Tim_C.

I don't follow? You cant remove the BS shaft by just pulling the side plate? The engine front cover has to come off? You can also use any old BS upper bearing to block the oil. Just turn the bearing so the hole doesn't line up, and seal it in place. Tim C.

Well, if it is 13 degrees off, can't that be taken up by jumping a tooth? I forgot how many degree advance that would be, but 13 degrees is a lot, and more than just about any adjustable cam gear goes? I thought most only go 12 degrees? I'll look at the aussie one, and see, but 13 degrees is a lot. Also, remember that advancing puts the intake valve closer to piston interference, so if it is adjusted too far, interference will happen. It matters what cam it is, etc..., but it can happen, believe me. I had interference with mine straight up, so if it were retarded, then I'd hate to see it advanced? I can check mine when I go to pull the cover off and check the roller cam for wear. I'll see if I can get a degree wheel and see where to take the readings & measurements from. Well, I just looked at RPW, and they don't say how much their wheel adjusts. Only that engines have been found to be up to 10 degrees retarded. Like I said, 13 degrees is a whole heck of a lot, and I would suspect something to be very different about the set-up it was measured on. Like a shaved head, or something? Tim C.

How much is it? Looks like an ultimate control system to me. Tim C.

Yeah, I agree that the heat diference would be more gain than the longer runner effect. Tim C.

Thanks Marc & Mike. And everyone. We really have pulled our thoughts together on this one. I am pretty confident the results will be worth it. Mine is already proving to be a screamer. As much as a stock non-IC, 5 PSI Boost, low compression/burned valve engine can be! I was just cruising along yesterday, and just barely gave it a little gas. It didn't even go to boost yet, & it stuck me in the seat when I wasn't ready for it. Very smooth, and just surprised me! It's knowing how much better it performs, and being able to share on here with everyone, and learn more and more, that really makes it fun and worth it. Tim C.

That sounds like a great idea. I wonder how long of one it would take to gain some noticable benefit? Tim C.

Yeah, we won't go that big. The lift is already about as high as we want to go. Maybe a tad higher, and some more duration, split on both. I think we could go up to 270ish duration as long as we close the INT before the piston comes up. We can open it a little sooner. Actually, there are quite a few things that can still be done. He already has a grind scheme in mind, but wanted to wait to see how this preload solve goes first. I really don't think too many of us will want more than this one. I took it straight to 6K RPM with ease, and it absolutely would not do that before. 5200 was it's peak, so it has gained quite a bit. I actually think this cam is already close to the ultimate for most of our applications. If we want to keep the revs @6K & under, then we can advance it in 2-4 degrees for a little lower range to come on very strong up to 6K even. I felt like I was short shifting at 6K. It went straight there, & wanted more, but I won't go past 6 with balance shafts. I may try to do the cam gear bushing kit thing for when I swap over to a rebuilt head. This stuff is starting to drain me physically. It is very exciting, but I'm losing interest in all this testing. I want to get something to work right, and run with it very soon. Tim C.

Well Chip, the length of the valve doesn't matter as long as the lash is the same. Bending the valves is what means you'll have to go deep. Going that deep would mean coming out some to cover for the flat face hitting too. That cut needs to be at least 1/8" (.125) past the present witness mark. They are supposed to be .060" clearance INT., & .100 clearance EXH. Due to the exhaust valve expanding more. I don't think your exhausts will hit. The exhaust valve diameter is small enough to not hit I think. Plus, you won't know exactly where to cut since there isn't a witness there. If you cut it at all, go .060 at least. Study the angle of the witness mark closely(valve angle). That will tell you how much to cut out for the valve face. Cut that angle all the way to the top of piston, once you get your depth directly below the witness mark. Actually, you will be cutting of the outer shelf some, and that's fine. Just try to not end up with any very sharp points, as they will become hot spots and melt. They don't have to be rounded, just chamfered. It still sounds doable, but just a little trickier than what I had to do. You really need an aluminum bit, as the steel ones will cake up with aluminum, and it is frustrating getting it out of there. You will need to use a steel bit most likely to do the finishing touches. You might want to buy a few steel bits if they don't have aluminum (hardware store). I guess you guys have big stores there, but I'm used to stores never having anything I need out here. I used 2 steel bits. One with a sharp edge, like it was cut off flush at the bottom, and one with a curved bottom edge. Tim C.

