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Unread 04-07-2013, 02:45 PM   #16
revelc
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I mean more of a flat cam or something along those lines would suck

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Unread 04-07-2013, 03:13 PM   #17
olliehopnoodle
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Quote:
Originally Posted by revelc View Post
I mean more of a flat cam or something along those lines would suck
Gotcha.. Well, it is an excuse to upgrade.
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Unread 04-07-2013, 04:51 PM   #18
brtncstm160
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As far as moisture it did rain here recently but i never tried starting it or anything when it was raining or wet out. Is there supposed to be a small plug in the bottom of the distributor because i did notice a hole that goes through the bottom of the metal housing for the distributor.

I pulled the distributor and the gears checked out fine not a problem there.

I didnt replace the cam but i did replace the lifters rods and rocker arms, springs werent replaced the machinist said they checked out when they did the heads. Checked the rocker arms and there are all fine nice and tight and no damage.

Looking like a bad intake spring at this point right?
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Unread 04-07-2013, 04:54 PM   #19
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Could be, most definitely work a look.
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Unread 04-07-2013, 05:16 PM   #20
revelc
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There should be a plug. If humidity or condensation getting there spark can jump.

Can you pull the valve covers and have someone turn it over by hand while you see if all the rockers are traveling the same distance.

Have your wires fallen on the headers at any point?
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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 04-07-2013, 08:08 PM   #21
olliehopnoodle
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New lifters, old cam. Did you do a break in ?
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Unread 04-08-2013, 09:51 AM   #22
super98lsc
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Compression test it> That will nail down the valvetrain, whatever cylinder is low will be the culprit if its a valve not seating.
Check plugs too, you can remove the plug wire from whatever cylinder is causing the backfire, if it goes away then you know which cyl it is for certain.

Were the block/heads decked and stock rockers retained? Valves "stretch" (especially new ones) which will cause the lash to become too tight. The valve bouncing/slamming into the seats as they close will cause them to stretch slightly, (one of the reasons i lash my solids loose for break-in) if the block was decked/heads milled then a head gasket used with a thinner than stock compressed thickness you will need shorter pushrods to alllow the valves to seat fully, it not it will place too much pre-load on the lifters and either wipe the cam or kill the valve/seat by not allowing it to shut all the way.

I am betting on a stuck or bent valve.
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Unread 04-09-2013, 06:14 PM   #23
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It was a set of new lifters on an old cam. I should have said that this vehicle is unique in that it only has 19000 original miles on it. very little wear on anything. i was able to reuse a lot of stuff without much work other than giving it a good cleaning. so the block and heads werent decked.

I did a compression test today and all the cylinders went up to 120 psi at a consistent rate after 4 cranks. The one weird thing was the number 4 cylinder sounded like it was trying to backfire each time pressure was building in the cylinder, but it still climbed to 120 at a consistent rate. This has me totally thrown off. Has anyone encountered this before. also after doing the compression test i fired it back up and it seemed to run pretty well but backfiring with even less consistency now.

Thanks for all the advice and replies guys really appreciate it.
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Unread 04-09-2013, 06:21 PM   #24
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Revel ill have to make a little plug out of something and stop that up, thanks. The wires havent fallen on the headers or anything, those are high and tight, one does touch the heater core box.

ollie forgot to answer your questions what type of break in do you mean? i didnt do anything special to lifters or the cam. just followed the manual as far as a 500 mile break in period not driving it hard or anything, i hit the wall at 150.

Im crossing my fingers on a spring haha.
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Unread 04-09-2013, 06:27 PM   #25
revelc
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Quote:
Originally Posted by brtncstm160
Revel ill have to make a little plug out of something and stop that up, thanks. The wires havent fallen on the headers or anything, those are high and tight, one does touch the heater core box.

ollie forgot to answer your questions what type of break in do you mean? i didnt do anything special to lifters or the cam. just followed the manual as far as a 500 mile break in period not driving it hard or anything, i hit the wall at 150.

Im crossing my fingers on a spring haha.
Can you measure the travel of the lifters on your problem hole, and compare them to another cylinder?

Maybe a rocker is broken, a cam lobe is flat, a lifter is muddled.

Using old cams with new lifters can be problematic sometimes.
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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 04-10-2013, 05:56 PM   #26
brtncstm160
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Today i went to check the travel of the lifters/pushrods and before i got started i noticed the lifter has no strength in it. Rocker arms are torqued to the specs and it still moves all over the place. i can push the push rod down into the lifter almost a 1/4'". i cranked the engine over by hand and it was loose throughout the sequence. not sure how i missed this before but none the less is it safe to assume i just have a blown lifter at this point?
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Unread 04-10-2013, 06:15 PM   #27
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Quote:
Originally Posted by revelc

My money is on cheap dizzy gears.
Yep ^^^

Sorry I should have read the rest of the posts, anyway sounds like a lifter or cam lobe problem.
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Unread 04-10-2013, 06:20 PM   #28
revelc
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Quote:
Originally Posted by brtncstm160
Today i went to check the travel of the lifters/pushrods and before i got started i noticed the lifter has no strength in it. Rocker arms are torqued to the specs and it still moves all over the place. i can push the push rod down into the lifter almost a 1/4'". i cranked the engine over by hand and it was loose throughout the sequence. not sure how i missed this before but none the less is it safe to assume i just have a blown lifter at this point?
You have a collapsed lifter, a chewed lifter, or a flat cam lobe. You'll have to pull the intake and get a new set of lifters. Or it would be a good time to install a different cam if you had a different one in mind. You'll have to break it in either way.
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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 04-10-2013, 07:31 PM   #29
RockRollin
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Can someone explain how a collapsed lifter or wiped cam lobe would cause an intake backfire
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Unread 04-10-2013, 09:28 PM   #30
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I think the lifter and cam responce's were more to the loose lifter condition. The back fire could be a burnt valve.

Bill
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1973 J 4000,
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1979 CJ7 360, TH400/Quadratrac trail Jeep.
1979 J20
1980 CJ5 trail Jeep.
1983 CJ7 pretty weekend and sometimes to work Driver in the summer, My first rebuild, if the Q-trac and 5 are broke, this one is the one to take. its just as capable as the other 2, except nice paint.
1984 Grand Wagoneer, 1 ton axles, great 360/727, and a big a$& tree fell on it .
1989 YJ the CJ to YJ conversion.
2005 TJ Rubicon.
2011 Grand Cherokee Laredo 4x4, Mrs. LUCDOG's DD.
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