HOLLEY 950 ALCOHOL CONVERSION BY JET PERFORMANCE

To run a racing engine on alcohol the carburetor must flow 2.0 to 2.2 times the amount of fuel compared to running on gas, requiring extensive modifications to the fuel metering circuits. The following steps are the basics of converting a Holley 950 to run on alcohol. Other modifications may be required depending on engine size and modifications. Like gasoline carburetors, alcohol modified carburetors may need to be fine tuned by re-jetting or tuning the air bleeds.

The main body is resurfaced on a mill.

For more information about performance carbs visit Jetchip.com or call (714) 848-5515.

ARCHIVE BACK TO BASICS

Article and photos by: August Cederstrand, Cederstrand Racing Engines

It has never been easier to design and build your street ground-pounder or racing engine. The explosion of aftermarket parts from seemingly every corner has given us all a lot of choices in the direction we want our engine project to go. Rather than talk about all the great parts that are out there, which could take quite a long time, we are going to focus our attention on some of the high points of engine building. Some of these tips are often overlooked, or the builder assumes that the manufacture has taken care of the part and it is ready to go. Sometimes the parts are ready, sometimes they aren’t. We are going back to basics.

We have all done it. We have our car project sitting there in the driveway and we start to think of all the things we could do to it. Paint, interior, wheels and tires; all the good stuff we would want in our car. The engine often is left to a professional engine builder, or a shop that will hopefully do what we want. The engine can be a large part of the budget of a car build, whether it is a race car or street machine. Many times in order to keep a project moving along, or because he is on a tight budget, or to keep the peace in the home, the car builder will undertake the design and building of their own engine.

It is very easy to be intimidated by a professional engine building shop. It may have lots of fancy boring, surfacing, and testing equipment, cleaning tanks and expensive measuring tools. Compared to a lot of other operations in dealing with a car hobby, engine machining and construction can take a lot of specialized equipment. Most of it is beyond the means of the weekend warrior who will build only a couple of engines over a lifetime. All of that great stuff is wonderful and good, and is extremely useful in the design and building of a top-notch engine, but not all of it is absolutely necessary. With a few simple tools and techniques almost anyone can build a well running, powerful engine that will exceed their own expectations.

One of the most often over looked areas of weekend engine building is checking bearing clearances, most notably the connecting rod and main bearing surfaces on the crankshaft. Really, this info applies to all the clearances in an engine. The old stand by, “Plastigage” has been used for years by many people, but it has its foibles. I have compared it to using a micrometer, and found it to be as much as one to one-and-a half thousands of an inch off. This was both to the tight and loose side of tolerance. This could spell disastrous consequences to the long term health of an engine. Micrometers, not dial calipers, are the way to go when measuring outside bearing surface diameters. You can measure diameter, taper, and even discern if there is any waviness machined into the bearing journal from the manufacture. Are micrometers cheap? Some are, but good ones aren’t. You may say, “Hey buddy it’s not the cards to buy a good micrometer right now and I don’t trust Plastigage, what do I do?” Good question! If a micrometer isn’t in the cards right now, don’t fret. Maybe a good friend would let you borrow his. Not likely! So, load up the crankshaft and head off to you local machine shop, or engine builder, and have them check it for you. Many of them will do it on the spot right there on the bench. For a nominal fee they will even check everything for you. Call ahead to check their schedule, and make an appointment. Most local shops are pretty accommodating when doing stuff like that because they want your machining and engine business. Get the clearances right in the beginning and you will have a good foundation for an engine that makes great power for a long time.

Cam timing is a misunderstood and overlooked area of engine building. Many times the weekend warrior engine builder slaps the timing chain on the engine, with the marks set straight up, and lets it fly. You can get away with that on a mild stock displacement engine with very moderate “RV” style cams. Generally there is lots of room for everything, and it all clears. Or the engine is just “warmed up” slightly and it doesn’t make a big difference whether the cam is advanced or retarded. But if you are trying to make a real performance engine, then proper and accurate cam timing is critical for maximum power and longevity. Possibly it is a stroker crank engine, and it is critical for the cam timing to be right so they don’t hit each other. How do we measure cam timing? Well, again there is some specialized measuring equipment needed to do this task. Most of your large cam grinding companies have put together their own cam degreeing kits that include all the tools required to do the job of phasing the cam in correctly. These probably include a 360 degree wheel, light weight checking springs, dial indicator with magnetic base, crank bolt, and of course, instructions. Sometimes they even include a video on how to do it. Your local speed shop, or parts retailer, can order these kits for you for under two hundred bucks. If the cost is still too high, maybe you and couple of your friends could go in as partners in buying a kit for the group to share. That way no one person shoulders the burden. Of course, you can always load the engine up in the truck and go to the local engine builder, or machine shop, and have them check it for you. Always check with them first what the cost of that procedure is, and then act accordingly. It will probably almost always be cheaper to have them do it than to buy the tools yourself. With the cam degreeing tools you can check the camshaft against the cam card that comes with your camshaft. You can then tailor the power band of your engine to suit your intended purpose. Everything that is manufactured has a plus and minus tolerance machined into it. Well, you start to add up all these tolerances together and they could have a significant effect on the performance of the engine. Degree the cam, adjust the timing chain to where it needs to be, and “BAM,” lots of cool horsepower!

The oil pump is the heart of every engine. High volume, high pressure, standard volume, standard pressure the list goes on. After the pump is selected, go ahead and check it. I mean turn the rotors around inside the housing, making sure they don’t bind, or make any un-natural sounds. Take the pump cover off and clean the inside and outside of the housing and rotors. We want to make sure that there aren’t any foreign materials inside the pump at all, such as casting flash, machined off bits of pump material, or ground-in dust from when they did the final grinding of the pump to tolerance. Check and clean all this stuff out of there. Wash all the pump parts out with brake cleaner, or solvent, to get them really clean. You are the last one to put the pump in the engine, so if it is not right, who’s to blame? The last guy to check the part of course! Fill the pump with some of the same gooey, sticky bearing lube you used to assemble the engine with. It will make a big difference in priming the engine the first time. Let’s not forget the bolts that hold the pump together and that hold the pump to the engine. A couple of small drops of blue Loctite thread locker go a long way towards keeping the pump bolts where they should be. Some engine builders even go so far as to safety-wire all the critical bolts together, so that it greatly reduces the chance that a pump won’t fall off. Bad things happen quickly when the pumps fall off. It gets spendy real quick!

Priming the engine. What does that mean? Generally it refers to the point when you’re ready to fire the engine for the first time, either in the car, or on a run stand. You fill the oil filter with your break-in oil, and the rest of the oil gets poured into the engine. At this point a ½” drive 120volt electric drill with the correct oil pump priming shaft is inserted into the distributor hole, where it engages the oil pump drive, and then you hit the “go” button on the drill. Make sure you are spinning the pump in the correct direction. I can’t tell you how many times I have solved a customer’s oil priming problems by changing the direction of the drill motor’s rotation. Now, make sure you have an oil pressure gauge hooked up at this point. It doesn’t have to be expensive, just reasonably accurate. Your local auto parts store will most likely have a no-name brand of oil pressure gauge that is fine for first time start up. A decent drill will get the oil pressure up pretty close to where the engine will run under it’s own power. Have those valve covers off, and check to make sure that oil is getting to the top of the engine at all the rockers. Run that drill for one to two minutes; you won’t hurt anything in the engine. On big block Mopar wedge engines, because of the way that the oil holes are machined in the #4 cam bearing journal on the camshaft, you have to rotate the engine through ninety degrees of crank rotation on either side of TDC in order to oil both sides of the valve train. On engines that have oiling through the pushrods, it won’t hurt any to rotate the engine 360degrees in 90degree increments in order to make sure that all the lifters’ oil holes have been exposed to the pressurized oil. All we are doing is double-checking to make sure that oil is getting everywhere in the engine. You can be reasonably assured that if you’re getting oil to the top of the engine at the valve train, the bearings are fully coated with oil and shouldn’t incur any damage when you start the engine up.

