Ranch Hand we can fix that problem with thicker head gaskets or by fly cutting the pistons if it's a problem.
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Slowpoke attempts to kill himself in a golfcart!
- Thread starter SLOWPOKE693
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For you math geniuses......
The head has a 41.38cc combustion chamber stock. Head was shaved .025. How or can I figure out the new combustion chamber cc volume with these two numbers or would I have to physically cc the head?
The head has a 41.38cc combustion chamber stock. Head was shaved .025. How or can I figure out the new combustion chamber cc volume with these two numbers or would I have to physically cc the head?
Ranch Hand
Red Skull Member
I probably shouldn't tell you how I fixed that problem on a 292 I-6 Chevy as a sixteen year-old kid, but I will. Clay impressions showed me where the interference was. I then stuffed a clay rope around the piston-cylinder gaps and added a little valve relief to the pistons with something like this on a small drill. It worked, kind of.
You will have to CC the head. They are not a constant angle going in.
arse_sidewards
Can't unlearn
No way to know exactly since we don't know the profile of the shape and even if you did it could be a pretty shitty math problem because the walls are probably a changing radius curve that varies depending on where around the perimeter you're talking about. You're better off just CCing it.
I probably shouldn't tell you how I fixed that problem on a 292 I-6 Chevy as a sixteen year-old kid, but I will. Clay impressions showed me where the interference was. I then stuffed a clay rope around the piston-cylinder gaps and added a little valve relief to the pistons with something like this on a small drill. It worked, kind of.
I hope you don't think I'm above doing that, because im not.
I've done that and much worse to several quad, dirtbike and car engines in my day. When your poor and like to go fast you do what you have to do to make things work. Ever shave a Yamaha Warrior 350 head on your grandfather's hand held belt sander clamped in a vice upside down? I have no idea how much I took off but the starter was never happy after that but I didn't care because it was faster. I also ported that same head with a die grinder using burrs and sanding rolls. Clearly I had no idea what I was doing at 15 but thst didn't stop me from making golf ball size holes in the head ports. It would bog if you wacked the throttle at idle or rolled into it to fast but that thing had top end for days.
That's a pretty slick way to do it!
Fixed. It took an eternity to do a GSXR head one hole at a time.
I'd still take slow over not being able to do it at all.
Firstram
Well-known member
What’s up with the 2 different lobe profiles on each cam?
Intake valves are shim and bucket and run directly off the cam lobes and the exhaust uses roller rockers to activate those valves so the profiles of the lobes are completely different.
Shipped the pistons off to the machine shop this morning and they are scheduled to be delivered on Wednesday. Before I boxed them up last night I pulled a new one out and compared it to an old one. Pistons look to be the exact same height from pin centerline to the top but the ring lands and spacing are very different. I wonder what the purpose of the big V groove between the top ring and 2nd rig is for on the new piston? The old one has something similar between the top two rings but it's much less pronounced and the rings are much closer together. Intresting.....
There is also a big difference in dome height and valve pocket depth vs the old piston. The dimple in the middle of the new one is for spark plug clearance.
There is also a big difference in dome height and valve pocket depth vs the old piston. The dimple in the middle of the new one is for spark plug clearance.
Nope. Engine guy balances it before it goes back together. Neither is far off of the stock weights but both are heavier from what I'm told
The Wossner pistons do, the CP's don't. I want to swap them but that may piss off the engine guy asking him to put used pins in new pistons/rods but I still might.
665.0coupe
Red Skull Member
As long as they are the same length and use the same lock style, you can interchange them. Just have to know which ones you are going to use when you balance the crank.The Wossner pistons do, the CP's don't. I want to swap them but that may piss off the engine guy asking him to put used pins in new pistons/rods but I still might.
Thanks for confirming my idea is doable. I'll be using those tapered pins.
What blows my mind is how you balance a crank with throws that are only 90° apart and how the heck you figure the balance shaft into all of that math to boot. I get the basic principles of engine balancing and how the RPM range and frequency plays into how it's done but the balance shaft thing sure seems like it complicates it a ton.
I told the engine guy I was going to cut the counterweight off the balance shaft and run it that way because it's a "short" course engine so a little vibration wouldn't be bad in short bursts and I'm pretty sure he dropped his phone when I said it because him yelling "I really hope you're joking about that because thats a horrible idea!!!" sounded far away.
