engine rebuild/valve timing

[BRS]

Dear friends,

I have a 58' Ford 800. I have just completed a rebuild on the engine(new pistons, rings, cylinders, valves, lifter springs, etc.) After completing the rebuild I could not get the engine to fire. I have good compression and good spark, but I fear my valves may be out of time. Or, perhaps the carburetor is acting up. When cranking the engine I do not see, smell, or feel gas(through the spark plug inlet) going into the combustion chamber. The intake valve on cylinder 1 starts to open approx. 5 degrees before TDC (exhaust stroke) and completely closes approx. 10 degrees past BDC. The exhaust valve starts to open approx. 20 degrees before BDC and completely closes right at TDC(exhaust stroke). So then, there is a very small overlap (about 5 degrees) between the intake and exhaust valve opening. It seems like the valves are opening and closing when they should, but I'm not an expert. Does this timing sound correct? I can't imagine the camshaft gear and crank gear slipping or getting out of time - the teeth look good and I did not do anything that would make that happen. I really don't want to tear apart the front end to replace the cam gear or fix the timing. Hopefully someone will say that it is a carburetor problem. I like old tractors, but a brand new New Holland at 0% is looking pretty good The soil is almost ready, so any help with this would be appreciated. Thanks. Brad.

 

[john_Bud]

How did you determine distributor timing? I think that if you just lined up the dots on the cam and crank gears and static timed #1, you are off 180 degrees.

Take out the plugs and stick your finger in the #1 hole (closest to the radiator) and verify that you are on the compression stroke (blow out pressure from the hole) when the distributor is trying to spark #1.

jb

 

[JMOR]

In other words, don't stab the distributor , aligned for #1 fire, with the crank & cam gear dots aligned. (on many, maybe all? these old Fords, that is a point where all pistons are at half way position in the bores).

 

[BRS]

I did determine the compression stoke as you described. I felt the air coming out. I can also see in the chamber with a flashlight and crank the engine by hand, getting the piston right at TDC. My problem is that there is no gas going to the chamber and I need to know if the valves are opening and closing at the right time(ie so many degrees before/after TDC/BDC). Thanks. Brad.

 

[john in la]

Your valve timing sounds about right. The intake should start to open before the exhaust is totaly closed on any motor. This is the purge the cylinder of exhaust gas and allow for a full dose of intake gas to fill the cylinder.

Before digging into the carb or valve timing I would want two questions answered.
1) are you sure the dist is set right and not 180 deg off.
2) can you feel a suction on the carb when cranking.

 

[john in la]

Here is the specs of when the valves should open/close

 

[Dave in MS]

I'm going to stick my nose in here and say you have a gas problem. If you crank the engine over, It doesn't matter what the valve timing is, you wll get gas in the combustion chamber if the carb and fuel delivery system are working correctly. The engine may not run, but you will get wet plugs. You say you are not getting gas in the chamber. If that's the case. you need to find out what is blocking the gas flow and when that is fixed, if everything else is OK, your engine will probably start.

 

[Keith Molden]

Call me a dummy, but it's usually a simple thing we overlook that's the problem. Did you by chance forget to turn the gas on when you hooked up the fuel lines after installing the gas tank. Just thought I'd ask.

 

[BRS]

I am getting suction on the carb. The dist. is set properly. When cranking the engine while holding my hand over the exhaust pipe I get a push of air and then a pull. Is that normal if the engine isn't running? Finger inside the spark plug hole did not even get a hint of gas on it. I'm thinking more and more that it is carb related. Carb is only two years old with minimal use, so I don't know. By the way, the gas tank shut-off valve was turned on. Thanks.

 

[Brian Allen]

BRS
A pull of air means that at least one valve is not seating.
Keep looking & post back.
Brian

 

[john_Bud]

(quoted from post at 05:48:24 04/27/09) I am getting suction on the carb. The dist. is set properly. When cranking the engine while holding my hand over the exhaust pipe I get a push of air and then a pull. Is that normal if the engine isn't running? Finger inside the spark plug hole did not even get a hint of gas on it. I'm thinking more and more that it is carb related. Carb is only two years old with minimal use, so I don't know. By the way, the gas tank shut-off valve was turned on. Thanks.

