Teague On Tech: Q & A with Bob Teague

As seen in Speedboat Magazine’s August 2018 Issue.

Metal in My Oil Filter

Dear Bob:
I recently had my engines rebuilt by a so-called reputable engine builder in California. After about 10 hours of running, I decided to change the oil. After removing the oil filters, I noticed a lot of metallic material in the oil filters. It looks almost like metallic in paint. There was also evidence of the material in the oil that was drained from the pans. So, I removed the valve covers and noticed quite a bit of the material around the valve springs. I was told that the valve spring retainers were titanium.

The engines were built with hydraulic roller cams and I can’t seem to get them to run much over 5600 RPM even if I put smaller props on the boat. I have CMI headers and have tried it with and without my slip in mufflers. What do you think the metal is coming from and should I be worried? Also, I was expecting to be able to run more RPM to increase the performance of the boat compared to the previous engines.
Thank you.
Simon Ayckbourn
Long Beach, CA

I believe the metal material is coming from the underside of your titanium retainers. Titanium retainers are great for drag racing or short track racing where ultra high RPM is needed and the lighter retainer is desirable. Titanium Retainers should not be used with valve springs that have a flat damper between the inner and outer springs. The damper is
sharp and will dig into the underside of the retainer step. This problem can be even more severe if the valve spring tension is too light for the camshaft profile because the springs have a tendency to dance under higher RPM.

In mild applications where the desired top RPM is between 5800 and 6200, steel retainers will do the trick. A typical titanium retainer designed for 1.550” to 1.560” diameter springs weigh about 18 grams. The steel retainer used on a Mercury 525EFI and most typical steel retainers weigh about 34 grams. The best alternative for ultra performance marine engines is a tool steel retainer which only weighs 6 grams more than the titanium replica. The good thing about the tool steel retainers is that they are very hard and are minimally affected by the spring damper. I like to disassemble the springs and polish the end of the damper which basically eliminates the problem when used in conjunction with the tool steel retainer.

On a motor with a hydraulic camshaft with more than .600” lift when used in conjunction with good low travel roller lifters, the valve spring tension should be in the range of 165 PSI when the valve is on the seat and around 600 PSI open. The higher pressure will keep the valves seated and help prevent valve float. Being that you are seeing material from your titanium retainers and you can’t seem to get the engine RPM up into a desirable range, your valve spring tension might be too low.

Lightweight valve train components on endurance marine engines that run constant higher RPM are not as desirable as many think because of durability compromises and harmonics that are created. I have found that running a heavier wall 3/8” push rod (.120” to .135”) also has advantages for stabilizing the valve train without any performance loss.

Too Slow

Dear Bob:
I own a 2007 Sleekcraft Heritage with a MerCruiser 496 HO and XR drive. I love the reliability of the engine package but am disappointed at the slow acceleration and low top end speed. At best, this boat will do 60 to 62 MPH. With reliability being important, will a Whipple supercharger get me into the 80 plus MPH range? If so, is hydraulic steering a requirement? I always knew I would not be the fastest boat on the water, but I also do not want to be the slowest.
Matt Harding
Des Moines, IA

First of all, I am sure that your boat is not the slowest. All things considered, your boat is larger than most single engine performance boats. I think it is important to maintain your reliability. Keeping in mind the size and weight of your boat, I would keep the boost on the mild side. You will experience a significant gain in performance with the Whipple kit but I
think that exceeding 80 MPH may be a little optimistic. There will definitely be a noticeable increase in acceleration and improvement of mid-range efficiency. It is likely that you will be able to go up a couple of sizes in prop pitch, which will lower your cruise speed RPM.

As an alternative, you may want tot to consider installing CMI Sport Tube headers that will increase the power by about 70 horsepower. There is not downside to reliability going this way but it won’t be as a significant performance gain as installing the Whipple kit.

I always recommend installing full hydraulic steering on performance boats for control and safety. At a minimum, install a dual ram assist system (not single ram). Single ram systems exert more steering pressure when extending the steering ram than when retracting the ram. Dual rams provide for a balance in exerted force from the hydraulic rams. Going to a full hydraulic system with a hydraulic helm will improve the control of the boat to another level. Once you have had a boat with full hydraulic steering, it is hard to go back to driving with a cable steering setup.

