Landracing Forum
Tech Information => Technical Discussion => Topic started by: sdroadster on December 28, 2013, 07:52:24 PM
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I have a Small Block Chevy in #352 Studebaker that I run at the Dry Lakes and Bonneville. The motor is a stroked 350 (368) and has a wet sump. The first pass at Bonneville was faster than we had ever been, 223 mph. Then the speed started to detoriate. We found that the ignition timing is retarding about 20 degrees at 5000 rpm. It has 36 degrees of initial advance, and a locked out MSD distributor. When free reving it in the garage you can see the timing begin to retard. At 5000 rpm there is a difference in the exhaust note as the timing falls off. It has had 2 new MSD digital 6al ignition boxs, 2 new distributors, a new MSD timing light and I pounded a paint paddle between the water pump and the timing cover to address possible cam walk. I have spoken to MSD Tech several times. They haven't been much help. The next thing I'm going to do is install an old points distributor and abandon the MSD electronics. If it still retards and falls off we will tear into the motor. Any ideas or suggestions? Thanks Terry
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have you checked the end play of the shaft in dist or lower bushing in housing?
J
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What is the exact model of the MSD box do you have? If you have a "Digital" box it is most likely is programmable to the RPM timing curve!
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The car has real basic ignition parts. MSD 6AL Digital box (no adjustments, just a rev limiter). Haven't checked end play in the distributor because I bought it brand new. The motor is really a circle track hand me down. Crower bottom end, Dart cast iron heads, Crower roller cam, Crower valve springs, and roller lifters. About 13 to 1 compression, and 850 Holley carb. No Nitrous, no start retard, simple motor that used to always run well. We shift at 7200 rpm. Car ran 185 at El Mirage, and 223 on the salt. We are not record contenders, just geezers that want to see how fast we can go in CG/CC. Thanks
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Reverse the two wires from the the msd dist to box. This should retard the base timing on your lite... if so, Then reset the timing... then you should be go to go.
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So does it the sound fall off precisely at 5k, or does it vary a few hundred rpm? If it varies, I'm thinking mechanical - if it's precisely at a given number, I'm thinking electronic.
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The engine falls off and "lays down" give or take a few hundred rpm after 5000. Sometimes 5200, 5600 etc. I ran at El Mirage in November. The motor reved to 5200 or so, and quit pulling. I never shifted to 4th gear, and went through at 117 mph. I ran 185 in July...
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223 is a good run, congrats.
Have you checked the valve train, the springs in particular? Has something happen where it is now going into valve float?
Sum
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More and more folks are going to valve spring oilers to prolong valve spring life---T&D rockers even have them built into their rocker arms if you want them.
My guess is Sum and MM is on the right track. If you have restricted oil to the top of your eng to make it live at B'ville you might want to consider "spring oilers" if you find your valve springs weaken.
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Thanks for the info on the valve springs. Although this was a new stroker motor in July, the valve springs were reused from a previous season. The owner of the engine said they tested fine. The motor started laying down at Bonneville. It didn't float it's valves (when is used to rev to 7600 or so) and doesn't shoot ducks. I agree the valve springs are getting old, but how would they affect the timing? You can watch the advance detoriate as the engine revs. It's loosing 16 degrees, maybe more.
In the next few days I'm going to install an old points distributor, and run it off the white wire on the MSD box. If the timing still drops off, I'm going to abandond the MSD, and run the distributor with a coil, and a ballist resistor like any old car. If the timing still goes away the owner will be pretty much convinced the motor needs attention. A friend loaned me a Vertex Mag I will probably install at the end of the testing. I wonder if putting a new Vertex in the motor is an option. I have been pouring money into MSD parts, and even MSD doesn't know whats wrong. It seems like a mag would be simpler. Thanks
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I am guilty of having an old one track mind that tends to get tunnel vision you did mention that you had watched it back track on the timing light---
YOU are not alone with problems with MSDs---I sent a 7-AL 2 back and they told me nothing was wrong with it but with no other change but replacing the box--- solved the problems--
Andy next door has had a 6 al quit him sent it back told nothing was wrong but we didn't get the same box back---this one works--something may be going on would not be the first one---check the HR article about bogus MSD parts you may be a victim!
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SD. If you put in a points dist make sure every thing is top notch. Stock points float at 5500 and good racing points may be hard to find today. Have you tried what jdeleon said.....I go to the ez stuff first....good luck JD
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Sparky is spot on.
It's the MSD.
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Sparky is spot on.
