Topic: 836 k pistons in f engine? trying to calculate static compression.

[Ben D]

hey guys i'm trying to find ways to use a standard 836 10.25:1 forged wiseco piston on an f head turbo motor. i cant seem to find any data on stock flat top piston valve reliefs (in cc's) or the stock F2 piston dome height (in ccs)

so my question is .... if i took a 836 wiseco 10.25:1 piston kit and used it in an F2 engine what would my compression ratio be? im shooting for 8-8.5:1. the reason why i want to use the wiseco kit is theyre the cheapest forged pistons available, ive found a couple sets on ebay for about 300 vs dynoman custom turbo pistons which would be an arm and a leg. I already have cyclex super rods and plan on running those too. maybe i could run a bunch of base gaskets?? (not sure what the longevity would be on that idea)

[MRieck]

hey guys i'm trying to find ways to use a standard 836 10.25:1 forged wiseco piston on an f head turbo motor. i cant seem to find any data on stock flat top piston valve reliefs (in cc's) or the stock F2 piston dome height (in ccs)

so my question is .... if i took a 836 wiseco 10.25:1 piston kit and used it in an F2 engine what would my compression ratio be? im shooting for 8-8.5:1. the reason why i want to use the wiseco kit is theyre the cheapest forged pistons available, ive found a couple sets on ebay for about 300 vs dynoman custom turbo pistons which would be an arm and a leg. I already have cyclex super rods and plan on running those too. maybe i could run a bunch of base gaskets?? (not sure what the longevity would be on that idea)

You will end up in that 8.5 range. Personally I think running more static compression (9:1) and less boost make the bike more fun to ride as it isn't a complete dog until full boost is attained. I think people get carried away with large boost numbers as it sounds much more exotic. Those primary chains and transmission don't do well with double digit boost numbers.

[Ben D]

Thanks Mike I appreciate the input! What would you say the most boost I could run with stock compression is? I am also planning on running a dyna 2000 to help with controlling detonation and ignition timing.

My goal is to have a reliable 120hp or so. I noticed when I was riding my drag bike around I had it cranked up to 12 psi (don’t have a lot of control of ignition as it’s just got a dyna now) and it would start to over heat just a little bit. I believe the heads are ported too.

[Don R]

   It's convenient when someone asks what I was wondering about, and I can learn from it without asking it myself. 
   I bought a set of Wiseco 836's off of ebay this morning. I couldn't sleep, it was 3am and the auction ended at 7 with no bids yet.
   I just can't get past the F2 head's reputation (deserved or not) for weak retainers and keepers though. I could clean up the port mismatch easy enough, but the good F valves and kit seem a bit expensive. None of my ported K heads have big valves either. I guess that's why there is boost.

[Ben D]

how much did you get em for? i saw a set for 399 which is cheap!!

[MRieck]

   It's convenient when someone asks what I was wondering about, and I can learn from it without asking it myself. 
   I bought a set of Wiseco 836's off of ebay this morning. I couldn't sleep, it was 3am and the auction ended at 7 with no bids yet.
   I just can't get past the F2 head's reputation (deserved or not) for weak retainers and keepers though. I could clean up the port mismatch easy enough, but the good F valves and kit seem a bit expensive. None of my ported K heads have big valves either. I guess that's why there is boost.

Don...if you buy a set of F2 valves from Dynoman they are only 19.00 each and they are Kibblewhite pieces. Get the F2 Beehive springs and retainers from CycleX and you are good to. It is not cost prohibitive.

[PeWe]

CycleX iron guides will fit an F2 head?

[Don R]

 Cool, thanks for sharing that info.

[Don R]

how much did you get em for? i saw a set for 399 which is cheap!!

 $316 shipping and tax included. I bid at 3am, won them at 7 am, paid shortly after and he shipped at 9 am. I should get them tomorrow. Insomnia sometimes has an upside. It's an older unused set, I'm hoping it stored well.  I have a couple projects, I'm not sure which bike gets them but at that price I had to try it.
 

[Ben D]

thats an awesome price!! nice! maybe we were looking at the same set

[MRieck]

CycleX iron guides will fit an F2 head?

Yes

[PeWe]

CycleX iron guides will fit an F2 head?

