#5 Running Hot - Chevelle Tech
Engine AdvertisementGeneral Engine Discussion. Advertisement

 1Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 17 (permalink) Old Jul 14th, 19, 12:24 PM Thread Starter
Tech Team
Scott
 
Join Date: Jun 2013
Location: Columbus, OH
Posts: 126
#5 Running Hot

I have a Gen1 383 with Dart SHP 200 Aluminum heads, Comp 274 Extreme cam, Performer RPM intake.

I'm getting #5 running hot/lean, about 125 degrees F hotter than my other cylinders when running a temperature gun on the header. I get mild fluctuations in the vacuum at idle and it's a little rough (not related to cam).

I've done the carb spray check for a vacuum leak. No difference. Compression checks all came back in the same range.

Anything else you could recommend checking for a hot/lean cylinder? thanks!
scottpreston is offline  
Sponsored Links
Advertisement
 
post #2 of 17 (permalink) Old Jul 14th, 19, 1:16 PM
Tech Team
 
Join Date: Jul 2019
Posts: 38
I was going to say and exahust valve not closing properly. Have you checked your valve lash again after noticing this condition
Ironman711 is offline  
post #3 of 17 (permalink) Old Jul 14th, 19, 1:18 PM
Tech Team
 
Join Date: Jul 2019
Posts: 38
And how close are the compression readings
Ironman711 is offline  
 
post #4 of 17 (permalink) Old Jul 14th, 19, 2:32 PM Thread Starter
Tech Team
Scott
 
Join Date: Jun 2013
Location: Columbus, OH
Posts: 126
Re: #5 Running Hot

Compression close within 5psi on all cylinders. Just reset valve lash last fall when I installed new rockers. I'll look again at the valve lash, but wouldn't an exhaust valve not closing cause the left bank to run rich? i don't see any difference in the exhaust between the two, right bank is steady 12.5 at idle.
scottpreston is offline  
post #5 of 17 (permalink) Old Jul 14th, 19, 3:44 PM
Tech Team
Harry
 
Join Date: Jan 2011
Location: Los Angeles
Posts: 251
Re: #5 Running Hot

Quote:
Originally Posted by scottpreston View Post
I have a Gen1 383 with Dart SHP 200 Aluminum heads, Comp 274 Extreme cam, Performer RPM intake.

I'm getting #5 running hot/lean, about 125 degrees F hotter than my other cylinders when running a temperature gun on the header. I get mild fluctuations in the vacuum at idle and it's a little rough (not related to cam).

I've done the carb spray check for a vacuum leak. No difference. Compression checks all came back in the same range.

Anything else you could recommend checking for a hot/lean cylinder? thanks!
Timing too retarded maybe ? Gas burning in header maybe ? Maybe try increasing the timing at idle 5 or 10 deg. and see what happens ? maybe that cylinder will clean up ?

Harry
1970 Chevelle SS396 (408), Fathom Blue,
Original Block & Forged Crank, KB Pistons, Edelbrock 6045 Heads,Comp Cam 292H, March Serpentine, RPM AirGap,750HP,100hp Nitrous
A/F Wideband,Tremec TKO 600, 12 bolt,
30 spline Moser Axles, Richmond 3:73's, Hotchkis control arms, swaybars, springs, Wilwood 12" rotors D/S, 4 piston calipers
hjdca is offline  
post #6 of 17 (permalink) Old Jul 14th, 19, 5:21 PM
Senior Tech Team
 
Join Date: Apr 2012
Location: Yerington, Nevada
Posts: 1,576
Re: #5 Running Hot

Valve in liftr not operating properly, not keeping valve set correctly.

I had a friend's chevelle years ago, brand new rebuilt engine my pal installed, would read good compression on test, fire it up, number 8 went away. Lifter for the intake on th number 8 was pumping past valve settng, holding intake valve open when oil pressure was raised when engine ran. Replaced brand new lifter, problem solved.

Recheck valve settings first, E-O, I-C method only.
1966Chev likes this.
Dave Ray is offline  
post #7 of 17 (permalink) Old Jul 14th, 19, 9:51 PM
Tech Team
 
Join Date: Jul 2019
Posts: 38
The lifter could be failing especially if it's sat for some time
Ironman711 is offline  
post #8 of 17 (permalink) Old Jul 14th, 19, 10:27 PM
Moderator
Levon
 
Join Date: Jul 1999
Location: Priddis, Ab. Canada
Posts: 9,224
Re: #5 Running Hot

Intake gasket leak on that cylinder??????????????

