...

Go Back   Lateral-g Forums > Technical Discussions > Engine
User Name
Password



Reply
 
Thread Tools Display Modes
  #1  
Old 04-23-2015, 11:36 AM
Sieg's Avatar
Sieg Sieg is offline
Moderator
 
Join Date: Dec 2010
Location: Pacific Northwet
Posts: 8,034
Thanks: 33
Thanked 101 Times in 41 Posts
Default

First thing you need is compression, as in no bent valves.

I'd want to know why it happened before going any further.
Reply With Quote
  #2  
Old 04-23-2015, 12:25 PM
Decline Decline is offline
Member
 
Join Date: Mar 2014
Posts: 56
Thanks: 0
Thanked 0 Times in 0 Posts
Default

I can do a compression test on it to see if the valve is damaged on more than just the top..
My assumption is that rockers were loose and got out of alignment with the pushrods.
Does anyone else have any theories on what causes this?
Another friend of mine recomended taking a look at the lifters as well to see if there s damage..
I really wanted to avoid taking the engine apart
Reply With Quote
  #3  
Old 04-23-2015, 01:58 PM
GregWeld's Avatar
GregWeld GregWeld is offline
Lateral-g Supporting Member
 
Join Date: Jul 2005
Location: Scottsdale, AriDzona
Posts: 20,741
Thanks: 504
Thanked 1,080 Times in 388 Posts
Default

You may be able to get away with a "lash cap" on the messed up valve. But then this push rod length would need to be adjusted due to the now "longer" valve stem.


Now then. - this didn't just bend like that as you were casually driving down the road. My guess is you experience a severe backfire or you were getting after it pretty good.

My question would be: what was the timing? Why did you decide to adjust it? And what did you adjust it to? And did you adjust and or check the TOTAL timing?? And what was that number?
Reply With Quote
  #4  
Old 04-23-2015, 04:27 PM
Decline Decline is offline
Member
 
Join Date: Mar 2014
Posts: 56
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Quote:
Originally Posted by GregWeld View Post
You may be able to get away with a "lash cap" on the messed up valve. But then this push rod length would need to be adjusted due to the now "longer" valve stem.

Never heard of a lash cap..i will look into it. This could be a possible band aid along with an adjustable pushrood[/COLOR]

Now then. - this didn't just bend like that as you were casually driving down the road. My guess is you experience a severe backfire or you were getting after it pretty good.

It happened as i was leaving work. I went a few blocks and heard the rattleing/clanking, so i turned around and came back. I thought it was just mis firing. A couple hours prior to that my buddy and I were in the parking lot attempting to check the timing again cuz the car seemed to be running rich and smoking covering my rear bumper with a thin film of black soot. The idle wouldn't settle down enough to check base timing..I rev'd it a few times at the carburator to try and get it settle. I heard some pings or pops during that time also.

My question would be: what was the timing? Why did you decide to adjust it? And what did you adjust it to? And did you adjust and or check the TOTAL timing?? And what was that number?


My engine has never really run right since after I got my suspension installed a few months ago. I've tried various fixes.
It is an AME front clip so the motor had to come out.
My old headers were "massaged" to fit which meant the shop beat one the tubes about 2/3rds closed..So I got the AME headers to clear control arms. That seemed to work for a while..
Performance was still spotty so I got new plugs and wires.. Was better.
Then it occured to me to check the timing..Well the distributor was loose so i thought id found my culprit.. I bought a timing gun watched a few youtube videos and set my initial timing to 12degrees, then i set my total timing to 36 degrees-ish.. I say "ish" because I had no tach to reference engine rpm so i manually rev'd it to what i figured was between 2500-3000..
It was actually running pretty good like that and i did the Del Mar good guys autoX a few weeks ago. Other than my high idle and crap gas mileage(10-12 down from 15-18) I thought i was in decent shape, just thought the carb needed tuning..
Reply With Quote
  #5  
Old 04-23-2015, 08:26 PM
Che70velle's Avatar
Che70velle Che70velle is offline
Senior Member
 
Join Date: Aug 2012
Location: Dawsonville Georgia
Posts: 2,251
Thanks: 648
Thanked 179 Times in 121 Posts
Default

Solid or hydraulic cam? Do you know how to check and set valve lash?
__________________
Scott
---------------------------------------------------------------
70 velle' on custom chassis w/custom RideTech coilovers, RED sleeved 434” with Mamo 265’s, F-body Magnum, 12 bolt 3:73, wilwood 6/4's, bla, bla, bla...build. thread https://lateral-g.net/forums/showthread.php4?t=39631
New 434” engine build here https://ls1tech.com/forums/generatio...ved-block.html

Thanks Dad!!

My Chevelle is old school... It has a belt driven power steering pump.
They're 17's, but I keep em clean!
Reply With Quote
  #6  
Old 04-24-2015, 09:10 AM
GregWeld's Avatar
GregWeld GregWeld is offline
Lateral-g Supporting Member
 
Join Date: Jul 2005
Location: Scottsdale, AriDzona
Posts: 20,741
Thanks: 504
Thanked 1,080 Times in 388 Posts
Default

An adjustable push rod is a checking/measuring tool.... there is no such thing that you could use to actually run the motor with.

At this point there is only ONE correct way to fix/diagnose your issue.

Drain your coolant
Pull the distributor
Remove the intake
Remove the head and fix the valve

There's something going on here that needs to be solved. My guess is you have a cam going flat.. which you'd be able to see if you remove the intake manifold. That would explain your running rough and inability to keep the car in a steady state of tune. The cam "going away" would allow the lash to open - pounding the pushrod - and stressing the valve train.
Reply With Quote
  #7  
Old 04-24-2015, 04:24 PM
Vince@Meanstreets's Avatar
Vince@Meanstreets Vince@Meanstreets is offline
Senior Member
 
Join Date: Nov 2004
Location: Bay Area, California
Posts: 5,532
Thanks: 13
Thanked 20 Times in 13 Posts
Default

Im with these guys, there's more than just push rods doing on. With possible mis matched stuff going on the best bet would be to replace the two bent push rods. Check ratio, check for coil bind and make sure your retainer isn't hitting the valve guide.

Did you over rev the engine recently?
Are you using coolant? Hydraulic that cylinder?

7&8 are the most common to go flat. Especially if you had just replaced an intake manifold and or gasket.
__________________
MEANSTREETS PERFORMANCE

Dealer for
ACCUAIR rideheight control systems
ENTROPY RADIATORS XXX radiators for your pro-touring vehicle
FORGELINE MOTORSPORTS Highline custom 3 piece wheels
WEGNER AUTOMOTIVE Custom engines and LSX drive systems
SPEEDTECH PERFORMANCE Bay Area stocking dealer

NEVER FORGET -11
Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 05:26 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2025, vBulletin Solutions Inc.
Copyright Lateral-g.net