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Motor rebuild done something wrong

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Blessed01 View Drop Down
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    Posted: 18 Feb. 2021 at 8:30pm
I sure would love for someone to help me out “PLEASE” I just rebuild my 134 flat head motor in my 46 CJ2A , everything seem to went good, the problem I have is while the engine is cranking pressure comes up though the carburetor, I have set the timing by the book, but still have the same thing, installed new bearings, pistons, valves everything what have I done wrong. It’s the first time I ever built a motor so have mercy on me please 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote smfulle Quote  Post ReplyReply Direct Link To This Post Posted: 18 Feb. 2021 at 8:37pm
Valves might be adjusted too tight so they don't close all the way on compression stroke.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Blessed01 Quote  Post ReplyReply Direct Link To This Post Posted: 18 Feb. 2021 at 8:43pm
I will try to check that tomorrow, I think I did it right by the manual, and by asking and hearing others talk about how it’s done. But that to me makes a great deal of sense thank you very much
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Chicodave Quote  Post ReplyReply Direct Link To This Post Posted: 18 Feb. 2021 at 8:44pm
You did line the dots on the crank and cam gear?
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Blessed01 View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Blessed01 Quote  Post ReplyReply Direct Link To This Post Posted: 18 Feb. 2021 at 8:48pm
Yes I line them up, number one piston all the way up, valves closed did I do that right I sure hope so
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb. 2021 at 8:13am
"installed new bearings, pistons, valves everything"

What does "everything" mean?

Describe what you did when you installed new valves.

There are only a few possible causes for what you describe.

1) The valves are not seating, as Stan mentioned. This could be because they are too tight, too long, were not lapped properly, a broken spring, or a retainer has come loose. Most likely too tight.

2) Cam timing is off. Unlikely if you aligned the marks as you describe, provided you know which cylinder is number one.

3) Is it the original cam shaft, or did you install a new one? Chain drive or gear drive?

First thing I would do is remove the valve cover and spark plugs, then turn the engine with a wrench while watching the valves, make sure both valves are closing when number one comes up to TDC on compression stroke. Check the lash which should be set between between .014 and .016. I usually set them .016 at first, then check and adjust after running for a while. Repeat the check and adjust on each cylinder in firing order. 




Edited by Oldpappy - 20 Feb. 2021 at 8:14am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote stevez Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb. 2021 at 8:50am
that was my first thought, is the right cam in there?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote russnj Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb. 2021 at 8:52am
Have a look at this rebuild website. See if you followed all the steps. http://jeepdraw.com/John_Barton_Engine_Rebuild1.html

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lee (MN) Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb. 2021 at 10:27am
I’m pretty sure you cannot have the wrong camshaft!, a chain drive engine has a sprocket that bolts to the end of the cam (3 bolts), and the gear driven engine its pressed on with one center bolt, but I guess you could have an F head cam in an L engine ?, the lift on the intake valves would be drastically different!....

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Post Options Post Options   Thanks (0) Thanks(0)   Quote cpt logger Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb. 2021 at 6:33pm
Are you trying to start the engine or is the ignition switch in the off position? In other words is there power to the coil?

The reason I ask is if there is power to the coil, the ignition timing may be way off & the valve train might be OK. OTOH, If there is no power to the coil, then we need to thoroughly inspect the valve train.

Let us know so we can help you with this problem, Cpt Logger.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steelyard Blues Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb. 2021 at 8:21pm
Did you correctly align the timing marks on the crank and flywheel when you reassembled? 


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 21 Feb. 2021 at 8:48am
The reason I asked what "everything" meant was I was wondering if he installed a new camshaft.

I was wondering if it might be possible to install a F head cam into an L head engine. I have never tried that so don't know for sure, but as already said the intake valve timing would be way off. Might be worth the time just to see if it is possible to do that. 

I asked if it was a chain or gear drive cam for another reason.

I once got an engine in a trailer full of parts I bought. It was complete and had nice shiny new grey paint. 

Someone had "rebuilt" it, so I put it in a Jeep to try it out.  

It would not run, but it would throw a lot of flame out of the carburetor. Within a half hour of looking into it I found a puzzle. It was a a GPW engine with a gear drive cam. That was more than 30 years ago, so don't remember everything else that was wrong, but it had the wrong cam setup, and wrong oil pump gear. I completely tore it down and started over with it using the correct parts, it was the engine I used in an M38 I had back then. 

A lot of Jeeps are described as "Salad" because of the mixture of parts, which is okay with body and chassis parts, but engine salad doesn't work so well.

I would advise folks to be very careful when buying parts off of Ebay or other internet auction sites.

I have seen WW2 surplus cams listed with a description saying they would fit the civilian Jeeps, and seen generator fans listed as fitting a CJ. A generator fan will indeed fit, but it will push air the wrong direction, and as I described above a determined person can make the wrong cam fit too. 




Edited by Oldpappy - 21 Feb. 2021 at 8:54am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MooCow Quote  Post ReplyReply Direct Link To This Post Posted: 21 Feb. 2021 at 1:13pm
Isn't it possible to have the points on the 2 gears lined up and still be 180 degrees out with the #1 TDC? Arn you supposed to be on the compression stroke to truly be TDC?  I got a little confused on this when I put mine together.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 21 Feb. 2021 at 1:38pm
  The #1 piston reaches TDC twice in each firing cycle. The camshaft determines whether it is on the compression stroke or the exhaust stroke. When the camshaft timing marks are aligned as they should be on assembly, #1 is at the top of the compression stroke, ready to start the power stroke. When the cam gear timing mark is on the other side of the gear (180* from the crankshaft gear mark), #1 and #4 are both at TDC with #4 in position to fire. Any time the marks are together it’s #1’s turn. 
BW 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MooCow Quote  Post ReplyReply Direct Link To This Post Posted: 21 Feb. 2021 at 2:25pm
I guess I meant when you are assembling the engine you could mistakenly thank you have the correct timing but put the gear on wrong so they appear to line up but are really 180 out. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WeeWilly Quote  Post ReplyReply Direct Link To This Post Posted: 21 Feb. 2021 at 2:48pm

   The gears are keyed, so impossible to install wrong.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 22 Feb. 2021 at 8:20am
I hope he comes back and tells us what he has found to be the problem.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cpt logger Quote  Post ReplyReply Direct Link To This Post Posted: 23 Feb. 2021 at 6:45am
Me too. I really would like to know the solution to this mystery.
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