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Dan (Florida) Member
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found a very interesting article on adjusting overhead cam valves without removing the cams/carriers (from Toyota performance). Not exactly the same but something that may work to make the whole process easier. Dan http://www.lextreme.com/valve_clearance.html |
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smcmanus Member 
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It is an interesting article. The 907 engine has the shims under the followers so it would be impossible to adjust the valves with the cam towers attached to the head. Have a nice day Steve |
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Dan (Florida) Member
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Well. I only have a couple of valves off, but not enough to undertake that project. I'm glad I found out before I started to tear it down, Thanks |
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edward_davis Member 
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If you have valves off, shouldn't you go ahead and adjust them? I'm in the process of adjusting my valves, and on cylinder one, I have two really tight intake valves - 0.02 or more too tight. If valves are left too tight, they'll burn pretty soon, right? I'd rather go through the trouble of pulling the cam carriers now than pulling the head later. Also, is it worth trying to adjust all of the other valves to the max of the acceptable range? Right now 2 through 4 are all exactly at the min acceptable clearance. I can't remember the numbers and I'm at work now, so I can't look them up. I was just going to leave the other valves alone, since they're within spec. How much do shims cost, anyway? Thanks, Edward |
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smcmanus Member
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I bought the shims I needed from Delta and it was very reasonable. After you figure out what size xhims you need, post it here and someone might be able to help you out. I have a bag full of shims left over. Have a nice day Steve |
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Greg Fletcher Administrator 
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Not sure what Dan in Florida is working on, but it can't be a JH with the motor it came with as you would need to pull the cylinder head to remove a valve. That goes under my category of significant maintenance. If you are adjusting any valve, it really is worth your time to check and adjust them all. A couple of Lotus mechanics back in the day told me they spec'd all the valve settings on customers cars on the high side + 0.001 or 0.002 in. extra to be sure they would not be back again any time soon for more adjustment. When I do it on my car I prefer to keep as many years as possible between adjustments and I set them all on the high side within spec. On my last JH, I could go 40,000 miles between adjustments. A couple of hours of extra work to get this right will keep you on the road much longer. The car will run much better when the valves are adjusted correctly, so it's important to check them every year or so and keep a log of the clearances. |
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Dan (Florida) Member
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To clear up any misunderstanding, my 907 is together and running fine. I was considering adjusting the valves but decided against it . I have one intake and one exhaust valve a little loose and am not willing to go through all that work for a car that is only run on sundays. I remember the hassle it was to seal up the valve covers. I thought that the shims were removable from the topside like everyone else's engines but I guess not. I will adjust the valves if I go in for some other reason. On another note I just picked up a used MSD-5 and installed it the other day and would recommend it to anyone who wants a smoother running quicker starting car. I still need the tach adapter, but I saw one on ebay for a pretty good price. Dan |
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edward_davis Member
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Well, my 907 is not doing so hot. All of my exhaust valves are too tight, and three of the valves need shims less than .060" in thickness, which the shop manual says is a no-no. Delta also told me that the smallest shims they stock are .064", and I have six valves that need smaller shims than that. So, what am I to do? Do I need to pull the head and take it to a machine shop for new valve seats? I'm not sure exactly how to proceed, since I've never fallen below the minimum clearance on a valve adjustment before ('course all previous ones were on an old VW 1600 cc engine). I'm tight on cash this year because we just bought a house, so I'm trying to find the solution that is cheapest without being 'wrong.' That is, I don't want to patch things up and have to do them again later; I'll let her sit through the summer rather than cutting corners. I have access to a machine shop here on campus, too, so I might be able to do some of the work myself, if it's not too complicated. What should I do next? Thanks, Edward |
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smcmanus Member
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The manual says you can grind up to .010" off the valve stem. How tight are your valves? Have a good day Steve |
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edward_davis Member
