Leon Posted July 29, 2014 Author Share Posted July 29, 2014 (edited) Hey Bill! Will do, but I'm not expecting any surprises. I did a test-fit with the Bilsteins tonight and looks like everything is kosher. I learned about the DP plates through this forum, there are a good number of guys running them. Here's the website (prices are not up to date, FYI): http://dpracing.co/ Don was great to deal with. Edited July 29, 2014 by Leon Quote Link to comment Share on other sites More sharing options...
Leon Posted September 14, 2014 Author Share Posted September 14, 2014 Finally took the time to pull the wiped cam out. Had to remove the hood, unbolt the engine mounts, remove the clutch fan, and jack the motor up high enough for the cam to clear the radiator if anyone cares for how it's done. On a related note, I got a $15 chain tensioner retention tool off of Amazon. Saves grief and anxiety about that thing popping out.Also, I believe I've confirmed my thoughts about why the cam was wiped. I'm sending it to Isky for them to check it out and give their thoughts but it seems pretty clear. During the rebuild, I sent 12 rocker arms out to Delta Cams for regrinding, as they've been recommended countless times and they're surprisingly cheap. When I got them back, something like 50% of them were not ground parallel when looking at the lash pad contact patch vs. the cam contact patch. Being in a hurry to put the motor together in an attempt to have the car ready for my wedding (and JCCS a few weeks later) I grabbed some used rockers I had lying around and prepped them using a belt sander/sand paper on a flat surface (as shown and recommended to me by a reputable source). I inspected the rocker arms after pulling them today and could tell which ones were the regrinds and which were home/shop-prepped since Delta sandblasts the rockers. The wear-pattern on the non-reground rockers was courser than the regrinds, so to say, indicating that those rockers/lobes were possibly wearing quicker. Also, it looked like another home-prepped rocker was starting to prematurely wear. All the rockers had a distinct delineation on their wear pad between open/closing ramps, something I don't remember seeing on stock rockers. However, do note that sanding the rockers leaves a different finish than grinding. It could be that the finish has just not been "polished" by the cam yet on those non-reground rockers. Based on the evidence, I think the lobe failure was caused by a hastily-done, improperly prepped rocker arm. It's a bit strange that it took out just the closing ramp of the cam lobe and matching rocker, so presumably the contact surface of the closing ramp section of that rocker was not prepped enough in that there was still an old wear-ridge present. I assume that the reason for the rocker being worn all the way to the edge is caused by a buildup of removed material from the cam/rocker essentially extending the rocker-cam contact area during rotation. Lesson learned: buy new rocker arms when swapping cams. If you're getting regrinds, either make sure that the shop can grind them spot on, or send in two-dozen and pick the 12 best from the lot. If you're doing your own prep, do a good job! Nifty tool Offending rocker arm Offending cam lobe, opening ramp Offending cam lobe, closing ramp Differences between reground and sanded rocker I will be sending the bad cam for analysis and a good core to Isky, and will hopefully be back on the road sooner than later! Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted September 14, 2014 Share Posted September 14, 2014 Wow. That hurts. A lot of talk about leaded gas and no lead. As well the oil we use, something about no zinc. Zinc is a big deal , supposedly. Dad has me using a Amsoil. Quote Link to comment Share on other sites More sharing options...
Leon Posted September 14, 2014 Author Share Posted September 14, 2014 Oil wouldn't have made a difference, it can't fix poorly prepped rocker arms! For the record, I used Brad Penn break-in oil for the initial flush and the first ~250 miles before switching to their partial synthetic 10W-30. This was recommended to me by Ron Iskenderian. The cam was already wiped by the time the 250mi oil change came around. The oil change was done in San Luis Obispo on the way to JCCS so the parts you see in the photos have something like 1000mi on them. Quote Link to comment Share on other sites More sharing options...
Swami Posted September 14, 2014 Share Posted September 14, 2014 OUCH. the offending photos look familiar. =( Curious to hear how Isky's analysis comes back. I've been planning to hit them up for a regrind next spring. Quote Link to comment Share on other sites More sharing options...
