Lifters, cam, timing and backfires - S-10 Forum
 
LinkBack Thread Tools
post #1 of 11 Old 09-30-2014, 12:48 PM Thread Starter
overthinker extraordinar
 
jcricket's Avatar
 
Join Date: Sep 2014
Location: littleton colorado
Age: 54
Posts: 650

User is: jcricket is offline
Lifters, cam, timing and backfires

Hey Folks,
I am pretty sure I know the answer to this question, but thought I would see if I can get some confirmation.

My motor runs just the slightest bit off. It his a mild miss, maybe two. I can hear some lifters clicking a bit excessively. Not absolutely horrid, but not quite right. I also get a mild backfire if I accelerate hard and let it drop to idle when I am in park. I checked my timing and it is correct. This is the 1985 2.8 2wd. It says 10BTDC in the manual, with altitude(about 5200 ft) I have added three degrees so I set it at 13BTDC. This is with the vacuum removed from the vacuum advance module on the distributor.

Anyone care to offer a diagnosis and repair? I think I know, but I won't say just yet.

TIA,
Mark

Please chime in if you can.


85 S10 Durango 2.8L extcab rwd 36k actual miles.
"true wisdom is knowing you know nothing" Paraphrased from Socrates
jcricket is offline  
Sponsored Links
Advertisement
 
post #2 of 11 Old 09-30-2014, 04:24 PM
Boozebag
 
Mad Max's Avatar
 
Join Date: Jun 2009
Location: Saipan (!)
Posts: 8,917

User is: Mad Max is offline
Re: Lifters, cam, timing and backfires

Did you replace the cam?
I suspect that you may have to advance the timing more than the factory recommendations. This is a carb engine, yes?
You can usually adjust the rockers to stop making noise.
Any more info on this? I am trying to remember some of your other posts, but my memory gets soggy after a while.

I gotta quit drinking beer...

S10 addiction:
1)'82 S10, 383, 700R4, Shorty
2) '85 S10, 3.4, 700R4 4x4 stretch cab (Redneck)
3) '90 S10 2.5, 5 speed shorty
4) '91 S10, Built 3.4, 5 speed shorty (Voodoo)
5) '92 S10, 2.5, 5 speed shorty, (Barbie)
6) '92 S10, 2.5 5 speed, Shorty
7) 1979 LUV, Buick 3.8 V6, TH 350 Shorty.
Mad Max is offline  
post #3 of 11 Old 09-30-2014, 04:45 PM
Awww..you ain't got shit!
 
jimmykicker's Avatar
 
Join Date: Nov 2005
Location: McCalla, Alabama
Age: 48
Posts: 3,242

User is: jimmykicker is offline
Re: Lifters, cam, timing and backfires

Jimmykicker goes to doctor...Doctor: "Jimmy..if you drink another beer...you'll die!" Jimmykicker: "Just how painful a death we talking about here doc??"...



1984 xcab s-10 3.4L GM crate engine 91 S10 TBI swap w bored intake, Edelbrock headers. 2" Rough Country Lift. Custom exhaust, shift kit, e-fan.


EFI swap https://www.s10forum.com/forum/f106/...e-help-513616/

My build thread (3.4L)https://www.s10forum.com/forum/f106/...stions-427168/
Quote:
Originally Posted by Racer_X View Post
I had to cut my nut in half .
jimmykicker is offline  
 
post #4 of 11 Old 09-30-2014, 06:04 PM Thread Starter
overthinker extraordinar
 
jcricket's Avatar
 
Join Date: Sep 2014
Location: littleton colorado
Age: 54
Posts: 650

User is: jcricket is offline
Re: Lifters, cam, timing and backfires

Quote:
Originally Posted by Mad Max View Post
Did you replace the cam?
I suspect that you may have to advance the timing more than the factory recommendations. This is a carb engine, yes?
You can usually adjust the rockers to stop making noise.
Any more info on this? I am trying to remember some of your other posts, but my memory gets soggy after a while.

I gotta quit drinking beer...
If you can remember what I post, even without beer you are doing better than me!!!
I have not replaced the cam, not yet. I intend to in the next several months. I know I can adjust the rockers a little bit. This is a carbed engine. I'll advance it a few more degrees and see if that helps. Maybe take it to 15/16 BTDC.

I was wondering if someone was going to ask about the cam. That was my first thought, maybe the cam is worn down a bit. I think my next step is to actually do a compression test an vacuum test and see if I can get a better idea of the condition of the motor.

thanks for the thoughts............

and yeah, no beer, no fun, no way!

