Cold lash after 500 miles, yikes!

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
Bishop540
Member
Member
Posts: 101
Joined: Mon Apr 10, 2017 6:58 pm
Location: Spring, TX

Cold lash after 500 miles, yikes!

Post by Bishop540 »

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
Expert
Expert
Posts: 598
Joined: Wed Jul 11, 2012 7:03 am
Location: BETHLEHEM PENNA.

Re: Cold lash after 500 miles, yikes!

Post by amc fan »

How did it sound after you adjusted the valves?
Bishop540
Member
Member
Posts: 101
Joined: Mon Apr 10, 2017 6:58 pm
Location: Spring, TX

Re: Cold lash after 500 miles, yikes!

Post by Bishop540 »

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
Cubic_Cleveland
Guru
Guru
Posts: 1163
Joined: Thu Feb 23, 2012 11:44 pm
Location: Australia

Re: Cold lash after 500 miles, yikes!

Post by Cubic_Cleveland »

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
Member
Member
Posts: 101
Joined: Mon Apr 10, 2017 6:58 pm
Location: Spring, TX

Re: Cold lash after 500 miles, yikes!

Post by Bishop540 »

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
F-BIRD'88
Guru
Guru
Posts: 9802
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Cold lash after 500 miles, yikes!

Post by F-BIRD'88 »

Checking lash at tdc will not give accurate results.
Try .018" cold , done right. IO EC
GARY C
HotPass
HotPass
Posts: 6301
Joined: Tue May 14, 2013 10:58 pm
Location:

Re: Cold lash after 500 miles, yikes!

Post by GARY C »

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.
Please Note!
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!
F-BIRD'88
Guru
Guru
Posts: 9802
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Cold lash after 500 miles, yikes!

Post by F-BIRD'88 »

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
Guru
Guru
Posts: 9802
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Cold lash after 500 miles, yikes!

Post by F-BIRD'88 »

Setting at tdc does not work.
GARY C
HotPass
HotPass
Posts: 6301
Joined: Tue May 14, 2013 10:58 pm
Location:

Re: Cold lash after 500 miles, yikes!

Post by GARY C »

I never did cold setup past the initial build, what it is hot is all that matters.
Please Note!
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!
F-BIRD'88
Guru
Guru
Posts: 9802
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Cold lash after 500 miles, yikes!

Post by F-BIRD'88 »

It's EO IC. Just want d to see if you were paying attention.
1972ho
Guru
Guru
Posts: 1299
Joined: Thu Nov 21, 2013 12:52 am
Location:

Re: Cold lash after 500 miles, yikes!

Post by 1972ho »

Are these Jessel shaft mounted rockers are stud mounted, maybe you should check lash more often than 500 miles.
pdq67
Guru
Guru
Posts: 9841
Joined: Thu Mar 04, 2010 8:05 pm
Location:

Re: Cold lash after 500 miles, yikes!

Post by pdq67 »

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
naukkis79
Pro
Pro
Posts: 383
Joined: Tue Jul 29, 2014 5:14 am
Location:

Re: Cold lash after 500 miles, yikes!

Post by naukkis79 »

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.
pamotorman
Guru
Guru
Posts: 2802
Joined: Thu Mar 06, 2014 11:55 pm
Location:

Re: Cold lash after 500 miles, yikes!

Post by pamotorman »

with aluminum heads the lash will grow .004 cold to hot as the heads expand. I used this for first setting.
You do not have the required permissions to view the files attached to this post.
Post Reply