Project Cafe Rocket 686 begins. Finally!

[catman]

Fitted X-4 cam to my extra cyl. head (Raptor) for the endless Baghira project and found that I had to use a die grinder on the floor of the camshaft galley to give enough clearance for the lobes to rotate through with out hitting the head. Also had to buzz some material off the heads of the two steel allen head cooling jacket plugs that are on the floor of this area. Maybe your cyl head is different in this area of the casting, but it is worth making sure.......I'm not sure what minimum clearance is advisable, (mine is set at.020 to .025 in). Also consider the effect of the cam lobes swinging through the pool of oil that normally is in this area if clearance is inadequate........

[edfmaniac]

UPS man just came by and the cam looks beautiful. I dropped in the head and it seems to clear everything just fine at first glance. Engine will go back together soon.

[mincehead]

Are you changing the wheels from the nasty and weighty Grimeca`s to lighter alternatives?

[edfmaniac]

Wheels are certainly on my list. I'll probably end up with some GS500 wheels unless I go nuts and spring for some Marchesini's.

[basser23]

why not some dymags? no, seriously, SV i think is doable cheaply and fairly easy

[edfmaniac]

You must be talking used. The only distributor in North America, according to Dymag's website, has pairs of rims starting at over $3000. Help me out here with some links and prices please.

[basser23]

I was not serious about the Dymags,knowing full well their prices.....imho I'd go for more function rather than bling,and therefore try to source what Bill J has been using...or suitable
Realize its a budget thing with me.....being retired on fixed income,saving for toys is long term
Crashed the F22 severly...airframe is toast,but at $3 for foam I'll make another.....already to make a new P51,Spitfire has not flown yet......hows the glider thing going?

[edfmaniac]

Still waiting on some other folks to become interesting in aerotowing but things are looking up. At least one pilot has moved to town with some 6 meter scale sailplanes and we've been in contact. And the word is that the new Moto Guzzi mechanic in town has been asking around about aerotowing. I'm hopeful that this coming year will be when it finally catches on with the masses. Eflite has even put out a 4 meter scale Red Bull themed glider.

[edfmaniac]

Looks like I'm cutting it mighty close on my piston/valve clearance. By my best guess, I have about .050" with the old head gasket, which is .009" thinner than the new Cometic gasket. Is the .055 - .060" range going to be enough room? Edit: I also had no valve lash for this test so I may be able to add another .005 - .007" to those clearances.

That gauge is a .035.

[edfmaniac]

Removed hi res version because it served no purpose.

[edfmaniac]

If you need a cam degreeing kit, don't fork out the dough for the Hotcams kit. Just buy the Motion Pro degree wheel($13), go pick up a flex mount, clamp base dial indicator from Harbor Freight($35) and use the method in the picture for finding TDC instead a piston stop. After fighting the wheel to get it synched up with the crank, I just took a degree reading at a known distance below either side of TDC(2 degrees and 27 degrees) and split the difference to get my actual TDC(14.5 degrees).

[edfmaniac]

After speaking with the machinist, he said that I wasn't getting quite enough clearance and the best thing to do would be to open up the pocket on the piston. Problem solved.

[edfmaniac]

After the second round of clay, things are looking a lot better, and I don't think I will need to modify my cam sprocket. The timing was only 2 degrees retarded and the nice lady at Megacycle said that was acceptable. Evidently a few degrees in the other direction can reduce the valve/piston clearance. My new results show nothing closer than .090" so I should be ready for final assembly.

[Bill Jurgenson]

from experience, I can say that you must have at least 1mm tolerance piston edge/top of cylinder, otherwise the piston will hit the head. This is due both to tipping of the piston and elongation of the conrod. OTOH i have never had problems with valve clearance. BUT never run a Megacycle without recommended valvesprings, either from Kibblewhite or RD. For the 5-valve head the Kibblewhite set is the best bet, both from my experience as well as various professionally recommendations given to me personally. I am running RDs in my 4-valve engine but these are not the catalogue set. They were the result of a telephone conversation with RD.
Do not fool around with the head gasket. If you need more height, use a thicker base gasket. Make it yourself as necessary from soft aluminum and use a suitable silicon sealant.

[edfmaniac]

I'm right on the limit then. It's hard to get the piston exactly level but I'm at about .96mm. Kibblewhite springs installed.