Chip: Thanks for the heads up on the E-Mail notification thing! We owe you one! I would think the curved clips would work in the flat/square groove valve, but not the other way around. So, you could try it. Let us know if you drop a valve! If you see a Chinese guy popping out of a hole in your piston, then you know you dremeled too far! :-[ Seriously, the clips are wedged in there, so the slight curve should not be enough to let the clip fall out. There is all the spring pressure there to hold it in, so it should be fine. Oh, & I just locked that thread so you don't keep getting notifications! Tim C.

Chip: That could have happened when the cam pin broke? However, it is highly possible you have interference problems with that cam. My .510 lift, 284 duration, 114 lobe sep, hit pretty hard. Yours has considerable more duration, which is what gets it closer. That cutter tool needs a mock head to do it with, that has the seat out of it. There is a small blade that sticks out, and you can't have a seat in the head when doing that. The dremel will work if you look at the mark, and go .060 deeper, and to the outside of it. Mark it with a scribe, and then grind until the mark disappears. Well, you can't mark the depth, but you can be careful, and go down as much as out, and know where it is close enough. Except you need to add the length difference of the valve too, which makes it harder. I suspected Mike K to be rigtht, and new he was, but just didn't know for sure it is that way in ALL cases. Looks like it is. I'll bet my '85 valves are longer too. My machinist said the added length was above the groove. I'll have to go shoot him now! (jk) Tim C.

Chip: Well, I think you need to order keepers & retainer rings for an '83 Starion. Those should work on the squared off groove. Mine had them stock on my '85, but I know some didn't have mechanical in '85, so I don't know how to order them? Mine is a non-intercooled '85 Automatic, so maybe that would get you the right retainers. Bent intakes: SUCK! That is too bad. I had one of my custom length SST ones that bent ever so slightly. We really had to inspect it close to se the problem, so we chanced it & took a stab a popping it back, and it actually worked! We could not see a bend after, so I used it. However, yours need replaced. It's good you have those others. The Slippers: You can look at them closely, and kind of shine a light on them while moving the slipper in the light, similar to examining a diamond. You will see a tiny wear groove in one spot. That is where the most friction occurs, and will start eating the cam. If you cannot see that very slight channel at all, then maybe you can use it. I would think the slipper can be re-cut, or whatever, but it would need to be a precision job. Try a parts house that sells Melling products. I bet the mellings are new, or aluminum rebuilds. A rebuilt rocker either has a coating on the inner dia to the rocker shaft, or a bronze insert. Plus, I bet they just shave the slipper some for truing. I wish I knew what Mitsu used to glue the slipper pads to the rocker. It looks like a steel plate between them. If we new how that was adhered, we could use the same stuff on lash caps, & be much safer that way. Might be hard to get off when you go to rebuild it though! Maybe a machinist can reface your slippers? I have talked to several machinists, and my cam grinder also says to put new rockers on the new cam. Tim C.

OK, all of these threads I'm starting on cams, are because I want to learn, so please feel free to correct me if I'm wrong. Slipper Wear: I took a look at lots of used slippers today that I have laying around. NONE of them would be acceptable to put onto a new cam. So, anyone using used slippers on their cam upgrade, is asking for trouble. All of the 50,000+ miles ones will have to some degree, a very small wear groove that goes front of engine to back of engine on the slipper itself. This groove will eat into the new cam. Slipper action compared to roller: The slipper is contacting the cam over a wider area than a roller. This wider area is also curved. This curving speeds up the action to allow for more duration without needing a big wide lobe. That's a good thing, but a slipper is very limited in how steep of a lobe it can handle, whereas a roller rocker can handle a steep lobe. The roller rocker may start out a little slower because it cannot be curved like the slipper, but the steep lobe that the roller can get over, more than makes up for slower action. Thus the need for stronger springs on the roller. However, anyone running 16+ PSI boost, should consider stronger springs because the boost will start working against the spring, & lobe. The steep lobe makes for a lot faster action than a slipper is capable of, so, the valve can be lifted higher, and longer duration over the same time period. In other words, when the slipper is still opening up, the roller is wide open. Then we can factor in the less friction with the roller, and see why it is so much better. So, when we cut corners and use used slip rockers, the chance of eating the cam up, i.e. considerably lessoning the life of the cam, goes way up. With roller rockers, you can go with slavage yard used ones, and not have problems. That is a money saver for those of us who need to save money where we can, w/o cutting corners. I am testing with used lifters too, and so far, they are fine. Tim C.

