Mickey Dunlap
06-10-2017, 12:04 PM
The most questions I get is about the 350x heads. Questions weather you need harden rockers, what valves to use and what kind of valve springs are needed, ect. ect.
We all have seen a lot of heads with bent valves, or valves that have dropped. Most of the time it's the intake valve because of what they are made of. The way to check if you have junk valve is to check them to see if they are magnetic, if they are and you run stock valve guilds chances are sooner or later if you run them hard you will drop a valve as they gull in the valve guild.The EX Valves drop mostly because the valve spring don't have enough seat pressure or the right valve springs. Now since 08' the oils have changed big time and you need to run a off road oil only. I run a Brad Penn oil, but Motul or Red-Line are among the best because they all have high zinc and phosphorus in them. We break our motors in with the Brad Penn straight 30wt break in oil. When the cams are welded up and reground they don't have any oil in bedded in them so they are very hard on the rockers that only have at best .007 worth of chroming on them so it doesn't take much with the stronger valve springs so they need all the help they can get.
As far as weather you need harden rockers, the best way to tell you need them is if there is a straight line across the pad showing they are worn and will soon break through the chroming with a new cam soon. I like the stock chroming better, slicker then the hard welded and with the good oil and a oil cooler that feeds 50* cooler oil in on top of the cam and rockers you will have no problems with them.
Another reason these engines drop valves is the heavy valve springs them selves. Some aftermarket springs are the same OD. as the stockers, the light weight springs with steel caps set up that are a lot smaller are the way to go for like our stage 1 cams, when we get into our stage 2 or 3 cams then we change to a titanium that are lighter and allow for a higher lift and higher rpm.
Stainless steel valves are the best way to go. I change to a lighter 5mm stem over the heavy stock size 5.5mm. This also gives you better flow a lighter/ bigger valve keep the over all valvetrain lighter then stock while adding reliability.
Even with the stock valves changing to bronze guilds will help the stock valve while adding getting the heat out of the valve better.
Changing the valve seats isn't needed with 2mm bigger valves like our stage 2 CNC porting, but if you go any bigger valve like our stage 3 porting you need to change to Nickel aluminum bronze which will give you better sealing and heat transfer. You can put there in with any size valve if you are wanting the best performance like our stage 2 race motors.
So I hope this will give you some simple help full ideas when building your 350x. If you have any questions please feel free to ask on here, or PM me, e-mail us at 4stroke@embarqmail.com or call 814-842-6159.
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We all have seen a lot of heads with bent valves, or valves that have dropped. Most of the time it's the intake valve because of what they are made of. The way to check if you have junk valve is to check them to see if they are magnetic, if they are and you run stock valve guilds chances are sooner or later if you run them hard you will drop a valve as they gull in the valve guild.The EX Valves drop mostly because the valve spring don't have enough seat pressure or the right valve springs. Now since 08' the oils have changed big time and you need to run a off road oil only. I run a Brad Penn oil, but Motul or Red-Line are among the best because they all have high zinc and phosphorus in them. We break our motors in with the Brad Penn straight 30wt break in oil. When the cams are welded up and reground they don't have any oil in bedded in them so they are very hard on the rockers that only have at best .007 worth of chroming on them so it doesn't take much with the stronger valve springs so they need all the help they can get.
As far as weather you need harden rockers, the best way to tell you need them is if there is a straight line across the pad showing they are worn and will soon break through the chroming with a new cam soon. I like the stock chroming better, slicker then the hard welded and with the good oil and a oil cooler that feeds 50* cooler oil in on top of the cam and rockers you will have no problems with them.
Another reason these engines drop valves is the heavy valve springs them selves. Some aftermarket springs are the same OD. as the stockers, the light weight springs with steel caps set up that are a lot smaller are the way to go for like our stage 1 cams, when we get into our stage 2 or 3 cams then we change to a titanium that are lighter and allow for a higher lift and higher rpm.
Stainless steel valves are the best way to go. I change to a lighter 5mm stem over the heavy stock size 5.5mm. This also gives you better flow a lighter/ bigger valve keep the over all valvetrain lighter then stock while adding reliability.
Even with the stock valves changing to bronze guilds will help the stock valve while adding getting the heat out of the valve better.
Changing the valve seats isn't needed with 2mm bigger valves like our stage 2 CNC porting, but if you go any bigger valve like our stage 3 porting you need to change to Nickel aluminum bronze which will give you better sealing and heat transfer. You can put there in with any size valve if you are wanting the best performance like our stage 2 race motors.
So I hope this will give you some simple help full ideas when building your 350x. If you have any questions please feel free to ask on here, or PM me, e-mail us at 4stroke@embarqmail.com or call 814-842-6159.
243825243829243824243826243827243828