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Engine Oil Systems - Oil Filter Block Adapters

Big/Small Block Chevy Gen 4 Thermostatically Controlled Engine Block Adapter
Your Price:
$299.99

Big/Small Block Chevy Gen 4 Thermostatically Controlled Engine Block Adapter

625-7703

Big/Small Block Chevy Gen 4 Thermostatically Controlled Engine Block Adapter

Thermostatically Controlled Engine Block Adapter Gen 4 BBC / SBC

Maintaining proper engine oil temperature has become critical to the success or failure of today’s performance marine engines. Prolonged use of marine engines in conditions where oil cannot reach its optimum working temperatures will result in sludge formation and crankcase dilution which leads to excessive wear especially in the cylinder bores and bearing surfaces. A thermostat assembly combats this by permitting 90% of the engines oil to bypass the cooler during warm up. The balance of the oil flow is allowed to fl ow through the cooler maintaining constant pressure and preventing air pockets while eliminating cold oil shock. This reduces scuffing and premature wear and inhibits engine blow-by. As engine oil temperature reaches its optimum operating temperature moisture and impurities that often cause a milky condition are eliminated.

Until now oil temp was controlled either by some guess of components or by the professional engine builders through the use of some sort of external engine oil thermostat. While these external oil filter/ thermostats were very effective they were also very large and very bulk . Making them hard to mount and creating a maze of plumbing. The problem was the only available parts up until now couldn’t move the necessary oil fl ow to be mounted anywhere. else. But thanks to Hardin marine and their engineering staff they took to solving this decade long nuisance. Hardin Marine has developed this new thermostatically controlled engine block mounted product. With this unit all oil temperature is now controlled through a integral 212 degree oil thermostat. The large 3/4NPT oil inlets/outlets assure the maximum amount of oil can be fl owed through the unit. So no more maze of external plumbing, no more big bulky external mounted components just the standard (2) lines to the filter and the standard (2) lines to your cooler. Sometimes evolution comes in the form of the simplest of things but this is one that has been deeply sought after. Overall Height: 4-3/4"

O-Ring Kit for 625-7914 Oil Adapter
Your Price:
$7.99

O-Ring Kit for 625-7916 Oil Adapter

625-7912

  • Designed to fit 625-7916 Gen. 5/6 Oil Adapter.
  • Kit Includes 3 O-Rings.
  • Note: Picture is example of O-Rings, not actual product.

O-Ring, Oil Filter Adapter
Your Price:
$2.50


Replacement Fitting For Hardin Thermostatic Oil Adapters
Your Price:
$34.99

Replacement Fitting For Hardin Thermostatic Oil Adapters

625-7763

Replacement inlet fitting for Hardin thermostatic oil adapters, 625-7703, 625-7704.

Xtreme High Flow 3/4" NPT Side Inlet Oil Block Adapter - Side Inlet Gen 4 BBC & SBC
Your Price:
$129.99

Xtreme High Flow 3/4" NPT Side Inlet Oil Block Adapter - Side Inlet Gen 4 BBC & SBC

625-7914

Xtreme High Flow 3/4" NPT Side Inlet Oil Block Adapter - Side Inlet Gen 4 BBC & SBC

This Hardin Marine Designed engine oil adapter is the preferred choice of  respected engine builders worldwide. Manufactured from 6061-T6 billet aluminum, these adapters provide large 3/4" NPT horizontal side inlets and outlets while providing easy access for leak-proof operation. The black hard anodized finish is attractive while providing corrosion protection.

Side Entry Billet Remote Cooler Sandwich Adapter - Generation 4 BBC
Your Price:
$135.99

Side Entry Billet Remote Cooler Sandwich Adapter - Generation 4 BBC

240-22-542

Side Entry Billet Remote Cooler Sandwich Adapter - Generation 4 Big Block Chevy

These unique adapters are used when a filter is desired to be used in a block mounted fashion.  This unit lowers the original filter location by 1-1/2" while providing 1/2" NPT inlets and outlets.  The factory oil bypass is eliminated in this situation.

When a marine engine is installed in the bilge of a boat there is little or no access to the bottom of the engine therefore a remote mounted oil filter is required.  An oil filter block off adapter must be bolted on the original oil filter location to accomplish this.  These block off adapters are constructed of 6061-T6 billet aluminum and then beautifully anodized for superior corrosion resistance in harsh environments.  They are completely O-ringed on the sealing surfaces to eliminate oil leaks, copper sealing washers are NOT used under the mounting bolt heads.


Stainless Steel Oil Filter Bypass Eliminator
Your Price:
$59.99

Stainless Steel Oil Filter Bypass Eliminator - BBC Gen 4 and SBC

625-7918

Stainless Steel Oil Filter Bypass Eliminator - BBC Gen 4 and SBC

This strong stainless steel mount does not have a bypass so it eliminates the possibility of unfiltered oil entering the engine while replacing the weak and often failed factory unit.

