basic baffle at the front, the outlet of which runs to a catch can I fabricated, which is baffled and has a breather. No PCV.

 

The Holden 6 KC rocker cover I had years ago didn't have any baffling at all. I had to add that. Very lousy piece. The casting was rough as, also.

 

The frustrating thing about KC rocker covers is they are very attractive, even though they are kind of shit.

Hey many thanks for the feedback Heath, sounds like a catch can with breather is the way to go.

Do you have to clean / empty the catch can regularly?

ps apologies for the late response too! 

[KevrevSLR]

The KC covers are well enough made and I reckon they look good, but Heath's comments certainly apply to the poor baffle situation. They seal better at the gasket face than the pressed tin style because they are much more rigid. I fitted extra baffles as well as a proper oil cap, larger/relocated breather and an oil separator for the PCV:

 

http://www.gmh-toran...-14#entry963169

http://www.gmh-toran...17#entry1076069

(note there have been some baffle revisions since, not shown - but you get the idea)

 

I wouldn't remove the PCV unless you absolutely have to, the breathers have to be very large to make up for it and you still lose some benefits.

Wow, some pretty cool innovations there!! that separator and oil cap are next level!!

Haha if I only had those machining skills and equipment!

Hmm interesting what you've said about the PCV, given Heath's comment about no PCV,...

Don't know about V8 ones, but recently fitted a KC to a 202. 

It was a whacky casting in as much as it sat up on the drivers side rear head bolt, by a mile.  Leaked like a you know what.

Had to keep taking bits out with a grinder until it sat down flat.

 

Once that was sorted, they do bolt down nice and firm compared to a pressed metal one.

 

Maybe just test fit yours a few times without a gasket to see if it sits down square?

Thanks for the advice, so looks like a bit of fine tuning on the fitment,...

[76lxhatch]

I've never experienced the fitment issues, unless the quality has gone downhill I imagine that was a bit unlucky. The heads themselves will likely vary a bit though too.

 

You can buy after market caps and oil separators. It depends on your engine as to what you will need, if it's not heavily modified then the breather department won't be such an issue.

[Heath]

Hey many thanks for the feedback Heath, sounds like a catch can with breather is the way to go.

Do you have to clean / empty the catch can regularly?

ps apologies for the late response too! 

Some people will occasionally un-bolt the catch can and empty it. Maybe a few times between oil changes? If the separator is doing its job, you'll mostly just build up water in the catch can (rather than oil).

 

I put a hose and tap on mine that sits behind the front spoiler, so I can drain it very simply and quickly without even opening the bonnet.

 2022-08-17 19.46.18.jpg   299.33K   2 downloads

 

You can also plumb the bottom of the catch can back into the sump so it drains back in there, like a turbo drain pipe. I have that on my Datsun and never have to touch it. (don't worry about the moisture; it won't dilute the oil of the motor because the motor is at an elevated temperature)

[KevrevSLR]

Some people will occasionally un-bolt the catch can and empty it. Maybe a few times between oil changes? If the separator is doing its job, you'll mostly just build up water in the catch can (rather than oil).

 

I put a hose and tap on mine that sits behind the front spoiler, so I can drain it very simply and quickly without even opening the bonnet.

2022-08-17 19.46.18.jpg

 

You can also plumb the bottom of the catch can back into the sump so it drains back in there, like a turbo drain pipe. I have that on my Datsun and never have to touch it. (don't worry about the moisture; it won't dilute the oil of the motor because the motor is at an elevated temperature)

Nice, thanks for the info, very innovative!!