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Unread 04-10-2013, 10:48 PM   #31
revelc
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Quote:
Originally Posted by RockRollin
Can someone explain how a collapsed lifter or wiped cam lobe would cause an intake backfire
There is plenty of info if you'd like to Google the correlation/symptom of backfiring and limited lifter travel indicating a flat cam.

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Cherokee Rebuilt 360, 2" Duals, mostly stock. SOON: Hot Street 401, 4'' Rustys, 33" BFG A/T's maybe a T-case to get rid of Q-Track <-TOW RIG
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Unread 04-11-2013, 04:00 AM   #32
RockRollin
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Quote:
Originally Posted by revelc View Post
There is plenty of info if you'd like to Google the correlation/symptom of backfiring and limited lifter travel indicating a flat cam.
I'm sure I could find an explaination for any scenario, but onward.
Backfire through carb is typically, timing too far advanced, crossfire, or lean fuel mixture retaining heat (bad). The lifter would have to be hanging open, typically not a symptom of bad lifter or wiped lobe. Not to say that a lifter can't stick open, but the compression test should negate, or confirm that
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Unread 04-11-2013, 08:22 AM   #33
revelc
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Quote:
Originally Posted by RockRollin

I'm sure I could find an explaination for any scenario, but onward.
Backfire through carb is typically, timing too far advanced, crossfire, or lean fuel mixture retaining heat (bad). The lifter would have to be hanging open, typically not a symptom of bad lifter or wiped lobe. Not to say that a lifter can't stick open, but the compression test should negate, or confirm that
Well he does definitely have a problem with his lifter/cam. After that he has to set timing again, and use the opportunity to check the carb. Then move on to the next possibilities. In my mind it makes sense if its the exhaust valve lifter/lobe. It can still build pressure but has nowhere to go until the intake valve opens again.
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Wag Rebuilt 360, 260H, 727, Locked 44, AMC 20, 208, 31" M/T's, 4" Rustys, 2.5" Duals. SOON:SOA SF, 496, T400, Doubler, D60's, 37" M/T's <-TOY
Cherokee Rebuilt 360, 2" Duals, mostly stock. SOON: Hot Street 401, 4'' Rustys, 33" BFG A/T's maybe a T-case to get rid of Q-Track <-TOW RIG
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Unread 04-11-2013, 08:48 AM   #34
super98lsc
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I never asked but was this popping out the exhaust or intake?
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Unread 04-11-2013, 09:03 AM   #35
revelc
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Quote:
Originally Posted by super98lsc
I never asked but was this popping out the exhaust or intake?
He's been saying it seems like its popping through the intake. Even during the compression test. Which leads me to believe fuel/spark are not factors.
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Cherokee Rebuilt 360, 2" Duals, mostly stock. SOON: Hot Street 401, 4'' Rustys, 33" BFG A/T's maybe a T-case to get rid of Q-Track <-TOW RIG
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Unread 04-11-2013, 05:51 PM   #36
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I should have made that clear after the compression test. I found it was an issue with theexhaust valve. So thats makes sense why it would still build pressure during the test then wait for the intake to reopen then backfire through the intake. Gonna order up some lifters and go from there i think at this point. Im really trying to stay away from replacing the cam right now.

do i need to be a full member in order to quote people?
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Unread 04-11-2013, 07:03 PM   #37
revelc
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Quote:
Originally Posted by brtncstm160
I should have made that clear after the compression test. I found it was an issue with theexhaust valve. So thats makes sense why it would still build pressure during the test then wait for the intake to reopen then backfire through the intake. Gonna order up some lifters and go from there i think at this point. Im really trying to stay away from replacing the cam right now.

do i need to be a full member in order to quote people?
Well pray for a collapsed lifter not a flat cam. Pull both lifters out with a magnet from that cylinder and compare sizes. If they are the same you don't have a choice about replacing the cam.
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Wag Rebuilt 360, 260H, 727, Locked 44, AMC 20, 208, 31" M/T's, 4" Rustys, 2.5" Duals. SOON:SOA SF, 496, T400, Doubler, D60's, 37" M/T's <-TOY
Cherokee Rebuilt 360, 2" Duals, mostly stock. SOON: Hot Street 401, 4'' Rustys, 33" BFG A/T's maybe a T-case to get rid of Q-Track <-TOW RIG
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Unread 04-11-2013, 07:15 PM   #38
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The cam lob is probably bad and it wore down the lifter enough to put a hole in it and the oil leaks out so the lifter collapses.