Well, the mod is very simple, but I don't want people trying it at home until I test it first. Plus, I am pretty open about things I have done here, and I feel it has contributed to padding someone else's pocket. When I do sell the cams, believe me, I won't be making much, so I hate to see people using the technology I come up with for their gain, especially when they are known to be shady. Not saying any names. However, it keeps me on my toes, and I wish I knew this trick before, when I did my first roller cam. The mod is done, and running now on the car. It did solve the pre-load & ticking issues. I am testing for wear on it & still on the cam. Absolutely no wear on the cam so far, after 100+ miles. Everything is getting oiled very well, and it looks like a go. The mod did increase the performance again, as my grinder said it would. What this does, is open up a whole new, very big window for bigger, high performance roller cams to work, and as cheap as any cam upgrade. That is saying a lot, considering going big before needed custom length valves, fly-cut pistons, and machining techniques to the tune of over $2000! Now we can grind a monster, and still be a bolt-on if we do it right. This one is pretty good already, and may be all the cam most of us will want. I looked into the cylinder with a bore scope as someone else turned the crank by hand. There was plenty more room to go bigger if needed. I really didn't need the bore scope to tell, be cause you could see the intake valvespring starting to close way before the piston got up. My 284RH does not do that. It has the same lift & duration for INT & EXH, and is very big on both, with a major wide center line. We can grind something that will outperform it, and not interfere. However, we are still stuck with hydraulic lifters that don't take too kindly to 7000+RPM like you can get the mechanical slip rocker cam to do. Tim C.

I don't know what "offset" printing is? I am interested anyway. Tim C.

Got to talking with my grinder again, and he let me in on a secret as to how to increase the preload on our hydraulic set-ups. Cost is next to nothing. I mean dirt. He does it on many different set-ups that involve a lifter inside the rocker as ours does. I am going to test it today for fit, and do the mod. He said I am losing 30-40% of the useable power from the cam because I am not preloading the lifters enough. I agree, and it makes perfect sense. Especially these lifters that require more preload than most hydraulic lifters. I found that the 3.0 Liter rockers don't put the valve any closer than ours. We measured the Melling version before, and came up with a different story, so I am going to measure it again to see if the Melling version of it is different? Also, I found a 2-3PSI decrease in oil pressure going from the mechanical set-up to the hydraulic. That makes sense too. It takes more to keep the lifters pumped, and loses a little volume down low, so that could be one reason. Plus, I had to use old rocker shafts that I had, so they may not pressurize as well? Thus taking even longer to get oil back to the pan. Preloading the lifter more should get rid of the ticking, and may be a mod we can use to eliminate ticking on problem lifters. Too many people are having that problem on lifters that aren't stuck closed, and this should work to fix that too. My grinder sells 20 cams at a time to a company that uses this same simple technique. They have been doing it for over 7 years with absolutely no returns, or reports of any problems whatsoever. I've got some more heads coming to get one prepped & installed to fix my compression problem. We think the gauge was inaccurate as to how low it really is, but there is a definite problem. The car runs too good for it to be as low as what it was reading. Tim C.

The kit is for Small Block Chevy, Big Block Chevy, and Big Block Mopar I think. summitracing.com Part# MRG-85 $14.95 Tim C.

