with most Kent's drained for the winter or on their way out of the car for service, it seems like a good time to discuss a subject that's not discussed nearly enough: block preparation . Engine preparation techniques and hardware that were considered state-of-the art thirty years ago are almost certainly do for a rethink and likely replacement. time, technology, and the rules stand still for no one including justifiably proud owners of Ford Kent engines.
there are a host of reasons to have absolutely round cylinders at operating temperature and they're all spelled H_O_R_S_E_P_O_W_E_R!!! therefore anyone interested in serious horsepower should have their block align honed, bored, honed, and finished at 180F (ie: HOT ). further it's critical to employ freeze plug cooling through the side of the block to maximize the probability that all four cylinders are at the same temperature (ie: round). there's NO hope pushing cold water in the front of the block and flowing it aft........ with very few exceptions, rings sold today are intended for "sorta round" cylinders and therefore have large amounts of ring tension measured however you choose to measure it. see "Cylinder Bore Refinishing" by Larry Carley in the May 2004 issue of Engine Builder being sure to recognize the bulk of the data that supported the 2004 article was almost surely based on 30wt street oil and tageted at the rebuild of engines for the street!! ring tension is drag and drag is horsepower going up in heat! absolutely round cylinders require very little ring tension compared to "sorta round" cylinders to achieve the same or better levels of sealing! competitors should have an explicit conversation with your engine builder about the pro's and con's of piston-to-bore clearance AND the finish required for the bores. required bore finish is a complex relationship between bore material, ring material, oil, oil operating temperature, and maximum expected rpm. whatever you and your engine builder decide on for finish, the top two rings need to be back-cut and the oil control ring adjusted for ultra-low ring tension. anyone using rings straight from any box will have a very difficult time keeping up on the straights!!! in addition to the lower ring tension benefits of four cylinders at the temperature, there's also ignition benefits. unfortunately, most FFord competitors today are running ignition timing for their HOT cylinder and the other three aren't close to what's needed to make power............................ given FFord water pumps have been "unrestricted" since the creation of the class, I recommend a Stewart electric water pump for the implementation of your freeze plug cooling installation. as long as the input voltage is kept above 12Vdc, the Stewart will supply significantly more water continuously (ie: without regard to engine speed) greatly improving heat transfer (turbulent
flow), overcome plumbing and heat exchanger installations with excessive back pressure, AND provide a simple means to improve reliability through the elimination of heat soak post ignition turn-off. hopefully a quick consultation with the calculator will help avoid another senseless visit from chicken little! according to Stewart, their water pump draws 10 amps at 12Vdc; recalling 746 watts is equivalent to 1 hp means the electric water pump costs (12Vdc x 10A)/746 = 0.161 hp. most competitors who have attempted to measure the cost of a crank driven Ford water (stock or prepared) report numbers on the order of 0.1 hp. therefore for the cost of 120 watts (12Vdc x 10A), competitors using electric water pumps net ~0.1hp at the flywheel, significantly improved heat transfer, greatly improved capability (ie: turbo-axial pump versus impeller pump) to deal with high back pressure plumbing/heat exchangers, and a simple means to improve reliability. since compliant $4,000-$10,000 sets of shock absorbers clearly offer more performance improvement, it's obvious that electric water pumps fall well below any rational, objective, or balanced need for a change to the Formula's rules that have been in place for the last fifty year! there's one other challenge to freeze plug cooling and it's what to choose for the plumbing connections to the side of the block. I recommend incorporation of provisions for -24 ORB ports or a close approximation of one. extreme care should be exercised if your block's casting requires spot facing to enable installation of -24 ORB fittings; about half of the blocks I've done have required spot facing. -24 ORB to -20 fittings are readily available from XRP. I recommend making your own -24 ORB to -16 fittings from off-the-shelf donors being sure to use Viton o-rings for additional operating temperature margin over buna-N. -16 tube/hose is more than adequate for the flow, weighs less (less water), and have a smaller bend radius for improved packaging options in the tight confines typical of FFord engine bays. when it comes to choosing between slip fit, 37° AN flare fittings, and Wiggins/clamshell fittings, I recommend the Wiggins/clamshell approach. the sealing reliability (peace of mind) that comes with two o-rings and the angular & axial compliance built into the fitting's geometry for ease of mating and mechanical isolation are the deciding features in my mind.
getting a block ready to ship to the engine builder's represents a significant amount of TLC. it all contributes materially to the bottom line on the dyno but certainly not anything I'm ready to pay $75-$100/hr to have done at the engine builder's! without
the investment in sweat equity at this level, options further along are either compromised or precluded....................... assuming you'll be making the recommended lubrication sub-system changes and will be using a previously used block, here's what your "to do" list looks like (some of us just do better with lists):
1.) after stripping and thoroughly cleaning your block, aggressively check for cracks in all the main webs, the rear mounting flanges, and around all tapped holes.