You should not have a pull of air from the exhaust. An old old test for burnt valves is to stick a dollar bill along the edge of the exhaust pipe while the engine is running. It should wave back and forth, but if there is a burnt or sticking valve it will get sucked into the pipe. Do you have a compression tester? Test all cylinders. Unless the engine is badly flooded, you shouldn't get any gasoline liquid on your finger from the plug hole.

Q: How did you set the valve clearances? Double check them (0.015 cold is a decent starting point) and while doing that (hand rotating the engine) inspect the valve action for any sticking valves.

Q: Are you getting a good flow of fuel into the carb bowl? Pulling the plug should get a nice flow out for 1 -2 minutes. Is there any chance that the float is stuck closed? While you rebuilt the engine, did the carb get gummed up ?

Last point -> a lot of folks that are answering are probably like me and still thinking you may have a distributor / electrical problem. It's one area where goof ups occur with regularity, even by the "experts". I know I've done silly stuff where the dist was 180 off or the wire were set for the wrong rotation direction, had a wire shorting etc etc. You may want verify that you are getting big fat blue spark at the plugs when there is blow out pressure by pulling one plug and hand rotating the engine with the ignition on.

 

[trucker40]

Check your intake over and see if all the bolts are tight and drawn up like they should be.If you arent getting gas it could be lots of things.The first thing to check would be pull the fuel line off at the carb and see if fuel runs out.It could also be 180 out.Draw a diagram of what your firing order and spark plug wires are now so you can put them back right if this is wrong.See which way the distributor turns,move number one forward 2 places,move the other wires in the firing order around as they should be just 2 places ahead.Try that.That is after you find out for sure if you have gas or not.Just to see I have soaked a rag in gas and held it over the intake of the carb while cranking it over to see if it would hit or not.If everything is right it will fire up doing that,then you will know you werent getting gas and if it fires you know its timed right.You might want to wear a glove.I guess it might be possible for it to backfire or something and get the rag on fire,but it never happened when I did it,but my motor wasnt out of time either.

 

[trucker40]

I just thought of something else since you dont think you have gas,pull your plugs and check compression if you have a compression gauge.If you dont have a compression gauge put your thumb or finger or something over the spark plug hole to see if you have good compression on all the cylinders.If you just rebuilt your motor the valves might be adjusted wrong,not closing,not pulling gas into the cylinder,just a guess.In order to get gas you have to have gas getting to the carb,and you have to have the motor pulling a vacuum on the carb so it can mix gas and air and pull it into the motor.If your intake is loose,or has a crack in it,carb gasket loose,valves not seating,this wont happen and motor wont run.If you have all of that working,are getting gas, but it still wont run its fire,or not in time maybe.

 

[Jerry/MT]

I don't know what your valve timing should be but are you sure that you timed the ignition properly? You know a 4 stroke engine fires every other rev so that you must be sure that #1 cylinder is on the compression stroke when you time it. It's an error that is made quite often.

 

[BRS]

OK finally got it running, but not how I anticipated. I took the carb off, checked the float, and soaked it for awhile. I put it back on and the engine ran. Now the problem.....smoke was pouring out of all 8 of the valve push rod holes in the head. The engine would not exceed idle(or a little more) rpm when I gave it gas. The rods are sealed off from the combustion chamber. Perhaps there is a crack in the head? Any ideas???? Thanks.

 

[steve n carolyn]

The valve 'push rods' do share the atmosphere of the crankcase. The crankcase develops pressure from 'blow-by' past the piston rings (typically). I don't know your particular situation. However, If this was just rebuilt, the rings may not have seated.
1) any idea what the compression is? (besides good)
2) broken ring(s)?
3) how much either id you use, trying to start it?
When you say 'pouring smoke', could you describe this a bit more?