Here is an example pic (not mine)



So the small hole lets oil out and the lifter doesn't stay pumped up. If it is an exhaust valve the exhaust is getting compressed since the valve is not opening all of the way. (keep in mind, it has expanded) and as soon as the intake valve starts to open it escapes out the intake.

New cam/lifters. Follow the break in procedure.
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Unread 04-11-2013, 07:49 PM   #39
super98lsc
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Replace both cam and lifters as a set if the lifter is ruined so is the cam..
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===================================
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01 WJ 4x2 4.7v8 Limited (needs valve job)
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Unread 04-20-2013, 08:51 PM   #40
brtncstm160
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well my fears were realized today when i finally got to take the intake manifold off and do a thorough look around. The lifter did collapse because a hole was worn in the bottom of it. ill see if i can get a pic of it, the bottom of the lifter is so concave i cant believe it could happen in just 150 miles of easy driving. So moving onto replacing the lifters and cam. Im looking for some suggestions for a good stock replacement cam/lifter kit. Not looking for more power or torque or whatever, this is going to be a daily driver. Any suggestions or recommendations is very appreciated. Thanks a bunch to anyone who replied and helped out. The engine also has a edelbrock 2131 intake and a 1406 carb so a cam that works in that rpm range i guess.
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Unread 04-20-2013, 08:59 PM   #41
revelc
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The Comp 260H will give you slightly more power, better fuel economy, and a reliable daily driver.


Sorry about the cam dude.
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Wag Rebuilt 360, 260H, 727, Locked 44, AMC 20, 208, 31" M/T's, 4" Rustys, 2.5" Duals. SOON:SOA SF, 496, T400, Doubler, D60's, 37" M/T's <-TOY
Cherokee Rebuilt 360, 2" Duals, mostly stock. SOON: Hot Street 401, 4'' Rustys, 33" BFG A/T's maybe a T-case to get rid of Q-Track <-TOW RIG
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Unread 04-20-2013, 09:21 PM   #42
super98lsc
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hone the lifter bores with a ball hone. Remember the lifters rotate so as soon as that rotation stops = wiped lobe and lifter.
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06-Corvette z51-6spd,b&b,K&N low miles.
77-Corvette Stingray 496 BBC/TH400 built 667hp+
===================================
00 WJ 4x4, 4.7 stroker, turbocharged,..lots more..
01 WJ 4x2 4.7v8 Limited (needs valve job)
90 Grand Wagoneer 401 Edelbrock Heads, Lunati .510/.527 FT Cam, Edelbrock RPM Air Gap, Holley HP 750, Thorley Headers, HEI, Electric Fan w Digital controller,4" lift 31x10.50 Goodyear Duratrac's on Pro-Comp Wheels,new interior, seats,seals,Alpine and JL full system, Remote HEI, Clifford 2 way with remote start,windows,tailgate.
96 Cherokee Country 4dr/2x2 White/Tan 3" Lift Sahara 18" Wheels 32.5"'s 99up head and intake- for sale soon!
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Unread 04-22-2013, 07:24 PM   #43
brtncstm160
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ill definitely hone the lifter bores out thanks for the tip super.

any other suggestions for cam kits? is something from summit worth it? i like the 260 but is there anything else that might be a bit cheaper. thanks for the help guys.
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Unread 04-23-2013, 08:29 PM   #44
olliehopnoodle
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some people have luck with the summit cams, some don't. I wouldn't save a few bucks on it.
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