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The tightest of them would require a .054" shim, so this might be possible. How would I tell whether the valve stem had already been ground down? Also, wouldn't this still require pulling the head? If I'm going to have to pay $140 for a new head gasket, I might as well renew the valves. I suppose I could grind the valve stem in place, but I'd be worried about getting metal filings into the oiling system. If I was very careful to cover the rest of the head while I did it, I might be able to pull it off. Is this something I could do with the valvesprings on? I don't have a compressor, so it would be difficult for me to pull the trick of getting the springs off with the head on. Of course, that would be a good excuse to buy a compressor. So: can I grind the valve stems with the head on? Do I need to pull the valves from the head to grind them? Last edited on 03-10-2008 03:26 pm by edward_davis |
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smcmanus Member
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I see no way you could grind the valve stems without pulling the head. The end of the valve is recessed in the spring retainer. That's where the shim sets. Most valve grinders also have a stem grinder. In fact, some older cars like flat head fords needed the stems ground to set the valve clearance. If you are doing a valve job, you will probably need to dress all of them after the valve job is done. Of course, you might find a knowledgeable helpful machinist that you could ship the whole head assy. to whom would set the whole thing up for you. Maybe Judson knows someone who can help. (yes, I meant the entire head, cam towers and all) Have a nice day Steve Last edited on 03-10-2008 04:21 pm by smcmanus |
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Greg Fletcher Administrator
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People often forget this, but it is super important that when your knowledgeable and experienced machine shop is doing the work on your head, they should have the camshafts in the cam towers in front of them as well or they have no way of matching the valve length to the correct shim range (which should generally be in the 0.070's). They will simply ignore this essential fact and hand over the finished head to you and now the problem of shims being out of range is now your problem! |
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Jensen Healey Super Moderator 
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Hi Edward, Paeco will make shims to any thickness. I don't know if it's a great idea to go thinner than .060 but for $12 each it's a lot cheaper. Get the SAAB 900 8 valve shims. They are a perfect fit. Kurt http://www.paeco.com/Saab%20Cams.htm |
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smcmanus Member
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The problem with using shims that are too thin is that the cam follower will rest on the valve spring retainer instead of sitting on the shim. This is bad. You might be able to get away with a little under 060. In fact, you could make your own thin shim with some fine emery paper on a flat hard surface and rub away. I think it took me half an hour per thousandth when I was adjusting mine. It really helps to have some heavy metal playing really loud while doing this. I prefer Sound Garden. It is also excellent music for cutting away rusty sheet metal. Have a nice day Steve |
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LambandAndy Member 
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Edward, Have you considered putting the gaskets back in under the cam towers? This would work as a temporary/permanent fix. It does make setting the clearance a little trickier because the compression of the gasket but if there is nothing else wrong with the head I'd hate to pull it just to get the clearances right. Andy |
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edward_davis Member
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Yes, the gaskets are a good idea. I've been talking to Ron Mau about it off the board, and I think it's the way I'll go. How thick are the gaskets when compressed? Shouldn't I be able to just add that thickness to the shim thickness I've already calculated, or do the gaskets vary enough that I'll have to remeasure? I can probably find this info elsewhere on the board, but I'll ask here before I go looking. As always, thanks for all of the help, folks! Edward |
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edward_davis Member
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Well, I'm going with the gasket to take up the slack in my valve adjustment. I only need it on the exhaust side, so I'm going to use the locktite 515 on the intake. I mic'ed out the gasket and it's .015", but I've read elsewhere on the board that it squashes down to around .010" when compressed. I'll write back with my numbers once I get it in place. I have one more question: since I'm using the evil, evil gasket, is there some gasket dressing or sealer I should use when I do my final assembly? Should I use the locktite 515 on it? Or do I just assemble it dry? I got two gaskets, so when this one starts to leak, I can replace it and put off that valve job a little bit longer.... Thanks again, folks! Edward |
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smcmanus Member
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Do put the sealer on the gasket. The reason the gaskets are "evil" is because it is very difficult to accurately set the valves when using a gasket due to crush. I use Loctite 518. I use it on almost everything now. If you can find it, it is wonderful. Have a nice day Steve |
