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Z1 head camshaft tunnel line boring specs
- retroautoelec@outlook.com
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- Wookie58
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- To the best of my knowledge nobody produces oversize/undersize bearing shells for these motors
- it is not uncommon for these heads to twist slightly when removed (which rights itself when torqued down on the motor) so clamping it to a boring table may not truly replicate it's rest position on the motor
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- Nessism
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I remember some old posts by Jay from APE, where he warned against big decking cuts off a cylinder head in an attempt to straighten a warped head. While you can remove material and true up the deck surface and make it flat again, he said on heads like this, the cam bores will be off as well, and there is no reasonable way to fix those. For that reason, he said that badly warped heads should be first straightened in a press, and only after it's returned to reasonable straightness, should it be decked.
Bottom line, if the cam binds due to having the wrong caps, you got a problem on your hands. Steve posted many long videos on how he went about trying to save a head that were missing caps (or something to this effect.) The simplest path would be to buy a new head.
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- Cra-z1
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- Wookie58
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Absolutely agree, line boring in the car world is quite common as manufacturers produce a range of under/over sized bearings. This allows the removal of material to rectify "ovality" etc and then the fitting of a thicker bearing to compensate for the removed material - in this case I am not aware of any options for cam bearing dimensionsWhen rebuilding an engine, like an old american V8, the main bearings can be "Line Bored" to resize the block/main bearing caps. This involves first skimming a few thousands of material off the caps, then reboring the bearing saddles with a special, and expensive machine. No doubt, Kawasaki has a special machine they developed for boring those cam bores, but trying to replicate that would be challenging for sure.
I remember some old posts by Jay from APE, where he warned against big decking cuts off a cylinder head in an attempt to straighten a warped head. While you can remove material and true up the deck surface and make it flat again, he said on heads like this, the cam bores will be off as well, and there is no reasonable way to fix those. For that reason, he said that badly warped heads should be first straightened in a press, and only after it's returned to reasonable straightness, should it be decked.
Bottom line, if the cam binds due to having the wrong caps, you got a problem on your hands. Steve posted many long videos on how he went about trying to save a head that were missing caps (or something to this effect.) The simplest path would be to buy a new head.
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- Wookie58
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Same as crankcase half's for motors with "shell bearing" cranks - same scenarioToo bad you see all those head on ebay without caps. Sellers think they can sell the head and caps separately
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- zed1015
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Any numbered cap can be used in positions 2 and 4 but 1 and 3 must use a either a 1 or 3 cap as these control cam end float.
Any adjustments must be confined to the caps only and not the head.
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- Wookie58
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Knew you would have the definitive answerOdd caps can be used but you need the head bolted down on the block or surface plate, a bucket full of spare caps , a bore gauge and know what you are doing.
Any numbered cap can be used in positions 2 and 4 but 1 and 3 must use a either a 1 or 3 cap as these control cam end float.
Any adjustments must be confined to the caps only and not the head.
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- SWest
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- 10 22 2014
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So it can be done and I figured all I had to lose was time and a $20 junk head.
I'm still using it today with my new 1075 kit installed and I'm RIDING THE PISS OUT OF IT.
Steve
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www.kzrider.com/forum/2-engine/619036-an...tion?start=12#885778
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- Wookie58
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Steve I've gotta say it sounds like you got lucky with that one but it's not a solution I would advise anyone else to follow (what you do with your own is your business) We have all stripped motors and found things that make us wonder how they were still running !!!So it can be done and I figured all I had to lose was time and a $20 junk head.
I'm still using it today with my new 1075 kit installed and I'm RIDING THE PISS OUT OF IT.
Steve
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Unless you honed it on a milling table I'm not sure how you maintained the hone at 90 degree's on 2 axis ?? So although the cam to bearing clearance may be in spec I don't see how there can be even clamping force on the back of the bearing shells so it's a bit of a lottery !!!
In answer to your retorical question regarding "what did I have to lose except a $20 head" if it spins a cam bearing and seizes a cam then along with your $20 head you will lose your 1075 kit when it makes love to the valves that are stuck open
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- SWest
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- 10 22 2014
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I had been watching it closely for a year before I installed the 1075 kit. This has been done before with success on other motors. Granted the caps must be close or it wouldn't work. My friend Jeff has a shop and has done lots of things others wouldn't even try. I wouldn't suggest buying a head without matching caps and fitting them would be a crap shoot but it can be done obviously.
Steve I've gotta say it sounds like you got lucky with that one but it's not a solution I would advise anyone else to follow (what you do with your own is your business) We have all stripped motors and found things that make us wonder how they were still running !!!So it can be done and I figured all I had to lose was time and a $20 junk head.
I'm still using it today with my new 1075 kit installed and I'm RIDING THE PISS OUT OF IT.
Steve
.
Unless you honed it on a milling table I'm not sure how you maintained the hone at 90 degree's on 2 axis ?? So although the cam to bearing clearance may be in spec I don't see how there can be even clamping force on the back of the bearing shells so it's a bit of a lottery !!!
In answer to your retorical question regarding "what did I have to lose except a $20 head" if it spins a cam bearing and seizes a cam then along with your $20 head you will lose your 1075 kit when it makes love to the valves that are stuck open
BTW the wear patterns on the shell bearings are identical to the ones on my old head. I still plan on rebuilding it with larger valves or even J valves that are shorter than the KZ valves. With what I've learned I will put into the old head and keep RIDING THE PISS OUT OF IT,
Steve
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