It's the MSD.
I'd have to agree and withdraw my earlier diagnosis as I forgot that he said he could see the retard and the springs aren't going to do that :oops: :oops:,
Sum
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Why the MSD?
Provided the wiring is solid and there are no ground faults or physical issues (leaky capacitor, poor solder joint that's sympathetic with engine vibration, etc.) an electronic error would tend to repeat at the same rpm - or event parameter - every time.
You could test it by putting it in a different car.
I'm not saying that there aren't physical conditions that effect electronics, but my experience has been that an electronic failure - even one that seems sporadic - is usually repeatable and/or absolute, if the test is performed with care.
If the symptoms occur in a range of event parameters - sometimes 5200, sometimes 5600 - I'm thinking that's heat, expansion, centrifugal force - elements that are more widely variable than the flow of electrons.
Conditions change more readily in an engine than they do on a circuit board.
20 degrees of timing at the crank, your turning motion takes a right hand turn at the dizzy drive. So that's really only 10 degrees at the base of the distributor. Stack up some tolerances with the gear on the cam, maybe a loose cam bearing. What kind of run out and end play are you seeing at the gear? The base of the distributor?
Jack Gifford pointed out that he was able to do adjustable cam timing of 16 degrees with as little as .001 change in gear mesh on a gear drive cam. It stands to reason that that kind of change on a helical gear could create similar changes in timing at the distributor.
I think this sounds like a combination of bushings and worn gears riding up as centrifugal force and oil temperatures and pressure changes.
But I would start with the box.
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I have no experience with MSD, but do have a dumb question. How do they control the dwell time?
The reason I ask, is that years ago (about 1980) I had a "semi-transistorized" ignition (used points to fire an igniter) which was good up to 9000 rpm or so. The problem I had, strangely, was at idle or very low rpm. With the turn signals on, the idle speed would rev up and down, and my timing light showed the advance drifting back and forth. Insufficient current was changing the dwell time for the coil and igniter.
It was a corroded wire harness feeding the igniter power, combined with low alternator output at low rpm.
so....fast forward to 2000 and a Pectel T2 fuel injection on a turbo banger. The actual timing, at the plugs, would not stay stable under load, and it just wouldnt rev up during high cylinder pressures. Pectel told me to go get Ford Ranger coils and wire them "Menard V6" style (small 6-volt battery in series to the coil 12V terminal). That worked and solved the problem of not enough dwell to build enough voltage in the coil secondary to get the spark off on time. In fact....it was pretty late, I suspect until cylinder pressure let down enough to make the jump!
Might have been a fuel vaporization issue, also, because you can't spark on time if the spark plug is surrounded by mostly compressed air. The timing light only flashes when the spark actually jumps, not when the ignition asks for a spark event. Anyway, hot coils and 18V took care of whatever was going on.
I still dont get it, but their recommended fix worked just fine.
JimL
PS: The Ranger coils held up to 18 volts ok, when the engine spent most of its time at high rpm. They were the coils from about '96 or so, when it took a lot of spark to fire lean across a wide gap. I dont think most coils will put up with that, but those never failed us.
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Do you run an alternator or is it a total loss system? If total loss, you need an alternator. Check for resistance between MSD box and battery, possible corrosion. If no resistance problem, try running it up with a battery charger hooked up. That will give more voltage and amperage.
On that thought, if you're running an alternator, are you sure it's putting out what it should. If a diode fails, alternators get weak on output but still work, then low voltage like was pointed out.
Ron
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I'm going to try to get the car started today with the points distributor. The car has had 4 ignition boxs in it, and 2 of them were new. When I installed the last one I ran the harness over the core support near the radiator, and wired in an ignition switch directly off the battery. This eliminated all the ignition circuty inside the car. We put the car on a chassis dyno at JBA and it reved well untill 5200 rpm. The motor then sounded like the driver lifted, and shifted gears. The horsepower on the computer screen peaked, then made a u turn and dropped like a rock. I suspect the problem is electrical, but what are the chances of 4 boxs, 2 of which were new, and 2 new distributors. The car is wired nicely. It has plenty of ground straps, and the msd box is wired directly to the battery. Beats me.. I'll keep you informed. Thanks for all the response.
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I just saw the last 2 posts. I am running an alternator, and I have had it checked, although I will have it checked again. The timing does retard then at about 4500 it starts to drift. The timing will drop off then come back and then drop. I have noticed with the tach pluged in the condition seem worse. Hopefully I will run this again today, and then reinstall the MSD distributor and add the battery charger. Thanks! Oh, based on the symptoms, I installed a new tach too. (money pit)
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Do you run an alternator or is it a total loss system? If total loss, you need an alternator....
I agree that it is best to run the alternator, but this year we ran out of time and didn't get an alternator on the car and ran on the battery only with an MSD Box and had no problems, even 4 runs on the same day back to back without having a chance to recharge the battery.
We will have an alternator on the car before it goes back as that is the best scenario,
Sum
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Years ago,(amazing how time corrupts some memories) 1968 when I had a service station (yes service), I had a customer that the same problem as yours on his 396 Chevelle, Your last post reminded me. This was before MSD existed. The problem was chased down to a faulty tach. It was semi-shorted and drawing way too much power therefore lowering voltage to the coil.
Have you checked voltages while doing your tests? Good Luck.
Ron
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JimL;
Regarding the question of how an MSD (or any modern electronic ignition box) controls the dwell time-- it doesn't. "Dwell" was the % time that the points were closed, allowing current to flow in the ignition coil primary. It takes some time for the current to rise when driving an inductive load such as a coil, so the voltage must be applied to the coil primary winding for enough time to allow the current to rise to a high level. The magnetic field increases as the current increases and when the points open, the current flow stops and the magnetic field collapses. This sudden change in magnetic field generates a high voltage in the coil secondary winding and that voltage fires a spark plug. This was the venerable "Kettering System" that was used for used for years.
The fundamental problem with the points system is that at high RPM the points must still be closed long enough to build up the magnetic field; to do that, the needed dwell time gets to be a larger percentage of the crank cycle; at some RPM there is simply not enough time to build up the required spark energy.
Ignition boxes such as the Crane (MSD may be similar) fire a short, high voltage pulse into the primary of a special coil (actually a pulse transformer) and the secondary voltage fires the plug. Since the pulse is very short it is not a big percentage of the crank cycle time even at very high RPM. These ignitions can deliver very high energy to the plugs.
A common problem is that noise pickup can cause the box to false-trigger and the spark timing goes spastic. It is important to have a clean 12VDC power source and a good ground. The most vulnerable place for noise is the timing pickup wire. Whether it is from a crank trigger or points trigger, it needs to be routed away from other wiring or ever shielded. Don't forget to use a heavy bonding strap or wire to ground the engine block to the chassis. Good grounds on everything are a must.
I hope this helps.
Regards, Neil Tucson, AZ
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Question??? Doesn't the tach work off of the trigger from the distributor or crank trigger, whether points or electronic wouldn't make much difference if the tach is robbing or distorting that signal.
Ron
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Further on what Neil said about the wire maybe picking up stray signals from other wires - and therefore run the wire away from others: Shielding might conceivably cause some capacitance effects, especially at higher revs, and those might maybe perhaps farkle with the signal to the coil(s). If you can, run the wire so that it crosses the other wires at a 90-degree angle - don't cable it neatly in with the other wires. It might take some doing -- but if that's the problem you're having, this "crossing at a sharp angle" trick might help a bunch.
(Ham radio training on building electronic stuff to the rescue, right, Neil?)
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Yes, Jon. We learned that stuff the hard way. :cheers:
Low capacitance shielded wire is a good idea if the length isn't fairly short.
Regards, Neil Tucson, AZ
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Also twisting in a couple of ferrite beads is a fairly cheap and effective method of filtering noise if you cant run Shielded wire for whatever reason.
I would still be tempted to look at the mechanical end of things if you have already tried different boxes and arrangements.
Mostly wear in distributor gear and shaft play up and down. The shaft play is easy to check. Pop the cap off and pull. It will rotate if it has any travel.
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Thanks for the ideas. Please keep them coming.Today I got the motor started with an old Chevy points distributor that I found it in a drawer with related "stuff". The timing jumps around a bit, probably because the distributor is worn. However, it doesn't appear to retard as rapidly, and as conistantly as the MSD. I checked the battery voltage with the engine running and it was 14.45 volts. So it appears there is plenty of voltage for thr MSD.I called an accociate in the San Diego Roadster club for help. He is coming over tomorrow with a tool to check valve spring pressure, and several known boxs and distributors off his dyno. Hopefully I'll have some more news in the afternoon.
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Sounds like maybe time to find an old Sun Distributor machine and test system.
John
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It almost sounds like a false rev limiter. In the bike world, that happens when the crank/cam sensor signal gets outside of the normal expected range (e.g. Pushing the cams too high). OR. When the ingnition box is reading the incorrect number of cylinders, then you get a 1/2 rev limiter.
