Has anyone had an issue with piston to valve clearance issues with a2250 or 2270 build that had 44mm intake valves? Just curious. As far as I know, I am not having this issue however I haven't fully checked yet. If you did, how did you rectify the issue.
Full Version: Anyone have piston/valve clearance issues w/2270
Do you know your target CR and deck height?
Are you at target deck height?
Are you at target deck height?
With that cam you will be very close to interference at 8*ATDC on the intake side. Yes you really should verify what you have for clearance.. Because in engine building you assume nothing and quantify everything.
I went out and checked and I have .053" clearance which is obviously not enough (IIRC should be greater than .100). What are my options now? I have KB flat topped pistons (from t4store).
Can I simply have the pistons pocketed (not sure of the correct term)? I am sending most of my setup to the shop this week so it would be perfect timing if that is an option?
Can I simply have the pistons pocketed (not sure of the correct term)? I am sending most of my setup to the shop this week so it would be perfect timing if that is an option?
Thats one of the issues with that cam.. It has a really fast ramp that causes these issues. You will have to pocket the pistons.
QUOTE(Jake Raby @ Sep 25 2011, 10:00 PM) 
You will have to pocket the pistons.
Do you think I can do that with a dremel tool?
Of coarse- I am just kidding!
QUOTE(tornik550 @ Sep 25 2011, 07:04 PM)
Do you think I can do that with a dremel tool?
You should have seen some of the things we used to do to our dirt-bike engines back in the day.
We used to run them lean to get more power but that also meant a lot of burnt through holes in the pistons.
The common fix at the track for that was a rounded flat-head bolt with short threads double nutted from the back.
Usually got you through the rest of the race!
Man, you have all kinds of issues 
You really need me to come help 
You really need me to come help
QUOTE(SirAndy @ Sep 25 2011, 06:20 PM)
QUOTE(tornik550 @ Sep 25 2011, 07:04 PM)
Do you think I can do that with a dremel tool?
You should have seen some of the things we used to do to our dirt-bike engines back in the day.
We used to run them lean to get more power but that also meant a lot of burnt through holes in the pistons.
The common fix at the track for that was a rounded flat-head bolt with short threads double nutted from the back.
Usually got you through the rest of the race!
If you tore it down that far and always had problems, why wouldn't you just carry an extra piston and replace it?
As for the OP, yes, I had trouble clearance problems. You have to machine the pistons. I've done it with a 44 mm end mill and tilted the head on a mill to make really nice pockets. I've also just used a ball endmill to make the pickets. The ball endmill is easier and just as good.
QUOTE(Dr Evil @ Sep 25 2011, 11:21 PM)
Man, you have all kinds of issues
You really need me to come help Where are you planning on going after residency? I've got space here!
QUOTE(Matt Romanowski @ Sep 26 2011, 12:06 PM)
QUOTE(SirAndy @ Sep 25 2011, 06:20 PM)
QUOTE(tornik550 @ Sep 25 2011, 07:04 PM)
Do you think I can do that with a dremel tool?
You should have seen some of the things we used to do to our dirt-bike engines back in the day.
We used to run them lean to get more power but that also meant a lot of burnt through holes in the pistons.
The common fix at the track for that was a rounded flat-head bolt with short threads double nutted from the back.
Usually got you through the rest of the race!
If you tore it down that far and always had problems, why wouldn't you just carry an extra piston and replace it?
Cause he was a broke kid at that time....lol
Rich
QUOTE(r_towle @ Sep 26 2011, 09:57 AM)
QUOTE(Matt Romanowski @ Sep 26 2011, 12:06 PM)
QUOTE(SirAndy @ Sep 25 2011, 06:20 PM)
QUOTE(tornik550 @ Sep 25 2011, 07:04 PM)
Do you think I can do that with a dremel tool?
You should have seen some of the things we used to do to our dirt-bike engines back in the day.
We used to run them lean to get more power but that also meant a lot of burnt through holes in the pistons.
The common fix at the track for that was a rounded flat-head bolt with short threads double nutted from the back.
Usually got you through the rest of the race!
If you tore it down that far and always had problems, why wouldn't you just carry an extra piston and replace it?
Cause he was a broke kid at that time....lol
Rich
Yupp, Rich nailed it. I was 16 at the time. My dad had loaned me some money to buy the dirt bike but maintenance and repair was up to me.
I was living off 300 DM a month working as a apprentice chimney sweeper ...
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.