Author Topic: F2 Head ID (Read 2923 times)

teebee67 · « **on:** June 17, 2015, 08:58:15 am »

Hi again,
I have what I think is a F2 head fitted on my RC Eng 1160cc kit (was fitted when I got it) which has 34mm inlet and 31mm exhaust valves. This is what makes me think it's F2 plus there are less oilways in he F2 head. I am needing to order some parts for it (valve guides, springs, etc) and want to ensure I order the correct parts. I think elsewhere on the forum I remember someone refering to an F2 head as a 410 head, mine has 410 cast into it - does this confirm it as an F2 head? If it doesn't is there a definitive way I can verify it as F2?

70CB750 · « **Reply #1 on:** June 17, 2015, 09:02:21 am »

The head on my F2 engine - 1978 - is 410.

koendd · « **Reply #2 on:** June 17, 2015, 11:54:29 am »

jep, 410 is F2, mine has it as well.

Also size/shape of combustion chamber is significantly different then K head (deeper)

teebee67 · « **Reply #3 on:** June 17, 2015, 12:42:09 pm »

Ok - thanks guys.

dragracer · « **Reply #4 on:** June 17, 2015, 12:42:26 pm »

Correct on the valve size.

Pat_at_APE · « **Reply #5 on:** June 17, 2015, 02:06:07 pm »

We can rebuild that F2 head for you. We've got all that it needs here and the skill to get it right!

Regards,
Pat at APE

http://cbrzone.com/sohc.html

Old Scrambler · « **Reply #6 on:** June 17, 2015, 02:10:13 pm »

Are you pulling stumps (drag-racing) or road-racing that motor? If on the road, my modified 410 head is reving past 11-thou and has peak HP in the mid 10s. I sourced new valves (35/31) with lighter stems and bee-hive springs/ti-retainers. Hint.........modern HONDA cars use same casting size for valve-guide retainers as motorcycles and also use the same style collets as the 410-head.

teebee67 · « **Reply #7 on:** June 17, 2015, 03:23:06 pm »

Cheers Pat, if I was on your side of the pond I would probably get the head to you but, as it is, it will probably be parts only that I need.

I'm road racing it and that info on the collets is very handy - do you know what model car(s) is involved? Where did you get the lighter valves from ?

Old Scrambler · « **Reply #8 on:** June 17, 2015, 07:40:39 pm »

www.ferrea.com

I used exhaust guides on all stems to keep maximum clearance for a high-lift cam from Mega-Cycle specific to the 410 head. All valve-train parts were for a car with 6mm stems...............they are longer than needed but we machined the stems to fit the 410 head. Much lighter..........take a look. The valves have a very steep seat angle which effectively increased the flow width to 34mm after we bored the throats.

We used a copper head gasket for final assembly. If you want a complete kit, the Ferrea dealer is about 7 miles from me. My machinist could size the stems and I could ship the complete kit. You would have to match the seats to the valves and do your porting. My cam is the same grind used by M3 Racing on their CR750......with an added differential to my liking regarding the lobe-centers. All valves clearance the piston reliefs but they had to be fly-cut for the larger diameter valves.

hotdog · « **Reply #9 on:** June 18, 2015, 12:45:59 am »

Old scrambler, I'll send you a p.m. about that kit.

Follow me on Instagram - thelumpycam

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dragracer · « **Reply #10 on:** June 18, 2015, 08:09:18 am »

Thanks for that info Old Scrambler. I'll be checking in with you later on those valve train parts.

Old Scrambler · « **Reply #11 on:** June 18, 2015, 08:58:19 am »

I was REAL hesitant to talk about this 'kit' until I was sure it worked............at 11,000+ rpms............and with a high-lift cam........it seems to work very well. The final proof will be in August when we make another run on the salt. Jerry has heard the motor run. It pulls very hard and fast from about 6500 rpms. You can machine your own valve-stems and collet-groves...........or Dave Murre can do it for you. I'll talk to him about a package cost over the weekend at our annual hill-climb event.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #12 on:** June 18, 2015, 10:00:16 am »

Yeah, and Jerry is VERY anxious to hear it break the record now that it's tuned

I'm expecting it to add 20mph to the record. Just hope the Japanese guys that got the record last year at 125 are going to be there also.

teebee67 · « **Reply #13 on:** June 18, 2015, 11:30:29 am »

Yes please let us know when you decide a price for the kit.

