yea they quit putting in the pressure reading's cause folks were in with the results from the test an saying hey the book says ie 160 psi , an I only got like 125 psi , I want my motor rebuilt .,, So now its a rule of thumb that all cylinders have to be with in 25% of each other ,,, also A engine has to have a min. of 85 psi for the cylinder to fire , Just so you know . ( chevy was bad about this in the early 80's with there TARGET MOTORs , suppose to be fresh factory rebuilds we found them with pistons that had been stamped .002, .005 over . then a stock one , then .010, An the motors ran rough !!!!! no wonder , an bird nests in them , valves frozen in the guides ), A vaccum gauge will tell you alot about the motor if you learn how to read them , An most all tech . books give you the compression ratio like was stated above like 8 to 1 etc.

 

Looks like we will be able to get around to the copression check this week ahead. He's taken it up to the shop for monday ( take a extra long lunch ). While taking the pictures we noticed that a plug wire cap was sitting off the plug on the #2 cylinder. Went to remove and the metal connector on the plug wire stuck on the plug. So he will need to get another set again. ( do I hear the nickle and dimes falling ) Might have been a faulty set of wires?

I added som pics of the engine to the gallery. ( make sure your shots are up to date first ) LOL


TailGater_73F100
Savannah, GA

 

Plug wires do this commonly. One way to avoid it is to use die-electric grease on the boot to keep it from siezing to the plug from heating and cooling repetitively. Next is to twist it gently from side to side while removing. If it requires excessive force, do NOT force it. Gently work at it until it comes free.

Would be interested in seeing those compression numbers.(dry and wet) posted here, if possible.

Use masking tape to number each of the plug wires to make re-install easier after. Also remember to pull the center coil wire on the coil side to avoid a surprize jolt should a plug wire head to ground.

I checked the pics in the gallery, even if it needs a rebuild, the truck looks clean enough to make it worth the effort.

 

Was able to start changing out the plug wires..... Now I do believe that on a rotor cap has a #1 stamped on it for the #1 plug wire to go. Correct?

The other guy that helped him hook up the plug wires incorrectly. I'm not sure how it was able to run as the #1 plug wire was hooked up to the #6 or #3 slot on the cap.

Thats where we stand for the time being. I should be able to install the new wires and run the compression check today.

Thanks

TailGater_73F100
SAvannah, GA

 

The distributor cap does have a 1 stamped on it.

If you were to look at the top of the cap, the wires should be installed in a counter clock-wise direction(rotation of the rotor) in the following order. 1-5-4-2-6-3-7-8.

Looking at the engine from the front of the truck, the cylinders on the left bank are numbered front(grill) to rear(firewall) 1-2-3-4 and the right bank(front to rear) 5-6-7-8. That should make getting the wires installed in the proper order easy. Keep us posted.

 

To add to what RR4E said, as long as you are following the proper firing order stated above, whether or not #1 cylinder goes to #1 on the cap is irrelevant, there are many things that could lead to a timing change to the point where the rotor is lining up with a different point on the cap when #1 is supposed to fire, if its running right timing wise, dont sweat it.

 

Before we get this gentleman confused. The number 1 wire DOES go on the post stamped 1 on the distributor cap. This is EXTREMELY relevant! If any vehical runs with the wires rotated one post to the left, it would indicate your timing chain has jumped a tooth or is extremely worn and needs replacement.

It's true that the rotor itself may not point directly at the post inside the cap, but that's a timing related issue as to how much advance you're running, and whether or not the number 1 cylinder is at true TDC(top dead center) on compression stroke.

 

No, not necesarily....

What if someone before him had dropped a new dizzy in and it wasnt the same as the old one and the #1 when the cap went on was in a different spot relevant to the old one?????

What would screw him up is if that or something else appropriate were the case and he put one to one when it was running fine before, and now has problems.

I saw a thread once where that was the scenario, and it went 5 pages with different people trying to help him and no one could figure it out, firing order was right. Just because the cap has a 1 on it, doesnt necessarily mean thats where #1 goes.

I just dropped a new dizzy in my 429 and that was the case, it WOULD NOT seat where the old one was, just the way the reman one was lined up when you clamped the cap on, wires were #1 cylinder to #1 on the cap on the old one, and now they are 2 over on the new one.

Thats all I was trying to point out, if its not like that now and firing correctly, leave it alone

 

Man oh man what a morning... Started off with out being able to check the thread from the shop until this afternoon.

Well after fighting for about 2hrs with the whole mind set of "this truck shouldn't be running like this" I had to set aside what I knew was correct and was only able to get it running by wiring it up as 1-5-4-2-6-3-7-8 with the #1 wire starting on the #2 post. Still blows my mind but anyways... it still dont run just right but it's better.

Was only able to check the #4 and #5 cylinders, both held 150psi. ( RAIN )

Not lookin to dark and the end of the tunnel after all. Now what should we do with our new found info?

Thanks

Tailgater_73F100
Savannah, GA

This place is the greatest

 

Wow, thats a good PSI number, check the rest when you get a chance, keep us posted, is that a dry number or a wet number?

 

Compression in the two you've tested sounds pretty damned good. Keep in mind, it's the difference between highest and lowest that counts in the final end. Not to be pessimistic there, but it's the final truth that tells all.

As for the wires needing to be rotated one post over...

