Scott Posted June 10, 2011 Share Posted June 10, 2011 Just wondering really. I know that some cams require re-shimming when fitting, and I guess due to wear stock ones at times will too, anyone any idea if I'll need to re-shim 269 GSC cams? When checking them for the shim sizes, should I head towards the upper limit or the lower limit? I was thinking upper limit so that there is less chance of wear? Thanks Quote Link to comment Share on other sites More sharing options...
heckler Posted June 10, 2011 Share Posted June 10, 2011 Just wondering really. I know that some cams require re-shimming when fitting, and I guess due to wear stock ones at times will too, anyone any idea if I'll need to re-shim 269 GSC cams? When checking them for the shim sizes, should I head towards the upper limit or the lower limit? I was thinking upper limit so that there is less chance of wear? Thanks when my HKS cams were fitted, they needed re shimming... not to sure on the shim sizes though... Quote Link to comment Share on other sites More sharing options...
Scott Posted June 10, 2011 Author Share Posted June 10, 2011 Cheers mate, I think it was the HKS cams I read about. Quote Link to comment Share on other sites More sharing options...
Scott Posted June 10, 2011 Author Share Posted June 10, 2011 Noone else fitted their own cams? Quote Link to comment Share on other sites More sharing options...
Kirk Posted June 10, 2011 Share Posted June 10, 2011 (edited) Shimming can vary between being nice and easy, no need for reshimming, or an absolute ball ache, lots of shims needing to be replaced. Regardless you need to check the clearances and make sure there as close to or within spec. Personally id try to aim to get them as close to the middle of the range but thats not always a possibility and higher range shims are needed. Edited June 10, 2011 by Kirk (see edit history) Quote Link to comment Share on other sites More sharing options...
Scott Posted June 10, 2011 Author Share Posted June 10, 2011 Shimming can vary between being nice and easy, no need for reshimming, or an absolute ball ache, lots of shims needing to be replaced. Regardless you need to check the clearances and make sure there as close to or within spec. Personally id try to aim to get them as close to the middle of the range but thats not always a possibility and higher range shims are needed. Normally I would always aim for mid limit. I just have something in my head telling me that I read something that said it was better to tolerance particular cams one way. I'm not sure if it was due to them being more agressive or whether it was down to them being a different make etc. Obviously with stock it would be mid tolerance. Quote Link to comment Share on other sites More sharing options...
David P Posted June 10, 2011 Share Posted June 10, 2011 (edited) They can sink into the seats and become tight just as easily as wear loose, that's why there is a tolerance to centre. Edited June 10, 2011 by David P (see edit history) Quote Link to comment Share on other sites More sharing options...
Kirk Posted June 10, 2011 Share Posted June 10, 2011 Its hard to say whether thats the right way to go as one set of cams made by one company will always be different to another set made by a different company. Mid range is ideal as it gives you the flexibility to go to the higher range or lower range if needed. Id measure the clearances on the stock cams and compare them to the new cams and make adjustments, if need be, from there. Then again i wouldnt listen to me about anything technical after ive had a few drinks. Quote Link to comment Share on other sites More sharing options...
Scott Posted June 10, 2011 Author Share Posted June 10, 2011 How are you at fitting tyres Quote Link to comment Share on other sites More sharing options...
TLicense Posted June 10, 2011 Share Posted June 10, 2011 Whenever you fit a new camshaft, the clearances need to be checked and corrected. The clearances should given by the manufacturer of the camshaft. I tend to err to the wide side of tolerance on a newly built head, as it's likely that the valves will push the seat in a little further. On a head where just the camshaft has been changed, I'll go towards slightly tighter as the valvetrain will settle by a little. (This should be less than the seat settling) Rather than buying new shims, I turn, grind, heat treat then final grind the shims myself. Quote Link to comment Share on other sites More sharing options...
Scott Posted June 10, 2011 Author Share Posted June 10, 2011 Whenever you fit a new camshaft, the clearances need to be checked and corrected. The clearances should given by the manufacturer of the camshaft. I tend to err to the wide side of tolerance on a newly built head, as it's likely that the valves will push the seat in a little further. On a head where just the camshaft has been changed, I'll go towards slightly tighter as the valvetrain will settle by a little. (This should be less than the seat settling) Rather than buying new shims, I turn, grind, heat treat then final grind the shims myself. Cheers Tony. I'm fitting new springs and retainers so I think I'll aim on the large end of the tolerance, your reasoning is what I was looking for. I'll check with the manufacturers on the sizes/limits though. I would do the work myself but I don't have access to the machines anymore Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted June 11, 2011 Share Posted June 11, 2011 If they are as badly ground as most American cams they'll definitely need re shimming Quote Link to comment Share on other sites More sharing options...
Scott Posted June 11, 2011 Author Share Posted June 11, 2011 If they are as badly ground as most American cams they'll definitely need re shimming The tolerancing is supposedly quite tight but I'll give them a proper check in work before they go in Quote Link to comment Share on other sites More sharing options...