....sl

 

[BRS]

1) any idea what the compression is? (besides good)

Do not have a compression gauge, but intend on getting one soon.

2) broken ring(s)?

Just replaced the rings when I replaced the pistons and cylinder sleeves. No evidence of broken rings when pulling the head and pan off.
Everything looked normal.

3) how much either id you use, trying to start it?

Started pretty much immediately, although I did choke it.

When you say 'pouring smoke', could you describe this a bit more?

I pulled the push rod cover off and white smoke was coming out of all of the holes next to the push rods. I think those holes go to the crankcase.


What do you mean by the rings being seated? Thanks for your help. Brad.

 

[trucker40]

Well its going to smoke after being rebuilt.The thing is none of us are there to see whats going on.I used to rebuild big truck diesel engines.After replacing the rings and liners the instructions were after getting it running to drive it 500 miles and dont keep it at the same speed to get the rings seated.Brand new rings dont completely fit the cylinder walls until its been "broken in".A gas engine will break in quicker probably,but it depends on what kind of rings you used.Old cast iron type rings break in quick,hard chrome rings break in slow.So you will see some blowby(white smoke in the crankcase)at first,and keep on seeing it if you broke a ring putting in new ones.
I think the reason it wont go above idle is that you could have the throttle linkage hooked up wrong.
I dont know about the cracked head since Im not there to see whats going on.If it is cracked it will leak water in the oil most likely.If it wasnt doing that before it shouldnt be doing that now unless you ran it a lot without water in it or something.

 

[BRS]

Could this white smoke that is coming from the crank case be the result of badly seated valves or bad timing on the valves? Doesn't the piston seal off any malfunctioning valve activity from entering the crank case? How then could there be smoke coming from the crankcase? The only logical conclusion seems to be a cracked head, block, or something. Thanks. Brad.

 

[BRS]

I don't know man, there sure is a lot of smoke pouring out. Should I let it run and see if it goes away? Don't want to ruin anything.

 

[JMOR]

(quoted from post at 20:54:50 04/27/09) I don't know man, there sure is a lot of smoke pouring out. Should I let it run and see if it goes away? Don't want to ruin anything.

Antifreeze/water in the oil pan? Look dipstick.

 

[john_Bud]

(quoted from post at 17:31:36 04/27/09) Could this white smoke that is coming from the crank case be the result of badly seated valves or bad timing on the valves? Doesn't the piston seal off any malfunctioning valve activity from entering the crank case? How then could there be smoke coming from the crankcase? The only logical conclusion seems to be a cracked head, block, or something. Thanks. Brad.

Due to valves? No. The pathway is from the intake manifold thru the head to the exhaust. Not going to be a valve problem, unless it's way too tight or way too loose and that will be the inability to go over idle.


What was the ring end gap? Too wide will allow a hurricane of blowby. How much oil is in the pan? If you were running it dry or if you have a failure in the oil pick up (crack, not seated, etc) you won't be pumping oil and it will get friction hot fast. You did coat the crank and bearings with gear oil right? You didn't leave out any plugs in the oil galleries? I am concerned that you may have a "high friction" situation and the smoke is from the new bearings burning up. That would also explain the inability to go over idle speed. With the crank in and the mains torqued down, you could still spin the crank easily by hand, right? (no rods yet)

jb

 

[Dave in MS]

JB I think BRS said at one point that he turned the engine over by hand, so I don't think or at least hope he doesn't have a friction problem. I still believe he has a fuel delivery problem. BRS, if this is the first time the engine has run since the rebuild, you will see smoke until the rings are broken in. Probably a few hours of run time. Now about that carburetor. Is the main jet set properly? Did you try opening it up some? If you did, did it make any difference? You said you removed the carb and soaked the float and put the carb back on and the engine ran. Sounds like you need to make sure all the carb adjustments, air, fuel mix, and linkage, are right and the gas is flowing like it should. Ignition timing is also a factor to consider. If it is retarded it will make the engine run slow and hot and make it smoke. Did you set the timing with a timing light?

