robsgp : so many questions

so many questions
Post by robsgp on May 21, 2006, 9:11pm

I'm fairly new to the zone and a shade tree mechanic with basic tools and skills. My m715 brush fire truck needs quite a bit of work. It had been sitting for 10yrs when I bought it. We got it to start but there was a lot of white smoke for the first 10min and gas was leaking from the carb.

I've never rebuilt a carb before. I bought a NOS kit to overhaul the Holley 1920. I pumped all the old yellow gas out using the cheap electric fuel pump that had been added. I replaced the fuel filter with a clear plastic one. I put it all back together, cleaned the sooty plugs, added fresh gas and tried it. It popped a few times but won't start. The fuel filter stays about half full. I don't smell gas so I poured a splash down the throat a couple times. One time it wanted to go, once it didn't. I read in a manual about checking the wet fuel level through the economizer diaphragm opening with it running, but don't know what to expect if it's not. What else can I check?

The rear brakes were dragging so I pulled the back drums. The left shoes are gummy I guess from leaking brake fluid. The wheel cylinder caps are pretty flexible and look to be in good shape. Should I rebuild or replace the wheel cylinders, or clean everything up and check for leaks after I get new shoes? The master cylinder has leaked, eating paint inside and outside the firewall. Brake parts seem to be a little rare (no one has everything) and expensive ($25/shoe?). Any recommendations?
I haven't even looked at the front yet.

The LR hub is missing one of the studs/bolts. Is this allowing muck into the bearings? Can just the stud be replaced?

I just received a set of data plates. Do all 5 mount to a plate that then mounts to the dash between the guages and glove box? Any good pics of a stock dash? And does anyone going to the FE have a set of number stamps? I'm thinking of attending the FE even though the truck won't be ready. It'd be nice to meet some of you and see a few m715's.
Thanks,
Rob

Re: so many questions
Post by drvnkaiserdaily on May 21, 2006, 10:54pm

The first thing to do is remove all the variables except the carb,since you know it ran before.First,make sure that the firing order is correct after cleaning the plugs(which I have never had much luck with,but save the new ones till after you get it running good) Be sure that the coil wire is secure(as im sure you had it loose while working on it)After checking these things and with the ignition off,look down inside the carb and pull the throttle open.There should be a spray of gas from the accelerator pump.If it does not suqirt a shot os gas ,either the pump isnt working or the carb has not filled with gas to supply the pump.If your truck sat for 10 yrs,the fuel pump diaphram could be damaged or bad.If it does squirt,you know you have fuel getting to the motor.Next would be to check to see if it is getting good spark.I would recommend getting an old plug and put it in the wire and grnd. it to the block.It should have a good blue spark,not weak and yellow.Did you check the cond. of the points.They should be inspected after sitting all that time. Good luck and keep this hobby going.

Re: so many questions
Post by binfordm715 on May 21, 2006, 11:34pm

Welcome aboard, Rob!

Some of the guys have talked about getting brakes relined by local shops. Either way, it's a bit costly. I think there is a modern brake cylinder swap you can do that only required slightly enlarding the mounting hole. Perhaps someone will chime in about that.

Yes, you got the data plate setup correct. Let's see if I can find a good pic among my collection for you. Here's an okay one:

http://img216.imageshack.us/img216/8...taplate7el.jpg


Hope to see you at the FE!

Re: so many questions
Post by jeepistdougiowa on May 21, 2006, 11:54pm

I'd check firing order first...all else shouldn't have changed much.

Re: so many questions
Post by wrecker on May 22, 2006, 8:57am

There is an easy, inexpensive upgrade for the master cylinder. The stock unit from a FSJ pickup about early 70's will work. This is a dual so you'll need to seperate the front and rear circuits at the splitter block on th e frame. The adapters, new line, T fitting and master cylinder all together was less than 30 dollars. The wheel cylinders from a E-350 Ford van from around 1993 will work with a little enlarging of the mounting holes. I think the rear shoes from a GM 14 bolt can be made to work but I can't exactly remember. Also, the drums and hubs are made to be indexed one way and if they aren't re-installed the same way as original, you can see some problems. Who knows how many times they were off before though right? You should expect some fuel tank mud/rust/sludge problems and a leaky fuel pump diaphram. An engine swap would be cheaper than rebuilding your Tornado, but if you wait, there are often parts for free that might get you running for now. Hope that helps. Bill

Re: so many questions
Post by brute4c on May 22, 2006, 9:10am

On the master cylinder, you can buy the stock one, rebuilt from NAPA...tell them to look up a 1966 Gladiator pickup...there is a picture of it in their parts book and it looks exactly like tyhe stock one...cause it is...