Morpheus Posted June 11, 2011 Share Posted June 11, 2011 (edited) I would think that the aluminium cylinder head would expand much more than the steel or titanium valve stems, meaning a looser gap as the engine heats up. Perhaps the ideal then would be tighter gaps when cold, to allow for valve-train bedding wear and to help reduce the hot gaps to keep the engine smoother and higher revving. So as long as the valves etc. can't expand in length more than the head expands in depth, tighter is better IMHO. This obviously assumes springs that are properly matched to the cam lift, to prevent valve float at high rev's. Edited June 11, 2011 by Morpheus (see edit history) Quote Link to comment Share on other sites More sharing options...
dude Posted June 11, 2011 Share Posted June 11, 2011 I would think that the aluminium cylinder head would expand much more than the steel or titanium valve stems, meaning a looser gap as the engine heats up. Perhaps the ideal then would be tighter gaps when cold, to allow for valve-train bedding wear and to help reduce the hot gaps to keep the engine smoother and higher revving. So as long as the valves etc. can't expand in length more than the head expands in depth, tighter is better IMHO. This obviously assumes springs that are properly matched to the cam lift, to prevent valve float at high rev's. All tolerances quoted will be measured either hot or cold the book should tell you ie with the engine cold, some cars are checked with the engine at operating temp. Quote Link to comment Share on other sites More sharing options...
Morpheus Posted June 11, 2011 Share Posted June 11, 2011 (edited) The tolerancing is supposedly quite tight but I'll give them a proper check in work before they go in Iirc, we're only talking 0.15/0.18mm or thereabouts, at least for the 7MGE in the MkIII. When I rebuilt my 7MGE head 10 years ago I was stunned by the precision and complete lack of wear on the lifters, bores, cam journals on the head and general condition after 120k miles. Only one shim had to be replaced to keep it all in spec. These things are like Swiss watches inside. Fantastic engineering. Needless to say, the car rusted to bits but I'm sure the engine is still going strong somewhere. Btw, I still have the SST's (Special Service Tools) for shim replacement with cams fitted if you need to borrow them. They're bound to be the same for the 2JZ. Looks identical in the manuals. Edited June 11, 2011 by Morpheus (see edit history) Quote Link to comment Share on other sites More sharing options...
Scott Posted June 11, 2011 Author Share Posted June 11, 2011 Iirc, we're only talking 0.15/0.18mm or thereabouts, at least for the 7MGE in the MkIII. When I rebuilt my 7MGE head 10 years ago I was stunned by the precision and complete lack of wear on the lifters, bores, cam journals on the head and general condition after 120k miles. Only one shim had to be replaced to keep it all in spec. These things are like Swiss watches inside. Fantastic engineering. Needless to say, the car rusted to bits but I'm sure the engine is still going strong somewhere. Btw, I still have the SST's (Special Service Tools) for shim replacement with cams fitted if you need to borrow them. They're bound to be the same for the 2JZ. Looks identical in the manuals. I was thinking about the requirement for the tools, but wasn't sure if I would need them? I have the head off the car and it hasn't got any cams in it. I might be making this up but are the tools not required when shimming with the cams in place? Not fussed about pulling the cams out and in, will be good for practice If I require them though, I would be very grateful of your offer Quote Link to comment Share on other sites More sharing options...
Morpheus Posted June 11, 2011 Share Posted June 11, 2011 I was thinking about the requirement for the tools, but wasn't sure if I would need them? I have the head off the car and it hasn't got any cams in it. I might be making this up but are the tools not required when shimming with the cams in place? Not fussed about pulling the cams out and in, will be good for practice If I require them though, I would be very grateful of your offer Unless you have a lot of luck and patience Scott, you'll need the tools once the cams are fitted for sure. I can hear people saying, "Just use a couple of screwdrivers" but trust me, it's easy with the right tools and you won't scratch anything where it matters. The SST's are a pair of curved tongs that lever the lifter down when you squeeze them and a spacer that jams it down while you fish out the shim with a magnetic pickup. Re-assemble it, check the clearances and let me know if you need them. Quote Link to comment Share on other sites More sharing options...
Scott Posted June 11, 2011 Author Share Posted June 11, 2011 Unless you have a lot of luck and patience Scott, you'll need the tools once the cams are fitted for sure. I can hear people saying, "Just use a couple of screwdrivers" but trust me, it's easy with the right tools and you won't scratch anything where it matters. The SST's are a pair of curved tongs that lever the lifter down when you squeeze them and a spacer that jams it down while you fish out the shim with a magnetic pickup. Re-assemble it, check the clearances and let me know if you need them. Yeah I remember seeing that in the manual. I'm guessing it's not as easy as putting it together, measuring the shim I need, stripping it & fitting the shim then rebuilding it? I take it the measurements may only be accurate for that particular "build" and by stripping it slight alterations may be made in the build process? I'll be starting the strip down process in August but I will most likely have the build of the head started well before then (due to curiosity). If you are happy to be without them for a little while I will happily, and greatfully, borrow them off you. I do afterall like to do a job properly and I certainly don't want to scratch any of my shiney bits My main concern would be any time constraints as I have a full time job (often riddled with overtime) and a family life. I wouldn't want to put you out mate and I would have no way of knowing when I could get them back to you. Quote Link to comment Share on other sites More sharing options...