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Gary Martin JH 15371 Member
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I'm checking the valve clearances on the engine I bought from Ron Earp out of the IT race car. The Exhaust ones are all fine. However I have two Intakes that measure out at .04 inch. Can't quite get a .05 in there. The rest of the intakes are all .05, although two of these are a tight .05. Should I be concerned? Should I re-adjust for more like .05 or .06 ? Also do the valve clearances Tighten Up over time as things wear, or loosen up ? Trying to get 15371 on the road this Spring. Thanks. Gary Attachment: IMG_2840-0002.JPG (Downloaded 36 times) Last edited on 04-05-2009 02:37 am by Gary Martin JH 15371 |
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Judson Manning Member 
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Gary, Upon assembling that engine I set the Exhaust on the high side of .012" and the Intake to the high side of .007" dry. Same thing I do on all my engines before putting it through the paces. I'm pretty sure I logged 200-300 miles (about 12-15 hours) before Ron took delivery. I take great pride in knowing every engine I deliver is "slightly used". That engine should be ready to run right out of the box. During break-in things do settle in, but also keep in mind tools vary in tolerance, and the measuring technique isn't an exact science. In my opinion, what you are observing is 'normal' when taking into account all of these factors. Intake valves don't burn. Howver, a VERY common problem with the 907 is Exhaust valves buring. People never check their clearance and the Exhaust valves tighten up to the point where the valve can't seat long enough to cool and they eventually burn. You'll be driving down the road one day and magically you'll lose a cylinder (or two) like a friend of mine this weekend! Should you worry? My aforementioned friend NEVER checked his valves since building that engine 80,000 miles and almost ten years ago. Of course now he needs a complete head-job, but one could argue he certainly got his money's worth out of that rebuild! By comparison over the Winter I check the clearance on my 907/910 hybrid built about 4 years ago terrified I'd be dropping a valve any day now. To my surprise all of the valves had shifted only about .003"-.004". The exhaust is most irritating to do when the engine is in the car. Intake is easy and rarely ever presents itself as a problem. I'd say install the engine and check things after a few thousand miles. If you do want to adjust the intakes, adjust ALL of them to the high side of .007", but that is no guarantee. On another note, I remember suggesting you change the Exhaust to a 107 grind. If you do change that cam then go ahead and re-shim the Exhaust to the high side of .012". Keep in touch, Judson |
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Gary Martin JH 15371 Member
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Thanks Judson, I was hoping you would respond. I will install it as is and run it for a few thousand miles and re-check clearances. I want to run it awhile before deciding on changing the exhaust cam. We finally have some nice weather here in Oregon which is helping me make progress on the car. Engine should go in the car tomorrow. Need to install the tank and fuel pump plus a few other things, but should be ready to fire it up in a couple of weeks. I have been posting pictures of my progress in the gallery under JH of Oregon, 15371 progress. Gary |
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Jensenman Member
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Has anyone considered or tried making an .010 aluminum cam tower gasket and using 518 on each side of that? That would eliminate the gasket crush problem. It's not unprecedented; Datsuns used to have 'head savers' which were steel shims for the cam towers, used when the head was resurfaced too much or the valve tips were too high. On valve clearances: I learned the hard way many years ago on motorcycles to always set them a little loose (an extra .001-.002). As the valve contacts the seat it will slowly wear and 'grow' out of the head, effectively closing the clearances and this leads to burnt valves, particularly on the exhaust side. Last edited on 04-07-2009 07:19 pm by Jensenman |
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Jensen Healey Super Moderator
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I'm guessing the intake side was tightened up to gain a couple thousandths of lift. Race engines get much more attention than a street engines so it would never be a problem. If you are driving on the street and don't want to check your clearances very often, adjust them according to the manual. I would drive it the way it is and adjust later! Kurt |
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Gary Martin JH 15371 Member
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Thanks everyone for the comments. I was initially checking the clearance with the lobes directly opposite the cam follower. I went back and rechecked, and I found that if I turn the lobes a few degrees past directly opposite the valve I gain another .015 to .02 in clearance! This puts me right in the .06 to .07 range for the intakes. The manual does not mention this. I just says to adjust on the heal of the cam lobe. Interesting. Gary |
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