My son's dart has been on the road now for about 4 months after we sheared the oil pump gear, and we have a quetsion about the engine. It seemed to only pull hard up to about 5000-5200 RPM. It seems to just run into a wall there. It pulls super hard up to that point.
We were running stock points all along and thought that may have been a problem but last week we switched it over to Electronic ignition and it is still the same. Do I remember correctly that there is a built in rev-limiter on the electronic ignitions?? Is it set this low. The plans are to go to an MSD unit in the future but the ECU on the car now is a standard auto parts deal.

Engine is ..030 over, .528 / 284 cam, big valve head, 600 Edelbrock and 6 X 1 Headers, 4-speed manual.

Thanks,
Rick

P.S. Does anyone know why the back tires are always going bald on this thing!! Ha!!

How does it sound when its "up there", it could possibly be having an ignition system brake down, the stock ECU's were good to 6000RPM so that may be a problem

that cam should be enough to hit 6000rpm and still pull. so to me it sounds like the spark is breaking down

Justin

The engine sounds great when it is running up at 5000. It is still running smooth, not missing...etc. It just seems to hit a wall there. The coil is a new Accel, the Ballast resitor and ECU are also new. Air gap on the Pickup is correct, and we are running about 12 degrees initial timing.
The only thing not replaced on the ignition side was the plug wires, and we picked up a set at Carlisle yesterday. So we will be putting those on shortly.

Thanks,
Rick

Rick, what vavle springs did you use? This cam is borderline for a double spring. 340 or single springs may not be enough and not allowing the valve to seat at the upper RPMs.

Cecil

I'm not sure what the valve springs are. I purchased the head complete some 20 years back. They are single springs but when I had the head touched up the machinist had to cut the guides down a little for the higher lift. He also checked the springs and said that they should be OK for this lift with a .030 shim. If memory serves me correctly the springs pressure at lift was 310#.

Rick

Rick,
I talked to Chad today. He had borrowed my MP 528 cam, to try. He told me it ran out of "steam" at the mid 5000 rpm range. Said it was very "peaky". Short on low end. then pull very hard, and then drop off drastily. I have not tryed the cam myself, but it will be going into my nitrous motor in about 2 weeks.

_________________
Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Thanks for the info Charlie. I'm not sure I understand the camshaft art? I had an Iskederian 460 lift cam in my 65 Valiant 20 years ago with the same cylinder head that is now on my sons car, and it would pull clear up to 6500 RPM. I assumed this MP. cam with more lift and duration would pull hard at least that far.

Thanks,
Rick

PS. Charlie, how much compression are you running with this cam and Nitrous? Be interested to know how it runs. Keep us posted.

I use a 170 engine, which has a "zero" deck hight. Mine is about .002 down in the hole. Head gasket about .040, now, previous .022 thick. Head milled .090 if I remember right. I will be cc ing the head before it goes back on. Will also have valve notches in the pistons, which i did not have with the old cam. Compression should be around 9.5- 10.0 to 1.
Lift and duration, don't tell the whole story, on cams. Lobe separation, centerline, and overlap are even more important.

_________________
Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Rick,

My first guesses would be carburetor jetting/secondary engagement, followed by ign timing or dist fault, followed by valve springs. Those are pretty old valve springs. I think I remember that you guys degreed the cam, and it should pull to 6000 no problem. The cam is not your problem, unless it's way advanced.

The ignition should not be a problem either. If your timing curve is way off, that could also be the problem. Get an advance timing light on there and check that full advance is no more than 30 degrees (I run 26-30 on my hot street motors with pump gas). Too much advance will kill your top end, in my experience. If that doesn't give enough initial advance (need 10-15 for that cam), then you need to weld up the slots in the dist to decrease the adv range.

Another slight possibility is the fuel pump running out, so you might try swapping in a new one. I have had fuel filters/lines and air filters clog and give similar results too.

You might try jetting the secondaries fatter by 3-5 thou and see if that helps. The engagement timing can also be changed with some work on the weights. I got best power and pull from a rich-jetted Edel 600 with my similar buildup to yours. This is the easiest thing to try, so may as well do that first.

FYI, my motor happily pulls to 6000 and always wants me to rev it higher (very tempting ), but I am nervous with stock rods and pistons.

Happy hunting,

Lou

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Home of Slant6-powered fun machines since 1988

Rick, I am getting ready to put that same cam in my motor today. Mike said that when they ran one it peaked out at about 55-5700, and they shifted at 6000. I'd look for a fuel delivery problem.

Charlie, e-mail me your shipping address and I'll get that Racer Brown out to you this week if you still want it.

Lou, Mike and Blaine shifted their stock rod motors at 6500 or so. I know one of those motors lasted 535 passes before a rod let go.

_________________
Official Cookie and Mater Tormentor.

Hey Dennis,

Thanks, I remember that figure and have discussed it with Mike at Gatlinburg this year too. Keep in mind that on a road race event of one weekend, I put at least the equivalent of 100 passes on my motor (probly more like 300), so I am erring a bit on the safe side.


Cheers,

Lou

_________________
Home of Slant6-powered fun machines since 1988

Thanks for all the info. I noticed the engine running a little rougher than normal so we pulled the valve cover and ran the valves and found several that were pretty loose and one that was very loose? Not sure why? The adjusting nut was still good and tight.
Anyway, my son took it out for a drive and said that this made a lot of difference. He said it now pulls strong up to about 5800 RPM. With the other tuning tips I think we will be right where we should be.
I don't have an advance timing light. Is there a way to check the total advance without one? Or should I just go buy one?

Thanks for all your help,
Rick

You can mark your balancer to show 30 and 35 degrees, you can use the timming tab to "index over" to that place. I punch two new marks right into the balancer, one at 30 and the other at 35, these end-up close together and it's easy to tell the total timming with a regular timming light.
DD