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I have a 318 engine that I have in a 1973 Dodge truck. While it's not a racer, I do like to have everything on it set up right. I have installed 3 timing tapes on the damper and can't seem to get them to stay on at high rpm. I have tried glue, nail polish, etc. but nothing seems to work. Any ideas?¬0100318, Via e-mail.
Dl00- A high rpm truck 318? I thought you said it wasn't a racer? Since you took the time to write I will give you the secret of keeping timing tapes on dampers. All you need to do is buy a 4th tape and install it as usual, after cleaning the damper with alcohol (nothing else!). After you get it stuck on the damper, simply take clear spray paint and put a heavy coat over the entire tape. When the paint dries, the tape will be sealed to the damper and will never fly off until that stock damper flies apart. Cool, no? Another Mapar Action quick, dirty, and cheap fix far all of our faithful readers (and even the cheapskates who are reading this over somebody else's shoulder).
I'm building a big block street engine and I have a question about camshafts. I would like to run a roller cam but I'm concerned about their durability versus running a regular solid lifter cam. I drive it about 1500 miles per year and rarely race the thing on the track. What do you think?-Chris Perry, Via e-mail
Chris- This is a good question that I get asked a lot in the course of building engines. As with most everything else, if you select the parts wisely, you will have no problems with a roller cam. Face it, almost all of the production cars in the world run roller cams at this time. Granted they are hydraulic rollers but this was done to lower the maintenance and internal friction of the engine, in addition to increasing its durability. In fact, many of today's engines incorporate many old racers' tricks inside for the sake of power and mileage increases. Most old car guys would flip out if they took apart one of today's high tech mills and saw the razor thin piston rings, lightweight parts and skinny stem valves. It is comforting to know that all of us grass roots racers were on the right track for so many years. For your situation I would say that it is indeed possible to run a roller cam with no problems for this use. There are roller cams and then there are roller cams. What this means is that some grinds will waste springs in 10 blasts down the quarter and some will run forever. All of the cam grinders have wild grinds and wimpy grinds so simply choose one that is a little on the wimpy side. If you study the cam lobe charts you will see that for any given advertised duration they may have 5 lobes with vastly different durations at .050"' and .200n lobe lift. A lobe with more duration at these more relevant lift points is consid¬ered "more square" than a less aggressive design. As the lobe becomes more square, the demands on the valvetrain go up and the durability goes down. If you study the charts and understand this, you should be able to pick a good compromise lobe. Most of the cam catalogs will tell you in the descriptions of a particular cam if it's recommended for the street. You can also look in their circle track sections since these cams are less radical than their drag race cousins. Most circle track guys run many hundreds of miles in an average season so if it holds up there, it will hold up on the street. Really the only thing you should be worried about are the valve springs. As long as they stay strong, things will work out fine. Once the springs start going away, all sorts of problems will start to happen with the rest of the parts. If the springs weaken, the lifter may not be able to follow the lobe correctly and may start to hammer itself apart. Many roller lifter, rocker and pushrod failures can be traced to weak springs. What I like to use are non-exotic material valve springs intended for circle track engines. Generally they can provide the same seat pressure with less open pressure than a drag race spring. They also will hold this load for many more miles than a more brittle drag spring. By definition, a drag engine is a full blast, short duration beast while a circle track or street engine has less peak power in exchange for more durability. As I have said before, there is no free lunch with these things. Basically what I'm saying here is to set your mill up with a bunch of circle track parts and don't worry. If you are concerned about it, buy an on-the-car valve spring tester and check your springs on a regular basis. With all of the material advantages we have today in the valve spring department, it is possible to run rollers on the street with no problems, but you do have to keep an eye on the valve lash. Remember that solids have durability problems too. I'm sure you know many people with "flat lobe" (wiped) solid litter cams. At least a roller will never do that!
I have a 500 cubic inch B1 drag engine that I'm having a problem with. It seems as though I'm not getting enough oil up to the heads because it is tearing up rocker arm adjusters and pushrod cups. r can get about 20 runs on it before I have problems with it. How can I get more oil to the heads?-Joe M. Via e-mail
Joe- It is very easy to increase the oil flow to the heads on Mopar B~ engines. Before I go into it, though, I want to point out a few things for you to look for before you go diving into the engine. The 81 heads use a 1.7 rocker arm ratio that is great for making power. Not only does it accelerate the valve faster, it also makes for a lot of valve lift. Most of the B1 stuff that 1 have run all run over. 750~ tift at the valve. Because of this, the valve springs have to be killers to handle the stress. This really puts a strain on the old fashioned ball-cup push rod deal. The only way for them to survive is to blast them with a bunch of oil. Make sure that the oil holes in the rocker aren't blocked. This can happen if you ever break an adjuster off and the pushrod cup hammers the bottom of the rocker. As a side note, this fact is true for all engines, not just 81 s. Check to be sure that the pushrod length is correct too. If the pushrods are too long, the cup may be too near the bottom of the rocker, which will not allow the flow of oil to spray into the cup. If the pushrods are too short, the oil spray may go right over the top of the cup. If you are only having problems with one specific rocker, check to be sure that these things are set up right. The 81 intake rocker has a huge offset because of the giant intake ports, which further places stress on the rocker-to¬pushrod interlace. For all of these reasons, I prefer to use rocker systems that use the ball on the pushrod and the cup in the rocker. These better units feature full pressure oiling right through the rocker for much better durability. Assuming that all of this stuff is on the money, you may just need more oil to the top to make things happy. The best way to get more oil up there is to groove the number 4 camshaft journal. These engines oil the heads via flow from this area of the block. The oil comes up from the main bearing and flows through the #4 cam journal when the passage in the camshaft lines up with the oil holes in the bearing. This engine does not have full-time head oiling, the oil only flows for a fraction of the cam's rotation. By cutting a small groove in the cam journal the engine will pump more oil to the top and hopefully solve your problems. It's best done on a lathe and I would say to go with about a .05a• x .050n groove to start. Don't overdo it here. Remember that in normal operation the oil is only flowing for a fraction of time. Now it will be flowing all of the time which is a huge increase right off the bat. Oil to the top is basically wasted oil since it will cause drag returning to the pan and is not being used to support the crank and rods. The B1 heads have poor drainback and need external oil drain lines for proper operation. t'm sure you already have them. Once the cam is installed you will have a lot more oil to the rockers which should solve the problem. If you have the chance to look at most Hemi cams, they usually have grooved #4 cam journals to keep up with the additional oil demand of their 4 shaft rocker system.