Morpheus Posted June 11, 2011 Share Posted June 11, 2011 (edited) Yeah I remember seeing that in the manual. I'm guessing it's not as easy as putting it together, measuring the shim I need, stripping it & fitting the shim then rebuilding it? I take it the measurements may only be accurate for that particular "build" and by stripping it slight alterations may be made in the build process? I'll be starting the strip down process in August but I will most likely have the build of the head started well before then (due to curiosity). If you are happy to be without them for a little while I will happily, and greatfully, borrow them off you. I do afterall like to do a job properly and I certainly don't want to scratch any of my shiney bits My main concern would be any time constraints as I have a full time job (often riddled with overtime) and a family life. I wouldn't want to put you out mate and I would have no way of knowing when I could get them back to you. Regarding your first point, there's no way it will be easier to check clearances and then remove the cams to swap shims. (Edit...because you'd have to be very lucky to not have to change some once re-installed anyway). The gaps won't change if you do remove the cams however, at least, not significantly if you torque the cap bolts the same. Whatever you do, ffs keep all the lifters and valves etc. on a board or something so they all go back exactly where they came from. This is absolutely critical with the whole valve-train. Technically you should check and shim the springs too, so that they're all exactly the same pressure. Anyway, I wouldn't worry about that unless you're building a race engine. I haven't used the SST's for ten years and may never need them again so no problem if you need them for a few months. I imagine Toyota still sell them but I paid about £25 back in 2000 so God only knows what they are now, if you can get them. All I'd ask is that you don't lose them! Edited June 11, 2011 by Morpheus clarification (see edit history) Quote Link to comment Share on other sites More sharing options...
Morpheus Posted June 11, 2011 Share Posted June 11, 2011 (edited) This is what I mean but Toyota's tools are as per post number 10, i.e. they fit properly. http://www.supraforums.com/forum/showthread.php?605492-How-to-use-a-valve-shim-removal-tool That said, if you do all your shim calculations in one go and remove the new cams you can probably get away without tools. Post 12's idea is quite good. This is what Toyota's tools look like... http://toyota.spx.com/detail.aspx?id=753 Hopefully you won't need these.... http://toyota.spx.com/detail.aspx?id=3&g=12 Edited June 11, 2011 by Morpheus (see edit history) Quote Link to comment Share on other sites More sharing options...
Andy-No-Knee Posted June 12, 2011 Share Posted June 12, 2011 Great thread....doing mine very soon on a 1JZ and a set of Crower 264 cams. Quote Link to comment Share on other sites More sharing options...
dude Posted June 12, 2011 Share Posted June 12, 2011 This is what I mean but Toyota's tools are as per post number 10, i.e. they fit properly. http://www.supraforums.com/forum/showthread.php?605492-How-to-use-a-valve-shim-removal-tool That said, if you do all your shim calculations in one go and remove the new cams you can probably get away without tools. Post 12's idea is quite good. This is what Toyota's tools look like... http://toyota.spx.com/detail.aspx?id=753 Hopefully you won't need these.... http://toyota.spx.com/detail.aspx?id=3&g=12 If you measure correctly there is no reason you cannot just measure the valve gap and remove the cams and workout what size shim you need, it is basic engineering/maths/mechanics, I have a large box of shims and have never had to take the cams out more than once to get a gap within tolerance. Quote Link to comment Share on other sites More sharing options...
Morpheus Posted June 12, 2011 Share Posted June 12, 2011 If you measure correctly there is no reason you cannot just measure the valve gap and remove the cams and workout what size shim you need, it is basic engineering/maths/mechanics, I have a large box of shims and have never had to take the cams out more than once to get a gap within tolerance. Ok, cool. Quote Link to comment Share on other sites More sharing options...
TLicense Posted June 12, 2011 Share Posted June 12, 2011 If you measure correctly there is no reason you cannot just measure the valve gap and remove the cams and workout what size shim you need, it is basic engineering/maths/mechanics, I have a large box of shims and have never had to take the cams out more than once to get a gap within tolerance. Agreed. I've measured the gaps, had the camshafts out, refitted them and re-measured the gaps. They often come in to less than 0.002" of where they were to start with, which is probably just down to how sensitive I am with a feeler gauge. I've tried using the camshaft in removal tools before, and it was a real PITA. The main problem is if the shims are really stuck down into the bucket, it's easier to pull the bucket and shim out together, then lift the shim out of the bucket with the aid of a strong magnet and a small straight pick / screwdriver. Quote Link to comment Share on other sites More sharing options...
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