When a marine engine is installed in the bilge of a boat there is little or no access to the bottom of the engine therefore a remote mounted oil filter is required.  An oil filter block off adapter must be bolted on the original oil filter location to accomplish this.  These block off adapters are constructed of stainless steel.  They are completely O-ringed on the sealing surfaces to eliminate oil leaks, copper sealing washers are NOT used under the mounting bolt heads.


Bottom Entry Billet Engine Oil Block Adapter - SBC & BBC
Your Price:
$89.99

Bottom Entry Billet Engine Oil Block Adapter - SBC & Gen 4 BBC

240-22-580

Bottom Entry Billet Engine Oil Block Adapter - Small Block & Gen 4 Big Block Chevy includes Merlin Blocks

These machined billet aluminum bypass plates are needed when using a remote oil filter. O-rings are captured in the plate for a tight seal against the block surface, and are installed under bolt heads for leak-free performance. Drilled and tapped to accept 1/2" NPT fittings. Includes all mounting hardware.

When a marine engine is installed in the bilge of a boat there is little or no access to the bottom of the engine therefore a remote mounted oil filter is required. An oil filter block off adapter must be bolted on the original oil filter location to accomplish this. These block off adapters are constructed of 6061-T6 billet aluminum and then beautifully anodized for superior corrosion resistance in harsh environments. They are completely O-ringed on the sealing surfaces to eliminate oil leaks, copper sealing washers are NOT used under the mounting bolt heads.


Big Block Chevy Gen 5 & 6 Thermostatically Controlled Engine Block Adapter
Your Price:
$279.99

Big Block Chevy Gen 5 & 6 Thermostatically Controlled Engine Block Adapter

625-7704

Big Block Chevy Gen 5 & 6 Thermostatically Controlled Engine Block Adapter

Thermostatically Controlled Engine Block Adapter Gen 5/6 BBC

Maintaining proper engine oil temperature has become critical to the success or failure of today’s performance marine engines. Prolonged use of marine engines in conditions where oil cannot reach its optimum working temperatures will result in sludge formation and crankcase dilution which leads to excessive wear especially in the cylinder bores and bearing surfaces. A thermostat assembly combats this by permitting 90% of the engines oil to bypass the cooler during warm up. The balance of the oil flow is allowed to fl ow through the cooler maintaining constant pressure and preventing air pockets while eliminating cold oil shock. This reduces scuffing and premature wear and inhibits engine blow-by. As engine oil temperature reaches its optimum operating temperature moisture and impurities that often cause a milky condition are eliminated.

Until now oil temp was controlled either by some guess of components or by the professional engine builders through the use of some sort of external engine oil thermostat. While these external oil filter/ thermostats were very effective they were also very large and very bulk . Making them hard to mount and creating a maze of plumbing. The problem was the only available parts up until now couldn’t move the necessary oil fl ow to be mounted anywhere. else. But thanks to Hardin marine and their engineering staff they took to solving this decade long nuisance. Hardin Marine has developed this new thermostatically controlled engine block mounted product. With this unit all oil temperature is now controlled through a integral 212 degree oil thermostat. The large 3/4NPT oil inlets/outlets assure the maximum amount of oil can be fl owed through the unit. So no more maze of external plumbing, no more big bulky external mounted components just the standard (2) lines to the filter and the standard (2) lines to your cooler. Sometimes evolution comes in the form of the simplest of things but this is one that has been deeply sought after. Overall Height: 4-3/4"



Xtreme High Flow 3/4" NPT Side Inlet Oil Block Adapter - Side Inlet Gen 6 BBC
Your Price:
$139.99

Xtreme High Flow 3/4" NPT Side Inlet Oil Block Adapter - Gen 5/6 BBC

625-7916

Xtreme High Flow 3/4" NPT Side Inlet Oil Block Adapter - Gen 5/6 BBC

​This Hardin Marine designed engine oil adapter is the preferred choice of the most respected engine builders worldwide. Manufactured from 6061-T6 billet aluminum, these adapters provide large 3/4" NPT horizontal side inlets and outlets while providing easy access for leak-proof operation. The black hard anodized finish is attractive while providing corrosion protection.


Bottom Entry Billet Engine Oil Block Adapter - Generation 5 Chevy
Your Price:
$89.99

Bottom Entry Billet Engine Oil Block Adapter - Generation 5 / 6 Big Block Chevy

240-22-584

Bottom Entry Billet Engine Oil Block Adapter - Generation 5/6 Big Block Chevy

These machined billet aluminum bypass plates are needed when using a remote oil filter. O-rings are captured in the plate for a tight seal against the block surface, and are installed under bolt heads for leak-free performance. Drilled and tapped to accept 1/2" NPT fittings. Includes all mounting hardware.

