Finally got around to "try to start" my rebuilt engine tonight. I timed it to fire on the first cylinder at 15 degrees after top dead center on the compression stroke and the spark retarded all the way. The coils are newly rebuilt, the TW timer is new, and I had gas to the carburetor. After hand cranking for an hour and fiddling with the gas mix (1 1/2 turns to begin) only one puff. Feel like I'm not getting gas into the cylinders ... the plugs are not wet.
Have to admit that when checking for compression on the first cylinder for timing ... there was not the compression I've come to expect. And ... the suction on the carb with the choke pulled was also weak. So ... what now? Like I said, the first cylinder plug is firing on the compression stroke and after TDC. Got to be something simple. I'm usually good at getting these going. So I must b overlooking something.
The engine block was rebuilt and has a NOS metal timing gear. The push rods are solid type and the valves are Chevy. The rebuilder set the gap. I feel like there is barely any compression. Maybe dirt between the valve heads and seats from sitting so long? I dunno.
Steve Jelf had a similar problem initially on his roadster engine. Since the rings hadn't seated yet, he found that squirting a little oil into each cylinder would help the rings seal and allow the engine to pull gas into the cylinders better. Do I have that right, Steve?
You know I was wondering about that. This was a rebuild that sat around for awhile. I worked on the transmission and fitting that to the crank in a shop ... and did squirt some light oil in the cylinders to make it a little easier for me to turn the crank while setting the magnet coil interface. Those rings really dragged on the dry cylinder walls while I was working on it.
I blew out under the valves and the bolt holes before I put on the head, but maybe I should have wiped under all of the valves. Was thinking maybe there is debris trapped between the valves and seats. But if Steve had a similar situation and fixed it by squirting some oil down there ... I'll try it.
Recently the roadster developed a hard-starting problem again. I was sure it was a fuel problem, but operating on the try everything principle I tried a set of new spark plugs. Bingo!. It proves once again that 90% of fuel problems are electrical, and 90% of electrical problems are fuel.
Might be that ... but am using old champions that are clean, set at .025 and worked well on my '19. The weak compression and vacuum are interesting on this. Did you have experience with this on a rebuilt engine?
No, the only problem I had was a defective valve lifter that wore out in less than a thousand miles. Had to pull the engine and put in a new one.
sounds like your cam timing is out
or your valves are sticking open a little bit
You might try a cylinder leak down test, sometimes when they grind valve's they don't always seat. It's probably the easiest test to do.
The rebuild on this block is five years old. The fellow who did the work suggested pouring some 30 weight oil in each cylinder and cranking it to work it down into the lower rings. He says the timing gears are set right ... and I know the timer brush is right. The plugs are all firing at the right time .. at 15 degrees after TDC
Just a random thought - have you checked for an intake leak?
Choke it, advance it a bit off of 15 degrees ATDC and crank it. If it wont pull up enough fuel to fire, squirt some into each pot via the sparkplug holes. If the plugs get wet but it still wont start, squirt some oil or your favourite penetrating elixir (Marvel Mystery Oil, anyone??) into the cylinders to give the rings something to work with.
If that doesnt bump up the compression noticeably on the handle, your valves arent seating.
Pull the covers and look at the clearances, or pop the head off and see if they are not seating or are stuck open.
A fresh rebuild that sits around for years can rust internally, and a skim of rust on a valve stem, or a freshly cut valve seat can stop those parts from doing their job.
If its a rebuild you may need to tow it for the first start.If you have tight bearings and a lot of ring drag it might not have enough power to start?? Been there done that.Bud.
Spend around 20.00 dollars on a new set of Motorcraft or Autolite plugs and see what happens.
Never had any of that trouble with my Joe Bell engines! They'll even start cold on mag.
Tim,Very true and Joe has a large drill he starts them with in a stand and runs them in.That is how he did mine many years ago,but not all people do the same?
Yes, new plugs might be good but I think I mentioned that the compression was very low as was the vacuum when I put my thumb on the spark plug hole. So .. the problem sounds like it's not getting enough gasolene .. or enough compression for firing. I am hand cranking ....
I'd be checking to see if the valve stems may have rusted in the guides and are popped open. I had that experience on an engine "that sat around for a few years". Secondly, how confident are you in the "rebuild" job? Seems everyone has their own definition of rebuild.
I had a problem starting my new motor so we decided to pull the car.
It went about two feet and the motor fired when I pressed the low pedal.
After wearing myself out cranking,I was very surprised that it was so easy
Am confident in the rebuild and the valves were moving in the engine before I installed the head.
the valves were moving in the engine before I installed the head.
hmmm- are you sure the head gasket was proper and fit correctly?
