345 No Compression

C

chico

Member
Ok. So I originally thought I had a carb issue on my 345. It had a 2210 on it so I rebuilt it and started the truck and still ran Rich and like spit. I then noticed the plug wires were ran different of the firing order stamped on the intake. The wires were ran by the po. So I switched them to the right order now runs way worse. Only the 3 and 6 were switched wrong. So I did a compression check and got 150-160 (warmish) on the left bank facing the engine from the front. (evens) then did the right bank and got 138 on #1 then 0 on #3 and 0 on #5 then 158 on # 7. I did that side about 4 times to make sure. What was wierd was one of the times on #5 the compression shot up to 167 and held then I did it again and got 0. So I have the motor ready to pull out and do a full gasket kit. Ordered the kit today from IH only. So I guess my question is do these engines have valve seals and do you think that could be my problem? I can see the needle moving as it was pumping but no dice on holding pressure. I checked the oil to see if it might be a head gasket but I didnt see any milkyness. I also pulled the valve cover and couldnt tell on bent rods but will be sure to look when I pull the head.

Is there anything else I should look for when going through the motor? I dont want to tare it completely down but just replace the gaskets and inspect as I go. Im in no rush to speed through it except to make the October jubalee.

I need to do a gasket kit anyways because the front and rear mains are driping oil pretty good and the wife isn't cool with that. Plus since it was neglected by the po I figured it would be best so I know for sure it was done. Alot of shady stuff was done to this beast like all the vents capped for the fuel cell and the hose from the canister to the fuel cell went into the frame. So I got that all right now.

I'm trying to not get the "might as wells" because the pocket book is a little low these days but I was going to replace the freeze plugs, water pump, rebuild the oil pump, oil sender,coolant sender, thermastat and just bought a 2300 brand new carb. "thanks IH only" since I have the motor out.

All you help is appreciated! Thank you
 
I suggest you go through mm's valve train rehab guidance to help make sure everything is clean and getting lubed properly. If your rockers are welding themselves to the rocker arm that could certainly keep them open when they should be shutin'. If thats the case its possible you May have thrown/bent a couple of push rods as well.
 
I'm suspicious of your results. The numbers that you got above zero seem pretty high. Getting a high reading and then getting no reading on the same cylinder seems very odd to me. Were all the spark plugs removed when you tested? Did you have the throttle blocked wide open on the carb?
So some plug wires were routed incorrectly. How do you know that the po hadn't pulled the distributor and then re-stabbed it incorrectly as well? That could really get your ignition timing all jacked up. I think you need to verify that your spark timing is somewhere close to where it needs to be.
 
You May have "igiition / timing" problems (as stated above),

but "zero compression" equals

sticking valve, bent valve, burnt valve, broken piston, broken piston rings...

Another possiblility is stripped cam / crank gears, but this is a slim possibility as IH gears are steel.

Valve stem seals do not have anything to do with compression - they do "control oil flow".

With a blown head gasket, you still get "some compression".
 
He May indeed have those issues going on. I'd still like to hear some more detail about the steps involved in his compression testing. Still, its not hard to pull valve covers and take a peek-see. Messed up push rods show up pretty easy.
 
scoutboy74 said:
he May indeed have those issues going on. I'd still like to hear some more detail about the steps involved in his compression testing. Still, its not hard to pull valve covers and take a peek-see. Messed up push rods show up pretty easy.
Click to expand...

From his first post:

"I did that side about 4 times to make sure. What was wierd was one of the times on #5 the compression shot up to 167 and held then I did it again and got 0."

the second sentence leads me to believe that a valve stuck one time and "released" the other time...
 
I had an anomalous reading like this when I did my compression test. I think the little reset blow-off valve in the compression tester didn't seat. Just a thought.
 
Thanks guys for your input. Sorry for the delay. The steps in my compression test was that I unplugged all the spark plugs, dissconneted the fuel and coil. Hooked up my tester one by one and cranked the engine 3 to 4 revolutions then took my readings. I did forget to block the throttle wide open tho. So I pulled the motor yesturday and spent some time looking and cleaning all the oil and dirt off it. I didnt see any bent rods and I havent pulled them out just yet to check how straight they are either but plan on it. But I read the "valvetrain thread" as stated above and started thinking. So I pulled the rocker assem. And sure enough I had clogged oil passages. I have only pulled the non-compression side so far. I took them all apart carefully to not mix up the parts. Cleaned them up really well and put them together. My hands hurt from taking all the posts off. I have the "boat" style btw. I know its pretty much all the same. Ill post some pictures. Im step by step taking pictures of my motor pull and gasket rebuild. When I drained the oil I saw no bearing shavings. It actually looked pretty good. Im still gonna pull the head off to look at the pistons and replace the head gasket since im this far. Anybody have a copy of the torque specs? Im sure its in the forums somewhere just trying to save time. Also my exhaust has the butterfly on the right bank. Is this nessary? Can I delete this?

Is there anything else I might be missing?
 
This would explain your artificially high readings where you got them. The plugs all need to be out. Just getting your lubrication passages cleaned is well worth the trouble you've gone to so far. That is a very common issue on a long neglected and poorly maintained engine. The head bolt torque sequence is detailed in all ihc service manuals. Those materials are subject to copyright, but occasionally the site mods will make an exception on a case by case basis.
 
I'm sorry, no all of my plugs were out when doing all cylinders. The only thing I forgot to do was put the carb on wide open throttle. So im going to have to get a service manual to get the torque specs? Ok
 
A manual will prove invaluable to you as you progress along fixing issues that pop up. The ihon store here carries many of the more common ones.
 
I'm still going through the motor and I had a few questions. First is the hole to the timing and dizzy normal? (the first picture).

Second is I looked at the fly wheel yesturday and have these heat cracks in it. Can I still run this or should I get a new one? (second picture)
 

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That rough hole is normal. They have to knock out the casting flash and it ends up looking like crap.

Those are usually surface fractures and they will 99% of the time go away upon re-surfacing. Have a close look after resurfacing and see that they are gone. If you can see them extending around the wear surface edge you should get another one.
 
Well just an update....... After a long vacation and a dead dog and a busy life im starting to put the motor back together again an hit my first "oh sh*t!" moment. Last night was the first time I've touched the motor in weeks and as I replaced the timing cover and reinstalled the dampner. I stripped the bolt bad! :icon_gonk: im gonna try and tap it first before I look into replacement of the crank. Nothing can ever be to easy to be true right?

The water pump tubes.....other than the o-rings how do they seal into the hole? High temp. Gasket sealer?

Thanks pictures coming soon.
 
Opps! Hey that can happen if you try to pull a balancer on by using the bolt. Dress up the threads with a good tap and use a balanced installer. Buy a bolt that is slightly longer so you pickup the most good threads as possible when finally tightening the balancer up.
 
Yep you caught me. I tried to suck it on with the bolt and trashed the threads. I tapped it and it looks and feels great. I havent tried to put the pully on yet but that will be this weekend. Here are some pics of where im at. The color is red ut the pis make it look pink and purple. The gasket kit I got from IH Parts America is working out just fine.
 

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