The brake shoes, you can try to do them yourself or pay the big bucks or have them relined locally...you can add semi metallic material instead of the stock, asbestos, type. Usually, if you have a NAPA nearby, they an get them done or know where you can...you can also check the phone book for a relining shop...you might have one local..

The wheel cyliners can be replaced with some that fit 93-94 Ford 1 tons. Tru torque part numbers W37262 and W37263, left and right.
The following are part numbers for one side, not sure which off hand
Bendix 33595
Raybestos WC37263
EIS EW73615
Wagner F73615

To fit these, you need to open the 2 bolt holes that mount the wheel cylinder by about 1/4 hole on the bottom side of the existing holes. Once you do that, I used a rat tail file, these will bolt in. These also feature stainless steel pistons...nice.

The rear axle/brake drum condition you describe as "gummy"...could be that the wheel cylinder leaks or that the rear axle seal leaks...need to verify which...you can see a line of geaar oil from the bottom side of the axle where it goes through the backing plate or the stuff smells like gear oil, replace the seal...they are pretty easy to do.

The missing stud on the rear flange...I dont think any of those are fluid bolts but I am not sure...so I cant answer the contamination part right off the top of my head...I would recommend putting something in their anyway and one can use a hardened bolt in place of the stud...

I would follow the carb info above...sounds good to me...as well, the data plate info is spot on.

Re: so many questions
Post by robsgp on May 27, 2006, 8:05pm

The firing order is on the valve cover but are the cylinders numbered 1-6, front to back? What is it telling me if my spark is orange?

Re: so many questions
Post by tomkirkman on May 27, 2006, 9:01pm

If the points are damaged the engine will not run. In fact, it won't even fire.

The carb will work and the engine will run even if the accelerator pump diaphram is bad, but you'll have a lag or drop whenever you hit the gas and try to accelerate. Plus, it'll be kind of hard to start.

The 230 engine floods easily. Don't keep pushing the gas pedal (if the accelerator pump is bad, however, it won't make any difference). Let it sit overnight and then give it 1/2 choke and hit the starter switch. Don't hit the gas pedal.

That is a very easy carburetor to rebuild. Takes all of 10 minutes. Just follow the instructions in the M715 tech manual. Not much to it. Pretty simple.

Re: so many questions
Post by warwick on May 27, 2006, 9:09pm

welcome to the madness

your truck sounds just like mine was when i brought it home.

good luck

and yes cylinders #s front to back 1-6, firing order 1-5-3-6-2-4 counter clockwise

Re: so many questions
Post by luckypabst on May 27, 2006, 9:23pm

15's too young. 36's too old. 24's just right.

Chris

Re: so many questions
Post by over2land on May 27, 2006, 9:28pm


Quote: <TABLE class=bordercolor cellSpacing=1 width="90%"><TBODY><TR><TD width="100%"><TABLE class=quote cellSpacing=0 cellPadding=2 width="100%"><TBODY><TR><TD width="100%">15's too young. 36's too old. 24's just right.

Chris</TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>

Dude, huh?

And check your mail.

Re: so many questions
Post by porkchop on May 28, 2006, 3:18am

That is an easy way to remember the firing order, Chris!

Re: so many questions
Post by robsgp on May 28, 2006, 10:25am

Thanks, I was scratching my head too. So kind of a weak orange spark is likely points? That'll be my next parts adventure. It's been converted to 12V and I haven't found any markings on the coil or dizzy cap so far. Are Champion RL87YC standard plugs? Just guessing I set the gap at .030.

Re: so many questions
Post by barrman on May 29, 2006, 5:00pm

The weak orange spark coming from a civilian 12V distributor could be the exact same problem mine had when I got it. Somebody had installed a 6V ballast resistor in the ignition wire to the coil.