NewZed Posted September 14, 2014 Share Posted September 14, 2014 (edited) Did you confirm oil flow through the cam? I remember that was a subject of concern. For the record, could you summarize the details? Who made the cam, was it reground from stock material, or was it new, which rocker arms failed (the Delta's or your home-reworks) and how many? Probably painful to relive but the clear path to a good cam swap still needs developing. Still seems odd that it's such a problem. And what path will you take now? New rocker arms? Do they exist? Nissan new or "new" from specs. by some shop somewhere? Also wondering if Delta knows their product is failing. Regrinding rocker arms is probably a job they give to the new kid. Maybe they don't know what's happening. Edited September 14, 2014 by NewZed Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted September 14, 2014 Share Posted September 14, 2014 Oil wouldn't have made a difference, it can't fix poorly prepped rocker arms! For the record, I used Brad Penn break-in oil for the initial flush and the first ~250 miles before switching to their partial synthetic 10W-30. This was recommended to me by Ron Iskenderian. The cam was already wiped by the time the 250mi oil change came around. The oil change was done in San Luis Obispo on the way to JCCS so the parts you see in the photos have something like 1000mi on them. I know my dad used that stuff "Brad Penn". On his vw stuff wiped a lot of cams. Quote Link to comment Share on other sites More sharing options...
Leon Posted September 14, 2014 Author Share Posted September 14, 2014 Did you confirm oil flow through the cam? I remember that was a subject of concern. For the record, could you summarize the details? Who made the cam, was it reground from stock material, or was it new, which rocker arms failed (the Delta's or your home-reworks) and how many? Probably painful to relive but the clear path to a good cam swap still needs developing. Still seems odd that it's such a problem. And what path will you take now? New rocker arms? Do they exist? Nissan new or "new" from specs. by some shop somewhere? Also wondering if Delta knows their product is failing. Regrinding rocker arms is probably a job they give to the new kid. Maybe they don't know what's happening. It's not an oil flow issue, there was no discoloration indicating excessive heat buildup. Furthermore, when initially priming the new engine I peaked through the oil filler cap hole in the valve cover to watch for oil coming out of the cam lobes, thus I know that the oil at least gets up there. Upon removal of the valve cover, the valvetrain was covered in a nice film of oil. The cam is an Isky regrind on an OEM cam. The rocker arm that failed in spectacular fashion was a home-prepped one but upon closer inspection there are signs of premature wear on a few arms, both home-prepped and Delta reground. Defects like small chips on the wear surface. At this point, only one rocker really failed but I can't say how long the others would've lasted. I bought new rocker arms from Rockauto, they are Sealed Power brand. We'll see how they hold up. I have not contacted Delta about the problem. At that time, I was in a rush and was not interested in extra headaches. Things just had to get done. Quote Link to comment Share on other sites More sharing options...
NewZed Posted September 14, 2014 Share Posted September 14, 2014 Thanks Leon. I just posted a new thread on Rocker Arms in the Nissan L6 forum, just for discussion. http://forums.hybridz.org/topic/119576-rocker-arms-state-of-the-situation/?do=findComment&comment=1120321 I was just on Rockauto and they only had ITM brand rocker arms. So even if the Sealed Power work, they may not be available. Parts seem to be going NLA in general. For example, new and/or resurfaced 225mm flywheels can't be found at the usual outlets anymore. Better start hoarding. Quote Link to comment Share on other sites More sharing options...
Leon Posted September 15, 2014 Author Share Posted September 15, 2014 (edited) Better start hoarding. Way ahead of you on that one! I probably have 4-5 flywheels and a few dozen rocker arms to play with, among other junk... Edited September 15, 2014 by Leon Quote Link to comment Share on other sites More sharing options...
Leon Posted September 15, 2014 Author Share Posted September 15, 2014 On another note, I had some time to paint the TWM intake that I plan to swap in. Paint color is "Cast Aluminum" so it didn't really change the color of the part much but I wanted to do it because painted parts are easier to maintain than bare metal. I also decided to take some measurements for the sake of documentation. The Cannon roughly measures about 145mm/5.7" long while the TWM is ~106mm/4.2". That's a 1.5" difference in length, more than I expected! This is nice because it'll open up some room between the air horns and inner fender and master cylinder. I just ordered 3/8" phenolic carb mounting blocks which will extend effective manifold length to just over 4.5". Quote Link to comment Share on other sites More sharing options...
