Advice-Changing the timing cure on your HEI distributor? Timing recurve kits suck
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- čas přidán 22. 07. 2017
- The best way for me (heavy car) to get faster mechanical advance with a GM HEI distributor is to add mass to the stock weights and use the stock springs. Learn from me and don't be afraid to try stuff; it just might work, like this did!
A little late to game... but im currently in same boat trying to figure out how to configure a ZZ4 crate engine distributor, the original one went caput from the previous owner and got replaced it with an aftermarket who knows what, it starts the engine instantly, great acceleration, pings somewhat mid throttle and lacks top end for some reason, even when using the recomended 93octane fuel. I'll tell you what though, the GM original #41(outer weights) and #375(center weight), what you have in this video, is what everyones lQQking for when it comes to the SBC engine, GM got it right wih those peices, the aftermarket weights dont even come close and more often than not, create more headaches than its worth. So in short, The 41/375 is KNOWN to give 21/22 crankshaft degrees of timing curve, nothing else does.
Ha ha, my 41/375 is sitting in the back of the car as a spare in case it's needed one day, I am glad that you left this comment, I didn't know that. I was going to go though the distributor this winter, I guess I'll try that one out.
I've had the welded one in service the entire time since this video we posted, its been running great. I too have a little issue at part throttle, on hill climbing, but I've change my driving habits and I can deal with it. I'm all full mechanical advance at 2000 rpm.
Never too late on this channel buddy, thank you from all of us reading the comments! I find allot of help in other video comments.
@@amateurism1 if you are getting ping under load at low/mid rpm, you may need to limit your vacuum advance or reduce its rate!
You completely overlooked the limiter bushing- the most important part of modifying your advance curve. Your goal is to shorten the amount of distributor advance so that you have more timing at idle & low engine speeds without having excessive total timing advance at higher engine speeds.
You are correct, I didn’t mess with that, however when I said “still a bit too much mechanical advance,” I didn’t include the word “rate.” My problem was the rate of mechanical advance; it was reaching full advance too soon; I didn't clearly states that.
The point of the video is this: these are pieces of steel stamped by a company that only intend to sell some widget to the guy at the race track; this would have worked fine with a track car where all I cared about was getting down the straight track as fast as possible-For street driving, I'd stick to the GM stuff, I think they spent a little more time trying to figure out the best combination of factors that influence drivability.
Are my welded weights better than the aftermarket stuff? No, but I bet you didn't think about doing that; that's the point of the video, the welding did the trick (for me).
It's been years and I'm still using the weights with the weldment adding mass to the weights, they seemed to have done the trick well.
I also have this HEI in a wagon ( heavy car), these problems/solutions to problems I've experienced may be different, than other people's experience.
Thank you for your comment, the next time i change the engine configuration and I'm messing with the HEI, I'll try larger bushings to stop the travel short. I still have some issues hill climbing and that might do the trick.
I kinda want the opposite with my manual trans 300-i6 van.
It falls off at high rpm with retarded timing, but too much base timing and it will either ping or stall off the line without precise throttle and clutch control.
With retarded base timing, it pulls like a steam engine at like 200rpm.
I want lugging and I want to be on the lean edge at the same time. Since it's slow I just want MPG and Towing capability.
I have the stock weights and the weakest springs on both sides. Love it, but the recurve kit is junk. You have to use those plastic bushing. What I'm not using. No plastic bushing. So I just left the stock weights and changed springs.
Stephen, I think you don't quite understand how these kits are supposed to work. These kits are designed to reduce the total advance NOT increase it. Although you didnt mention it they include a bushing that's supposed to shorten the travel by about 1/8th of an inch. Then you're supposed to increase the initial timing by the amount you removed from the centrifugal advance.
the stock springs are two different weight one heavy on light thats how its suppose to work a simple trick is to just pull the heavy spring off and leave the light or to remove springs all togethjer and weld the slot on the cross mount forcing the weights out all the time
just stretch the stock springs to make the mechanical advance react faster. if the idle sounds high, lower the idle on the throttle screw. I don't have the time to thoroughly explain how I can have full advanced timing at higher speeds and still have a nice low idle when my foot is off the pedal. So many amateur backyard wannabe mechanics who have several years more experience than me are still dumbfounded by the HEI ignition systems. Every vehicle I've owned since I was a kid have been all the same thing. I made plenty of mistakes in the past with incorrect timing, even wrecked a camshaft from doing improper valve lash adjustments. I also snapped a crankshaft in half once at 55mph in 2nd gear while passing slower traffic. In a motorhome! I've lost licenses, been in high speed chases in the past. I'm insane at the wheel. I don't quite get why anyone spends so much time on making extra mods to part of the timing advance mechanism and they're still not satisfied with the results.
Watch this:
czcams.com/video/uZPpxbAITlM/video.html
I'm not going to tell you you're wrong, but I don't want people reading your comment to try that.
That same kit worked well on my cad 472.
how did your engine behave with it.
How its laying on the floor - the piece in the middle just needs to be flipped over.
If you are running it the way you have it on the floor you need to flip the center piece
I followed the instructions, that’s all I’m going to say. I’m currently switching over to a locked out system with a c.b. Black box and msd cdi. All I can do is hope it works better, time and some tweaking will tell.
Going to heavier weights is the same effect as going to lighter springs. Probably bought in full timing sooner, doubt it changed it any.
My goal was just that, bring full timing in sooner, but being able to return to base timing all the time was another goal, thats the point of the video, the aftermarket weights are junk, don't fit right, and don't always return to base timing 100% of the time.
Was their a chance... ur timing chain/belt was stretched???
I'm with you. I fiddled with a kit and went back to OEM. I started with using the new weights, but shit canned those and went back to OEM. The kit's light (black) springs seemed lighter than OEM, but the OEM springs definitely looked lighter than the kit's medium and heavy springs. With the light (black) springs my idle timing jumped from 10° to 20°. I was expecting my idle timing to be the same. Are the springs so light that timing is advanced at 800 RPM? I didn't try retarding the idle timing with the light springs. Did you? I was running out of daylight so I put it all back to OEM. I'll mess with this another day.
can you add the weld underneath?
I don’t think you can, I can’t on mine.
It's a combination of buying a Made in China
curve kit and not knowing what you're doing.
Why is he screaming 😅