Backfiring while driving, not while sitting still?
11-19-2008, 12:58 PM
#32
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Originally Posted by Trailerpro
Using flat tappet. THe cam is a 351, and I already switched the wires to a 302 order just to make sure that wasn't it. After doing that, I replaced the plugs just to be sure it wasn't something like that. I'm still using a stock ignition for now - yeah, I know...young racer on a tight budget :cry:
It did start doing it while in park and revving the motor.
It's only flaming out the pass. side of the front of the carb. I pulled the cover off that side, and everything seems to be working fine.
It did start doing it while in park and revving the motor.
It's only flaming out the pass. side of the front of the carb. I pulled the cover off that side, and everything seems to be working fine.
11-19-2008, 01:18 PM
#33
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Cam is the 1108. Not sure about the lifters?
Also, if it is a lobe on the camshaft, is there a way to tell w/o tearing the motor apart again? Not sure if it would work, but it seems like I could pull the plug wires off one at a time and see if it quits doing it with one of them??? Would this be possible, or is my brain fried pie from all the thinking it's done today?
Thank ya'll so much for the help so far!
Also, if it is a lobe on the camshaft, is there a way to tell w/o tearing the motor apart again? Not sure if it would work, but it seems like I could pull the plug wires off one at a time and see if it quits doing it with one of them??? Would this be possible, or is my brain fried pie from all the thinking it's done today?
Thank ya'll so much for the help so far!
11-19-2008, 05:51 PM
#34
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back firing
Sounds like a valve train issue to me. If it is back firing through the carb under load. I have had the same thing happen with a fresh set of rebuilt heads, the valves were not cut right and it would run fine at idle but when it was put under a load it would start popping. Just a thought ?
11-19-2008, 06:33 PM
#35
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John, when you put the timing chain on is there any chance you got the timing marks off?
I'm starting to agree with bjuice.
Just my opinion but my next four steps would be.
1. borrow your dads carb for a second to eliminate your carb.
2. pull your valve covers to see if all the rocker arms look like their
moving the same amount.
3. check your timing chain to make sure your dots are lined up at tdc.
4. do a compression check on all cylinders to see if they are the same.
The compression check will tell you if you have a valve leaking.
I'm starting to agree with bjuice.
Just my opinion but my next four steps would be.
1. borrow your dads carb for a second to eliminate your carb.
2. pull your valve covers to see if all the rocker arms look like their
moving the same amount.
3. check your timing chain to make sure your dots are lined up at tdc.
4. do a compression check on all cylinders to see if they are the same.
The compression check will tell you if you have a valve leaking.
11-19-2008, 10:33 PM
#36
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Location: Independence, Missouri
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Originally Posted by dparker
John, when you put the timing chain on is there any chance you got the timing marks off?
I'm starting to agree with bjuice.
Just my opinion but my next four steps would be.
1. borrow your dads carb for a second to eliminate your carb.
2. pull your valve covers to see if all the rocker arms look like their
moving the same amount.
3. check your timing chain to make sure your dots are lined up at tdc.
4. do a compression check on all cylinders to see if they are the same.
The compression check will tell you if you have a valve leaking.
I'm starting to agree with bjuice.
Just my opinion but my next four steps would be.
1. borrow your dads carb for a second to eliminate your carb.
2. pull your valve covers to see if all the rocker arms look like their
moving the same amount.
3. check your timing chain to make sure your dots are lined up at tdc.
4. do a compression check on all cylinders to see if they are the same.
The compression check will tell you if you have a valve leaking.
11-19-2008, 10:55 PM
#37
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Join Date: Sep 2007
Posts: 4,137
Originally Posted by Trailerpro
Cam is the 1108. Not sure about the lifters?
Also, if it is a lobe on the camshaft, is there a way to tell w/o tearing the motor apart again? Not sure if it would work, but it seems like I could pull the plug wires off one at a time and see if it quits doing it with one of them??? Would this be possible, or is my brain fried pie from all the thinking it's done today?
Thank ya'll so much for the help so far!
Also, if it is a lobe on the camshaft, is there a way to tell w/o tearing the motor apart again? Not sure if it would work, but it seems like I could pull the plug wires off one at a time and see if it quits doing it with one of them??? Would this be possible, or is my brain fried pie from all the thinking it's done today?
Thank ya'll so much for the help so far!
11-20-2008, 10:04 PM
#38
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If it was a totally flat lobe it would be hissing back thru the carb at idle or low rpm something you could definately hear, not to say it's not, a compression check would definately tell that story, what no one has mentioned if a week or broken valve spring, just a thought, because i too have no idea what the problem is without looking at it and investigating it myself.
JMO
Zip.
JMO
Zip.
11-21-2008, 08:03 AM
#39
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Originally Posted by Trailerpro
They're non-adjustable.
11-21-2008, 08:24 AM
#40
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Very good advice DADMOD and your first post. I got the noted part DADMOD had referred to.
***Note: To provide the most accurate valve adjustment on hydraulic lifter camshafts, the heads must be machined to accept screw-in studs (on engines not originally equipped). On engines equipped with bottleneck type studs, using 270-99768-16 positive locking nuts will permit valve adjustment. For engines equipped with pedestal mounted rocker arms and hydraulic lifters, excessive lifter preload can be easily remedied by using Crane's rocker arm pedestal shim kit 270-99170-1. Crane offers a pushrod guideplate and rocker arm stud conversion kit 270-36655-16 for street applications, enabling the 1977-00 302ci and 351W engines with pedestal mounted rockers to have adjustable rocker arms without cylinder head removal or machining.
***Note: To provide the most accurate valve adjustment on hydraulic lifter camshafts, the heads must be machined to accept screw-in studs (on engines not originally equipped). On engines equipped with bottleneck type studs, using 270-99768-16 positive locking nuts will permit valve adjustment. For engines equipped with pedestal mounted rocker arms and hydraulic lifters, excessive lifter preload can be easily remedied by using Crane's rocker arm pedestal shim kit 270-99170-1. Crane offers a pushrod guideplate and rocker arm stud conversion kit 270-36655-16 for street applications, enabling the 1977-00 302ci and 351W engines with pedestal mounted rockers to have adjustable rocker arms without cylinder head removal or machining.