Exciting 720

[jagman]

This has been the first day I used the truck for pickups and deliveries. I filled the tank earlier last week and put about 50 miles on it.  The starter was not turning strongly every time but would start the truck after a few tries. I thought it was the battery. Today on the last run I was coming up a hill when it began losing power. I pulled off the road and she wouldn't restart. My son raised the hood and told me that the battery clamp was melting.  We walked 4 miles to the nearest gas station and called for the wife to pick us up and get us back to the shop ( always a bad move when she had told me the next one that follows me home will cause me to raise my arm to pee ). Fixed the battery post problem, and just for shits and giggles we put 4 gals of gas in the tank.  I am now aware that the gas gauge may read half full but is really empty and I thought the mileage was spectacular!

I want to thank everyone who has helped with her build and hope that that help will continue for the niggling things that still need to be fixed. I can live with the gas gauge.

[datzenmike]

Might be the gauge or the sender sticking at 1/2.

 

If the gauge drops to empty with the key off then it's in the sender. Maybe stuck. Driving with sloshing tank might loosen it. If not take the tank out when empty and remove the sender and try loosening by hand.

 

 

[jagman]

I will definitely check the guage problem after I replace the head gasket. The lower hose decided to depart the radiator and she blew the gasket. Back to rebuild.

[jagman]

Got her into the shop and have dismounted the top hat and the hot side thingy along with the fingers do dads on the top and the lines, tubes and such.  Tomorrow I will lift the top off and peruse the damage to the flat thing in between.  I ordered two of each flat thing in case I fuck it up again.  Give me a week and it will be back with only a guage problem.

[datzenmike]

BEFORE YOU DO THAT

 

 

You know that in order to remove the head the timing chain tensioner has to be blocked from falling out BEFORE you loosen and remove the cam sprocket? Failure to block the chain tensioner will allow it to fall out and add 3-6 hours more work taking the entire front of the engine off to retrieve it and get it back together.

[jagman]

The last time I used the timing chain wedge it slipped and my timing was off. I will remove everything and start from scratch to make sure all is well.

[datzenmike]

If the wedge slipped but the tensioner didn't fall out then the cam sprocket just goes back onto the chain where you marked it. Even later you can move the cam to timing chain positions.

 

 

Get one of these. Foolproof and saves unnecessary hours of work.

[jagman]

Hi Mike,

I have one of those and yes they work but I want to go through the complete sequence from start to finish so that I can check my work and make sure that I have all the timing stuff right.

These days I have the time. The back hoe work lags a bit because of the cramped lifting conditions and my broken rib.  I am in the process of designing the brake hold for the Riley. The fabrication will begin when I can accumulate the mower bits to complete it.

[jagman]

Hey Mike,  It turns out that the one I have is too short and the spring tensioner popped out anyway.  The engine is now back together and I will time it today.  I had replaced the 90 weight in the tranny before the last fiasco with 30 weight to flush it. Now I have clean 90 weight in there. Wish me luck.

[jagman]

Well I got to drive it for 12 miles before the Little hose let go (evidently not tight enough on the clamp) so back to the new head gasket again! Mike do you have a source for the chain wedge you have and what head gasket do you recommend? I have been using the kit supplied by RockAuto but they don't seem to that robust. I will replace the head gasket one more time but I think I'm wearing all the bolts out!!!

[datzenmike]

Why are you changing it again???

[]2eDeYe]

Is this an L or a Z series motor?

 

[jagman]

Mike,  The engine overheated a tad and I blew the head gasket again.  I need to get one of those chain pucks you have because I don't want to change anything but the head gasket. If you have a source for one I would gladly buy it.  I have been buying the head gaskets from RockAuto but they appear to be a bit tender and so would appreciate a recommendation as to a more rugged gasket. Thanks. Steve

[Draker]

felpro is another option. I've used the rockauto house brand and it's ok.. felpro is probably marginally better, but I've heard from machinists these are pretty rigid as well.

 

Most importantly, make sure your head and block surface are flat and I mean perfectly flat.

[datzenmike]

You have a temperature gauge. Use it. Never boil over an aluminum head. Spend the night on side of road, it's cheaper. Aluminum expands twice as much as steel.

 

Possibly the head is warped making it easier to blow again. When I knew nothing I put an L20B in that a friend had who had blown the gasket.... and it blew on me too. I changed it and 3 weeks later it blew again. This is when I learned that it was warped. Had it leveled and all was good.

 

Now I know to check these things when the head is off. Last summer I took the warp out with a sheet of glass with sand paper glued to it.

 

Take the rockers off so the valves are closed. Lay it face down and pull towards you, push away. After 20 passes you can see the untouched high area. Every 20 blow away the aluminum powder or it rolls on it like ball bearings.

 

 

Another 30-40 passes. Now more of the head is rubbing and it takes more passes.

 

 

Now just slightly high between cylinders.

 

 

Going. Now it takes a lot of passes to remove even a small amount.

 

 

Gone. I think maybe 45 min. Checked with an industrial straight edge. Couldn't get a 0.002" feeler gauge under it. Originally it was 0.015 or almost 4 times the allowable limit of 0.004

 

 

Cost a few bucks for the sand paper. 80 grit to knock it down and a few passes of 150

 

[jagman]

OK I will deck the head as you suggest but I will need the chain wedge that fits this engine.  Mine it turns out is too short and does not hold back the tensioner.  If you have a source for the right one it would help a lot.

[datzenmike]

Check the head for flatness first.

 

Amazon used to, e-bay?

 

 

Others have folded a garden hose double and shoved it down in till it stops beside the chain oiler in the picture

[jagman]

Lordy Mike I did as you suggested and bought a chain wedge to fit and that worked well.

I also sanded the head to flatten it ( It must have been out of true by a lot ) over three days.  My arms may drop off.  This time I am cranking on the hose clamps til I see the rubber deform so I won't have to do this for a fourth time. 1 Hose blew due to bad hose. 2  Hose clamp broke made in China.  3 Hose disconnected from lower rad inlet - owner not over tightening the clamp

 

I am rechecking everything as I put it back together..........

Thanks for your perseverance and advice.

 

 

 

 

 

 

 

[Charlie69]

I buy hose clamps at NAPA.  When I change out hose calmps next time I will change to the fuel injection hose clamps.

[jagman]

I have been driving the truck to and from the shop ( 200 feet ) and now have a banging sound coming from the rear. Near as I can tell it is the loose spare tire.  Does one of you have a spare jack handle or a jack handle you can photo so I can make one to fit?  I would greatly appreciate it.

[Charlie69]

Jagman  do you need the handle or the rod between handle and jack also used to raise and lower the spare under the bed.  I have both and also have spare factory jack.  I will get pictures this weekend for you.

[jagman]

I really need the rod if the handle is a separate item.  It turns out that I have two jacks but no rod to tighten the spare carrier.

[Charlie69]

Here is a stock 720 rod and handle for the jack.

 

 

 

 

 

 

 

The rod is 33.5" long.  Let me know what piece or pieces you need.

Edited July 14, 2020 by Charlie69

[jagman]

Charlie69 if you are willing to sell both pieces I am a willing buyer!!!  Let me know.  If not, what is the diameter of the rod and end pins? Thanks Steve 

Phone 1 276 694 2499 after 5:00 pm EST

[Charlie69]

I will call you tonight.