85 S10 Durango 2.8L extcab rwd 36k actual miles.
"true wisdom is knowing you know nothing" Paraphrased from Socrates
jcricket is offline  
post #5 of 11 Old 10-01-2014, 08:52 AM
Boozebag
 
Mad Max's Avatar
 
Join Date: Jun 2009
Location: Saipan (!)
Posts: 8,917

User is: Mad Max is offline
Re: Lifters, cam, timing and backfires

Mad Max: Confucius... why is beer so good?

Confucius: Man not ask stupid question....


Check the slack in your timing chain... that's probably why you need to advance your timing. I am guessing you know how to do this.
Also, you can pull one valve cover at a time and see if you have any "lazy" rocker arms. If one or 2 aren't moving much, then you know your cam is whipped.
I can't count how many toasted cams I have replaced in small blocks. I pulled one that had 4 PERFECTLY round lobes. Funny thing, the engine still ran.

Even though it is not as common for the 2.8s to wear cams, it does happened. Greasemonkeys posted a thread about this.

Modern oils are crap for flat tappet cams. ZDDP additive is expensive, but it sure beats repalcing a cam...

S10 addiction:
1)'82 S10, 383, 700R4, Shorty
2) '85 S10, 3.4, 700R4 4x4 stretch cab (Redneck)
3) '90 S10 2.5, 5 speed shorty
4) '91 S10, Built 3.4, 5 speed shorty (Voodoo)
5) '92 S10, 2.5, 5 speed shorty, (Barbie)
6) '92 S10, 2.5 5 speed, Shorty
7) 1979 LUV, Buick 3.8 V6, TH 350 Shorty.
Mad Max is offline  
post #6 of 11 Old 10-01-2014, 12:08 PM Thread Starter
overthinker extraordinar
 
jcricket's Avatar
 
Join Date: Sep 2014
Location: littleton colorado
Age: 54
Posts: 650

User is: jcricket is offline
Re: Lifters, cam, timing and backfires

Quote:
Originally Posted by Mad Max View Post
Mad Max: Confucius... why is beer so good?

Confucius: Man not ask stupid question....


Check the slack in your timing chain... that's probably why you need to advance your timing. I am guessing you know how to do this.
Also, you can pull one valve cover at a time and see if you have any "lazy" rocker arms. If one or 2 aren't moving much, then you know your cam is whipped.
I can't count how many toasted cams I have replaced in small blocks. I pulled one that had 4 PERFECTLY round lobes. Funny thing, the engine still ran.

Even though it is not as common for the 2.8s to wear cams, it does happened. Greasemonkeys posted a thread about this.

Modern oils are crap for flat tappet cams. ZDDP additive is expensive, but it sure beats repalcing a cam...
Hey Mad Max,
I actually just replaced the timing chain. And yeah it was badly stretched. I believe it is the cam is worn. That isn't too bad as I was going to replace it with one of those crane cams you linked to in your performance thread. The bigger concern is what other wear is in the engine.
I'll start with the cam and go from there I guess.
thanks for the help!!!

85 S10 Durango 2.8L extcab rwd 36k actual miles.
"true wisdom is knowing you know nothing" Paraphrased from Socrates
jcricket is offline  
post #7 of 11 Old 10-02-2014, 09:54 AM
Boozebag
 
Mad Max's Avatar
 
Join Date: Jun 2009
Location: Saipan (!)
Posts: 8,917

User is: Mad Max is offline
Re: Lifters, cam, timing and backfires

Man, I am a DUMBAZZ... Yeah, I did make a few suggestions.

Usually, the cam is the worst wear factor in flat tappet engines. The majority of modern engines have roller cams or overhead cams which do not have the same wear factors involved. Flat tappets have big pressure on them, where ZDDP helps to releive the wear on the interface of tappet to cam. Take ZDDP away and problems develop.

Also, most other engine components are similar in modern engines - like psitons, bearings, rings etc. So, usually you don't see other wear problems overall.
If you replace a worn cam, your engine will act like a new unit.
Especially of you install a performance type grind.

