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Hi all, I was wondering which 928 16V cam towers were better. I have a set of 4.7 cam towers from a 1980 4.7 euro motor which have steel inserts for lifter bores, which push into the aluminum cam. Also, a 79 4.5 motor which has the same design. On the other hand, I also have a set of 1982 4.7 euro spec cam towers that do not have the steel inserts anymore, as the lifter rides directly in the aluminum bore in the cam towers.
Any thoughts on which design is better/stronger, the earlier or the later? The spacing between the lifter bores in the early heads has a lot less "meat" between the lifter bores, as compared to the later design to make room for the steel lifter inserts. Much more spacing in between the lifter bores the later cam towers since they ride directly in the bore. It seems that Porsche made improvements in the 928 design of the engine as time went on, perhaps this is one of them? My thinking is that perhaps the early cam towers were originally meant to be "rebuildable" in that the steel cam bores could be replaced. (Yet, no removable cam bearings....which is odd). As time went on, Porsche may have figured that the cam towers hardly experience any wear so they may as well not bother with steel, removable lifter bores. I guess they figured that the cam bores would take forever to wear out..
Also, the cooling and oil passages are different shaped and sizes
on the two designs (earlier versus later).
Question: Do you all think that the later design (lifter riding directly in the aluminum bore) is the superior design? If so, are there any other reasons other than the ones I mentioned? I am putting together a motor and want to use the better design, which ever one that is.
I think the main reason Porsche went from the more complicated to manufacture cam housings with sleeves to the later design having no sleeves is cost saving.
The later cam housings can if needed fairly easily be repaired by machining and installing of bronze bushings.
Åke
Thanks for the info. Good point it almost certainly is cheaper to build without removable sleeves, and also probably makes the tower a little bit lighter. I never thought about putting in bronze guides.
Since you have both 4.5 and 4.7 motors to choose from, make sure you use the cams from the 4.5L motor. I just did this same thing this year. The 4.7 obviously has slightly higher displacement, but it also has higher compression, and the cams from the 4.5 have higher lift and duration than those in the 4.7. Using the 4.7 bottom end and heads with the 4.5 cams and is and ilifters in the 4.7 cam towers is a great combination. Because I used the 4.5 cams I also used those cam lifters and kept each lifter associated with it's original cam lobe, which I was told is the way it should be done. Also used Greg Brown's can tower gaskets when installing and they're nice and dry. I used the 928MS neoprene end cap gaskets too.
Hi all, I was wondering which 928 16V cam towers were better. I have a set of 4.7 cam towers from a 1980 4.7 euro motor which have steel inserts for lifter bores, which push into the aluminum cam. Also, a 79 4.5 motor which has the same design. On the other hand, I also have a set of 1982 4.7 euro spec cam towers that do not have the steel inserts anymore, as the lifter rides directly in the aluminum bore in the cam towers.
Any thoughts on which design is better/stronger, the earlier or the later? The spacing between the lifter bores in the early heads has a lot less "meat" between the lifter bores, as compared to the later design to make room for the steel lifter inserts. Much more spacing in between the lifter bores the later cam towers since they ride directly in the bore. It seems that Porsche made improvements in the 928 design of the engine as time went on, perhaps this is one of them? My thinking is that perhaps the early cam towers were originally meant to be "rebuildable" in that the steel cam bores could be replaced. (Yet, no removable cam bearings....which is odd). As time went on, Porsche may have figured that the cam towers hardly experience any wear so they may as well not bother with steel, removable lifter bores. I guess they figured that the cam bores would take forever to wear out..
Also, the cooling and oil passages are different shaped and sizes
on the two designs (earlier versus later).
Question: Do you all think that the later design (lifter riding directly in the aluminum bore) is the superior design? If so, are there any other reasons other than the ones I mentioned? I am putting together a motor and want to use the better design, which ever one that is.
Thanks a lot.
Use the ones with the threaded holes to seal the access to the hardware, instead of the early rubber plugs.
(It appears that the early cam carriers in your picture have been bead blasted. You will never get all the beads out and they are essentially junk, if this is the case.)
Other than the above, pick one or the other and install them....you will never know which one is on the engine.
If you pick the ones without the steel lifter pieces, you can use my cam carrier gaskets, without needing to modify them.
Trust me, you'll be much happier, if you use my gaskets, instead of the stock gaskets.
Use the ones with the threaded holes to seal the access to the hardware, instead of the early rubber plugs.
(It appears that the early cam carriers in your picture have been bead blasted. You will never get all the beads out and they are essentially junk, if this is the case.)