Old Scrambler · « **Reply #14 on:** June 18, 2015, 07:01:42 pm »

I'm working on the kit.............or kits. 34mm intakes are available. The first reason we went to 35mm was to clean up some pits on the seats. After Dave saw how steep the seat-angles would be, the throats got a bit larger

I will price the basic parts as a kit........and have the machining expense as an add-on. Lash-caps are part of the kit. Dave tells me that an advantage of cutting your own collet-groves is choosing your desired spring seat-pressure.

I have a spare of each item, so will post a pic when I get to it.

BTW........for anyone that would want Dave to install everything in their head........I can ask..........but he has a schedule that includes family time.

PeWe · « **Reply #15 on:** June 19, 2015, 03:14:25 am »

These valves will increase compression too? It look like that
- 34mm valve with same lenght as K valve possible to make? Minus 1.5mm for lash cap. (or how thick it is)

Below photo of my K head with F2 34mm inlet valves, std 28mm exhaust (K valves).

F2 valves are shorter than K.....adj screw get different angle and more prone to dig hole in valve stem with K valve train. Large mushroom at only 10.000 kms. I have now lash caps on that can be replaced. Or the std F2 valves have very soft stems?

Then an Ex valve K style, 28mm or slightly larger.... I might leave the head and cyl block to the local tuner next winter for fine decking. Additional porting for larger ex valves possible if it will increase power.
(I'll pull engine to stop my worries about weak std rod (attached on a heavy crank) thru the case.

Old Scrambler · « **Reply #16 on:** June 19, 2015, 09:50:31 am »

PeWe..............yes to potential increased compression...............I am also researching the availability of valves to fit the K-heads..............go to 29mm or 30mm on exhaust, but too large is not good. Shrouding should not be a concern on big-bores. I like the lash-caps as they keep the adjusters honest

PeWe · « **Reply #17 on:** June 20, 2015, 12:47:36 am »

Quote from: Old Scrambler on June 19, 2015, 09:50:31 am

PeWe..............yes to potential increased compression...............I am also researching the availability of valves to fit the K-heads..............go to 29mm or 30mm on exhaust, but too large is not good. Shrouding should not be a concern on big-bores. I like the lash-caps as they keep the adjusters honest

34mm K style would be nice for me. If possible, I'm interested as long as the price is not skyhigh.
About ex valve size... when will valve to valve clearance be an issue? CX-7 and similar cams should be possible.

Retro Rocket · « **Reply #18 on:** June 20, 2015, 05:16:18 am »

Subscribed, interested to see prices on these kits....

Old Scrambler · « **Reply #19 on:** June 20, 2015, 07:06:18 am »

Overlap was OK with 35/31 at .407 lift and extra wide lobe centers. The base cam is the Megacycle 125x29. Duration at .040 is 268-degrees with lash at .005...........We set the cam at factory timing and had a 'like-new' cam-tower and rockers.

Yes, I can source standard and oversize valves to fit both the K and 410 heads............correction on stem size........its 5.5mm..............Certain sizes are available with super-flow stems.

I will be away at our club's 32 annual hill-climb event until Monday.

Old Scrambler · « **Reply #20 on:** June 26, 2015, 01:54:09 pm »

F2-3 Valve-Train Kit.............Stainless 35mm intake and 31mm exhaust with 5.5mm stems, beehive springs, Ti Retainers, Chrome-Moly Spring Centers, Collets (Locks), Intake and Exhaust Seals, and heat-treated Guides reamed to correct tolerance. We have to machine the stem length and cut the lock grove. $995.......shipped to US-48......actual shipping cost to all others.

Here is the catch............I need a minimum of 5 kits to get the proper discount from Farrea.......Dave Murre has machining cost of $250...........If you want to do your own you could save that amount.

Kits for K and early F motors with various valve sizes would be the same price............please note: This would convert your K motor to the same locks as used on the F2 Kit. Also note, we will build a K-head to properly measure the valve stem length.

Thanks.........I'll post a few pics tomorrow.

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Author Topic: F2 Head ID (Read 2923 times)