When a marine engine is installed in the bilge of a boat there is little or no access to the bottom of the engine therefore a remote mounted oil filter is required. An oil filter block off adapter must be bolted on the original oil filter location to accomplish this. These block off adapters are constructed of 6061-T6 billet aluminum and then beautifully anodized for superior corrosion resistance in harsh environments. They are completely O-ringed on the sealing surfaces to eliminate oil leaks, copper sealing washers are NOT used under the mounting bolt heads.


GM LS Series Remote Oil Filter Adapter
Your Price:
$128.99

GM LS Series Remote Oil Filter Adapter

740-23688

GM LS Series Remote Oil Filter Adapter

  • Replaces Moroso Spin-On oil filter adapter on Moroso #'s 20142, 20143 & 20151 oil pans, comes standard on Moroso # 20146 oil pan.
  • Ideal when chasis restrictions don't allow the use of block mounted filter or when a larger external filter is desires.
  • Billet aluminum construction
  • -10 AN "In" and "Out" ports
  • Includes mounting hardware and engine block sealing O-Rings

GM LS Series Remote Oil Filter Adapter
Your Price:
$93.99

GM LS Series Remote Oil Filter Adapter - 90 Degree

240-22-632

GM LS Series Remote Oil Filter Adapter - 90 Degree

This billet aluminum adapter is designed to install under the pan rail of  LS1 pans and provide inlet and outlet ports for installing lines to a remote oil filter. Adapter features o-ring seals between the pan and the adapter and 1-1/16" -12 AN oil inlet and outlet ports.

  • 1/2 NPT Inlet and Outlet 
  • Ports are set at 90 Degrees
  • Lightweight Billet Design

GM LS Series Remote Side Mount Thermostat Oil Filter Adapter
Your Price:
$269.95

GM LS Series Remote Side Mount Thermostat Oil Filter Adapter

625-4526

GM LS Series Remote Side Mount Oil Filter Adapter

Earl's billet side mount oil cooler adapters are the slick way to add an oil cooler to your GM LS or Gen-V LT engine. The slim design of these adapters clear most headers and other components and feature -10 AN male connections. These adapters are black anodized and use O-Ring seals for a leak free installation. Fits OEM & Holley Wet Sump oil pans only (Does not Fit Dry Sump Engines).

  • Billet Aluminum w/ Black Anodized Finish
  • Includes 0-Ring Seal & Hardware
  • (2) 1/8” NPT Accessory Ports
  • -10 AN Male Connections
  • Available w/ 180 Degree Thermostat
  • Add an Earl’s Oil Cooler and AN Plumbing to Complete the Installation

Bottom Entry Billet Engine Oil Block Adapter - 460 Ford
Your Price:
$123.99

Bottom Entry Billet Engine Oil Block Adapter - 460 Ford

240-22-460

Bottom Entry Billet Engine Oil Block Adapter - 460 Ford

These machined billet aluminum bypass plates are needed when using a remote oil filter. O-rings are captured in the plate for a tight seal against the block surface, and are installed under bolt heads for leak-free performance. Drilled and tapped to accept 1/2" NPT fittings. Includes all mounting hardware.

When a marine engine is installed in the bilge of a boat there is little or no access to the bottom of the engine therefore a remote mounted oil filter is required. An oil filter block off adapter must be bolted on the original oil filter location to accomplish this. These block off adapters are constructed of 6061-T6 billet aluminum and then beautifully anodized for superior corrosion resistance in harsh environments. They are completely O-ringed on the sealing surfaces to eliminate oil leaks, copper sealing washers are NOT used under the mounting bolt heads.


Ford and Chrysler Spin-on Bypass
Your Price:
$65.95

Ford and Chrysler Spin-on Bypass

550-1178

Ford and Chrysler Spin-on Bypass

These units are designed to spin-on in place of the factory oil filter so that a remote filter or cooler can easily be plumbed.


Replacement Oil Adapter Inlet For Hardin Thermostatic Oil Adapters
Your Price:
$54.99

Replacement Oil Adapter Inlet For Hardin Thermostatic Oil Adapters

625-7766

Replacement inlet fitting for Hardin thermostatic oil adapters 625-7703 and 625-7704.

O-Ring Kit for 625-7914 Oil Adapter
Your Price:
$8.95

O-Ring Kit for 625-7914 Oil Adapter

625-7911

  • Designed to fit 625-7914 Gen. 4 Oil Adapter.
  • Kit Includes 6 O-Rings.
  • Note: Picture is example of O-Rings, not actual product.

Service Kit for Hardin Thermostatic Oil Adapters
Your Price:
$17.99

Service Kit for Hardin Thermostatic Oil Adapters

625-7706

This handy kit contains all the o-rings to rebuild Hardin Thermostatic oil adapters 625-7703 and 625-7704 .

Washer, Crush Oil Adapter, Gen 2
Your Price:
$2.89

Washer, Crush Oil Adapter, Gen 2

625-7768

Washer, Crush Oil Adapter, Gen 2

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