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have you checked the whether the MSD and the tach will work with each other-- some tachs you have to run a "black box" with them and some MSD systems---go online a check if they will work with each other.
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Nobody has mentioned anything about the coil. MSD requires a certain type of coil for each box. i.e. 6al,7al. Maybe you need a new coil.
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Today was a long noisy day. The points distributor didn't work out well. The timing was erratic and jumpy because the distributor is worn. I gave up on that. A friend who has built many motors, and is a land speed guy came over today with a trunk load of MSD boxs, coils, and distributors. We installed a analog MSD, a digital 7al box and a associated coil. We also installed new ignition circutry, and another new coil. It still retards. The timing is kind of consistant, but does change somewhat. The motor lays down usually between 5000 and 5500 rpm. There is an audibale change in the exhaust note. At that same time the timing typically retards 8 to 10 degrees. BUT, one time it ran up to 6000 with no retard, and one time the timing began to retard at 4000 when the motor was cold. We made 12 tests today and have pretty much decided the problem is not electrical. I have borrowed a Vertex mag that I will install after New Years. If it retards with the Vertex installed I'm going to pull the engine and take it back to the owner/builder. (I own the Studebaker, he owns the motor) Thanks Guys I'm going to give the neighbors a rest for a week or so.
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What kind of cam drive are you using? The distributor is driven by the cam so if the cam drive is erratic, the distributor will be as well. If you are using a timing chain, it or its sprockets may be worn. If it is gear-driven, look for a bad bearing.
Regards, Neil Tucson, AZ
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The cam drive is a chain. Also I forgot to mention we tested several valve springs and they were in the 180 to 200 pound range. thanks
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Have you thought about checking the end play of the camshaft to front cover? Sounds to me like you could be getting cam walk.
You should have some kind of button on the front of the cam to limit movement to .005-.010, and make sure you have a sturdy timing cover that does not flex. Cam walk is common when using roller cams, since they are not ground on a taper to keep the cam pushed back in the block like hydraulic and solid lifter cams are.
You might want to pull the timing cover and take a look, As little as .040-.050 cam clearance could be causing your problem.
Tom G.
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Thanks, I agree with you. In order to retard timing does the cam have to back into the block, or forward into the timing cover? Doesn't the helical cut gears, and the resistance of the oil pump want to draw the cam back?
Unfortunatly this is not my motor. I have to convince the owner because he disagrees that there could be anything wrong mechanically. Soon I'm going to pull it, and send it back to him Yellow Freight.
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We had the same type of problem with the 6AL. Anything below 12.5 volts and it wouldn't make power. Put a volt meter on the battery to see if its the problem.
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14.45 volts. Thanks
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Thanks, I agree with you. In order to retard timing does the cam have to back into the block, or forward into the timing cover? Doesn't the helical cut gears, and the resistance of the oil pump want to draw the cam back?
I am not an expert on SB Chevy's by any means of the imagination so I would have to look at a block to determine whether forward of backwards movement of the cam would cause the timing to retard.
Spring pressure coupled with non perfectly machined blocks or possibly cams will cause cam walk when using roller cams. So if the button on the front of the cam is worn or damaged and the cam wants to walk out of the block the spring pressure will keep the cam pushing out towards the timing cover. It would only be a guess on my part to say whether the the oil pump and helical cut of the gears would be able to pull the cam back into the block. Sorry.
I am not saying cam walk is the issue, just saying that is something else I would look into.
Tom G.
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You probably already tried this, but, put the negative probe of your voltmeter on the battery Positive post, and put the positive probe of your voltmeter on the 12V input to your coil or MSD (maybe try one at a time). Rev it up and see if the voltmeter starts showing voltage (positive or negative volts). It basically tests your supply circuit under load. Reading voltage from negative ground to the supply point will only show battery voltage (minus a tiny bit), but reading voltage drop will show if there is resistance under electrical load.
You can have every strand but one broken in a length of wire, and it'll still read full battery voltage and show zero ohms resistance on your voltmeter doing traditional test methods. This way, anything over .1 volt is a pretty big problem (except when testing a starter cable....those are still ok up to about .5 volt with this test method). Its also a good way to see if your battery cable is maybe too small for the run length.
If I have these numbers wrong, dont throw rocks....I am old, forgetful, and dont duck as fast as I used to!
