Topic: K2 head on F2 engine but using F2 cam/sprocket/rockers?

[AbbyRider]

Hello all. I'm currently rebuilding a '77 F2 that was weather seized. I managed to get the stuck pistons out thanks to Hondaman's advice of splitting the cases and unbolting the rods etc. Once I got #2 and #3 out, I realized that there's no way I'm going to get away with just a hone, and I need to bore these out properly. So... why not do the overbore? Problem is that with limited funds I'd like to purchase the inexpensive eBay 836 kit, but it doesn't work that well with an F2 head. (don't want to start another long debate on this)

One possible solution is that I've got a K2 donor motor that has sat outside for a while, so there's surface rust on the cam, rockers, sprocket etc. Based on an old posting within the Engine FAQ, I know that a K2 head will work on an F2 engine. However, my question is this: can I use the cam, cam mounts, sprocket, rockers etc from the F2 and put them in the K2 head, but get new K2 valves and guides? I can't see any reason my it wouldn't work, but I'm wondering if there's something I'm missing. I don't want to bother with the overbore if the mix-and-matched head is going to cause performance issues.

Many thanks,

Dwayne

Reference:
----------------------
Dr Rieck says the following:

...once and for all.

First, the 77/78F2/3 heads shared a common head drain back hole which early K,F and late K heads did not.
This eliminated the middle drain back holes in the F2/3 heads.
The 4 studs next to the eliminated drain back holes require cap nuts and copper sealing washers on the F2/3 head only.

The late F2/3, 77/78 cylinders CAN accomodate the knock pins(or dowels) and the rubber gaskets which allows you to run these early/late K and earlyF/F1(75/76) heads.

The later F2/3 castings are good as they are more stout but this does add weight.

Trying to run a Wiseco 836 kit with an F2/3 head will result in low compression secondary to the increased volume of the F2/3 chamber.

Bottom line....early/late K and early F1(75/76) heads will work on late (F2/F3) cylinders and early/late K and F1 upper cases with mild opening (joining) of the F2/F3 two inner drain back holes at the base of the cylinder

[70CB750]

Subscribed - I want to know too 

[SOHC Digger]

CycleX does sell 836 kits for F2 engines.

At $489, they're not the cheapest big bore kit, but if you can save money by not replacing those K valves, it's not much of a price difference.  AND they ARE made in the USA!  If it were my engine, I don't think I would take a chance with the $200 "Made in China" kits.  Plus these will let you take advantage of those big F2 valves.

[AbbyRider]

Yeah - I've been wondering about the quality of those kits, but haven't heard anything negative from those on the board who have actually used them. But without turning this thread into an 836 kit debate, my original question remains: are there any issues with using the F2 cam, rockers etc in the K2 head while keeping the K2 valves?

[SOHC Digger]

I believe everything's the same except for the cam, which I think just features a longer duration for more high rpm horsepower.  As long as the LIFT is the same on the K as the F, you shouldn't have issues.

[70CB750]

I would PM Hondaman to be sure.

[Retro Rocket]

Maybe i am not understanding things here but the F2 head has a far bigger combustion chamber, I'm pretty sure F2 pistons won't fit in a K head without hitting , either that or you will have a huge rise in compression ratio....   Compare those cyclex F pistons to the K piston kits on their site, the K pistons are almost flat top when compared to the F piston.. .

[AbbyRider]

Retro - you're right, which is why I want to use the 836 kit with the 'K' flat-top pistons that don't need the larger combustion chamber. My F2 head is toast for various reasons, and I have a K2 head, so thus the original question.

[CB750F2]

Dayne, I am 99% sure that you can do what you want. I intend to do the same. I will assemble the head to the block using a used head gasket, some light springs to hold the valves in place, degree in the cam and measure valve to piston clearance. Remember to modify the oil drain back holes of your F2 block. Thanks for replying to my older post in which I was asking similar questions. I have added a reply to your reply in that post. Pat

[AbbyRider]

Thanks Pat. Appreciate the reply (and yes I did see the other one too - thanks). I think I'm gonna do the same as you with used gasket and measure clearances etc. I'll take photos and let you know how it goes. Might be a little while, as I haven't ordered the piston kit yet.

Cheers.

Dwayne