 

[BRS]

I do not know the ring end gap. I purchased new cylinder sleeves, pistons, rings, and rocker arm bearings at the same time from Yesterday Tractor. It was an overhaul kit, so I'm assuming all the gaps were what they were suppose to be. I did rotate the gaps evenly between all three rings as well. After running the tractor for about an hour, I decided to replace the valves and lifter springs, because there was smoke coming out of the head cover and the tractor would stall when it needed more power (like going up a hill). I did not replace the valve guides, but they still looked good. So, now it appears that there is even more smoke with the new valves. Maybe it just needs broken in??? I did NOT coat the crank and bearings with gear oil, however the crank turns easily by hand. Do you recommend I do this? This is my first engine rebuild, so I have probably missed some things like this. The oil pan is full. Thanks for your help. Brad

 

[trucker40]

Well,it shouldnt be as much smoke as a worn out motor.With new rings it will smoke a little.Now depending on what you cleaned it with and how much oil you got on like the head it will smoke until that burns off.Maybe you ought to do a compression check.If the compression is low on one of the cylinders there is a chance you have a broken ring and you dont want to run it until you fix that.A broken ring might make it smoke like that.Whenever I broke a ring I knew it before I got the motor running.Seems like motors I tore down that had broken rings smoked a lot.There are lots of things that could cause it to smoke,like a rod cap or main cap on backwards.Also if its that it will spin a bearing.Something not getting oil would smoke because of friction.Rebuilding a motor is harder than it looks.Did you torque all the bolts?The pipe on the oil pump with the screen on it wasnt broke or plugged up or fell off did it?How much oil pressure do you have?Seems like I remember those rods have an oil hole that goes up to the wrist pins,if they do,did the new bearing have a hole in them that lined up to the one in the rod?Did you line all of them up?I think I would pull the pan and check all of that,look for any rod or main cap thats clean and dry or blue colored.That would mean its getting hot and has something wrong with it.Check and make sure all the rod and main caps are on the right way and that the bearing holes are lined up to the rod holes if it has them.

 

[trucker40]

If you are sure all of that stuff is right like it should be and the motor turns over easy,what else could it be?It just about has to be something to do with the rod and main caps,bearings,or something too tight or not getting oil.Im not real sure a broken ring would make it smoke a real big bunch.Maybe,but Im starting to think its something worse.If it was me,I would pull the pan and see what things looked like,check my bearing tangs,OH yeah,if you replaced the pistons,can they be put on the rods wrong?In other words on most motors the numbers on the rods go to the cam side of the motor,the piston has a mark that goes to the front,if you put the rod on backwards and the mark on the piston is to the front,the rod bearing could be rubbing the crank radius hard maybe causing smoke.Just a guess.I dont know on a motor like that if it makes a difference,but it does on Cummins Diesels.

 

[JMOR]

(quoted from post at 11:04:51 04/28/09) If you are sure all of that stuff is right like it should be and the motor turns over easy,what else could it be?It just about has to be something to do with the rod and main caps,bearings,or something too tight or not getting oil.Im not real sure a broken ring would make it smoke a real big bunch.Maybe,but Im starting to think its something worse.If it was me,I would pull the pan and see what things looked like,check my bearing tangs,OH yeah,if you replaced the pistons,can they be put on the rods wrong?In other words on most motors the numbers on the rods go to the cam side of the motor,the piston has a mark that goes to the front,if you put the rod on backwards and the mark on the piston is to the front,the rod bearing could be rubbing the crank radius hard maybe causing smoke.Just a guess.I dont know on a motor like that if it makes a difference,but it does on Cummins Diesels.

Maybe I missed it, but what about smoke out exhaust? With smoke, anywhere, you ought to be able to determine whether it is oil smoke or antifreeze smoke, by the color and smell.

 

[BRS]

I did a compression test and the results were as follows:

Cylinder 1 - 105 lbs.
Cylinder 2 - 60 lbs.
Cylinder 3 - 45 lbs.
Cylinder 4 - 80 lbs.

