Tapping when cold and trouble shifting to first
Hi All, Recently rebuilt my L6 230. Broke it in, and changed the oil. Running SAE30 this change with ZDDP additive.
When I first fire it up, its very tappy. I don't know if this is normal or a symptom of a misadjustment. I followed the compcams instructions to set pre load on the lifters, 3/4 turn past when the pushrod wont easily spin in my fingers. Video of cold start: https://imgur.com/l6cKica Video after it warms up: https://imgur.com/x6ZlTGi Any thoughts? My second problem is thus: It's the manual 3-speed transmission with 3OTT. Sometimes when I go to shift into 1st gear at a stop light or stop sign, it sort of jerks/thunks/grinds into gear even with the clutch pedal fully depressed. I believe this is a non-synchro transmission, but even from a dead stop this happens sometimes. What's going on? Any thoughts on how to fix it? I've tried to double clutch, I've tried to goose the engine a touch before attempting, no dice. I don't think it's happened when switching from Reverse to 1st gear, only when downshifting from 2nd to 1st at a complete stop. |
Re: Tapping when cold and trouble shifting to first
Instead of twist the pushrod, try the wiggle all the slack movement out of the rocker method. Some knuckle draggers like me can twist the rods even with the valve spring compressed.
Your shift problem could just be a need for a pedal adjustment. Tighten the linkage up a bit. |
Re: Tapping when cold and trouble shifting to first
I didn't watch the videos, so no comment there. You probably have no synchro for first if it is the original trans, so it's going to grind on a downshift. Wait until you are completely stopped before shifting to low (truck still in 2nd or 3rd gear, clutch disengaged). Check your clutch free pedal, and if that's OK, pull the trans into 2nd or 3rd before going to reverse or 1st, as that will stop the cluster gear from spinning, and you will be able to put it in those gears with no clashing.
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Re: Tapping when cold and trouble shifting to first
The ol' three speeds are touchy in the sense that if you depress the clutch, go into neutral, and release the clutch (engine running), the non-syncro first gear needs quite a bit of time at an idle with the clutch depressed before you can slip it right into first. You can avoid the delay (for instance at a long stoplight while idling in nuetral with the cutch out ) by depressing the clutch, then just moving the stick enough to kiss the syncros on second (or even third) and then a properly adjusted clutch will let you drop right into first. I do that a lot in traffic, and for a quick stop sign I just make sure I roll up braking while decelerating in third, then just before it starts to lug I depress the clutch, and keep it down until I finish stopping and it drops right in. The trouble comes when you go to neutral to rest your leg. That's when you gotta touch a synchronized gear before she'll drop in.
Regarding the lifters....when I do a static adjustment, I dont spin the pushrod but rather try to click it up and down until all the lash disappears, then take my additional quarter turn. It always seems to me that they spin pretty easy, even when they have a bit of torque on them. I still follow up with a running adjustment afterward though, backing off each one untill it clicks then slowly tighten until it just quiets down, then give it the extra 1/4 to 1/2 turn. Edit: looks like I took so long that geezer and steeveedee stole my thunder :) oh well....good luck! |
Re: Tapping when cold and trouble shifting to first
Folks seem to be implying that my pushrod spin method will result in me setting the valves too tight, but my symptom is more like they are too loose, right? When properly adjusted, will I still have this kind of tapping on cold starts?
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Re: Tapping when cold and trouble shifting to first
That doesn't sound like a lifter. It has a ting to it.
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Re: Tapping when cold and trouble shifting to first
That’s better.
Got the videos to work this time. Cold. That’s not normal. Sounds too loose. Hot. Still some ticking a tiny bit. Pull the cover and set them hot running. What weight of oil are you using? |
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I'll pull the cover and set them when running and see how that goes. Might also have an exhaust leak judging by the comments on ticking I guess? |
Re: Tapping when cold and trouble shifting to first
When you pull the cover watch all the rockers for movement too.
Use cardboard along the sides to deflect any oil splash. My method is to loosen each one then tighten until clicking stops, then do the rest like that. Then shut it down and adjust them all 1/4 turn more. This way your motor won’t tend to quit if a valve hangs open momentarily. And it’s more accurate. But try some lighter oil first. Might save a mess. |
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Re: Tapping when cold and trouble shifting to first
So I didn't hear a ting sound? :dohh: Not that I have great hearing anyway. If you have a mechanics stethoscope you might be about to pin point where the noise is coming from. Just a bit of advice, don't buy one from Harbor Freight. :D
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Re: Tapping when cold and trouble shifting to first
Well I tried to adjust twice while running and in addition to making a mess, i might have made it sound worse. I'm honestly tempted to just get rid of the truck. I'll try another time to set them with the engine off, manually turning the engine to find the bottom of the lobe.
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Re: Tapping when cold and trouble shifting to first
It goes away after running awhile - sounds like one of the lifters is going flat.
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Re: Tapping when cold and trouble shifting to first
If you didn’t tear the motor down completely to flush all the fine metal out from the first cam failure then there’s a good chance it’s come back to bite you in the butt.
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Re: Tapping when cold and trouble shifting to first
That's the recommended method, or you'll just grind the next one down.
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Hydraulic lifters are sort of suspended by oil. You turn the motor off, the bad lifter goes flat from the spring tension. Start the motor up and the lifter is noisy till the oil gets back in it. It runs OK when warm- that means the cam is OK. Take off the valve cover and turn the engine over a few times- the loose rocker should be easy to find. Make sure the pushrod isnt bent. |
Re: Tapping when cold and trouble shifting to first
Sold the truck this morning. It went fast, people are thirsty for these old trucks. Thanks for the help, some day I'll get another project when my family and house situation is more conducive to it.
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Re: Tapping when cold and trouble shifting to first
Ouch. I hope you got a decent amount of money for it. People are asking incredible money for not-so-incredible trucks.
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Re: Tapping when cold and trouble shifting to first
I have an extra short bed truck and a corvette lt1 engine. Maybe it is time to put another one together, and make some extra dough.
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