He also wasn't very receptive to the idea of machining windows or holes into the new Crower rods to lighten them. Crower says the rods are good for 250hp each in boosted applications and I'm at best going to make 75hp a hole N/A so do I really need 100% of the rod to be there for it to not fail?
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I'm not sure what went on with the rear most intake valve in the #2 cylinder but one of these things is not like the other. It almost feels like it was bead blasted when I run my finger over it. Would detonation do that and would it only do it to one intake valve in the same cylinder? The top of the piston is spotless in that area so I'm not really sure what to make of it. Guess I'll order a new intake valve in the morning because im sure its not good to run it with the coating worn off.... Yay me 
Well that was much easier than I expected. I found the receipt for the intake/exhaust valves in and old email and Googled the part # for the intake valves I bought and found several places with them in stock. I ordered one up from OEM Cycle in Tennessee and should see it before the end of the week.
Well that was much easier than I expected. I found the receipt for the intake/exhaust valves in and old email and Googled the part # for the intake valves I bought and found several places with them in stock. I ordered one up from OEM Cycle in Tennessee and should see it before the end of the week.
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gt1guy
Apparently a racist
Thanks for confirming my idea is doable. I'll be using those tapered pins.
What blows my mind is how you balance a crank with throws that are only 90° apart and how the heck you figure the balance shaft into all of that math to boot. I get the basic principles of engine balancing and how the RPM range and frequency plays into how it's done but the balance shaft thing sure seems like it complicates it a ton.
I told the engine guy I was going to cut the counterweight off the balance shaft and run it that way because it's a "short" course engine so a little vibration wouldn't be bad in short bursts and I'm pretty sure he dropped his phone when I said it because him yelling "I really hope you're joking about that because thats a horrible idea!!!" sounded far away.
He also wasn't very receptive to the idea of machining windows or holes into the new Crower rods to lighten them. Crower says the rods are good for 250hp each in boosted applications and I'm at best going to make 75hp a hole N/A so do I really need 100% of the rod to be there for it to not fail?
Got any casting flash, forge lines or manufacturing lettering on the rods? That kind of shit can be removed and might not send your builder into fits.
Just tell him you want the rods polished.
Got any casting flash, forge lines or manufacturing lettering on the rods? That kind of shit can be removed and might not send your builder into fits.
They are H beam rods. What would shaving down the sides of the beams a bit hurt in my application? Make them weigh the same as stock and call it done. Same with the pistons. Dimple the bottoms on a drill press until they weigh the same as stock and call it good. No balancing needed if the rotating assembly doesn't weigh any more or any less than stock, right?
If I wasn't poor and could afford to blow up an engine or two I wouldn't be joking about trying shit like that with my race car. You can't beat them if you ain't trying something different than the rest of the pack.
Does anybody remember the company that used to advertise in the back of Circle Track magazine that sold small block Chevy titanium rods that had what looked like machined in lattice work between the big and small ends of the rod? Similar to these but slightly different......
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arse_sidewards
Can't unlearn
I told the engine guy I was going to cut the counterweight off the balance shaft and run it that way because it's a "short" course engine so a little vibration wouldn't be bad in short bursts and I'm pretty sure he dropped his phone when I said it because him yelling "I really hope you're joking about that because thats a horrible idea!!!" sounded far away.
That doesn't make sense. A balance shaft takes forces that would otherwise cause external vibration that imparts force on whatever the engine is bolted into and instead directs that force into the block itself by being out of balance in an equal and opposite way.
So unless the block is engineered to within an inch of it's life in every regard and therefore can't handle dealing with those forces being applied externally but does have the meat to deal with them in the intended manner internally (which very well may be the case) that doesn't really make sense.
arse_sidewards
Can't unlearn
The rest of that sentence was kind of important.
I understand that it's a high strung powersport engine but OP might be at the point where the difference between a blanket "high strung" and more precise "components X have nothing left to give but component Y has a little more" matters.
IDK what his engine builder knows but that have been what he was getting at, deleting the balance shaft may be counterproductive on this specific engine because managing those forces there is better than elsewhere.
But OP still needs to make him explain it in detail because usually deleting balance shafts frees up a couple ponies.
Big difference just holding them, no need for a scale.