S10 addiction:
1)'82 S10, 383, 700R4, Shorty
2) '85 S10, 3.4, 700R4 4x4 stretch cab (Redneck)
3) '90 S10 2.5, 5 speed shorty
4) '91 S10, Built 3.4, 5 speed shorty (Voodoo)
5) '92 S10, 2.5, 5 speed shorty, (Barbie)
6) '92 S10, 2.5 5 speed, Shorty
7) 1979 LUV, Buick 3.8 V6, TH 350 Shorty.
Mad Max is offline  
post #8 of 11 Old 10-02-2014, 11:32 AM Thread Starter
overthinker extraordinar
 
jcricket's Avatar
 
Join Date: Sep 2014
Location: littleton colorado
Age: 54
Posts: 650

User is: jcricket is offline
Re: Lifters, cam, timing and backfires

I opened up a Chilton's and Hayne's manual yesterday. My next move is to systematically go through ALL of the emissions controls. I have 14 pages of thing to cover an test/replace. Mostly not very expensive, but a pain. I figure I will learn a great deal about how this motor works too. If it is still rough, then I will be looking at a new carb. Once that is done I feel I will have ruled out all possibilities for reasons of rough idle.

After that is done, I WILL do the cam. The question at that point is do I pull the motor and do the rear main seal too? And, what other considerations will I need to look at when the time comes? Fortunately that is a ways out.

As to the wear on the cam, and specifically the new cam, are there better lifters that can reduce that wear? Is there such a thing as roller lifters? Time to google.

85 S10 Durango 2.8L extcab rwd 36k actual miles.
"true wisdom is knowing you know nothing" Paraphrased from Socrates
jcricket is offline  
post #9 of 11 Old 10-02-2014, 03:37 PM Thread Starter
overthinker extraordinar
 
jcricket's Avatar
 
Join Date: Sep 2014
Location: littleton colorado
Age: 54
Posts: 650

User is: jcricket is offline
Re: Lifters, cam, timing and backfires

My google searches showed roller lifters for performance v-8's. They had the same diameter as the lifters in the v6. I would bet they would work if a person could get the correct length push rods.

hmm.......................

85 S10 Durango 2.8L extcab rwd 36k actual miles.
"true wisdom is knowing you know nothing" Paraphrased from Socrates
jcricket is offline  
post #10 of 11 Old 10-02-2014, 04:00 PM
Awww..you ain't got shit!
 
jimmykicker's Avatar
 
Join Date: Nov 2005
Location: McCalla, Alabama
Age: 48
Posts: 3,242

User is: jimmykicker is offline
Re: Lifters, cam, timing and backfires

I think GEARS has some rollers on his...might ask him what he has.



1984 xcab s-10 3.4L GM crate engine 91 S10 TBI swap w bored intake, Edelbrock headers. 2" Rough Country Lift. Custom exhaust, shift kit, e-fan.


EFI swap https://www.s10forum.com/forum/f106/...e-help-513616/

My build thread (3.4L)https://www.s10forum.com/forum/f106/...stions-427168/
Quote:
Originally Posted by Racer_X View Post
I had to cut my nut in half .
jimmykicker is offline  
post #11 of 11 Old 10-03-2014, 10:31 AM
Boozebag
 
Mad Max's Avatar
 
Join Date: Jun 2009
Location: Saipan (!)
Posts: 8,917

User is: Mad Max is offline
Re: Lifters, cam, timing and backfires

Quote:
Originally Posted by jcricket View Post
My google searches showed roller lifters for performance v-8's. They had the same diameter as the lifters in the v6. I would bet they would work if a person could get the correct length push rods.

hmm.......................
There is a little more to it than that... You will need a roller cam too. Duh.
You will also need lifter retainers. These keep the roller lifters from turning in their bore and causing catastrophic damage.
I know that some later blocks have roller cams in them (Aluminum head blocks), but I am pretty sure that all 2.8s did not have this upgrade.
I don't know if you could retro fit one either. The later blocks had bosses that were threaded to accomodate the lifter retainers.

I know you were looking for cams... here some more info:
http://www.howardscams.com/chevrolet...-34l-1978-1984

S10 addiction:
1)'82 S10, 383, 700R4, Shorty
2) '85 S10, 3.4, 700R4 4x4 stretch cab (Redneck)
3) '90 S10 2.5, 5 speed shorty
4) '91 S10, Built 3.4, 5 speed shorty (Voodoo)
5) '92 S10, 2.5, 5 speed shorty, (Barbie)
6) '92 S10, 2.5 5 speed, Shorty
7) 1979 LUV, Buick 3.8 V6, TH 350 Shorty.
Mad Max is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the S-10 Forum 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.


Email Address:
OR

Log-in










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



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
Trackbacks are On
Pingbacks are On
Refbacks are On

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