JimL
PS: This is another dumb question, but you dont have "heavy fuel' by chance, do you? If you see sooty exhaust pipe ends, and the spark plug porcelain is very white, you might have heavy fuel that wont vaporize fast enough. It works ok, if the engine is hot enough, but not when you get the revs up and the time to vaporization becomes longer than the combustion events can handle it. Wont rev worth a darn on a cold engine, but always makes high exhaust temperatures (EGT).
SpeedWeek 2000 we fueled up (I forget which gas) and took the roadster to the line. Car ran 102 mph (after previous years speeds had been 150-170). We didnt touch a thing, just went back to the fuel truck and changed to A19A, and went straight back to the line. Next pass was 183 mph. No change but the 90% distillation temp of the gasoline choice.
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I just got a call from the fellow that owns the engine. He said we have tried everything, and he want's it back for repair. Thanks to everyone! I'll keep you informed if he discovers anything.
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Me being a bad one for "showing my dumb side", I am still thinking this could be a false timing read. As I read the literature, these MSD can double or triple strike each spark event.
I had a bad experience with that method, while working with a fellow who wrote the double-strike spark code used in some early OBD II Ford software. When our supercharged engines (with add-on spark processor he wrote code for) had high cylinder pressure, and a lean mixture, the "first spark" didnt make the jump. The second one did, which was late in time-event, and then caused our fast 32-bit engine ECU to detect the change in crankshaft revolution as a misfire event.
This shouldnt be an issue with a race engine, of course, unless that spark plug is surrounded by highly compressed air with the gasoline not yet vaporized enough to lower the electrical resistance of the compressed air. If that happened on a multistrike system, your timing light will only flash on the following spark and the engine wont rev cleanly.
This late vaporization can be really ugly. I have had this "heavy fuel" discussion with a number of folks experiencing lack-of-rpm, misfire, low-power, black sooty-exhaust, high EGT, and burn in the cylinder so bad that they smoked pistons. These are very experienced people that are really good, but got bit by this issue as I did.
I will butt out now, but this sure seems similar to what happened to us, (and some really top notch teams). Sometimes the old "its the gas" story can be true. When the only thing youve changed is the gas...well, thats how my 76 year old Mom figured it out for me at Speedweek '98. After two days of frustrating inspection and attempted repair, she was the only one with the right answer in our pit!
If it ran fine, and you didnt change anything..... :? ....and if you already tried some fresh, lighter gasoline, my apology for wasting everyones time.
JimL
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I also partially agree witih what JimL is saying.
Have you tried narrowing the gap on the plug, making it easier for the spark to jump?
usually it will misfire instead of retard timing, but with a multiple spark, it could be just firing on the last spark thrown, resulting in retarded timing.
I am now very curious as to why this is happening...
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If you don't know what is causing the problem, how does the engine guy know what to repair :? :? Hate to see him replace all of the parts and have the same problem.
Ron
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Thanks. I don't have an ECU. The tank has new VP C12 in it. The engine builder is going to have a look at everything, but concentrate on the cam. I'm sure he'll lay hands on the gears, chain, cam button, and end play. He's going to run it on a engine dyno when finished. I'll keep you informed if I learn anything.
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What MSD coil are you using, it has to be designed for a longer race than drag racing.
But any coil should be good for a dyno test
JL222
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C12 should be sweet enough. It must be something wearing out, because it looks like you've had enough fresh fuel to eliminate my idea. At any rate, file that gasoline info away in the memory banks. It can bite you in the strangest of circumstances, and its just hard to believe what it can do to a healthy engine.
Good work on your testing and reporting, and we all appreciate reading about it first hand.
Regards, JimL
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I don't know about MSD, but the Crane ignition changes from multiple sparks to a single powerful spark above a certain RPM.
Regards, Neil Tucson, AZ
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most do above 2000-2500
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Jack Gifford pointed out that he was able to do adjustable cam timing of 16 degrees with as little as .001 change in gear mesh on a gear drive cam. It stands to reason that that kind of change on a helical gear could create similar changes in timing at the distributor.
Do you have a link to the Jack Gifford thread?
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I think that was in the Milwaukie Midget Thread
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My experience with gasoline not burning fast enough for the rpm and spark advance curve is simply the lack of power at high rpm. The torque and hp curves appeared to be smooth. There was no noticeable transition from good to poor running like "the engine goes flat..."