Leon Posted September 28, 2014 Author Share Posted September 28, 2014 Had a great conversation with Ron at Isky last week. Got some enlightening information out of it. Ron recommended either using new rocker arms or even reusing used rockers as long as they're in good shape, i.e. you can't feel a ridge at the ends. We discussed rocker arm prepping and regrinding, and how difficult it is to actually get them right. He absolutely did not recommend sanding them which I had done based on a recommendation from a very good source. As far as grinding goes, we discussed the difficulty of properly fixturing rockers in order to regrind them. I mentioned how surprised I was at the cost of Delta's regrinds and Ron said that he would expect it to be at least $6-7 worth of work to properly regrind a used rocker. It's been proven, in my mind, that Delta does not fixture the rockers precisely. I'll try to give Delta a call to discuss their procedures but I'm not expecting them to give me much thought because I don't think they make much money on regrinding these things. In the meantime, Ron was able to actually fix the wiped lobe but since I sent another cam core in, I had him grind that one too as a backup. Finally making some progress here! Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 28, 2014 Share Posted September 28, 2014 Same grind, or slightly different one to quantify a results change? Quote Link to comment Share on other sites More sharing options...
NewZed Posted September 29, 2014 Share Posted September 29, 2014 Here's a recent thread with the similar comments about new aftermarket versus reground versus used rocker arms, from Schneider instead of Isky. Post #25. http://www.classiczcars.com/forums/help-me/50052-cam-wear.html Quote Link to comment Share on other sites More sharing options...
Leon Posted September 29, 2014 Author Share Posted September 29, 2014 Same grind, or slightly different one to quantify a results change? Same grind, didn't think to try a different cam. That would've been a good idea... Here's a recent thread with the similar comments about new aftermarket versus reground versus used rocker arms, from Schneider instead of Isky. Post #25. http://www.classiczcars.com/forums/help-me/50052-cam-wear.html Good find, thanks NZ. Quote Link to comment Share on other sites More sharing options...
Leon Posted October 6, 2014 Author Share Posted October 6, 2014 I actually had some time to work on the Z today! Got the fresh cam installed and timed. When initially putting the motor together, I had installed the distributor 180* out even though I had thought I did everything right. Rookie mistake. Since the cam was out, I decided to fix that by installing the new cam 180* from where it was to get everything all lined up again. Pulled the old ZX distributor out as well so I could put the reman unit in. I also pulled the intake off in preparation for swapping in the TWM. I plan to port-match it to the carbs before tossing it on so that's the next step there. Still need to install the new rockers, check wipe, and finish the fuel system before the engine comes back to life! It's been about a year since I last drove this thing... Quote Link to comment Share on other sites More sharing options...
Leon Posted December 14, 2014 Author Share Posted December 14, 2014 Finally some more progress! I helped a buddy do the first startup and break-in of his L30 last weekend and it seems to have reinvigorated the thirst of hearing my L28 purr again. I port-matched the TWM manifold on the carb side Friday after work and ground the areas where the intake flange interfered with the MSA 6-1 header flange yesterday. I touched up the affected areas with some new paint. Today, I got the carbies all mounted up along with the heat shield. The last bit left is to finalize how I want to do the linkage and then finally reinstall! Quote Link to comment Share on other sites More sharing options...
bradyzq Posted December 17, 2014 Share Posted December 17, 2014 Looks great! You don't specifically mention it, but since I think I see some sanding marks on the port side of the TWM intake, I'll assume you matched the runners to the ports too. MANY moons ago, like 20 years ago, I had my TWM intake matched to the intake ports. Surprisingly, the runners didn't line up perfectly with the ports. It was as if the bolt holes were evenly off a bit. Did yours line up well? Quote Link to comment Share on other sites More sharing options...
Leon Posted December 18, 2014 Author Share Posted December 18, 2014 Looks great! You don't specifically mention it, but since I think I see some sanding marks on the port side of the TWM intake, I'll assume you matched the runners to the ports too. MANY moons ago, like 20 years ago, I had my TWM intake matched to the intake ports. Surprisingly, the runners didn't line up perfectly with the ports. It was as if the bolt holes were evenly off a bit. Did yours line up well? Thanks Brady! I didn't want to do the ports as not to mess up the taper in the intake. I did check to make sure that the runners match the ports via using the gasket as a template. All seems good! Quote Link to comment Share on other sites More sharing options...
bens1088 Posted December 19, 2014 Share Posted December 19, 2014 Leon, email me when you're ready for lighting. Have something you might be interested in. Ben@dapperlighting.com Quote Link to comment Share on other sites More sharing options...
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