De-Humping the 1KZ? Thoughts? (1 Viewer)

[Tigris]

But seriously, what is the purpose of the hump on top of the valve cover of the 1kz? I read that some folks lobbed it off. But I am interested in long term effects of such a mod.

I am currently overseas away from my KZJ78. But I am planning on performing a series of mods when I get back. One would be a liquid-air intercooling setup. This bulge will be in my way and I will need it gone.

Side note: I know that some of the 1kz flavors out there (Surf, HiAce, 90, 95, 120, etc) have that hump at different locations on the rocker cover, some more forward than others. So, are these covers interchangeable?

Cheers!

 

[Tigris]

Bump.

Any thoughts guys?

Thanks.

 

[RHINO]

But seriously, what is the purpose of the hump on top of the valve cover of the 1kz?

Some humps contain a windage type tray, acts like an internal catch can for crank case vent. If you don't have a vent hose attached to yours it should be an empty hump.

The one in the picture looks to be an empty hump style cover and could easily be de-humped

 

[Tigris]

Great!
Thanks @RHINO yeah my cover has the hose coming out the side of the back like the one pictured. This is good news as this lobotomy would buy me more space under the hood.

 

[simonliew]

Bump.

Any thoughts guys?

Thanks.

i cut it off and glued a piece of lexan when i install a top mount intercooler on a 93 surf

 

[Tigris]

Nice. So being composite, do you remember if it had enough meat for taps?

Also, any ill effects?
Thanks!

 

[simonliew]

i dont remember how exactly i did it,might have use screws to screw the lexan on,that was like 3 or 4 yrs ago,ill take a look tomorrow.

 

[KZJ71 YotaFreak]

Hey guys, I'm about to remove the hump on my top cover too, to fit a top mount intercooler + fan. Mine is just like the one in the picture attached by @Tigris.

Just curious to know if this mod has worked well and no issues were encountered. How did you go about sealing it again? Plastic welding? Polycarbonate/lexan?

Any tips and suggestions will be greatly appreciated!

 

[ATL Cruiser]

Some humps contain a windage type tray, acts like an internal catch can for crank case vent. If you don't have a vent hose attached to yours it should be an empty hump.

The one in the picture looks to be an empty hump style cover and could easily be de-humped

This is correct. It's for the valve cover baffles to let oil slosh around while still relieving crankcase pressure.

You're supposed to adjust the baffles when turbocharging. Nobody ever does though. Read this:

PCV Valve Baffle vs. Oil Consumption Test Study – M/E Wagner Performance Products

 

[Tigris]

@ATL Cruiser
Very interesting study you have there. I wonder if there is a benefit to re-engineering the baffles on our valve covers for better oil retention and vent-residue reduction, especially after deleting the EGR

I'll be considering that when I get to perform the lobotomy on that hump. Thanks!

 

[KiwiBogan]

@ATL Cruiser
Very interesting study you have there. I wonder if there is a benefit to re-engineering the baffles on our valve covers for better oil retention and vent-residue reduction, especially after deleting the EGR

I'll be considering that when I get to perform the lobotomy on that hump. Thanks!

Hey mate, how did you go with removing the hump? I asked this question a while back but no one really knew the answer so great to see some positive respones here. Keen to hear how you went! Pics? Cheers, Sam

 

[ATL Cruiser]

Hey mate, how did you go with removing the hump? I asked this question a while back but no one really knew the answer so great to see some positive respones here. Keen to hear how you went! Pics? Cheers, Sam

The only modification I did to my valve cover was to slightly close the baffles upon adding a turbocharger. Safari recommended doing this per their install guide.

My guess is that the venturi effect goes up with the turbocharger pressures, so the vents need to be closed a bit to compensate.

 

[KiwiBogan]

The only modification I did to my valve cover was to slightly close the baffles upon adding a turbocharger. Safari recommended doing this per their install guide.

My guess is that the venturi effect goes up with the turbocharger pressures, so the vents need to be closed a bit to compensate.



Ahh sorry mate. my question should have been directed at Tigris. Interesting about this baffle thing though! I might look into that myself though I have a factory turbo so it might not affect me. Cheers, Sam

 

[KiwiBogan]

@ATL Cruiser
Very interesting study you have there. I wonder if there is a benefit to re-engineering the baffles on our valve covers for better oil retention and vent-residue reduction, especially after deleting the EGR

I'll be considering that when I get to perform the lobotomy on that hump. Thanks!

How did you go with removing the hump?

 

[Rigster]

The only modification I did to my valve cover was to slightly close the baffles upon adding a turbocharger. Safari recommended doing this per their install guide.

My guess is that the venturi effect goes up with the turbocharger pressures, so the vents need to be closed a bit to compensate.

View attachment 3270966

Interesting, thanks for sharing this.

I have my unit turbo'd, and prior to it being (and after) I never used a drop of oil. However in the hotter summer, and when I was pulling a trailer and maintaining higher boost levels, I noticed more blow-by when I replaced the gasket on the crossover pipe and was considering a catch-can.

I assumed it was more because of the EGR delete, but now I wonder about this baffling baffle option. I may end up doing both. I had not considered this venturi effect because of increased pressures. I rarely put my foot into the right pedal when just driving normally, there is more than enough power. On bigger mountain climbs, sure, but that is for shorter periods. It seems only when I have the trailer on (not often, couple of times a year) that I am maintaining higher boost levels (15-18) as apposed to 8-12psi. Either way I am religious about EGT's and keep them around 1100F.

 

[Tigris]

How did you go with removing the hump?

I have yet to perform this surgery as I just got back into the country. I have a set of OE injectors to install and an EGR to delete so removing the hump might be happening at the same time.

I am still undecided on the patching material. I am contemplating a metal patch with fasteners but I'm not sure how much meat I have to tap into. Maybe I should consider fabricating some bosses (out of epoxy or CA+carbon powder) to tap into or to hold captive studs

Your thoughts are always appreciated guys!

Cheers!

 

[KiwiBogan]

I have yet to perform this surgery as I just got back into the country. I have a set of OE injectors to install and an EGR to delete so removing the hump might be happening at the same time.

I am still undecided on the patching material. I am contemplating a metal patch with fasteners but I'm not sure how much meat I have to tap into. Maybe I should consider fabricating some bosses (out of epoxy or CA+carbon powder) to tap into or to hold captive studs

Your thoughts are always appreciated guys!

Im thinking even more low-tech. Like a thin aluminium sheet patch bent/arched over top of the rocker cover should suffice? Gasket glue to seal it and riveted from the inside out maybe? Or there might still be enough space underneath to rivet from the top for a cleaner look? It might not look pretty but would be hidden by the top mount intercooler, and should then allow a puller fan to be installed underneath the TMIC. I have a guy coming around this week to buy my spare rocker cover as his metal crossover pipe wore through his. Maybe I might ask for his old one and use it as a practice subject.

Just brain farting here but I wonder how much that hump is just there for aesthetics and performs no real purpose....

 

[KiwiBogan]

I forgot to ask the bloke about getting his old valve cover. I could probably still ask I suppose. He knows these 1KZs pretty well. Has rebuilt a few of them... but we discussed the hump thing and he agrees theirs no real purpose to it and removing it should be harmless. We oth agreed it looks like its just for asthetics as it sits up between the two air intake pipes with the Toyota logo on it. The one I sold him had a long baffle the entire length of the cover with the hump in the centre.
I am about to face an engine rebuild so thats taking priority atm but once the engine is rebuilt, I'm going to readdress this as I have a big new intercooler and SPAL fan I need to fit on top and the hump is right in the way!