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Post by anthonyvs on Oct 16, 2009 20:49:47 GMT -5
Well its been a while since i did the 4 valve head mod on my scooter. I got great performance out of the engine with this head but in the end i had to scrap it. there is a major flaw with this product. And i challenge anyone on this site to tell me different. The major problem is the fact that air chamber for cooling the head is open to one one of the four mounting holes. And i had Major oil leaks as a result. They sell the kit with an oring thats supposed to seal this hole and prevent oil from leaking but it doesn't work. I even went as far as putting jb weld all around the mounting stud and hole to try and seal it. Here is a pic.   I'm going back to the 2 valve head. I would love if some more people with more engine experience would do this mod. I know sin did. But i have a feeling he had issues with oil leaks as well because I think in his write up he states he applied rtv sealant to some hole that was made during the casting process and the whole i think he is talking about is part of the air chamber. If you did rtv this hole up it might not leak oil but I'm sure you get no cooling to the head that way. Let the experts speak now. |
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Post by indy50 on Oct 16, 2009 21:47:17 GMT -5
Some high end manufacturers have had much sucess with the 4v
But for me and my everyday gy6..........
I'll take my ported 2v with a better spring & cam setup anyday for the price
BTW... I have a big monitor but, dude your pics are HUGE !
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Post by anthonyvs on Oct 17, 2009 14:18:33 GMT -5
Well trust me i had them tight. I played with this thing for months trying to stop the leak. So just using the oring seals it for you? I used a piece of wire in the picture to show the flow of oil out of the head. I'm sure your familair with it anyways. My kit was missing the oring when i got it. I experimented with different sizes. I probably should tried to find somone that sells this oring, maybe its a matter of getting just the right size to seal it. I would love to take another shot at making this work. It ran awsome. See what happens when i make challenges. I get good feedback lol. When I first did this build which was over a year ago i couldnt find anyone who knew anything about this head.
Well i guess the next step is find out exactly what size o-ring is required. And a part number if it exist.
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Post by performancescoot on Oct 17, 2009 23:45:17 GMT -5
I have a 4 vavle head engine and can say it doesn't leak any oil like you have discribed. I will say that the head I have does look slightly different than the one you have and it did have a couple of casting flaws, but nothing major at all. Maybe it's a different MFG?
Also, I'm a believer in the 4 valve head. I wasn't prior to installing it going from a very ported/milled 2 valve head, but in my opinion, there isn't one better for these engines. It did need some cleaning up in the ports, but not that much.
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Post by anthonyvs on Oct 18, 2009 6:20:14 GMT -5
Interesting. Maybe there is more then 1 manufacturer out there. I got this one from an autralian company. I couldnt even tell you who manufactured this head. It came shipped all in generic looking packing material. Not like when you buy something from pfs. And the head looked kind of beat up too. You could see little dings in the casting. Also the head actually had two bent valves. lol. I couldnt get the company to warranty it either. I ended up buying new valves for it.
Did you need to install an oring on your mounting hole?
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Post by performancescoot on Oct 18, 2009 14:11:56 GMT -5
I did install that O-ring. The stud is exposed other wise and that is probably the source of your problems. Just another thought, but did you put in the O-ring under the rocker arms on that very stud as well? That O-ring keeps the oil out of draining down that stud.
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Post by anthonyvs on Oct 18, 2009 17:11:54 GMT -5
Yes i did. Keep in mind that this kit did not come with an o-ring. They must have left it out when they shipped it. I had tried different sizes on the stud with no luck. I even tried sealing this with jb weld but it didnt work the oil still leaked thru. But after talking with some of you who have this head, with no oil leaks, apparently i just need to get the right size oring. This is great information.
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Post by medman1952 on Oct 18, 2009 23:11:43 GMT -5
Thanks for posting your problem with the 4 valve head, in the future please keep the picture size to about 600px wide so that it is not an issue for others to view. It is not hard to resize pictures before you post.
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Post by kliff on Oct 19, 2009 6:41:45 GMT -5
Hmmmmmm, could probably fix that, by boring ot the stud hole and sleeving it.....
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Post by anthonyvs on Oct 19, 2009 7:03:27 GMT -5
yeah if the oring doesnt work i may try that. I went back and resized the pics. Hope there small enough now.
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Post by anthonyvs on Oct 19, 2009 11:05:47 GMT -5
I called scooter works today.They dont sell the 4 valve head or the seal. Neither does parts for scooters. Going to keep searching for a source.
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Post by skyetone on Oct 19, 2009 14:41:09 GMT -5
just a though about this. why are you using JB? I'd think more twards a high temp sylicone gasket seal setup. Oil and water are equal is sneaky ness. sylicone always works better but yea HF sells a cheep o ring kit that has almost every size you could want too. Would last longer... I have a 16" gy6 has anyone had any issues mounting the four valve to any particular block?
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Post by chrish on Oct 19, 2009 15:22:38 GMT -5
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Post by anthonyvs on Oct 19, 2009 16:53:33 GMT -5
wow I stand corrected. well I'm going by what the girl there said. lol. I hate when you call some of these places and they know less about what they sell then you do. The other thing is i did try rtv sealant, the orange stuff made for oil and it didnt work. Its just a matter of finding the right seal. Now that i know that people have these heads and they dont leak. I'll keep searching till i find the right o -ring.
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Post by chrish on Oct 19, 2009 18:16:15 GMT -5
You might also try carlos (autotech) on fleabay
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Post by skyetone on Oct 20, 2009 13:15:27 GMT -5
so the four valve universally is better than a big camed two valve? I don't want to spend money twice  |
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Post by unclepablano on Oct 20, 2009 13:48:39 GMT -5
so the four valve universally is better than a big camed two valve? I don't want to spend money twice Absolutely! They achieve superior flow without requiring a radical cam profile. This gives you better top end performance without killing your low end. Four small valves are easier to control than two large ones, so you get by with much lighter spring tensions. That gives you reduced friction on an engine that will be less prone to valve float. I think it mostly boils down to if you can get one that is well made. If you order one, inspect it closely. If it looks like it is poorly made, send it back. |
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Post by anthonyvs on Oct 21, 2009 8:56:59 GMT -5
Also the combustion chamber is much smaller on the 4 valve head then on the 2 valve head. You get much high compression as a result.
Btw I emailed provoscooter.com. There technical Rep measured the o-ring out one of the boxes. Its a 9mmx 6mm o-ring. I was trying much smaller o-rings so I Think i'm closer to getting this problem solved.
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Post by skyetone on Oct 21, 2009 13:19:09 GMT -5
good to hear. I have a 16" roketta and it runs at 60 - 65 but really want to get up to 70 - 75 cuz I try freeway alot. But I bet my head already is different than 13" scoots. So I wonder if bolt paterns are all the same. Then could I put my head on a 13 and have it improve flow?
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Post by turboaz2 on Nov 25, 2009 15:06:23 GMT -5
If you continue to have the leakage problem, I would just clean it with brake parts cleaner, then bake it in the oven at 300deg for an hour to get any oil oil, then reclean with brake parts, and fill in the hole with Lab metal. www.alvinproducts.com/Products/Products.asp?id=1 |
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Post by anthonyvs on Nov 26, 2009 10:20:52 GMT -5
No it turned out I Just needed the right o ring. I bought this head from a supplier in Australia and it was missing parts and beat up. I actually had 2 bent valve stems. Luckily I checked it out before installing it. I dont know what the deal was. But i will stick to either E- Bay or local suppliers from now on.
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