Other than the above, pick one or the other and install them....you will never know which one is on the engine.
If you pick the ones without the steel lifter pieces, you can use my cam carrier gaskets, without needing to modify them.
Trust me, you'll be much happier, if you use my gaskets, instead of the stock gaskets.
If only Porsche didn't spec graphite on the ends of the gasket
Thanks for the info and pictures. Yeah, I agree, you should keep the proper lifters with the cam lobes, it's just a good practice. However, I have noticed that the lifters in these 928 motors seem to show very little wear on four different 928 motors I have disassembled, cams, too. All lifters came out easily, flat on the bottoms, no mushrooming on the bottoms. Even so, I would still mark the lifters.
Dude, our motor looks fantastic! Did you use powder coat or high temp paint on your intake and cam towers, gears? I have those same exhaust manifolds. They are getting expensive!
I have two sets of the stock iron exhaust manifolds of 80 and 84 4.7 euro S motors lying around, but I understand that the exhaust manifolds are the same as on a regular 4.7..so it's like who wants them? Can't hardly sell them. Hate to give them to the junk man.
Crap, I soda blasted them!. You don't think it will come out if I soak them in water and blow them out with compressed air?
If the are crap, I guess I could use another set I have on a 1979 4.5 euro motor. I think they are the same part number as the 80 4.7 euro S cam towers you see in the picture in my post.
As for the newer design 82 cam towers, I decided last night to just put them back together with the 187/188 euro cams and lifters that were in them, and sell them on ebay, unless someone on the list wants them. Glad I didn't blast and paint the towers off the 82 euro, I was getting ready to do it!
Thanks for the info and pictures. Yeah, I agree, you should keep the proper lifters with the cam lobes, it's just a good practice. However, I have noticed that the lifters in these 928 motors seem to show very little wear on four different 928 motors I have disassembled, cams, too. All lifters came out easily, flat on the bottoms, no mushrooming on the bottoms. Even so, I would still mark the lifters.
Dude, our motor looks fantastic! Did you use powder coat or high temp paint on your intake and cam towers, gears? I have those same exhaust manifolds. They are getting expensive!
I have two sets of the stock iron exhaust manifolds of 80 and 84 4.7 euro S motors lying around, but I understand that the exhaust manifolds are the same as on a regular 4.7..so it's like who wants them? Can't hardly sell them. Hate to give them to the junk man.
Fresh, thanks a lot. Everything except the timing gears is powdercoated and the headers are a high-temp cerakote. The on the timing belt gears, I masked off the belt running surface to prevent any issues with belt wear with the paint or irregularity that the finish might cause. To use those SS round tube headers on an older motor, you need a gap filler piece which I got from Dave at Motorsports in UT.
Parts back from the powdercoater. Exhaust gap piece on left side in photo
Made sure critical ones were really clean before installation
Cam gear with result of belt path masked off from paint
Crap, I soda blasted them!. You don't think it will come out if I soak them in water and blow them out with compressed air?
If the are crap, I guess I could use another set I have on a 1979 4.5 euro motor. I think they are the same part number as the 80 4.7 euro S cam towers you see in the picture in my post.
As for the newer design 82 cam towers, I decided last night to just put them back together with the 187/188 euro cams and lifters that were in them, and sell them on ebay, unless someone on the list wants them. Glad I didn't blast and paint the towers off the 82 euro, I was getting ready to do it!
Greg is the expert here, but if the soda is soluble in water I would think you could get them clean and usable. The outsides of my cam towers and spider intake body were blasted with the openings being masked off in order to prep them for the powdercoat. When I got them back, I put them though a cycle in my ultrasonic parts washer to agitate loose any media that might have snuck in there, then ran them through a pots & pans cycle in the dishwasher without any soap or a drying cycle just to make sure they were super clean.
Thank you. It looks to me like the oil veins going to the cam bearings and the 8 lifters are pretty straight and uncomplicated, unless there is some other twisty oil vein that I am not seeing. If I am correct, couldn't I just blow them clean and salvage the cam towers? Thanks.
Thanks. It is now. Didn't used to be, but while I had the motor out, tried to do everything the right way so I didn't have.to park over a drip tray anymore.
My car is actually a convertible, so kind of unique with the engine mods, Corvette 6-speed transmission, 997 seats, etc.
Your car is beautiful, well done! I wish mine looked half as good. I'll bet it's nice having the corvette gearbox. Thanks for sharing more pics of your car. Have a great holiday!
12-16-2019, 03:08 PM
Which Are Better 16V cam Towers?
