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Post by 2strokd on Sept 14, 2009 9:16:14 GMT -5
Well it looks good anyway . Dont loose hope just cuz one POS comes along. Havent you owned a turd yet man . It happens! I thought i had one of those headlight but went out to snap a pic and cant find it . When, and if i do i will take one and if it is the one you need you can have it
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Post by 90GTVert on Sept 14, 2009 10:26:29 GMT -5
Thanks man. I'm considering trying to fit something else in there for a headlight, something like my Triton has. Not sure it would handle 55W though with it blinking with the blinkers. Maybe a 35W would still be better than the stock 35W? Not sure it's worth all the trouble though. It's not exactly a bolt in fit. I did some checking and my lighting circuit has no juice at all now. The leaks are really ticking me off too. I think I'm gonna put some "Right Stuff" on the head and base gaskets and see if that seals it. I was told to try that by a machinist when I was looking at copper head gaskets for my car. He says it does a good job of sealing. I used that on Bob's gaskets when I put his big bore on... or tried to put his big bore on since the new gaskets wouldn't work. He's had no troubles with leaks. Here's a section of the floor to show how much it leaks when the engine is hot. That's from parking in slightly different spots after tuning runs, it doesn't actually leak in a 5ft patch.
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Post by 90GTVert on Sept 14, 2009 12:05:24 GMT -5
Just for grins, I cc'd the 50 and 70cc heads to see how much difference there is. I got 5.3cc on the 70cc and 4.8cc on the 50cc, to make a 5cc difference. It isn't a huge difference, but it is free, so I think I'll use the 59cc head this time. I didn't do it the first time around mostly to be sure I could stick with 87 octane. After seeing it run, I think I'll be fine with 87 still and if not I don't care. I just don't wanna stay at 32MPH. I had done some port work to the new head already, now I gotta do it over on the old head. The valves are the same size. If anything, they look like they'd be the bottleneck to me. I can make huge ports and slap on a big exhaust and big carb, the valves will still be tiny. The valves on the pitbike/midbike clones were a bit bigger when I was messing with those and they seemed to put out better power. They had the benefit of sharing a common head design with engines of 110-125cc though, so the valves were real nice for a 70cc. Here's a fun fact for you... Minarelli heads share the smae bolt pattern as the 50cc GY6 or very close to it. The plexiglass piece I made to cc my minarelli worked just fine to do these heads.
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Post by 2strokd on Sept 14, 2009 14:08:15 GMT -5
Come on 40mph! Interesting about the bolt pattern
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Post by 90GTVert on Sept 14, 2009 17:24:46 GMT -5
The outlet of the carb is 18.8mm, so my plan is to make the intake and intake port of the head as close to 18.8mm as I can and make the path more direct if possible. Sorry, but I'm not going to remove material in one area and build another up etc... Just trying to get good flow without days of work. Sorry, the pics suck. Stock intake port, 16.5mm diamter. I shoulda been smart enough to remove the valve before taking the before shot. Oops. 1hr45min later, 18.8mm intake port. The intake port really narrowed down inside, but I opened it up. I mostly worked the side that would create the more direct path to the valve. I left the surface kinda rough... well, not rough but not smooth. The pile of metal dust should give you an idea of how much material was removed.
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Post by 90GTVert on Sept 14, 2009 20:30:54 GMT -5
The exhaust port started out at 16.8mm. The passage is incredibly small on the exhaust side and not much direct flow area. You can see that there's a nice improvement. I opened the port iteself up to 21mm to match the header that I opened up as far as I could. The header quickly gets funnels to a smaller size though, because the exhaust pipe is only around 5/8 to 11/16" inside diameter. The exhasut port isn't quite done because I wore out some dremel stuff and I'll have to get more tomorrow. I opened the intake up on the bend and a little all the way through. I port matched the intake, spacer, and head. I'm still debating what I wanna do with the head and base gaskets. The oil leak is at the base gasket. I'm considering not using any base gasket and only using "The Right Stuff" or maybe just Ultra Black RTV silicone. I'm thinking I can apply a bit of sealant as a base gasket and let it set up with mild pressure on it, then complete the install and torque to spec to make it seal. Not sure if that will work or not. I've built enough pitbike style engines that are pretty similar and never had trouble with just a base gasket. I'm guessing a serface isn't true or soemthing and a bead of silicone can often remedy a leak in that situation. I wish I could run no head gasket to up compression, but I'm afraid it may not seal even with sealant around the studs and cam chain passage. I'll prob end up picking up a new head gasket and base gasket so I'm covered either way.
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Post by stepthrutuner on Sept 14, 2009 21:43:04 GMT -5
I'm glad to see that you are opening up and smoothing things out. I think it will pay off. Tuning four strokes is much more intuitive and flow through the engines is not near as complicated as it is with a 2t.... at least for me.
I noticed that there are valve reliefs in the tops of your piston. I'm sure you will check clearance issues there since you you're thinking about closing things up.
Watching with interest. Reg
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Post by stepthrutuner on Sept 14, 2009 21:54:30 GMT -5
Point of order. I made the last comment before I read that you reswapped heads.