Yes

Thanks Mike.
This thread reminds me about my engine build I have in parts. Very difficult to not look for more go fast parts

[Don R]

thats an awesome price!! nice! maybe we were looking at the same set

 Turns out I bought an 812 kit, that's what happens at 3 am. lol. It's all there still wrapped in the oiled paper and packed with 1977 newspaper.

[Ben D]

CycleX iron guides will fit an F2 head?

Yes

Thanks Mike.
This thread reminds me about my engine build I have in parts. Very difficult to not look for more go fast parts

so hard not to keep buying stuff lol!

[PeWe]

CycleX iron guides will fit an F2 head?

Yes

Thanks Mike.
This thread reminds me about my engine build I have in parts. Very difficult to not look for more go fast parts

so hard not to keep buying stuff lol!

Bad idea to not order while still available.
Ordered a set of Heavy duty primary chains from CCC Germany. Their last set. They are really durable.
Making my own to save $100, cutting and rerivet without new master link and good tooling should give me bad thoughts when riding.

Soon possible to assemble.

[Don R]

[/quote] Don...if you buy a set of F2 valves from Dynoman they are only 19.00 each and they are Kibblewhite pieces. Get the F2 Beehive springs and retainers from CycleX and you are good to. It is not cost prohibitive.
[/quote]

 I do listen on occasion and after missing out on the "was in stock but not now" CycleX 890 kit I remembered "buy it when you see it" so I took Mikes advice and bought a set of Dynoman F2 valves today.   
  I also bought a cylinder hone for a couple stock bore motors that were low miles and really clean but I took apart and now need new rings. The machine shops near here suck azz.

[MRieck]

Don...if you buy a set of F2 valves from Dynoman they are only 19.00 each and they are Kibblewhite pieces. Get the F2 Beehive springs and retainers from CycleX and you are good to. It is not cost prohibitive.
[/quote]

 I do listen on occasion and after missing out on the "was in stock but not now" CycleX 890 kit I remembered "buy it when you see it" so I took Mikes advice and bought a set of Dynoman F2 valves today.   
  I also bought a cylinder hone for a couple stock bore motors that were low miles and really clean but I took apart and now need new rings. The machine shops near here suck azz.
[/quote] 👍

[Don R]

 Dynoman is out of their F2 exhaust valves, they would be able to ship the same valves with kibblewhite branding for double the price. 

[PeWe]

K valves possible?
CycleX has sale on their stainless 34mm valves.
They claimed that their Iron guides work with them.

My former 5mm valve stem kit head got CycleX Cryo Iron guides and these valves, 34mm and 28mm. Only 34mm valves for stock stem thickness I could find.
http://www.cyclexchange.net/Engine%20Parts%20Valve%20Trane.htm

My K2 head that has F2 stock in valves will get a set too. I have the valves, back cut and ready with TI retainer. Just install.
The F2 stock stem tips mushroomed really quick.

Lash caps did not last long either. 0.25 mm dimple before 10.000km.

[MRieck]

K valves possible?
CycleX has sale on their stainless 34mm valves.
They claimed that their Iron guides work with them.

My former 5mm valve stem kit head got CycleX Cryo Iron guides and these valves, 34mm and 28mm. Only 34mm valves for stock stem thickness I could find.
http://www.cyclexchange.net/Engine%20Parts%20Valve%20Trane.htm

My K2 head that has F2 stock in valves will get a set too. I have the valves, back cut and ready with TI retainer. Just install.
The F2 stock stem tips mushroomed really quick.

Lash caps did not last long either. 0.25 mm dimple before 10.000km.

Nice thing is they are easy to replace. 

[PeWe]

Lash caps, yes.
3 caps easy to replace, the 4th needed rocker arm off. That valve must be sitting a little deeper.
 Maybe 0.1mm missing to get it off. Rocker arm max lift against base circle, advancer screw released completely.
Another cam with slightly smaller base circle would have been enough.

I hope CycleX will have more sales, iron guides, springs etc.

[newday777]

Not a sale on but CycleX has the cast iron guides and super rods available

http://www.cyclexchange.net/Cryo%20Treated%20Parts.htm

[PeWe]

So they have Super rods in stock?

[newday777]

So they have Super rods in stock?

Looks like they do

[CB750R]

Oh jeez this forum is bad for the wallet!