Suitable cr and cam

[65Pearl]

Gents,
My search for Holy Grail of Cal Look has begun and I have an engine on sight, 2054cc (74x94) with some new parts and something used. The engine should be a full street engine with good cooling characteristics, but should have enough grunt to bring a grin on my face as a weekend warrior machine. No real racing for me, pure fun.

Initial plans included Engle W125 with 1:25 rockers and double Dellorto 45s.
As far as the heads are concerned, pair of used CB 044 magnums with 42x37.5 valves are on the list. With a closer look the of these heads the cc of the comb chamber is only 44cc. This with the 0.06 deck height brings the compression up to 10.44. This got me worried a bit.
- What cr can the W125 withstand?
- If keeping the heads as they are should I think of different cam (FK8?) and maybe 1:4 or 1:5 rockers? The heads should flow enough; they were used in a bigger engine with more hp and a wilder cam like FK87 or FK89.
- If swapping cams and keeping the cr as is, will this get me into trouble with pump gas and over heating? I can use 98 octane fuel in Europe and I’ll definitely get an external oil cooler.

 Unfortunately I do not have all the data available to calculate dynamic cr and frankly at this point it would not tell me much.

With all this on the table, what would you suggest?

Thanks!

[Jim Ratto]

Same combination that comprised my first "stroker motor" in my '67 daily driver-commuter back in 1990, except I ran 7.8:1 CR (before you LOL and shy away from what I am going to tell you, realize, this was my first semi expensive big motor, so I was err-ing on the side of caution, I drove the car everywhere, no limits, and back in 1990 it was low CR city, everybody but the full race guys were drinking the low CR Kool Aid, in North Calif it was unheard of running a big motor @ 9:1 or higher). I like the direction you're taking with your engine, these types of "fun drivers" are to me what owning a fast VW is all about.
I have no experience with 98CR fuel, so I can't answer what CR you can run up to. I am guessing it is close to where you are, provided a few other factors are paid attention to. I would, if you are going to shoot for the moon on CR (like where you are) NOT install the Engle 125 as it bolts up, which is around 4 degrees advanced. I would back it up, or at least check it, and run it straight up. Cam advance can exacerbate detonation in a sensitive motor.
I wouldn't drop an FK87 in your motor if you want just somethign fun to drive. I made that mistake in 1991, removed the 40 x 35 heads and 125 and replaced them with Super Flow 1 46 x 37 and Engle FK87 and it was slower unless I was over 5500rpm. The K8 will work though. Again, straight up not "dropped in"
I recently swapped cams in my own car from a Pauter R6E8 which was advanced to 104ATDC (intake lift) which was 272 @ .050 and 304 @ .020 to Web 86C which dialed @ 274 @ .050 and 315 @ .020, so similar to Pauter, except valve lift...BUT I run the 86C 1.5 deg advance (106.5ATDC), which eliminated a pinging I was getting just off idle with Pauter. Same CR of 9.8:1, same total advance of 30 (locked dist). Cyl pressure buillds a little later = less chance of detonation when on the edge.
What cooling parts are you going to use on this motor (fan, fan shroud, coolers, pulley, air into eng comp. etc?)
Have fun,
Jim R

[65Pearl]

Jim Thanks for a really valuable info!
Somehow I still feel I'm too high with the cr.
Maybe I should try to get it down to 9.5, even if I'd need to get new heads... Yeah I know, I'm a wuss.
I'm definately going to use the fan and shrouds plus external cooler. Not sure if I should use the doghouse cooler or not, but use all that airfolw from the fan to cool the heads?
Any other suggestions: should i leaveit  or should I go
Cheers.

[Jim Ratto]

by adding .015" to your .060 deck you could get CR down to 9.7:1 and keep your heads

[65Pearl]

Jim, no I don’t think I would want to increase the deck height above 0.06.
BTW, I did give some false info regarding the heads. The valves are 40x35.5, not the bigger ones.

Actually I did some studying last night regarding the Dynamic CR and it opened my eyes quite a bit. Well, at least I think so. 
This all got started when I had a chat with one of the guys that have been there and done that for decades. He gave me some facts and after discussing this with the engine builder we agreed on which way to go with the cam.
It strongly looks like we’re going to build the engine with Buckpack 4063-10 since we got the cam and to us it looks good with the rest of the combo. Any opinions? 

I’m no longer worried about the static CR being what it is, since this cam needs SCR and I can keep the heads. The theoretical dynamic CR will only be around 7,3 due to the long duration @ 0,050 and late intake vlv closure. (I’m aware of the things that will affect the effective DCR, thanks to John Mahers excellent post on some earlier topic, hence “in theory”.)

If the 7,3 is too low I need to start over again.
Strange, but fascinating, how these cams keep us awake at night… 

[Zach Gomulka]

Run .040" deck & dish the pistons for more CC's.

[65Pearl]

Zach, we did think that optio also, but for the moment, I'm not too worried about the SCR anymore that I 'd need to lower it immediately.
I'm definately not saying it's important since the more SCR one has the more heat in the heads and since the fuel air mixture will self ignite at some given press and temp one still needs to pay attention to it. 
I did start a topic on DCR to better understand the key parameters and more importantly to think the system as a whole assy, instead of concentrating on one little detail.
I do hope it would help few others as well.   
Thanks

[65Pearl]

Zach , I didn't read your post carefully enough on the deck height. The 0.06 is a tad high.
Actually I'm thinking on going to 0.05 deck for 10.7 SCR and 7.5 DCR.   
Unless someone tells me not to with good reason.