Spark Plug Query

Dear Bob:
In a recent conversation with a friend, he stated that you told him to use NGK BPR6ES spark plugs in his 525EFIs. But I can’t find that plug for that application on the NGK website. According to the web site the proper plug is a BR6ES. Can you shed some light on this for me as I would like to change the plugs in my 525EFIs also? Thanks for your help!
Jay Johnson
Seattle, WA

I am not sure exactly what web site you are looking at. I am holding some NGK BPR6ES spark plugs in my hand. It is what we use on all Mercury Racing stock 525 EFI engines. It is the recommended plug (Mercury Racing Service Manual) and has an extended tip.

If we install a WhippleCharger on these motors, we switch to the NGK R5671A-8, which is a colder plug without the extended tip. Our experience on supercharged engines has shown that there are fewer tendencies for the spark plug to cause pre-ignition and detonation when the tip is more protected.

Vapor Lock

Dear Bob:
I have a Baja 272 with a MerCruiser 502EFI Magnum motor package. At the end of last year, and this year also, I have been experiencing vapor locking at low rpm. When I start the boat for the first time, the boat will idle and run fine. When I run it at speed, then stop and park somewhere, and then start up and leave for another location, as I am idling out of a cove it stutters and then dies. If I pour cold water over the steel fuel line and wait a couple of seconds, it will start and run fine until I go to another location and stop the engine. Then, I have to go through the whole procedure again, or the engine will die the same as before. I am not sure what is causing this problem or what to do to resolve it. I need help because no one around here seems to know what to do. Can you provide some insight and help with my problem?
John Christensen
Des Moines, Iowa

Your problem is definitely related to a vapor lock condition. There are several reasons that it could be occurring now compared to a couple of years ago. One of the major factors is that you are now probably using fuel that contains Ethanol. A couple of years ago, most marinas still offered fuel that did not contain Ethanol. Fuel containing Ethanol has a lower boiling point and will in turn vaporize at a lower temperature. Your bilge ventilation is probably marginal and now that the fuel has changed, vapor lock is more likely in hot weather.

A vapor lock condition is simply air that has developed in the fuel delivery system. A vapor lock condition can occur more readily if there are other contributing factors. If air is entering the fuel supply line because of a poor connection, loose clamp, loose fitting, or faulty pick up in the fuel tank, vapor lock is more likely. Check the entire fuel delivery system for problems. You can check your fuel pick up tube by connecting a clear hose to the fitting on the tank and drawing fuel straight up (like in a straw) and closing off the top of the hose. If the fuel stays up in the tube, the fuel pick up is probably okay. If the fuel level returns to the tank, there is a leak somewhere in the pick-up tube (probably in the tank
itself ). Many fuel tanks have a plastic pick up tube that slips onto a barbed fitting in the tank. As the plastic gets older and brittle, it may become loose and create an air leak. If you notice that the problem is worse when the tank is low on fuel, I would be more
suspect of the fuel pick up.

Vapor lock conditions also occur more often if there is a restriction to fuel flow. Make sure that your fuel filters are clean. If your engine is equipped with a “cool fuel” unit, there is a filter screen inside the “cool fuel” assembly between the fuel pump and the cooler. In order to clean this screen, you will have to remove the entire assembly and take it apart in order to service it.

A weak fuel pump could cavitate which will also contribute to the problem. Replacing the fuel pump may also solve the problem.

If everything checks out okay, you may have to add a supply fuel pump to the system. Many of the fuel injected engines like yours were equipped with a mechanical fuel pump mounted on the raw water pump. For a couple of years, Mercury omitted this pump relying on the injection pump to draw fuel. It was discovered that the omission of the supply pump resulted in vapor lock problems in the warmer climates. Subsequently, a retrofit kit was offered to resolve the problem. This kit is no longer available. If your engine does not have a mechanical supply pump, the best solution is to add an electric in line supply pump in the boat. This will require that you also install a remote in-line water separator fuel filter assembly. The electric fuel pump should be connected to a relay that is controlled by an oil pressure switch so it will not run when the engine is not running. It can also be wired with
a relay connected to the supply wire to the fuel injection fuel pump. If your engine does have a mechanical supply fuel pump, it may be defective and needs to be replaced.

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