How to perform a cylinder leak-down test

How to perform a cylinder leak-down test

Ray Bohacz is a journalist in the automotive field and author of CarTech’s book “How to tune and win with Demon Carburetion”. He is also a monthly contributor to Hemming’s Muscle Machines magazine. Additionally, Ray writes short articles for the agriculture industry and is featured in a series of videos as the SF (Successful Farming) Engine Man. His videos introduce brief, informative features which apply to both farm and automotive equipment. A leak-down test measures air pressure that escapes around closed valves or piston rings in diesel or gasoline engines – information particularly useful for street engines. Cylinder leaks greater than 15 – 20% are considered excessive and can result in lower power or an unstable idle. Here in fewer than 2 minutes, Ray shares valuable information on performing a cylinder leak-down test. Click here or on the video to view....
Drive Belts: How not to install them

Drive Belts: How not to install them

Ray Bohacz is a journalist in the automotive field and author of CarTech’s book “How to tune and win with Demon Carburetion”. He is also a monthly contributor to Hemming’s Muscle Machines magazine. Additionally, Ray writes short articles for the agriculture industry and is featured in a series of videos as the SF (Successful Farming) Engine Man. His videos introduce brief, informative features which apply to both farm and automotive equipment.  Topic: drive belts When drive belts are first installed, their molecule structure conforms to the belt’s direction of travel. As a result, drive belts don’t perform well when fitted in the reverse direction. Here, in fewer than 75 seconds, Ray shares valuable information on installing a drive belt that was previously used. Click here or on the video to...
Competition cylinder heads: How would you know if air-fuel movement is good or bad?

Competition cylinder heads: How would you know if air-fuel movement is good or bad?

By Ben Mozart: The race engine requires a precise mixture of air and fuel, approximately 13.0:1 by weight ratio.   But the power it makes depends upon how well the mixture is emulsified and atomized. How well it is delivered through the intake manifold runners and cylinder head ports. And it’s ability to negotiate the intake valves and to swirl in the combustion chambers, which are an extension of the ports, and to occupy the cylinders.   For most of us, arranging and controlling the movements of the gases in the cylinder head ports are beyond our imaginings. Is the air-fuel mixture moving efficiently in the intake tracts or clinging, vexingly, to its sides? If so, how could it be reintroduced into the air stream? And further downstream, how is it negotiating the short turn, the five valve-angles in the throat, and does it demonstrate swirl as it moves into the combustion chamber? Read...
Three reasons why power steering systems fail

Three reasons why power steering systems fail

By Archie Bosman, Photography by Moore Good Ink: You might be surprised to learn that one of the three principal reasons for power steering pump failures is forgetfulness. To run a hydraulic power steering pump safely during a dyno run, simply form an oiling loop. Connect the power steering reservoir to the pump’s inlet port and the pump’s outlet port back to the reservoir’s return port. Then fill the reservoir with fluid, about 1in above the return port. “With the best will in the world though,” says Ken Roper, head of KRC Power Steering, “it’s easier to remember to put oil in the engine than it is in the power steering reservoir, and the consequences of the oversight can be severe.” As most power steering pumps rotate at engine speeds, the internals of one without oil will soon turn blue and invariably weld themselves together. The same transgression is common when breaking-in a new camshaft or similar. Although break-in speeds are usually significantly lower, often around 2,500 to 3,000rpm, a dry power-steering pump may survive the torture, though it usually suffers some adverse consequences. The second reason for power steering pump failure occurs when the oil hoses have not been thoroughly cleaned in the aftermath of a previous pump wreckage. Avoid this demoralizing calamity by ensuring all related hydraulic hoses are flushed clean. If not, the new replacement pump will be soon sabotaged by shrapnel from the previous failure. The third condition that causes power steering pump failure is improper bleeding or worse, disregarding the bleeding procedure completely. In common with a dry-sump lubrication system, expelling air bubbles from...

Inspecting a Multi-disc Clutch

by Jim Mozart Photos by Moore Good Ink Commonly, multi-disc racing clutches vary from 4.25-inch to 7.25-inch. Racers often favor the smallest diameter clutches available because they believe an advantage can be found in its lighter rotating mass. Yet experience demonstrates that smallness rarely makes an appreciable difference—except in diminishing the clutch’s durability. Some clutch makers fervently believe that the slightly larger diameter clutch with thicker friction materials can withstand much more abuse than its smaller counterpart. Constant racing starts, for example, on a small unit can result in severe wear. Such doctrine is firmly held by Ram, the Columbia, S.C., long-time racing clutch maker. Monitoring the condition of the multi-plate racing clutch is an essential yet simple operation. When replacing the friction discs during servicing, renew the full pack and ensure the pads are in vertical alignment to apply the clamp load evenly down through the pack. Also, oils and grease cause slippage and damage to clutch components. Always check the oil pan and main seals.  Here is how Ram checks their 6.25-inch Assault Weapon. Read the entire story as it appeared in Late Model Racer magazine here → For further information contact: RAM Automotive Company 201 Business Park Blvd. Columbia, SC 29203 Telephone (803) 788-6034...