2.) confirm there's adequate deck height to skim the deck of the block parallel to the mains.
3.) based on a conversation with your engine builder regarding piston to bore clearance for +0.005" forged pistons, determine if sleeves will be required and procure nodular cast iron sleeves as required (LA Sleeve).
4.) acid wash the inside of the water jacket to remove all deposits, scale, and rust. the objective is clean heat transfer surfaces and not weight reduction!!
5.) polish all of the surfaces in the crankcase as required to facilitate rapid and complete oil recovery.
4.) bottom chase or through chase all tapped holes in the block.
6.) pipe tap both of the cylinder head return drain holes above the installed camshaft location.
7.) on the lower surface of the block, drill & NPT tap the dipstick hole and the two holes under the stock oil pump location.
8.) remove the plug or ball plug from the rear of the aft cylinder head drain galley and tap for 3/8"-NPT in a manner that enables
installation of a stainless steel 90° 3/8"-NPT to male AN-6 pointed in the correct direction at minimum height for the mating tube's b-nut.
9.) remove the plug from the rear of the main oil supply galley and tap for 3/8"-NPT in a manner that enables installation of a stainless steel 90° 3/8"-NPT to male AN-6 pointed in the correct direction at minimum height for the mating tube's b-nut. (NOTE: the 3/8"-NPT end of the fitting will need to be shortened so as not to block the oil supply galley to the rear main)
10.) on driver's right side of block, drill and tap the cross block oil galley for a 1/4"-NPT for installation of a stainless steel straight 1/4"-NPT to male AN-6 fitting at minimum installed height. (NOTE: the fitting will have to be shortened so as not to obstruct
the oil galley. stainless steel fittings for fatigue strength; the last thing a Kent competitor needs is a fatigue failure of an aluminum fitting in an oil supply line. hoses and tubes full of oil are heavy and impart significant dynamic loads)
11.) machine and tap both freeze plugs on driver's left for -24 ORB ports.
12.) drill and tap four holes 10-24UNC around the rear freeze plug to secure the installed freeze plug.
13.) procure and drill for safety wire stainless steel socket head cap screws for all of the engine's fastening requirements (except main studs and head studs).
14.) procure ARP main studs, washers, and nuts (longer studs required for triple scrapers)
15.) procure ARP head studs, washers, and nuts
16.) if you plan to powder coat the block, it's my recommendation to do it at this point prior to shipping the block to your engine builder for machining. if in doubt, there's always Cardinal 80% Gloss Blue powder!!!
Art
artesmith@earthlink.net
there are a host of reasons to have absolutely round cylinders at operating temperature and they're all spelled H_O_R_S_E_P_O_W_E_R!!! therefore anyone interested in serious horsepower should have their block align honed, bored, honed, and finished at 180F (ie: HOT ). further it's critical to employ freeze plug cooling through the side of the block to maximize the probability that all four cylinders are at the same temperature (ie: round). there's NO hope pushing cold water in the front of the block and flowing it aft........ with very few exceptions, rings sold today are intended for "sorta round" cylinders and therefore have large amounts of ring tension measured however you choose to measure it. see "Cylinder Bore Refinishing" by Larry Carley in the May 2004 issue of Engine Builder being sure to recognize the bulk of the data that supported the 2004 article was almost surely based on 30wt street oil and tageted at the rebuild of engines for the street!! ring tension is drag and drag is horsepower going up in heat! absolutely round cylinders require very little ring tension compared to "sorta round" cylinders to achieve the same or better levels of sealing! competitors should have an explicit conversation with your engine builder about the pro's and con's of piston-to-bore clearance AND the finish required for the bores. required bore finish is a complex relationship between bore material, ring material, oil, oil operating temperature, and maximum expected rpm. whatever you and your engine builder decide on for finish, the top two rings need to be back-cut and the oil control ring adjusted for ultra-low ring tension. anyone using rings straight from any box will have a very difficult time keeping up on the straights!!! in addition to the lower ring tension benefits of four cylinders at the temperature, there's also ignition benefits. unfortunately, most FFord competitors today are running ignition timing for their HOT cylinder and the other three aren't close to what's needed to make power............................ given FFord water pumps have been "unrestricted" since the creation of the class, I recommend a Stewart electric water pump for the implementation of your freeze plug cooling installation. as long as the input voltage is kept above 12Vdc, the Stewart will supply significantly more water continuously (ie: without regard to engine speed) greatly improving heat transfer (turbulent
