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Cold lash after 500 miles, yikes!

General engine tech -- Drag Racing to Circle Track

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Bishop540
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Cold lash after 500 miles, yikes!

Post by Bishop540 » Sat Sep 01, 2018 8:54 pm

Yikes! I have about 675 miles on my 540 now and i pulled the valve covers off today (last time was 50 miles or so, when new). Most of the cold lash readings were in the .040's. Thats about .017-.025 too much. I originally set the cold lash at .024 and the hot lash at the recommended. .030. They all ranged from .038-.049, and one of them was .029 (which was weird).

Now, I did set both valves at TDC when I did it at 50 miles. This time I checked them at EOIC, and set them that way too. I went ahead and set them a bit tighter than recommended this time because I have been wanting to try a different lash for a while. Tonight I set them cold at .020, which should be around .026 hot.

Is that much variation in lash normal for the "1st check after 500 miles"?

Aluminum AFR heads
Dart block
Lunati 40110515 solid roller cam
1.8/1.7 rockers
Eric

amc fan
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Re: Cold lash after 500 miles, yikes!

Post by amc fan » Sat Sep 01, 2018 9:22 pm

How did it sound after you adjusted the valves?

Bishop540
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Re: Cold lash after 500 miles, yikes!

Post by Bishop540 » Sat Sep 01, 2018 9:31 pm

I haven't started it yet, or checked it hot. But thats a good question and i cant wait to see if it runs a bit different. With too much lash I guess it "acted" like a smaller cam. ????
Eric

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Re: Cold lash after 500 miles, yikes!

Post by Cubic_Cleveland » Sat Sep 01, 2018 9:41 pm

Did you check any of the valves using the same method you set them at originally when you found they were loose? Did you check the valves after you re-set them this time using the same method as originally set? That might have provided some answers for you...

Bishop540
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Re: Cold lash after 500 miles, yikes!

Post by Bishop540 » Sat Sep 01, 2018 9:54 pm

Cubic_Cleveland wrote:
Sat Sep 01, 2018 9:41 pm
Did you check any of the valves using the same method you set them at originally when you found they were loose? Did you check the valves after you re-set them this time using the same method as originally set? That might have provided some answers for you...
No to both, but if I would have checked them the TDC method I assume they would have been a little tighter.
Eric

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Re: Cold lash after 500 miles, yikes!

Post by F-BIRD'88 » Sat Sep 01, 2018 11:36 pm

Checking lash at tdc will not give accurate results.
Try .018" cold , done right. IO EC

GARY C
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Re: Cold lash after 500 miles, yikes!

Post by GARY C » Sat Sep 01, 2018 11:37 pm

Bishop540 wrote:
Sat Sep 01, 2018 9:54 pm
Cubic_Cleveland wrote:
Sat Sep 01, 2018 9:41 pm
Did you check any of the valves using the same method you set them at originally when you found they were loose? Did you check the valves after you re-set them this time using the same method as originally set? That might have provided some answers for you...
No to both, but if I would have checked them the TDC method I assume they would have been a little tighter.
My friends use to make fun of me because I would pull the plugs and rotate the engine with an old tq wrench to make sure I was on the lowest point of the base circle but it was because I had found discrepancies before using all the other methods.
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Re: Cold lash after 500 miles, yikes!

Post by F-BIRD'88 » Sat Sep 01, 2018 11:40 pm

Post the cam part # and brand and I will look it up see if I can determine design lash point. If it a UDHarolds cam lunati and Bullet can both advise on lash setting +\- tolerence. With aluminum heads you need to set the cold setting sorta tight. So .018" is none too tight for it.
Last edited by F-BIRD'88 on Sat Sep 01, 2018 11:42 pm, edited 1 time in total.

F-BIRD'88
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Re: Cold lash after 500 miles, yikes!

Post by F-BIRD'88 » Sat Sep 01, 2018 11:40 pm

Setting at tdc does not work.

GARY C
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Re: Cold lash after 500 miles, yikes!

Post by GARY C » Sun Sep 02, 2018 12:04 am

I never did cold setup past the initial build, what it is hot is all that matters.
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THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!

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Re: Cold lash after 500 miles, yikes!

Post by F-BIRD'88 » Sun Sep 02, 2018 12:51 am

It's EO IC. Just want d to see if you were paying attention.

1972ho
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Re: Cold lash after 500 miles, yikes!

Post by 1972ho » Sun Sep 02, 2018 1:39 am

Are these Jessel shaft mounted rockers are stud mounted, maybe you should check lash more often than 500 miles.

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Re: Cold lash after 500 miles, yikes!

Post by pdq67 » Sun Sep 02, 2018 3:56 am

I always checked mine hot while idling!

This way I know what it is!!

It's messy so I would just drape a clean red shop towel over half the rockers to hold squirt down and set the open half and then move the towel to the adjusted half.

Hy-cam, use the spin the push rod between your fingers!

Solid lifter cam, use good feeler gauges AND it is a, "feelie-deal"...

pdq67

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Re: Cold lash after 500 miles, yikes!

Post by naukkis79 » Sun Sep 02, 2018 5:25 am

When lash opens that usually means that something in valve train is bending - so at least check lashes again after another 50 miles. If lash is actually opening and that was not from just different lash checking method you will have soon problems.

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Re: Cold lash after 500 miles, yikes!

Post by pamotorman » Sun Sep 02, 2018 9:43 am

with aluminum heads the lash will grow .004 cold to hot as the heads expand. I used this for first setting.
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