Setting timing for a first time engine start-up is very easy. After we have primed the engine with oil and determined that all is well, we must stab the distributor into the engine for the first time. First, bring the engine to top dead center on #1 cylinder. Watch your harmonic balancer to double check that the zero indicator, or TDC, is indeed in the right place and is indicating Top Dead Center on cylinder #1. As a side note, you can also double your balancer with your cam degreeing kit to double check that it is accurate also. See, good tools are used in many different ways! This is pretty universal on all your American made V-8’s, which is what this article is mostly aimed at. The principles are the same though, and do apply to other types of engines. How do we determine #1 cylinder on the distributor? I will tell you right now, THE ENGINE DOESN”T CARE WHICH POINT ON THE CAP YOU MAKE #1. Many people refer to the factory’s established placement on the cap, which is okay, but not necessary. As long as the firing order goes in the right direction and sequence it is gravy from there out.. I like to have the rotor run parallel to the crankshaft centerline, pointing towards the front of the engine. Why? It makes for a quick visual reference when I am in the field and have to do any timing adjustments. I just mark on the cap which terminal is number #1, and make an arrow indicating rotation. Sometimes I will even write the firing order on the cap to make it easier for the customer later down the road. Alright cylinder #1 is at TDC, we have installed the distributor and marked the cap where #1 is, and also marked the body of the distributor. Get the rotor as close as possible to center on the electrode as possible. Lock the distributor down, not all the way just tight enough so it doesn’t move when you crank the engine over. Run your plug wires in their correct firing order from your #1, and you are ready to bring your shiny new beast of an engine to life, at least distributor wise.

My final basic pointer before you light your engine off for the first time is to put fuel in the carburetor. More than one flat tappet style cam has been flattened before the engine has ever been lit off, because there wasn’t any fuel in the carburetor. It sounds simple and obvious at first, “who wouldn’t run fuel in the carb for the first start up”???? More people than you would think, but they won’t admit it. It’s a simple concept: fuel, spark, and oxygen are placed together and you have your fire triangle as we all learned about back in grade school. I have seen and talked to more than one person who cranks their new engine over and over for many minutes trying to get fuel to the carburetor with the mechanical fuel pump. The two most popular style of carburetors out there are Holley carbs. and their variants, and the Edelbrock Performer series and their variants. Edelbrocks are easy take the top off the carb. with a #25 TORX screwdriver, and then fill the carb. with fuel. Done, ready to light off. The Holley type is little more tricky, but not impossible. On top there are two vents for the float bowls. Make, or buy, a small funnel, or pinch together a cap off a spray can and carefully fill each float bowl. No tricks, it is ready to light off. Now if you truly want to impress your friends and get smiling admiration from your favorite girl, go buy yourself one of those hand operated vacuum pumps used for bleeding brakes. Insert the cone shaped tip in the fuel line at the carb, and vacuum the fuel all the way from the tank to your fuel pump, then right to the carb. You will look cool, and your favorite girl will make a nice dinner because that is just too slick. At this point you are ready to go. Light it off, get that RPM up to 2000 to 2500 and then set your timing and break that cam in. Boy, that was easy!

These are just some of the basics to keep in mind when building, designing and firing an engine for the first time. Use your head, and take your time. There nothing common about common sense, just try to think everything out, and then check and recheck. It can take years to become a good engine builder. Everyone does it a little bit differently than the next guy. Just take your time, and don’t be afraid to ask questions if you don’t know something. Many times we guys will let our ego get the better of us, and we will destroy our nice engine because we were too embarrassed to ask a simple question. Well, it is your thousands of dollars sitting there waiting to be turned into recyclable material because you didn’t want to ask a question and seem ignorant. It is your money. So to sum it up: think outside the box, ask questions and use your head! You will gain knowledge and hopefully have a wonderful and successful engine building experience. Remember, back to basics doesn’t take lots off money, or a shop full of equipment. It just takes hard work and careful planning, and then you have got it made.