To me that would indicate worn distributor and drive gear, as well as a worn timing chain assembly(possibly jumped a tooth). Don't worry to much at this time.

If the compression readings all look good, here is my recommendation.

Since your buddy was looking for a few mild performance upgrades to begin with, a mild RV cam, lifters and push-rods(you may want to go with new valve rocker arms here too, or look at having the heads done too if vacuum readings are not good) new distributor(rebuilt should be fine, but take the numbers stamped into the side of it in to get a proper replacement).

If you do the cam, the timing chain assembly has to come off anyways, no point in putting the old one on. The stock units were slider chains with nylon gears, and they were horrible. A new set-up with steel gears and a double roller(pre-stressed) timing chain is only a few bucks more than the stock unit, and well worth the upgrade. If all of that doesn't put the timing into a correct state, you've got a wrong part somewhere, or something not installed right.

One thing to be wary of when installing "some" aftermarket timing assemblies. Some come with a "3" position option. The default(stock) timing position is marked with a stamp, the other three are options for running extreme cams, and other performance options. If you're not going past a mild RV cam, the "other" options should be ignored. All of this should bring your timing back into "spec".

Once again, since you're there. You'll have the intake manifold off for this, so you may as well replace it with a decent intake and small 4 barrel carb. You'll get many opinions on cams, carbs, intakes for choices.

What I generally run with is a decent dual plane intake(my preference is an Edelbrock Performer or the older Torker or TorkerII series, for a truck) A 600cfm off-road carb(will perform very well on the street, but also allows for off-angle roads very well too)

For cams, I prefer the Competition Cams dual plane 260/270 RV cam, it works well with any truck.

My own recommendation. Even if the vacuum readings show good. I'd at least rent a valve spring compression tool and remove the valves and springs, get the tension checked on all the springs, and replace the valve seals.

May as well also just buy a complete engine seal kit, as they are cheaper than buying individual gaskets, and come complete with head gaskets. Fel-Pro is a good brand, but there are other competant mfgr's out there too.

Once again, keep us posted on the compression values. Let's go from there first, before we get to much deeper into what options are available.

As stated before, the body looks pretty sweet on this truck, even a total re-build would be worth it, IMO.

 

Well thanks again for the replys and recommendation.

Wouldn't you think that being 4 posts over is alittle far?

We are going to check out the rest of the copression values as soon as weather and boss permit ( shhh ). Also a vacuum test.

Also looks like we are going to be in need of a wiring harness at some point. Some of the wires to the distributor are cracked. But like we all say one thing at a time.

Thanks

TailGater_73F100
Savannah, GA

 

Yep , I've seen that my self before , for what ever reason , the #1 plug wire is started off on another hole ,, but as long as the firing order is followed it should work . Lots of ppl have a hard time putting dist. in, cant get them to sit just rite - so you end up way off the the #1 postion . Also whats kinda fun is watching a CHEVY guy work on a FORD , As the #1 cylinder is on the oppisite side of the block, it will drive them crazy trying to get it to fire up !!!!!!!,,

 

LOL... Yup... Chevy and Ford number the cylinders differently, makes for a great amount of entertainment when you've got a Chevy guy that doesn't know that working on a Ford... Interesting part is, if you number the cylinders on a Chevy like those on a Ford, the SBC firing order works out to 5-4-2-6-3-7-8-1... Yes.. I was really bored and looking at my DD GMC the day I figured that one out... LOL

Anyhow, as for having #1 at a terminal other than #1, personally, I recognise that as not being a sign of a loose timing set or jumped chain, for it to be that far off, the engine would pretty well not run.
Normally, It's from someone trying to drop in the distributor, it not lining up with the oil pump drive, and instead of turning the engine over until it drops in, they keep moving the distributor around and re-dropping it until it goes in. To check for a loose/worn timing chain, the best way to do it is to pull the distributor cap off, put a socket and breaker bar on the crank, and turn the crank one way until the distributor starts to move, and then turn the crank the other way, there shouldn't be much play there, spec is 1/2" deflection in the chain, which doesn't translate into much movement of the crank before the cam starts to turn.

 

My two cents. Putting oil in the cylinder is the way to test the rings. The oil absolutely will seal the rings and if the compression raises significantly, the rings are bad. Any diesel shop will tell you that if a diesel is not starting, there is a chance you have dry cylinders and putting a bit of oil in the cylinder will help to get it started. (Now we can hear the opinions that you will break a rod trying this). The BEST way to test low cylinders is with a leakdown test. Close the valves of the cylinder, attach an air line to the sparkplug hole, and see where the air goes. There are smoke kits available that make it easy to spot the air. It does not matter where the #1 printed on the distributor is. What matters is that the timing of the wire attached to #1 is actually timed to TDC of the #1 cylinder. Take out the number one plug, put your finger in the hole and bump the engine over until air blows your finger out of the hole (disconnect the coil wires so the engine won't start). When you know the engine is coming up on compression stroke of number one, line up the timing marks either by bumping the engine very carefully to not pass the mark, or with a breaker bar and socket. Once the timing marks are lined up and the engine is on the compression stroke of number one, pop the dist cap and see where the rotor is pointed. It will be pointed to the post that you want to attach the number one plug wire to. This is foolproof. Ensure that you check distributor rotation and follow the wiring order for the remainder of the wires.