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From an outside perspective, I do not understand why the motor would just drop off so suddenly when the timing retards to about 16* BTDC. I have found my motor works best at full throttle, WOT with the timing retarded to about 20* BTDC (my timing disc is homemade and could be wrong). Is it possible that the MSD is designed to retard at high RPM? And, that the drop off in power could really be due to other causes, such as insufficient fuel, or insufficient air? How about bad fuel, even though you said it was a new can? Just saying, keep a wide open mind. Quite often (speaking for myself) it seems we jump to conclusions.
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Bo, the heavy fuel issue (when it has really high 90% like VP mr12) kicks in suddenly (depending on engine temp) when you reach an rpm that does not allow enough time span for about 90% vaporization.
At that point, a cascade effect occurs which drives exhaust temps high, but poisons the next intake charge causing soot on the combustion chamber. It really falls on its face, and the weird clue is that the spark plug porcelains are pretty clean and white, but the end of the threaded plug barrel is totally black soot. I think its caused by the lean partial burn, that doesnt make enough heat in the combustion chamber to:
A- make power
and B- put enough heat on the surrounding aluminum to prevent the soot build.
All the fuel burns, but not necessarily in the top of the cylinder. Thats why so many folks have scored pistons running this way, while not making any power. It is a really ugly thing when it happens to you, because all your diagnostic methods go right down the drain. :-P
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Thanks for the info Jim. I wish I knew then what I am learning now. Any advice on interpreting the distillation specs would be nice. All that is a mystery to me. Maybe a new "Fuel Spec" topic can be started.
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Bo, long and rambling PM sent. Sorryyyyyy! :oops: :lol:
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A few weeks ago I was looking at all sorts of advance curves for my Triumph. They were developed for different sets of engine modifications. Several of them reduced the spark lead at high rpm.
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When we mapped our turbo car, years ago, I learned about reduced cylinder fill as the rpm got up high. You just dont have enough time to actually fill the cylinder, like you would at mid-range, and what you get is later. That means you are going to get a smaller bang, so to speak. If you picture the time event, over the range of piston position where "pushing" on it does any good, you see that the smaller bang needs to back up in time, a little bit, to get the largest proportion of "push" on the "sweet spot" of the power stroke. It really is milliseconds of difference, but that is quite a few degrees at high rpm.
That "less air" business meant that my injector duration pretty well flattened out above 6000-6500 rpm....and I may have left it a little rich. Unfortunately, my crank trigger mount broke, the engine banged the turbo (hard enough to break bearings) and the exhaust blew some chunks out of the dyno bay concrete floor. I wasnt invited back to play with their big toy.
Variable valve timing race engines sometimes have two places where the intake cam is fully retarded....idle, and anything from somewhere past the torque peak all the way to rev limit. Anywhere else, you are about as well off to just go to full camshaft advance and tune with fuel and spark. Trying to fish around with interval hold positions just makes stuff wear out, anyway...except maybe Suzuki's ramped lobe system. Thats pretty cool but I dont know if it is used, yet. Probably all kinds of stuff I never heard of, going on by now.
Anyway, knowing that variable intake cam timing gets retarded for high rpm, kinda explains why spark needs to back up as well, dont you think?
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Intake cam retarding increases volumetric efficiency at that rpm with more intake/exhaust overlap.
Any time you have less cylinder fill due to rpm increase, ve is falling and will plateau power or fuel needs. Better head of camshaft to get ve back up at those rpms is now necessary. Turbos and blowers help, buthere are still flow limitations in head.
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I was wondering if you had a chance to try the MAG in the motor and what results it had?
Hooley
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Thanks guys. The engine builder asked me to send him the engine back prior to installing the mag. He called today and said the cam button was worn, gone, missing, or detoriated and the cam had the ability to move/walk 1/4 of an inch forward. He said everything else looked fine. I asked about the condition of the timing chain, and he said we were going to buy a Jessle belt drive for the cam. He said that design locks the cam into place, and we will no longer have a potential problem. I'm glad he found something. Soon i am going under the dash of the Studebaker and comb through every wire, ground circut, and switch. Come on El Mirage!!!
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Have you thought about checking the end play of the camshaft to front cover? Sounds to me like you could be getting cam walk.
Tom G.
What do I win? All kidding aside, I am glad you found the problem. Now go out and set a record with the extra HP you will have with the belt drive. :cheers:
Tom G.
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I am glad they found the problem. We carry a spare mag just in case the MSD has a failure.
It seems to me that in the old days of drag racing the guys would run a sloppy timing chain so
it would retard at high RPM's. I'm not sure of the old memory.
Good luck,
Hooley