Check and make sure you are getting 12V to the + side of the coil. If not, make it so. If you are getting any spark at all, then your points are working. They "turn" the spark on and off is the simplest way to put it.

Look at your power supply and get back with us.

Re: so many questions
Post by luckypabst on May 29, 2006, 5:11pm

Tim, most coils require a ballast resistor or resistance wire to run on 12v. If not, the coil will run hot and you might end up burning points. Some coils have internal resistance. Best to break out an ohmmeter to be sure.

Chris

Re: so many questions
Post by barrman on May 29, 2006, 5:28pm

Good point Chris. A proper 12V ballast resistor should be installed if it is not there already. A 12 V coil should actually have around 9 volts to work properly over the life of the points and coil. Your system can handle a full 12V for a limited time. Sorry if I gave the impression of something else.

Reading about the "weak orange spark" has me thinking he has a power supply problem or a bad coil. Hot wiring the coil to make it start is not going to mess up his coil for the few minutes he will be using it.

Re: so many questions
Post by robsgp on May 31, 2006, 6:25pm

I replaced about 18" of the pos wire to the coil. Between oil and exhaust heat the insulation was crumbling off. I do need to check voltage at the coil. Per the earlier suggestions, I did find the firing order wrong too. In trying to correct that I pulled the no.1 plug, laid it on the valve cover and put my finger over the hole to feel for the compression stroke and had the wife crank it. It doesn't seem like I get a spark on every compression stroke and I can't tell if it's at the right time. Should it be just after the woosh or in the middle? I may be fighting more than one problem. Obviously I have more work to do.

Re: so many questions
Post by amphi on May 31, 2006, 8:16pm

This is what I would do:

Never done it on one of these 24v but this should be close.

Remove all plugs (this makes it easier to crank by-hand)

Take the distributor cap off and take the rotor off.

Roll it over by-hand in correct running direction (rotation)... don't use the starter -- ( you should be able to roll it with the fan blade keeping tension on the belts.

While turning the engine make a mental note of the direction of rotation of the distributor shaft.

Put your thumb or finger over the spark plug hole like you did when your wife was cranking. Feel for the compression stroke on #1 to begin. You can also put a spark plug in loose and listen for air as compression begins.

Stop as soon as you determine you are beginning the compression stroke for #1.

Now look at the timing mark on the cover and watch as you slowly roll it (in the correct running direction) until the timing marks on the pulley begin to appear near the cover mark. Stop when zero degrees lines up with the mark on the cover. If you go over move it back slightly to get it at zero.

You now have #1 at top dead center on the compression stroke.

Turn on the power to the ignition.

Loosen the distributor clamp

If the points are closed – slowly rotate the distributor body (in a direction opposite to rotation noted earlier) until the points just open (they might spark).

If the points are open – slowly rotate the distributor body (in the same rotation noted earlier) until the points just close and then back until they just open.

You now have spark with #1 at TOD.

Tighten the distributor clamp.

Now install the rotor and look at the cap to determine which plug wire it is pointing to. It should be #1. Now follow the wires in the direction of rotation around the cap and position them in the correct firing order.

Your timing will be slightly off (probably retarded) but it should run.

Somebody please chime in if this is off in any way or I left something out.


Let us know the results.

Re: so many questions
Post by barrman on May 31, 2006, 9:37pm

Perfect walk through on how to find TDC for #1 and set the timing. I do that with my students all the time. It is neat to see their eyes light up when they finally make the connection between what they have read about and it the different parts of the engine working together.

Re: so many questions
Post by amphi on May 31, 2006, 11:41pm

Thanks barman ---- wasn't sure I had it all in there correctly.

Another thing I do, when there is an external coil, is to connect a spark plug to the coil output and look for spark. That way I know exactly when the points open. You probably do this with your students. Right?

Re: so many questions
Post by rjenkins on Jun 1, 2006, 7:46am


Quote: <TABLE class=bordercolor cellSpacing=1 width="90%"><TBODY><TR><TD width="100%"><TABLE class=quote cellSpacing=0 cellPadding=2 width="100%"><TBODY><TR><TD width="100%">15's too young?! </TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
Thats what the guys on the show Dateline said last night.