Can I bore These Sleeves??

Well, here goes...
I hope someone can help me with this question, but I realize it may be hard to answer through a forum. Anyway, I just tore down my motor to upgrade it (again). I removed the block and measured the bore, and it is 77mm (1229cc) as I had thought. I had the work done originally around 15 years ago, so I couldn't remember for sure. The strange thing is, it's a stock block. I was told when I had it done that it was resleeved for the MTC kit, which seems to be exactly right. Since then, I have seen on many web sights that anything above an 1197 kit requires a big block. What gives? It had me wondering if I really had the 1229 that I thought I had.

So here is the question...finally! How can I tell if these sleeves can be bored? I'd love to go to the next size up (1261cc) but I don't want to have to change the sleeves (or go to a big block) and bore the crankcase again. Is there some magical measurement that I can use to see if this can be bored? Any advice would be greatly appreciated. Thanks!

1197 is as far as i ever go with a stock block but thats with a 900 block,1000 blocks are thinner.check with wiseco or APE and ask them how much meat you need for the next size over.goodluck,happy wrenching!

wireman wrote:

1197 is as far as i ever go with a stock block but thats with a 900 block,1000 blocks are thinner.check with wiseco or APE and ask them how much meat you need for the next size over.goodluck,happy wrenching!

Well, that's where things got interesting. I live about 5 minutes from Wiseco and I sent an email today asking a few tech questions and was ready to fork over the cash for a piston kit and to have the cylinders bored to match. I was told that Wiseco no longer offers big blocks or machining services, and was referred to Fast by Gast. They also don't offer the 1261 kit in the 10.25:1 ratio I need for the street. They offer it in the drag race comp only. I have emails with tech questions in at FBG, APE, and MTC right now, so we'll see what I hear. I'm very disappointed in Wiseco. I used to take my stuff there and they would do all of the machining on the spot. Those days are apparently gone.

BTW, maybe I've just been very lucky, but I've had my 1229 kit with the stock block since 1990 with no leaks, ever. That includes several very long road trips (1000 miles+) and quite a few very hard miles, a 1/4 mile at a time! I just figured that most sleeves should be good for at least one bore ( two bore sizes). It would be great if I could just have these bored and go the next size up without boring the crankcase again.

you could put the 1260 drag pistons in it with a j motor head that would drop it a couple points.mtc tends to have more options as far as compression ratios go.what are you going to do with your other pistons?:whistle:

MTC does list a 1261 kit at the 10.25:1 comp ratio, so if they still have it I may buy it. I asked about it in my email to them. I thought a lot about the J-head route, but I have a MKII head at the shop right now being ported, o/s valves, etc... If I can find out about these sleeves I have right now I'll buy a kit from somewhere and have them bored to match. In that case, I wouldn't be needing the old pistons anymore:whistle: But if I have to bore my cases to go any bigger, I'll probably throw it back together with the new head. I just wanted to go to the next size while I had it apart.

The 1200 used a sleeve with a 3.200" O.D. As a repair to damaged 1200s, people used to bore them 1mm over and put 1229 pistons in them. That leaves .084" wall thickness which is OK. However, you can't put 1260 pistons in there and expect it to live. A 1260 requires a sleeve with 2.275 O.D. Putting that in a KZ block causes it to borte thru the alum between into the air passages. It will be a leaker in time, if not right away.

Jay

Post edited by: APE Jay, at: 2006/02/25 13:48

theres your answer!thanks jay;)

Hi Jay - Thanks for the info. I have read many of your posts and considering where you work I certainly value your opinion. OK, enough brown-nosing:)
From what I have been able to measure with calipers, the sleeve OD is around 3.2400 and the bore is 3.029. That would leave around .211 (.1055 wall thickness) or around .085 thickness at 3.070 (1261cc). Does this sound possible? It doesn't look like there's a step at the bottom of the sleeve, but I think the OD would be the smallest where it goes into the crankcase anyway, right? (that's where I'm measuring) Is there a minimum wall thickness for the sleeve to be considered reliable?
Thanks

If it is indeed a 3.240 ( have never seen that size sleeve in the aftermarket ), then you could put 78 mm pistons in it.

Jay

The OD of the sleeve wouldn't be any smaller inside the cylinder, would it? I can only measure what sticks out at the bottom (turn down, I think it's called?). I will try to borrow a bore mic and 3-4" OD mic to get more accurate readings. Since I'll probably have to ship the block somewhere to have the boring done, I'd like to get a good idea if it can even be bored before I waste the time and money to have someone look at it, ya know?

Any chance of a "KZ Rider" discount at APE?

Update:
I finally got the cylinders measured tonight and I was nearly right on with the calipers. The bores measure 3.0300-3.0315 and the sleeve OD ranges from 3.2380-3.2400. Unless the portion of the sleeve inside the cylinder is smaller that the portion sticking out the bottom, it looks like it would be OK to bore to the next size. I sure wish I could find out what my old engine builder did with these sleeves. I have not been able to find any sleeves this size. Maybe they are the 3.275's but turned down at the bottom to 3.240?? I really doesn't look like they've been turned down at all though. A nasty divorce sent my old builder to another state, so I may never know exactly what I have.:huh: If anyone here sees any reason not to have these cylinders bored, please speak now or forever hold your peace:P

shhhhhhhhhhh! everybody be verrry qwiet im huntin the olll swugggggs hehehe!:whistle:

Post edited by: wireman, at: 2006/03/02 10:14