Your truck has the same parts as your Harley only more of them. Any engine needs three things to run; compression, fuel at the right ratio and spark at the right time. You can do it !!!

 

Yep it's all comes down to trouble shooting 1 or 12 cylinders all the same..
Time to get greasy.
But we All like to see what your working on so please post some pictures..

orich

 

So this may be a dumb question but.....say I rebuild the carb and put the new dist. in and it runs okay. How bad would it be to tool around town a bit only running on 7 cylinders? I don't have money right this second for a valve job and it won't be crazy driving. Just to cruise ins and what not. Be nice guys....I'm just excited.

 

I'd check the plug wires as they may be bad.

Any thing could happen if it is a burned out valve seat so your taking a chances Right!
It's a 50-50 chance you be the judge. I'd first do a compression test to see what's happening with #8 tho May even pull the valve cover check for bent push rod or what ever just see the it's functioning like it should be..
Orich

 

How do I know if a rod is bent? Take off the rockers?

 

Also....how do I identify my carb to tell the carb shop which rebuild kit I need. I see no numbers on the whole damn thing. Just a circle clock looking thing on the drivers side.

 

Remove valve cover then bring the piston all the way up to the top then turn each one push rod. Put a socket wench on the crank bolt turn until piston is up.
Push rod Should not be more then .020 bent, as they will not spin and will cause the lifter not to turn then wiping the cam lobe if run long enough.

Another way to check is messy start the motor and watch them spin look for any bent one while they spin..

orich

 

Using a vacum guage - with it connected to the manifold it will either hold steady or flutter.

The flutter indicates a bad valve or valves. The flutter is caused by the cylinder pressure leaking past the valve back into the intake system.

If it is steady look at how much vacum you have at idle. You should be able to acheive at least 15"Hg. You can watch the reading and adjust the distributor timiming to find the highest reading possible. A worn out engine will make less vacum...but so will a poorly tuned engine. If the vacum level is low you will need to do a compression test.

A compression test will pin point which cylinder is having a problem but it won't tell you if it's the bottom end or the head. That is why a vacum guage helps.

Driving on 7 out of 8 cylinders works the other 7 cylinders harder. They will be carrying about 12% more load.

 

Number 8 has 75lbs on the compression test. Going to tear down the carb and clean it tomorrow. See if that helps it run a little better for now. Soaking the bolts on the exhaust manifold with pen. spray so I can get a new gasket in there. Valve job and maybe rings over the winter if I can swing the cost. Single dad makes money tight. As long as lil man gets to ride a bit this summer he will be happy for now. Oh,and putting in a new distributor. Still have to pull the valve cover and make sure the rockers and rods are good on #8 also. I'm really hoping a clean carb will help with the bogging down issue. I bought a vacuum tester but have NO IDEA what to do with it. I'll need to research that. Thanks all!!!

 

Unleaded gas over heats the valve seats this a common problem with these classic.
And In 1972-76 ford added harden exh. seats. Alots of guys go to junk yards pull the heads from these yrs of trucks then have a valve job done.

The cost is about 2/3 less then having a shop convert the regular heads with out the harden seat. Cost to convert the standard heads runs $700-800+-

The Exh manifold gasket do not last very long!
As they our the wrong type to use. Ford used a all steel (Exh. shields) with locking star type washers. But most everyone don't use them as they don't come in a gasket kits. as they our Special Order.

The lock washers our a real pain to use. Replace bolts anytime you remove them with grade 8 type.
Auto zone has these exh shields as well as many other auto parts stores about 15 bucks.

Best to run a 3/8x16 tap through to the clean threads out.
Try not to have the new bolt threads stick out beyond the upper thread boss as they'll rust making it hard for removing them next time or breaking them off in the head threaded boss.
Use a anti-seize type lube on the all the exh bolts aid in removing next time.

I'd say since you have 75psi in #8 is just the burnt exh valve seat and not a bent push rod..
I don't think the rebuilt carb will help the bogging tho!
Orich
Orich

 

I call it bogging. Idle great. Starts great. But give it gas and it wants to quit. Fluttering the peddle keeps her alive. I have to think that's a carb issue.

 

Could be the gas filter most have one built into the lower part of the fuel pump. Its a little canister that unscrews about 4" long you may want to check it also..
orich

 

Okay folks. Let the learning begin. I have a vacuum guadge but don't know what to do with it. Teach me please.im putting the new distributor on tonight and cleaning the carb. After that if it doesn't fix the bogging down issue when you step on the gas I don't know what will. Everyone talks about vacuum so maybe that is part of it. Thanks guys

 

Hey Alley, where are you in NY? If near I might be able to swing by and help you out.

 

Upstate. Oneonta.