Obviously these are below normal and all over the place - I'm not even sure what specs are.

The timing light indicated ignition 10 degrees before TDC. The Tractor would not start when I tried to get it to ignite any closer. If you think about it - 10 degrees only accountants for about 1/8 of an inch of movement in the piston, correct? Timing is good. It is either badly seated valves, a broken ring, or a cracked block. Three of the cylinders have pretty bad compression, and I doubt all three have broken rings. Besides, there was no indication of a broken ring when I pulled the pan - everything looked good. There is no smoke coming out of the exhaust, although there is plenty of hot air. The white smoke and the smell of it could be antifreeze(it is what I would imagine it to be). There isn't an appearance of antifreeze on the dipstick. I originally replaced the pistons because one busted into pieces - perhaps that would indicate something? Who knows, I guess all I can do at this point is tear everything down again until I find the problem.......unless someone wants to buy a tractor before I begin! Thanks. Brad

 

[trucker40]

Sorry its taking so long for me to get back to you,I had stuff to do.If you torqued the head down,did you go back over the bolts?I always find loose bolts when I do.Try retorqing the head if you think the rings are alright.Maybe I should ask this first,did you push the pistons in or did you have to beat them in?Chances are if you pushed them in the rings are alright,if you beat them in you have a chance of having broken rings.Did you adjust the valves?If your valves arent adjusted right it might run,but not very good.It even could be so bad out of adjustment on the valves that it wont run.Also you said you replaced the valves,did you lap them in?If you didnt lap them in that could be another reason for low compression.Now dont get discouraged.Lots of people could never tear apart a motor and get it running again if their life depended on it.Yeah I know its a lot of work,but it has to be done right or as you can tell now,it wont work.If you didnt lap in the valves,and if your motor was wore out before,and you didnt adjust the valves,there could be your low compression problem,valves way too tight and not seating.
Now 10 degrees is 10 out of 360 degrees.Not much,but it doesnt take much for a motor to run or not.So if your valves are set wrong,and not seating good,that 10 degrees of timing is even more important because your valves being set wrong will affect the timing in a bad way.
Check your head bolts if you didnt beat the pistons in,be sure your rod and mains are on right,and the oil sump is not broke or loose or plugged up.IF you still have antifreeze in the motor put a clean piece of cardboard under the motor and see if you see antifreeze dripping anywhere.Does that motor have wet or dry sleeves?I think they are dry if I remember right and if the block was cracked it should cause antifreeze to go into the pan.You might want to take the head to a machine shop and test it for cracks and have them lightly grind the valves and seats to get them sealing.While the head is off would be a good time to pull the 3 worst compression pistons and see if the rings are good.While you have a piston out,check the ring end gap and see what you have.The way things are nowdays who knows,they could have put the wrong rings in your kit and you have too much gap.
Main thing is dont get discouraged,its just work.When you are done and satisfied everything is right,it should run and last a long time.If you get mad and try to take a bunch of shortcuts it will cause frustration and having to do it over again.What I did at first when I built motors was make a list of what I had to do,as I got things done I crossed them off the list.Thats the best way if you dont do this every day.You can do everything I said and still miss something,but if you do reply and I will try to help,and others will too.You already tore it apart and got it running which tells you that you can do this,it just will take a little more work to get it right.These motors are made for farmers to be able to fix them for the most part.

 

[BRS]

Appreciate the effort that you have put into helping me - that's hard to find these days. I will take your advise and take the head to a machine shop for testing and better seating. Hopefully this will solve the problem. I will keep you posted. Thanks again and may God bless you. Brad.

