Pontiac V8 engine
(→The bottleneck stud) |
(→The bottleneck stud) |
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| Line 581: | Line 581: | ||
*Valve stem length | *Valve stem length | ||
*Head gasket thickness | *Head gasket thickness | ||
| − | So if any of the above changes are made, the stock Pontiac bottleneck stud/net lash set-up may no longer preload the lifter properly. Unless the studs are changed to allow for an adjustable valve train, different length push rods may be needed to set the lifter preload. For that reason it is | + | So if any of the above changes are made, the stock Pontiac bottleneck stud/net lash set-up may no longer preload the lifter properly. Unless the studs are changed to allow for an adjustable valve train, different length push rods may be needed to set the lifter preload- but changing the length of the push rod can adversely affect the [['''valve train geometry''']]. For that reason it is advisable to use straight studs to replace the bottleneck studs. A good replacement is ARP '''p/n 190-4003''' w/hex nuts, or p/n '''190-4203''' w/12-point nuts. Be aware that there can be clearance issues between the polyloc and valve cover if polylocs are used. Check the clearances carefully; you might be able to use a shorter polyloc. If possible (and the valve cover are so equipped) keep the oil drippers. The oil drippers are a separate piece from the valve covers on the RA II/IV engines. |
While it is not recommended, the bottleneck studs will sometimes work as an adjustable valve train if a stock SBC lock nut is used and the camshaft is very mild. But this does nothing for the inherently weaker design of the bottleneck stud. | While it is not recommended, the bottleneck studs will sometimes work as an adjustable valve train if a stock SBC lock nut is used and the camshaft is very mild. But this does nothing for the inherently weaker design of the bottleneck stud. | ||
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