flow), overcome plumbing and heat exchanger installations with excessive back pressure, AND provide a simple means to improve reliability through the elimination of heat soak post ignition turn-off. hopefully a quick consultation with the calculator will help avoid another senseless visit from chicken little! according to Stewart, their water pump draws 10 amps at 12Vdc; recalling 746 watts is equivalent to 1 hp means the electric water pump costs (12Vdc x 10A)/746 = 0.161 hp. most competitors who have attempted to measure the cost of a crank driven Ford water (stock or prepared) report numbers on the order of 0.1 hp. therefore for the cost of 120 watts (12Vdc x 10A), competitors using electric water pumps net ~0.1hp at the flywheel, significantly improved heat transfer, greatly improved capability (ie: turbo-axial pump versus impeller pump) to deal with high back pressure plumbing/heat exchangers, and a simple means to improve reliability. since compliant $4,000-$10,000 sets of shock absorbers clearly offer more performance improvement, it's obvious that electric water pumps fall well below any rational, objective, or balanced need for a change to the Formula's rules that have been in place for the last fifty year! there's one other challenge to freeze plug cooling and it's what to choose for the plumbing connections to the side of the block. I recommend incorporation of provisions for -24 ORB ports or a close approximation of one. extreme care should be exercised if your block's casting requires spot facing to enable installation of -24 ORB fittings; about half of the blocks I've done have required spot facing. -24 ORB to -20 fittings are readily available from XRP. I recommend making your own -24 ORB to -16 fittings from off-the-shelf donors being sure to use Viton o-rings for additional operating temperature margin over buna-N. -16 tube/hose is more than adequate for the flow, weighs less (less water), and have a smaller bend radius for improved packaging options in the tight confines typical of FFord engine bays. when it comes to choosing between slip fit, 37° AN flare fittings, and Wiggins/clamshell fittings, I recommend the Wiggins/clamshell approach. the sealing reliability (peace of mind) that comes with two o-rings and the angular & axial compliance built into the fitting's geometry for ease of mating and mechanical isolation are the deciding features in my mind.
getting a block ready to ship to the engine builder's represents a significant amount of TLC. it all contributes materially to the bottom line on the dyno but certainly not anything I'm ready to pay $75-$100/hr to have done at the engine builder's! without
the investment in sweat equity at this level, options further along are either compromised or precluded....................... assuming you'll be making the recommended lubrication sub-system changes and will be using a previously used block, here's what your "to do" list looks like (some of us just do better with lists):
1.) after stripping and thoroughly cleaning your block, aggressively check for cracks in all the main webs, the rear mounting flanges, and around all tapped holes.
2.) confirm there's adequate deck height to skim the deck of the block parallel to the mains.
3.) based on a conversation with your engine builder regarding piston to bore clearance for +0.005" forged pistons, determine if sleeves will be required and procure nodular cast iron sleeves as required (LA Sleeve).
4.) acid wash the inside of the water jacket to remove all deposits, scale, and rust. the objective is clean heat transfer surfaces and not weight reduction!!
5.) polish all of the surfaces in the crankcase as required to facilitate rapid and complete oil recovery.
4.) bottom chase or through chase all tapped holes in the block.
6.) pipe tap both of the cylinder head return drain holes above the installed camshaft location.
7.) on the lower surface of the block, drill & NPT tap the dipstick hole and the two holes under the stock oil pump location.
8.) remove the plug or ball plug from the rear of the aft cylinder head drain galley and tap for 3/8"-NPT in a manner that enables
installation of a stainless steel 90° 3/8"-NPT to male AN-6 pointed in the correct direction at minimum height for the mating tube's b-nut.
9.) remove the plug from the rear of the main oil supply galley and tap for 3/8"-NPT in a manner that enables installation of a stainless steel 90° 3/8"-NPT to male AN-6 pointed in the correct direction at minimum height for the mating tube's b-nut. (NOTE: the 3/8"-NPT end of the fitting will need to be shortened so as not to block the oil supply galley to the rear main)
10.) on driver's right side of block, drill and tap the cross block oil galley for a 1/4"-NPT for installation of a stainless steel straight 1/4"-NPT to male AN-6 fitting at minimum installed height. (NOTE: the fitting will have to be shortened so as not to obstruct
the oil galley. stainless steel fittings for fatigue strength; the last thing a Kent competitor needs is a fatigue failure of an aluminum fitting in an oil supply line. hoses and tubes full of oil are heavy and impart significant dynamic loads)
11.) machine and tap both freeze plugs on driver's left for -24 ORB ports.
12.) drill and tap four holes 10-24UNC around the rear freeze plug to secure the installed freeze plug.
13.) procure and drill for safety wire stainless steel socket head cap screws for all of the engine's fastening requirements (except main studs and head studs).
14.) procure ARP main studs, washers, and nuts (longer studs required for triple scrapers)
15.) procure ARP head studs, washers, and nuts
16.) if you plan to powder coat the block, it's my recommendation to do it at this point prior to shipping the block to your engine builder for machining. if in doubt, there's always Cardinal 80% Gloss Blue powder!!!
Art
artesmith@earthlink.net
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