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| Head questions https://slantsix.org/forum/viewtopic.php?t=28903 |
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| Author: | Charrlie_S [ Sat May 17, 2008 3:35 pm ] |
| Post subject: | |
Quote: Somebody please correct me if I'm wrong (I've never actually built an '81+ hydro-lifter engine) but I believe the mechanical-lifter pushrods, rockers, and rocker shaft can be installed in conjunction with a cylinder head originally equipped for hydraulic lifters. Oil volume to the top end would probably want restricting (the oil to the top must be increased in volume when going the other direction and installing hydro lifters in a solid-lifter engine, for the lifters are fed from the top, through the rocker shaft, rocker arms, and pushrods.)
Yes, the complete mechanical valve train can be installed on the hydro head/engine. It is not necessay to restrict the oil to the top end. The hydro cam has a groove on the rear cam bearing journal to give increased oil flow to the top end. The mechanical cam has the "metering" holes in the rear cam journal, which limits the oil to the valve train. The rear rocker shaft hold down bolt, must be from the hydro head, however. The mechanical heads had a couple of different rear bolts, depending on the year.
Tappet clearance adjustment periodicity with solid lifters is roughly 20k miles, plus or minus as needed. Camshaft selection is indeed much wider with the solid lifters. |
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| Author: | tlrol [ Sat May 17, 2008 3:45 pm ] |
| Post subject: | To recap... |
Ok, so let me re-state this to make certain I get it: 1. IF I rob a mechanical lifter head of all its "stuff", i.e. rocker arms, rocker shaft, pushrods, etc I can then put this on the hydro head. 2. I can then use a mechanical tappet camshaft (good selection with that), associated lifters, and pushrods. I suppose I would have the added benefit of the larger holes for removing the lifters (although why I would do this after I got everything running is beyond me). 3. I can KEEP the hydro head. 4. I do NOT have to remove the head on the junkyard Dart (if this is true, thank god!). Thanks again... |
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| Author: | SlantSixDan [ Sat May 17, 2008 3:58 pm ] |
| Post subject: | |
All of this what you write is true and correct. The solid lifters can only be removed from the top with a '74 or earlier cylinder head, but you will be using new solid lifters, not used ones, so that's not an issue. New pushrods are cheap and probably wise, too, though if you're trying to minimise cost you can roll used ones down a sheet of plate glass to check for warp. Check the rockers for tightness of the lash adjusting screw; review the link I posted to the valve adjustment procedure for more info. The Erson camshaft group buy info is located here. |
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| Author: | tlrol [ Sat May 17, 2008 4:14 pm ] |
| Post subject: | Thanks Dan |
Thanks Dan--removing the rocker arm assembly is just a little bit easier than removing the head, especially in a junkyard. I wonder if there are any hidden gotcha's in doing this swap. Doesn't sound like it and it seems reasonable enough to assume that as little as possible was changed when the Slant went from mechanical lifters to hydraulic lifters. I will nab the rocker assembly this week--I will grab the pushrods since they are easy enough to grab, but I will get new ones before I put a new cam in. I think the camshaft can be removed with the engine in the truck (minus the radiator, water pump, and grill)--but I don't know for sure (I hope so). I like the idea of getting the head milled, etc and NOT having to play games to get the valve geometry right--too much room for error there. The Slant is much better on tappet clearance adjustment than my Rover's 200 TDI--that thing wants to be tweaked every 6000 miles... |
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| Author: | SlantSixDan [ Sat May 17, 2008 4:18 pm ] |
| Post subject: | |
I've fixed the Erson group buy link (Thanks, emsvitl) |
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