Levon Hovagimian
Team Chevelle #279
2015 Camaro ZL1 Summit White (Bone Stock)
70 Chevelle SS 454 LS5 4 speed. SOLD
Current Engine VortecPro 460 (513 HP) Original is resting
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

1966 427 Corvette SOLD
1973 Camaro IHRA Hot Rod (LS-6 Auto)11.00 @121 (Chased a 10.99 or better) SOLD

Priddis Greens, Ab. Canada


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
LevonH is online now  
post #9 of 17 (permalink) Old Jul 15th, 19, 6:12 PM Thread Starter
Tech Team
Scott
 
Join Date: Jun 2013
Location: Columbus, OH
Posts: 126
Re: #5 Running Hot

Lifters were just replaced <500 miles ago, my first thought was Intake Gasket leak. Seems to be conflicting installation, some say to use Gasgacinch sealant, some say to use RTV. I didn't use RTV on the intake side, in fact the gaskets I use already had a bead meant to seal them.

scottpreston is offline  
post #10 of 17 (permalink) Old Jul 15th, 19, 11:31 PM
Gold Founding Member
 
Join Date: Aug 1998
Location: the Seasonally Frozen Wastelands
Posts: 10,877
Re: #5 Running Hot

Where does the vacuum for the power booster come from? #5 runner?

Did you SEARCH BEFORE POSTING a new thread?
Did you post in the CORRECT FORUM?
Schurkey is offline  
post #11 of 17 (permalink) Old Jul 15th, 19, 11:48 PM
Senior Tech Team
 
Join Date: Apr 2012
Location: Yerington, Nevada
Posts: 1,576
Re: #5 Running Hot

Actually, the sealer on the intake manifold gaskets, you have the end sealing covered, RTV works in place of the rubber end seals.

That stuff around every intake port and water port is a compound used not only on gaskets, but as a gasket for metal to metal junctions, metal to rubber, etc.

The motorcycle industry uses a sealer that is the same as the beads, called Three-Bond, and is anything from 4, 1104, 1194, and other levels of sealer. They use it between engine cases that have no gasket but the T-B compound, on gaskets, and just about anything except exhaust heat areas. Motorcycle manufacturers have it as well, Honda Bond, and the number, Kawasaki Bond, Yama-Bond, Suzuki seal, and on.

I use it to seal rubber intake manifolds on bike engines, to the aluminum head flanges,

I don't know what it is called in the automotive industry, but it is great stuff, and different colors on different gasket sets.

Key is to get the surfaces clean, clean, CLEAN, and install, let set up for a couple of hours before use. Cleans up easily with acetone or lacquer thinner, and it stays a touch wet.
Dave Ray is offline  
post #12 of 17 (permalink) Old Jul 16th, 19, 8:26 AM Thread Starter
Tech Team
Scott
 
Join Date: Jun 2013
Location: Columbus, OH
Posts: 126
Re: #5 Running Hot

Quote:
Originally Posted by Schurkey View Post
Where does the vacuum for the power booster come from? #5 runner?
No actually I have a Holley 4160, the Brake Booster comes off the Carb near the rear. The manifold in the rear has a plug.

scottpreston is offline  
post #13 of 17 (permalink) Old Jul 16th, 19, 9:47 AM
Tech Team
 
Join Date: Jul 2019
Posts: 38
Did you recheck the valve lash and how much do you run the motor or how long has it sat up. And if it sat up or wasn't run very much. Bc if you set the valve lash and then the motor sat for a period of time with the spring pressure on the lifters its possible even if it was done 500 miles ago that it could be bad. Over winter when my motors are not being run I loosen the rockers so there is no pressure on my lifters just for this reason. And I've seen brand new comp cam roller lifters be stuck now as soon as we called them about it they made it good on there end. They set another set no questions asked
Ironman711 is offline  
post #14 of 17 (permalink) Old Jul 16th, 19, 10:17 AM
Gold Member
Gene
 
Join Date: Sep 2000
Location: Buffalo NY
Posts: 14,001
Re: #5 Running Hot

an intake leak would also be pulling oil mist from the galley. So #5 plug would look sooty.

Gene
ACES 3112/Team Chevelle Gold #62
Be big, be a 'builder'!
427L88 is offline  
post #15 of 17 (permalink) Old Jul 16th, 19, 1:48 PM
Senior Tech Team
 
Join Date: Apr 2012
Location: Yerington, Nevada
Posts: 1,576
Re: #5 Running Hot

Not if the leak was only at the top of the port/gasket, Gene.
Dave Ray is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in










Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome