Engine InquiriesI have a number of questions about my racing effort, and I am in hopes that you can offer some answers and advice.
I ran a '78 Camaro with a 350 this year at my local dirt track, which is a half-mile, slightly banked oval. The motor ran good, but I am considering rebuilding it for the next season. I have a lot of questions I feel I need to ask before I get my motor rebuilt.
First, let me state the rules of the track where I compete.
*No high-performance replacement parts.* No more than .447 valve lift.*No engine more than .030 over stock bore (mine is already .030 over).*Heads must be stock with a minimum of 72 cc.*150-psi compression maximum.*Holley 1850, 600-cfm vacuum-operated or any size quadrajet.*110-octane racing fuel.
When I tore the motor down for inspection, this is what I found:
My block casting is No. 3970010 with 020 and 010 casting under the timing cover. It is also a four-bolt main. Is this a good block?
Steel crank with casting No. 1182. Is it good for racing? What is it worth?
My intake that came off was an aluminum with casting No. 14014432. Is it a good intake?
My heads are casting No. 333882 with 1.94 and 1.50 valves. Are they good heads? If not, which set of heads should I try and still stay legal (within my rules)?
My pistons are No. 2244p4 eyebrow flat-tops. Are they stock, and are they any good for racing? My rods appear to be stock GM. Would it all right to stay with these?
My cam is No. 1003R. Can you tell me the specs? This cam seemed to work well, but what would be a good one that would have good low-end torque to get me off the corners and still be within the rules?
My timing chain is No. 8-78 and s-100a. Is this a true double-roller chain? Should I change the chain when I rebuild the motor?
I have a stock oil pan with an oil pump that reads No. M6 5HV H22. Would this be a good oil pump to reuse? Or, would it be a good idea to get a better oil pan with trap doors, that holds more oil, and is supplied with a high-volume oil pump?
I am looking at building a motor that will last all season, but on the other hand, I am not looking at spending a lot of money because I don't have it. I also will be running a Saginaw three-speed with a locked rear end via a mini spool with 3.73 gears. If I have to go .040 over on the motor, will I be able to get away with it? I'm not trying to cheat; I just don't have any other motor to use right now.
When the motor is built and ready to run, what should my timing be to start off with?
What about the jets in the carb?
Which plugs should I run?
I know I have a lot of questions, but I figure you'll give me an honest answer. Keep up the great work, guys. You have an awesome magazine!Chris HullPort St. Lucie, FL
You are right about one thing-you sure have a lot of questions! Let's tackle them one by one and see if we can help you.
Before we get to specifics, allow me to say that without some further information on some of your questions, I won't be able to give you absolutely complete answers. However, a number of your questions can be answered.
BlockStarting with your first question concerning the engine-the block you have is good, especially the 010. Just as a side note, this block is becoming a bit harder to find because it is popular, and of course the best place to find it is in the boneyards. But as a foundation for your engine program, this four-bolt main block is good.
CrankThe 1182 is a good forging. This steel crank actually comes in two versions within that numbering nomenclature. One is nitrited and the other isn't. Both will work well for you however if you have the nitrited version it will likely wear longer because the nitrite process gives a heat treated surface that is meant for long life.
The nitrite surface is only 2 to 3 thousands deep, so be aware that if you turn the crank for any reason, the nitrite advantage will not be available. That's not to say that if the crank is machined (turned), you shouldn't use it; it just means the heat-treated surface will not be there. Again, both versions of this crank are good to go in the engine you are doing.
As far as the value of the crank, if it's the standard 1182 version, it's worth approximately $150; if it's the nitrited version, it's probably worth around $250.
IntakeOn the intake, GM has offered some good aluminum heads that should work well for you. I do not recognize the number you cite, but you can confer with GM or other race supply houses on the stock nature of your intake.
HeadsRegarding the heads, casting No. 333882 with 1.94 and 1.50 valves is a good set of heads for your needs. In your situation where you have to run a 72cc chamber, these heads are probably as good as you can buy for that size. These are older versions and are not as available as they once were.
PistonsAs for the pistons, the number does not sound like a GM number to me, so you may have to take the same route as the intake. You may have an aftermarket piston. I believe that to be a Sealed Power part number.
RodsThe rods appear to be stock, and according to your outline, you have to use stock rods. These should work well, but the big ends are in good shape. You have good bolts, so they should be sufficient.
Cam1003R cam-not sure, but not a GM number; however, rules prohibit high-performance replacement parts, and the cam cannot have 447 valve lift. If you take the option to push the envelope on that, there are some options available.
Timing ChainWithout seeing the timing chain, I don't know if what you have is a true roller, but your second question on this part is, should you replace the timing chain? The answer is yes. This part is vital, and since we don't know how much use the chain has seen, I recommend that you replace it.
Oil PumpOn the oil pump, I don't think it's a GM because the part number you list includes an HV nomenclature. That appears to represent that pump as a high-volume pump, which would mean it is not a stock GM part. But again, like the timing chain, it is my recommendation to replace it if you can. It will give you peace of mind, and you will have confidence that it should not fail because it's new.
Oil PanIf your track rules will allow for a non-standard oil pan, then a trap-door-style pan is a good idea. This style of pan is preferred because it was designed for circle track racing and will keep the engine lubricated well in competition.
BoreI think you already know the answer to your question on going .040 over on the cylinder. Your rules say that's illegal. So your best bet is to clean the engine up and maybe hone the cylinders. It is, of course, up to you, but be prepared if a tech inspection gets you in trouble.
TimingIt's always a good idea on a small-block with flat-top pistons to start out with a total timing of 35 to 36 degrees. How much advance you have in the distributor depends on how much initial timing is allowed in trying to reach 35 degrees total timing. For instance, if you have 24 degrees advance in the distributor, then you will have an initial timing of 12 degrees. The initial timing is only a part of the picture; total timing is what the engine actually sees.
Carburetor JettingIt would be hard to go wrong by running jets two or three sizes larger than stock in your carburetor. Those sizes are not necessarily the ultimate number, but you are not likely to burn pistons with that increase of jet size. Going much larger in jet size is counterproductive because the carburetor isn't designed to handle that fuel load.
Spark PlugsBased on the specs of your engine, you can run a fairly warm plug because of the low compression. In your case, something like an AC 44 heat-range-type plug will work. The 44 number is specific to AC but can be cross-referenced to other makes at your retail outlet.
I think that covers the questions you have asked, and I hope it gives you some help. Like I said in the beginning, your letter did not give full details on some of the topics, so I have answered as best as is possible.
I would also like to say in closing that I understand your need to keep your program affordable and that you have to watch every dollar. But I also believe that if you go too inexpensive, you can sometimes underbuy when it comes to quality, so it winds up costing you more in the long haul. It's important to buy right.Good luck.James FryCompetition Cams, Memphis, TN
Pushrod ProblemsI love your magazine, and I want to say thanks for all the great information you supply every month. It is very useful to me, and I always look forward to the next issue.
I am a racer that runs on a 31/48-mile, high-banked oval. My engine is fairly stout, but I am always looking for ways to improve it. Now that the season is over, I have time to look at some things to see if I can make my engine better.
One of the things I have heard and read about is pushrod lightness. Some have the opinion that light pushrods in an engine will give a weight advantage, which could result in more performance.
I am wondering if that is true. I am also wondering if there is any advantage to running a single-piece pushrod instead of three-piece units. I know that this is probably splitting hairs, but I would really like to know.
Thanks for taking the time to answer my letter.
Name and Address Withheld by request
The debate on running lighter or heavier (stiffer) pushrods has been going on for a while, but in the recent past, there has been significant information provided through many hours and months of research that the pushrod is really a source of power in an engine.
I say that because a pushrod does not simply connect a lifter to a rocker; rather, it is the main conduit of delivering the message from the camshaft to the valve. For the pushrod to do its job properly, the maximum amount of the cam message needs to be delivered to the valve, and if there is any flexing, then the message is not being totally delivered.
Sure, a lighter pushrod can gain you some slight valvetrain weight advantage, but if you don't get the most out of your cam-to-valve message, what's the point?
You don't say in your letter what your engine specs are, but let's say you are running in a Street Stock class with stock springs and a lift rule. In that instance, a 51/416-inch (light) pushrod will do the job and should successfully deliver the message to the valve.
However, if you are running an engine that has an aggressive cam, you will want to run a heavier (stiffer) pushrod. I say that because our research has shown that a light pushrod in an environment of high-performance requirements will flex. That action actually has the net effect of changing your duration at lower lifts, which in turn robs the valve of some of the cam potential, not to mention durability issues.
Although running a stiffer (heavier) pushrod will add some weight to your valvetrain, it has to be looked at in the context of power. It's a balancing act, a trade-off; you don't want to add unnecessary weight, but you don't want a pushrod that's not heavy (stiff) enough to deliver the message from the cam to the valve.
Stated another way, the power gains from a stiffer pushrod can easily offset any valvetrain increase in weight.
To your question of running single-piece pushrods versus a three-piece. I don't think there is any particular advantage to using a three-piece, and in my opinion, a one-piece is the way to go. The technology that's been put into today's one-piece pushrods has produced an excellent high-quality and reliable unit. A one-piece can also provide peace of mind because you will not have to worry about any separation of the pushrod ends from the tube, and that's just one less thing to worry about. I can't imagine wanting extra pieces floating around in the valvetrain.
In the coming months, we will be doing a broader expos on pushrods for Circle Track, so stay tuned. In the meantime, I hope these answers have helped you.John BarilkaHendrick EnginesHendrick Motorsports,Harrisburg, NC