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Post by 90GTVert on Sept 14, 2009 21:55:20 GMT -5
Honestly, I wasn't gonna check clearances with all the room left from the piston to the deck. I might now though, since I have a bigger cam on the way. I know the idea was to make it go without more money, and I know you'd probably grind on the stock cam. I just don;t feel comfortable messing with the stock cam so I added one into my order from Jermey when I picked up a stator, new bulb socket, and a few other odds and ends. I believe he is sending me some titanium valve springs from a 150cc to try out for him, so checking clearances would give me some peace of mind that the springs are good to go. I still don't think piston to valve clearance will be an issue unless i had the cylinder or head milled, which I don't plan to do right now.
4 stroke porting is a lot easier. You can't just go nuts, but at least you won't screw up your timing or entry angles and ruin it like you can do easily on a 2 stroke if you aren't careful. I've done some other 4 stroke stuff before, but I usually spend less time on 'em and don't bother removing the valves.
With all of this, I still don't think it'll get anywhere near 45MPH. I'd be suprised to see 40MPH cruising speed, bt I can see it as a possibility. +13MPH, that would be miracle status dor this thing.
I haven't touched the carb yet. I see what you are talking about, but I can't see how I could shave 2mm off without the screws being useless and the butterfly falling off. I might pick something up from going from an 88 to an 85 main jet. My plug looked good to me with the 82, but it would bog and had more power at 7/8 throttle than WOT. With the 88 it seemed fine, but the plug was pretty clack when I pulled it out today. Maybe go to the 85 and cahnge the needle clip position if necessary.
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Post by 2strokd on Sept 15, 2009 6:18:39 GMT -5
Nice work! Gotta help some. Porting a four has gotta be a bit less intimidating than doing 2 stroke port work. Come on 40!
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Post by 90GTVert on Sept 15, 2009 6:31:40 GMT -5
I'm a dumbass and I'll never get my car on a dyno because I keep spending money on scooters, but I picked up an aftermarket exhaust on ebay last night. I was going to order some tubing and a muffler then build the pipe, but the bends, muffler, welding supplies, etc... didn't seem worth it when I could pick up something that bolts up (hopefully) and allows me to keep the stock exhaust in once piece (prob woulda used the header flange on a pipe I made) for just about the same price. The pipe was $115 shipped. The builder kit for 1" mandrel bends is $84 without shipping (granted it includes more than I'd actually need) plus finding a muffler that looked good. I did order steel though, just incase there are fitment issues I can weld it easy. I guess I'll open up the exhaust port just a little more.
With all the head and intake work, bigger cam, and bigger exhaust it should certainly flow anything the carb will allow. I dunno that there would be a lot of point in a bigger carb with these little valves. Maybe a 19mm or 20mm slide carb so there is no butterfly in the way.
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Post by 2strokd on Sept 15, 2009 6:38:10 GMT -5
Your not a dumbass... The stang isnt going anywere is it? You got all winter for that, plus dont you have a head sealing problem to get ironed out? I know that costs money . Hope the exhaust helps, these four 50,s have a very small stock header pipe. At least the ones ive worked on do...
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Post by 90GTVert on Sept 15, 2009 6:49:17 GMT -5
Na, the stang should just need a dyno tune now. The head sealing problem turned out to be one lean cylinder (which is a problem that baffled some very knowledgeable people including machinists, engine builders, tuners). I've done so many tests it's silly. Everything from electrical issues, to ignition problems, to sealing problems, to fuel delivery, to you name it. I'm using locwire gaskets and had the heads milled to be true and checked the deck to be sure though. I haven't been running lean on one cylinder since I put on the Edelbrock RPM II in place of a Holley Systemax II. The fuel map needs to be changed around now. I can lean it out to make the idle more bearable, but then it doesn't have any power above maybe 1/4 throttle. Even down to 32psi of fuel pressure, from 40psi that i was on with the Holley, I'm idling and cruising around 11-12:1 AFR. So it really is just waiting on me to have a couple thousand bucks to spare for the tune and a rollback at least one way. I'm not so sure about driving it there because of the C4 with 3.73 gears and I would have to be on a highway with a 65MPH speed limit. That would be somewhere around 4,000RPM cruising speed I think and I'm already having cooling issues with the turbo heat and the big intercooler slowing down air to my radiator. Not to mention the idea of breaking down on the Chesapeake Bay Bridge worries me a bit. It probably wouldn't be an issue, but that's the kinda luck I usually have. 1hr30min drive may not be much in a regular car, but when you are revving high, burning tons of fuel, and heating up, it's quite an ordeal.
Stock exhaust is something like 5/8" to 11/16" I.D., not too impressive.
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Post by 2strokd on Sept 15, 2009 7:41:17 GMT -5
Glad its sealed up now, it should stay that way with a good tune since everything is smooth and true and your using good gaskets. The intake huh? Trailer it please! There and back, that would suck ass to hurt on the way to a tune. What kinda fan or fans you using to keep it cool? Maybe we should open a new thread lol. Oohh wait, this is your place.
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Post by 90GTVert on Sept 15, 2009 7:56:39 GMT -5
Mark VIII fan, Be Cool rad, high flow pump, Moroso race thermostat 180. Trust me, I got it covered parts wise, but wow does a turbo make some heat under the hood. Couple that with the intercooler that blocks off the radiator on an engine that's bored and stroked and lookout. Anyway, I'm not sure why but I did a quick (15min) polish job on the valve cover. You can tell it's quick cause theres a lot of imperfectiions. Still better though.
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