 

[trucker40]

I was watching a NHRA race the other day and the guy that won had his motor rebuilt in an hour,maybe a little longer,and that was right there in the car at the track.Sure they had new heads and everything they needed right there,all the tools and 5 or 6 guys working on it,but that was running and valves set,supercharger hooked up with a computer hooked to it ,and then down the track over 300 MPH in first place in about an hour.I bet they took every short cut they could,but they knew everything they could get away with,and what they couldnt.There are some things you must know when building a motor,like ring end gap,feel for bolts being tight or not,valve adjustment,timing,and lots more.Its doubtful that you could ever get it running right without checking that stuff,but you might get lucky.I would rather know if it was me.The last gas motor I built I had number 2 and 5 rod caps switched and it wouldnt turn,but I struggled for 2 days before I took it apart and saw it just as soon as I got to the number 5 rod.It was stamped real light but somehow I saw it was 2 instead of 5,switched them and motor probably has 40000 miles on it now.

 

[trucker40]

Thanks for the reply.Most of the time I never get a reply at all.The reason I answer questions about motors is because when I was a kid I helped my dad work on his Ford tractors.Since then I have built lots of motors,mostly diesels.While I may not be an expert on Fords,Ive built enough motors to know a few things about them,and messed up lots of times myself.I have even spent a bunch of time fixing what somebody else messed up.I cant count the times somebody ordered the wrong parts and tried to make them fit then brought it to the shop where I worked to figure out.Ive had people bring a transmission or a motor in that was torn apart and want us to fix it.Many times Ive worked all night on a truck so I could drive it the next day,or somebody else could.Its a pleasure to answer your questions and I hope it helps you.Much easier for me to push the buttons on a computer than to turn those wrenches.

 

[john_Bud]

(quoted from post at 13:42:31 04/28/09) I did a compression test and the results were as follows:

Cylinder 1 - 105 lbs.
Cylinder 2 - 60 lbs.
Cylinder 3 - 45 lbs.
Cylinder 4 - 80 lbs.

Obviously these are below normal and all over the place - I'm not even sure what specs are.

The timing light indicated ignition 10 degrees before TDC. The Tractor would not start when I tried to get it to ignite any closer. If you think about it - 10 degrees only accountants for about 1/8 of an inch of movement in the piston, correct? Timing is good. It is either badly seated valves, a broken ring, or a cracked block. Three of the cylinders have pretty bad compression, and I doubt all three have broken rings. Besides, there was no indication of a broken ring when I pulled the pan - everything looked good. There is no smoke coming out of the exhaust, although there is plenty of hot air. The white smoke and the smell of it could be antifreeze(it is what I would imagine it to be). There isn't an appearance of antifreeze on the dipstick. I originally replaced the pistons because one busted into pieces - perhaps that would indicate something? Who knows, I guess all I can do at this point is tear everything down again until I find the problem.......unless someone wants to buy a tractor before I begin! Thanks. Brad

BEFORE you tear it all down....

please outline the procedure you used to set the valves.


At this point, I suspect that you may have valves that are too tight. If you just replaced the rocker arm assembly after a valve job, they are no longer correct. Hand turn he engine until the intake then exhaust valve move just after the ex stops there will be a place where both are loose. That is where you check the gap. It should be 0.015 inch with the engine COLD and 0.018 inch with the engine HOT. It's not hard to do, but at the same time is easy to mess up (if you know what I mean). The books all show a fancy scheme for only having to rotate the engine a couple times to get all valves in a spot to check them. I always goof that up, so I do one cylinder at a time. Slow but accurate.

jb

 

[Dave in MS]

You got some good advce so far, so here's my $.02. New valves will not seal well on old seats. Take the head to a shop as trucker says and have the seats ground and the valves touched up. That should solve you compression problem. While the head is off do all the stuff trucker40 said, and after the head is reinstalled follow John-Buds valve setting proceedure except set the valves at .018 cold or .015 hot. (sorry JB you know they get tighter when hot. lol) Also make sure the head is torqued in the proper sequence, and retourque it after running the engine up to temp.

 

[john_Bud]

(quoted from post at 07:52:14 04/29/09)

(sorry JB you know they get tighter when hot. lol)

Phew! What's that smell?? Oops, it was me making a brain fart!

Oh well, you knew what I meant to write before magnetic field from the plate in my head scrambled it up! :lol:

jb

 

[Dave in MS]

:lol: :lol: