When pros have been in the business long enough, they’re certain to encounter some common—and uncommon—customer mistakes regarding gaskets and seals. For example, Nickolaus DiBlasi, from Irvine, California-based JE Pistons/JE ProSeal Gaskets, has seen racers use a gasket too thick to compensate for compression ratios. “When gaskets get too thick, they provide the weakest link in the cylinder to head surface,” he said. “Use the correct gasket thickness and piston combination.”
At Mundelein, Illinois-based Flatout Gaskets, builders constantly ask whether or not to retorque any of the head gasket technologies. “We always tell them that if you can do it and have the time, do it,” explained Mark Adelizzi. “Between the gasket material, fastener yield, and engine flanges on the late model engines being so lightweight, there is always some relaxation and torque loss.”
He also discussed the practice of spraying sealers on copper head gaskets. “Use a copper head gasket with the silicone coating applied to it from the factory,” said Adelizzi. “There is no coating technique that can replicate a coating applied to a copper head gasket at a factory that provides the correct copper surface finish, pre-applied primer and proper silicone curing method before the gasket is shipped.”
“Slathering on all types of sealants destroys gaskets, dissolves special coatings, and is bad,” said Bill McKnight from Victor Reinz Gaskets, MAHLE Clevite, Farmington Hills, Michigan. “If a Victor Reinz gasket requires a sealant, it is included with the gasket or the set.”
Steve Henry, from Iowa Falls, Iowa-based Metal Tech Industries, also noted that applying incorrect coatings and sealants is a common mistake. “Most gasket materials are designed to work without additional sealants applied. Sometimes incorrect application of these products tends to weaken or lubricate the gasket to failure.”
Along the same lines, Micky Hale, from Concord Township, Ohio-based Cometic Gasket, explained the mistake of applying additional sealants to its MLS gaskets that already have a Viton rubber coating on them. “The additional sealants added can often lead to improper clamp loads being applied to the gasket, and a handful of other problems. Basically, additional sealants added to an MLS gasket can actually hinder how well it works,” he said. “Make sure your head and block surfaces are smooth within a 50RA surface finish, flat, and free of any debris or fluids. Install the gaskets dry, and follow the manufacturer’s torque procedures. If using aftermarket hardware, please consult them for proper torque specs. Do not reuse torque to yield (TTY) hardware.”
Ryan Hunter from SCE Gaskets, with plants in Valencia, California, and Spencer, Iowa, noted that the improper use of RTV silicone ends up plugging the oil pump pickup, leading to engine failure. “Use an adhesive (such as Gasgacinch) to affix a gasket; let the gasket do the sealing,” he said.
A representative from Trick Flow Engineering, Trick Flow, Tallmadge, Ohio, noted the mistake of not putting thread sealer on intake rocker arm studs/bolts. “On some cylinder heads, the intake rocker stud bolt hole is drilled into the intake port because of space constraints and/or port design. If not properly sealed, an internal vacuum leak or engine oil leakage into the intake port can occur.” The solution? “Clean rocker stud bolt hole threads and rocker stud/bolts with a solvent to remove any oils; then apply a quality high-temp PTFE based thread sealer and allow it to fully cure following the manufacturer’s directions.”
McKnight shared that cleaning heads and blocks with power tools and abrasive cleaning disks causes very uneven sealing surfaces and gasket leaks. To fix this, he pointed to specially designed plastic scrapers and very careful attention to flatness of the parts.
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