That sounds great! The cam works very well, but I just don't think the preload is quite enough, so we are going to not reduce the bas as much. He says he can get the same figures too. We had a slight miscommunitcation, so we are fixing that. I am keeping this cam in. It has slight ticking, but but not bad. Less than you hear with a performance solid. I am trying to come up with an inserrt for the rocker to extend the lifter out some. That may make it possible to do even the 284RH cam as a less expensive afair. Tim C.

jinx: Yeah, the lower exhaust duration is better when there is a lot less overlap, so that is one reason this cam works. The roller set-up is cheaper if everything is done right on the mechanical swap. The reason so many people chew up cams is mostly because they don't use new rockers. A must for a new slipper lobe. Not all cases, but most for sure. Then comes lack of sufficient oil, and cam metal strength vs. spring pressure. Used roller rockers are dirt cheap as kev and I found out. The engine tricks are all posted pretty much. I just spent the bucks to get it done right. Line honing is most important. The rest is common sense lightening, and strengthening. We went closer/tight on the main journal tolerance, and dead middle of spec on rod oil clearance tolerances. That gives better oil pressure to the top of the engine. There are others on here who really know more than I ever will. Mike K. is very knowledgeable, chiplee, kev, shelby117, and many others. We did microhone the cylinder walls too, for a quicker seating time on the Total Seal Rings. Tim C. Tim C.

Shelby: You are correct about the test not being good enough to say much. The head is virgin untouched. Everything is too perfectly stock. I want to switch heads just to reduce downtime. I will want to take more time on the present head to get it right, like take it to a machine shop. That puts it a few weeks out around here. Yes, many times shops only cut the exhaust valve seats, so they will stick up more, and be closer to the lifter. I may end up having the shop do that, since they take a little more than I'll need on just a regular cut. I'll just have them do all to the same height. I'm getting there, slowly maybe, but surely. Tim C.

That sounds good. Hey, is that '59 Biscayne a Pro Mod car? I saw an 8 second one that was yellow in Grand Junction CO. Tim C.

Yeah, I meant cylinder pressure readings. Also, I think there is some validity to what Chip is saying. My valves sure look to be the same length above the keeper as my stock hydraulic valves (I've got a box of 'em!). My machinist said the aditional length on longer ones, is all above the keepers. That distance on these is the same as hydraulic. The adjuster screws are pretty long too. This is for sure the original set-up. I forgot to compare the keeper groove to the hydraulic ones, but I did take a close up digi pic, so maybe that will show it. We actually took a digi pic of the chamber, looking through an Opti bore scope. Kind of cool. The car is still running, but I am getting another head for it. I drove it today. It sure does have more power, so we'll see how it lasts for wear. I'll try to drive it until I get another head. Tim C. Tim C.

Well, got the cam in. The preload was fine on all but one rocker? I'd have to think it is in the lifters. There was like .006 gap on one lifter/rocker, and the rest were loaded about .015-.020". I know, not very much, but anything over .010 is considered enough on most hydraulic lifters. I think ours may be the exception, and they really need a good .020" There is some lifter tick. Not bad, but some. I am driving it to see if they pump up more? The cam grinder said he can get the same grind w/o taking as much off, so that will solve the preload issue. Performance: Bottom end (off idle), The same as stock= no loss. 2200-5500=Much more power. I would say a good 20HP across the range. It isn't just a seat of the pants increase. The car lifts the front end a lot more than before. It rears you back in the seat. Top end=definitely more power felt, but I regret to say, that my head has bad/burnt exhaust valves, so I don't know how much of an increase there really is in any RPM. My CR is 1-86; 2-66; 3-90; 4-100 With oil: 1-92; 2-75; 3-111; 4-112. We found the problem when we went to do the valvespring swap. It was shoving air out the talipipe whe the exhaust valve was supposed to be shut? Guess I'm in the market for a new head. Maybe a ring job? All I know is there is lots more power from low-mid to hi-mid; 2200-5500RPM. Changing the springs was a major pain. I don't recommend anybody to try swapping cams & springs unless they know what they are doing. The stem seal replacement wasn't easy either. You need a perfect sized tube to fit over the seal, and tap it into place. My '85 had a mechanical valve train on it too! So, it means there should have been more preload on the lifters? My mock/test head with hydraulic length valves had plenty? Except, I'm not so sure the '85 mech valves are longer than hyd. The length above the retainers was the same as the hyd. I did have to swap in an old set of hyd rocker shafts I had laying around. The mechanical shafts did not have the oil holes to feed the lifters. I also retorqued the head, but it won't help burnt exhaust valves. I am going to keep driving it to see how the cam wears, unless it gets undriveable. There are some driveability issues, but I've had them for a while, and I should have known to check the CR. The car ran 16.97 on a "G-Tech" 1/4 mile before the swap. 16.82 after. Same MPH of 86.5. That's a non-IC car @5PSI boost, and the above CR ratios. Tim C.

That describes the hydraulic roller cam I'm trying tomorrow. INT Lift: .480 EXH Lift: .459 INT Duration: .207 @.050 Â (265 seat-to-seat) EXH Duration: .196 @.050 (258 seat-to-seat) Lobe center separation:111 RPM range: 2500-6500+ We'll see how she runs! This cam will be available as soon as it is tested for wear. I'll keep everyone posted. On the mechanical cam that my grinder does, the duration is high, but split to reduce overlap. Cylinder fill is an issue for speed of spool, and holding the same boost level up high in RPM. We all know it will eventually fill the cylinder, but how fast & for how long? That's where the split patterns really help. IMHO You can keep the duration a tad higher if you split the pattern and widen the separation, to reduce overlap. We're thinking that the 270 or so duration is about the max as far as what we've seen work well. But, if you split the duration, and widen the separation, you can raise each valves duration some, because the split has kept the cylinder fill characteristics closer to the lower duration figure. That's as far as the ratio of fill. You get a lot more fill volume at close to the same amount of time that the exhaust valve is closed, compared to intake valve being open. If that makes sense? With the roller, the lift can be raised considerably, due to the steeper lobe profile that a roller can handle, thus the more capability to do better, what mike c. is saying, i.e. increase lift. One thing I know for sure is my other roller cam in the '87 has a very wide RPM power range. It comes on sooner, & stays on much longer. This helps negate the need to run the engine at too high of an RPM for the lifters? You can keep it below 6500, and know the lifters can handle that. Can't ask for much more? Tim C.

The specs given are at the valve, so the rocker ratio is figured into that. Tyrell's .430 lift is exactly that, and not hard to get when grinding a stock cam since theratio is much greater from 1.4 to 1.6. Tim C.

Well, their #2 is a 278 duration, .436 lift, and a 114 Lobe Separation. Another bad thing about a 114 separation is the computer may want to go into open loop. In my opinion, all of their cams really need aftermarket computer control. If you are locked into the GP, then the #2 is your closest best bet to work fine with the computer. It still has a big duration, and it might even still be too much cam? Plus, their advertised RPM range is pretty wide. I would not expect quite that much out of any of those cams. To actually get that wide of a range on just about any cam, the tuning has to be perfect, and the matching of parts has to be perfect. They really should go more into what parts match up with those cams. Maybe they do on their web-site. What one of us has the perfect match of parts? Who has perfect tuning? If I were you, I wouldn't make the mistake of going too big on the cam. #2 is plenty of cam for your mods, and more future mods. Really, you can go big duration on a cam, but it needs to be a split duration that is profiled for a turbo. That means the exhaust valve needs less duration, and needs to open a tad later. That is how it can build boost faster, and hold the boost longer. That's why a bigger exhaust valve really helps because it can flow extra volume in the shorter & later time it is open. But, the bigger exhaust vavle really isn't needed, unless we are talking big 700+ CFM turbo, and 16+PSI boost. I've got a better cam available for our application. I wish it weren't me that has got this connection, because I don't want everyone thinking I'm just trying to sway people toward cam specs that I can get, but I really think my grinder has the better cams across the board, unless they are all out race engines, which few of us have, or want. Tim