HarleyFDMD Posted December 7, 2015 Share Posted December 7, 2015 I'm rebuilding an NA head ready for NA T and require some help please regarding valve clearances/lash measurements. I have found some information on lash measurements: Inlet 0.15 - 0.25 Exhaust 0.25 - 0.35 However I think these measurements reflect the gte and I have a ge. Are the measurements the same? Where can I buy new shims should I need them? Can I switch shims between buckets to meet measurements? Thanks for any help Quote Link to comment Share on other sites More sharing options...
bignum Posted December 7, 2015 Share Posted December 7, 2015 I don`t know on the measurements but you can buy shims at toyota and also yes you can swap shims around to get the correct clearance. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 9, 2015 Share Posted December 9, 2015 Check for valve guide wear, if the guides are knackered the head will never make proper power. Most guides in 2JZ's are shot by now. Quote Link to comment Share on other sites More sharing options...
HarleyFDMD Posted December 9, 2015 Author Share Posted December 9, 2015 Ok thanks chaps. Chris can you supply guides and seals? Quote Link to comment Share on other sites More sharing options...
MKIV-Supra Posted December 9, 2015 Share Posted December 9, 2015 How difficult is it to change the Valve Guides? Is there any how to replacing the 2JZ Valve guide? Head is already removed and Valve Stem Seals are disassembled. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 9, 2015 Share Posted December 9, 2015 The knocking out and knocking in of new guides will almost certainly result in none concentric seats and pocketed valves, you need to have the existing guides linered on a modern air bed machine. I cannot stress enough the problems just replacing guides can cause on modern engines. I just don't have time to go into the technicalities of it, but it really is a BIG issue. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 10, 2015 Share Posted December 10, 2015 (edited) If you do fancy trying to do a guide change at home, best of luck! You need excellent facilities, and knock out the old ones is very risky in case they crack or mushroom and get stuck. Fitting new ones is best done by freezing the new guides in liquid nitrogen, and heating the head in an oven. Then they need reaming and the seats cutting, which is where you find the holes in the new guides are no longer concentric with the valve seats and you need to pocket the seats to such an extent the valves are shrouded, you need custom shims, and the head flows like a 1920's tractor head. Linering the existing guides is by far the best option, but they need doing on a modern machine like a multiple air bed Serdi, which is tens of thousands of pounds. That's how I get my guides done on engines and it's saved a LOT of grief since using this method. These machines leave such accurate seat angles, and such a good finish that with suitably prepped valves no seat lapping is needed. Edited December 10, 2015 by Chris Wilson (see edit history) Quote Link to comment Share on other sites More sharing options...
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