In 40 years of working on / driving a model T have never had a problem installing a head with a new gasket. ..... but there's always a first time. Hand cranked it to check clearances and cleaned out the holes before buttoning it up this time as usual.
fuel + spark + compression = ignition
if you have fuel and a healthy spark (new plugs just to be safe) and you say from 40 years experience the compression feels weak. then you have a problem with your valves or your rings, or more unlikely, a warped head or a bad head gasket. Of course if you slowly crank it over you should be able to hear air slowly leaking past your rings, or if your manifolds are off, past your valves if they are the culprit.
You may need to artificially raise the compression on your first start until your parts bed in by turning it over faster than humanly (and humanely) possible by pulling it or rigging up a friction drive to spin a rear wheel.
Yes, it's odd and probably simple as the title if the post says. The head is newly planed and the gasket new and installed with copper spray. Will take off the valve cover after dinner and look at the valves / push rods tonight. Then will pour a little light oil in each cylinder and hand crank for the rest of the evening to work the oil into the rings if I can. Then try again with the plugs in to see if I'll get gas to the cylinders. Should start if it will draw in the gas .. and have some compression when the spark fires.
If the plugs spark while out and laying on the head a little splash of gas in each cylinder might get it to run. If it dies then a fuel problem. I don't use instant start up the intake...good way to have a fire.
Like Fred said, a tow strap or rope or chain (lots of room to stop) is much easier on your heart and back and I have started stubborn cars and tractors in a few feet. That will tell you if it is going to run or if there is something wrong. You can't crank as fast as a tow on first start up, but go slow with the tow vehicle.
Good news. Put some Marvel Oil in each cylinder and cranked off and on for about ten minutes. Put my leather gloved thumb on the first spark plug hole and now I have compression. Popped my thumb off the hole as it should. Same with the rest of the cylinders. Also heard gas sucking through the carburetor
for the first time when choked while cranking. I pulled the valve cover off and all valves and push rods seem to be moving as they should. Will check gaps next.
So, it seems that any lubrication that was on the engine block during rebuilding had more or less dried up over five years on the shelf causing the rings not to seal very well. Raining steadily right now so can't easily attempt starting. Will wait until tomorrow after work. I think it should start now.
Ken, last time I watched Joe "first run" my engines he just used his (albeit very strong) arm! Man that boy does have muscles. But my second engine surprised him, I recall his switch was on mag for whatever reason and while he was priming it, it fired right up! And still does, even on a cold start.
Another supporter for MMO?
Mark, I noticed that you're in Rochester, NY.
I worked there for three years for Ward's Natural Science Establishment.
Our founder, Henry Ward, was a famous Rochester native who helped found the University of Rochester. I became very interested in the city's history and had a great time exploring on my days off.
Ok gang. Got it started by hand crank and battery .. and ran it for a couple of minutes on all cylinders. Couldn't get to the carburetor in time to dial it back. Hard to get to everything at the right time in the dark, but at least I know it's timed right and the valves are fine.
All it took was Marvel Oil to be worked into the rings for initial compression and vacuum to draw in the gas. Anxious to have some quality time to tweak it, but am busy teaching an albumen printing workshop all this week. That job stuff sure gets in the way.
MMO strikes again!
I'm the photographic process historian at the George Eastman Museum. Have bought chemicals at Wards over the years. Very interesting place. Rochester is a very pleasant city. Nice houses and aside from a long winter the weather is actually pretty nice.
This is cool Mark. :-)
Like a character said during the 1st Disney Atlantis movie "She lives!"
I wanted to smart off about oils on the cylinders since the pistons come up past the top of the deck and regular motor oils generally just get pushed up on the deck and then stay there...
I've watched thru the spark plug holes.
I set the cylinders about halfway up/down, inject oil and walk away. :-)
Hehehe, a little Marvel oil... :-) Nice touch. :-)
Very glad to hear it's up and talking to you. :-)
Yes, I cranked until all cylinders were half way. Put the oil in and left it for a couple of hours and then cranked it over with the plugs out. Checked the compression with my thumb (wearing leather gardening gloves for a better seal) and then put in the plugs.
It started on the second or third pull, billowing white smoke in the exhaust but running smoothly enough on all cylinders. I reached over to advance the spark ... but when I went to lean out the carburetor it died. I don't have the right carb adjusting rod ... it just has a very tiny swivel right now from a different set up I had on my other T to a cable that went up to the steering column. This made it a little hard to fiddle with in the dark. But ... it ran for a couple of minutes. When I have more time, no rain and daylight ... I'll tweak everything.