Noddle Posted July 19, 2009 Share Posted July 19, 2009 Hi, Wouldn't you be better to have a sprocket on the 'pulling' side, since you would not want this to 'flex' thus changing the cam timing, see picture Nigel Quote Link to comment Share on other sites More sharing options...
ozconnection Posted July 19, 2009 Share Posted July 19, 2009 psssst...look at the Kameari chain tensioner for the L-series. Chances are you won't need the curved Datsun guide anymore, or the chain tensioner, but it's expensive. But I bet it would work. Good idea, however, isn't that piece of equipment designed to fit the L head where the inspection plate goes? Removing the L head doesn't necessarily preclude its use, only that further adaption/fabrication will be required to fit that 'expensive' Kameari setup. Could another 'sprocket/cog/tensioner thingy be found from a more local source, a domestic late model twin cam engine perhaps? Wouldn't that be cheaper initially and possibly easier to adapt than the Kameari item? Fantastic idea using the Merc head.....I have a couple of them local to me that I could get....lets see how this all pans out. So far so good! Keep it up! Cheers! Quote Link to comment Share on other sites More sharing options...
MAG58 Posted July 19, 2009 Author Share Posted July 19, 2009 The original 3.0-24 head actually did have a wheel tensioner as you describe, but it was changed to the slider arrangement, it just looks like it's movable on that side because I haven't drilled and tapped the block for the bottom part of the slider... once i get a chain that fits, I'll drill and tap the block and be done with it. As far as the side I plan to use the Kameari tensioner, I'd consider it if it were a race engine and I wanted to mechanically adjust the chain tension. It's going to be a street engine, so I'd like to maintain as many stock parts as possible including the hydro tensioner in an effort to make a more streetable engine. Quote Link to comment Share on other sites More sharing options...
jeffp Posted July 20, 2009 Share Posted July 20, 2009 Looking at the angles of the chain from the crank to the sprockets you will have a good amount of loading on the sliders, and the tensioner. The nissan head if you look at how the chain runs is almost a strait shot at the cam sprocket, and the tensioner adds the additional tension on the chain. Your setup is much different and you will have problems keeping the chain tight if you don't ensure there is enough positioning tension to begin with. The chain is going to slop around and it very easily give you a high wear area on the sliders, and make the cam timing unstable. I think in your case a standard idler gear is in order for both sides of the chain. This will give the assembly a "static" tension that will not wear and then can be tensioned by a the stock tensioner. Otherwise I would be very surprised if the chain does not eat through the slider in short order. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted July 20, 2009 Share Posted July 20, 2009 I would MOST definitly make it a STRAIGHT shot from the cam gear to the crank on the tension side. If not, you will most definitly shear off any idler gear that is put there. There is a crazy amount of force that is needed to drive those cams at high speeds. Make a custom WIIIDE lower cover, or make a jack shaft mount like the 240zx engine does. Quote Link to comment Share on other sites More sharing options...
MAG58 Posted July 21, 2009 Author Share Posted July 21, 2009 Call me retarded, but Mercedes used that slider in that same position (as it's using the same factory mounting points on the head, and I'm matching angles for use on the L block) so why exactly would it not work? I mean Mercedes thought it was good enough to put on their flagship 6 cyl for 10 years and it could safely spin to 8k and never had known timing rail issues... As far as timing gears on the crank, A handy cross check with ATI revealed that the mercedes crank snout diameter is actually the same size as a small block chevy. After talking with them, using an internally balanced SBC super-damper will accomplish the same as the superdamper for the L. just have to sleeve, or cad & machine a timing gear and we're good to go. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted July 22, 2009 Share Posted July 22, 2009 If you calculate the Forces involved with those cams, at 8000 RPM you will see that a sholder bolt or equivilent, as shown in that drawing will shear off. You always want to pull in a STRAIGHT line, therefore no real force on a tensioner, etc. Just like stock L series. Quote Link to comment Share on other sites More sharing options...
MAG58 Posted July 22, 2009 Author Share Posted July 22, 2009 I don't plan on using the idler there for that reason. IIRC the early M104-24 that was basically the "pre-m104", an M103 with a 24v head used the idler gear arrangement. They switched to the slider when the production M104 hit the market. The slider is a pretty big investment cast piece that's held in place with 3 hardened steel pins that go into the head and block and screw into the front cover as well. I plan on replicating this, the angle isn't as intense and the force is transmitted along the entire length of the slider, allowing for more stability at the top end where the force is initially realized. The real question is the guides on the other side, going up towards the exhaust cam, there are many options, I'm just trying to find the most compact option that would still be semi-efficient. Quote Link to comment Share on other sites More sharing options...
back-to-zcars Posted July 28, 2009 Share Posted July 28, 2009 Bob, do you have any updates? I hope the Merc slide works on the tension side, would a simple idler on the slack side (where you finger is in the photo) be enough to keep the chain from jumping a tooth. I am watching this biuld with much interest. Dave Quote Link to comment Share on other sites More sharing options...
MAG58 Posted July 28, 2009 Author Share Posted July 28, 2009 I'm filling the head this week and the ol' block is in machine shop jail . I should have an update or three in a a week ish or so. Quote Link to comment Share on other sites More sharing options...
PanzerAce Posted July 28, 2009 Share Posted July 28, 2009 Damn you for putting crazy ideas in my head, DAMN YOU I SAY! Quote Link to comment Share on other sites More sharing options...
Daeron Posted July 28, 2009 Share Posted July 28, 2009 Damn you for putting crazy ideas in my head, DAMN YOU I SAY! +1... Went to the junkyard today, just browsing, and I couldn't pass a single Mercedes without thinking about it.. and who am I kidding I looked under most of the hoods, too. Quote Link to comment Share on other sites More sharing options...
Barrel_Ball Posted August 4, 2009 Share Posted August 4, 2009 (edited) Geez. now I wanna rebuild my old L28 using an M103 head for a crossflow setup. I've seen a few around the junkyards, just not lately. But even the M103 looks like a mean setup. Come to think of it, the M103 closely resembles the Nissan RB30E, now that I look at them side by side. Wierd... Edited August 4, 2009 by Barrel_Ball Info/comparison update Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted August 4, 2009 Share Posted August 4, 2009 LOL daeron......there must be 10 of those in west palm alone. Quote Link to comment Share on other sites More sharing options...
dhp123166 Posted August 4, 2009 Share Posted August 4, 2009 This is gonna be cool... Quote Link to comment Share on other sites More sharing options...
PanzerAce Posted August 4, 2009 Share Posted August 4, 2009 +1... Went to the junkyard today, just browsing, and I couldn't pass a single Mercedes without thinking about it.. and who am I kidding I looked under most of the hoods, too. The worst part is I know where a MB of the right year/trim is for it to have one of these heads is located in the local PnP. WAY back row, four in...... Quote Link to comment Share on other sites More sharing options...
Daeron Posted August 4, 2009 Share Posted August 4, 2009 The worst part is I know where a MB of the right year/trim is for it to have one of these heads is located in the local PnP. WAY back row, four in...... and its something you've thought about a zillion times over the years. And it probably won't be that hard to do, but hard enough to keep it from being even feasible for so many. Not because it is beyond anyone, but because it is just really so low priority when compared to the cost. But the bloody thing just sits there under those hoods, with so many of them hardly even touched..... Quote Link to comment Share on other sites More sharing options...
MAG58 Posted August 4, 2009 Author Share Posted August 4, 2009 It won't be that hard, I'll have my pics up as soon as she gets out of machine shop jail but the biggest procedures that have to be undertaken to get this done is filling the coolant ports and re-cutting it and having the crank snout turned. Everything else can be done, I believe by your averageHBZer... On the other hand, which M104's do you guys find? If you can find one out of a 1992-1993 300-24 car (the 3.0L not the 2.8 or 3.2) I'd really like to get my hands on the entire motor, and they're few and far between in this part of the country. Quote Link to comment Share on other sites More sharing options...
ModernS30 Posted August 4, 2009 Share Posted August 4, 2009 I am heading to the pick and pull today to try and find some lf suspension parts I need. I sure hope I don't see a merc or I'll be popping every one of their hoods hahaha. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted August 4, 2009 Administrators Share Posted August 4, 2009 Call me retarded, but Mercedes used that slider in that same position (as it's using the same factory mounting points on the head, and I'm matching angles for use on the L block) so why exactly would it not work? I mean Mercedes thought it was good enough to put on their flagship 6 cyl for 10 years and it could safely spin to 8k and never had known timing rail issues... …. Finally got around to reading this thread. I have been putting it off knowing full well I’d get immersed in it, distracted from everything else vying for my time... I was right! VERY cool Bawb Dawg! Don’t let any of the naysayers or stone throwers get to you. Looks like you crossed some of the biggest hurdles of retrofitting a multi valve head to an L-series block, bore spacing being one. Coolant flow and cam drive can be difficult, but doable, oil feed should be as simple as an external feed from the block feeding a galley/s in the head! Found a couple pics, VERY nice looking heads… Regarding the cam drive, I totally see where one would want to keep the tension side of the chain as straight as possible, plenty of reasons why it should be. As 1 fast z mentioned, the forces are crazy on the tension side. In looking at Mercedes approach to altering the path of the timing chain on the tension side, they utilized a nice curved slide which absorbs the thrust loads over a large area. If the OE Mercedes chain slides can be made to fit, it seems like the preferred method of altering the chain path on the tension side as it is proven in hundreds of thousands of street miles. Even if it consumable, a part that needs regular replacement, it seems worth it in the long run. As an alternative, using a stationary idler gear, (in roller bearings or oil pressure fed plain bearing), seems like it would have less over all friction, though in using an idler gear in that capacity, if it is able to take the loads imposed on the tension side, wouldn’t the chain run much hotter and wear faster being in tension as it traverses the tighter radius of the roller vs the slide? It would be interesting to know what modifications the big racing teams perform to the M104 cam drive if any?... Found these shots of the Mercedes chain slides; Quote Link to comment Share on other sites More sharing options...
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