Author Topic: 1954 Ford 850 Tractor w/blown Head Gasket (at the very least) (Read 101921 times)

vtsteam · « **Reply #75 on:** May 22, 2014, 06:31:34 PM »

Filed relief into the sides and the end:

vtsteam · « **Reply #76 on:** May 22, 2014, 06:36:40 PM »

To bed early gentlemen for tomorrow we temper steel with the blood of the stream for our greatest trial!

(ie. water....)

After that........

probably retreat to one or the other above sensible tips!

vtsteam · « **Reply #77 on:** May 22, 2014, 07:47:49 PM »

I spoke with the tractor repair man this evening. He doesn't think he has a cap, but will look around tomorrow. He said he has a complete head, So if something goes awry, I guess that's backup.

awemawson · « **Reply #78 on:** May 23, 2014, 03:13:55 AM »

You are supposed to temper silver steel in the blood of a virgin, but they are increasingly hard to find these days

vtsteam · « **Reply #79 on:** May 23, 2014, 02:37:21 PM »

The stream was close by! Anyway it was a simple matter this morning to heat the drill to cherry red and dunk it in a cup of cold water. I decided not to temper it -- I haven't had a problem with chipping or cracking for small low speed tools, which this definitely is, and the extra hardness helps I think.

I set up some half inch drill rod in the lathe using the 4 jaw chuck ( I still don't have a collet chuck) and used a center drill to start a hole in the end. Then chucked up a Q size drill in the Jacobs chuck to get me somewhere near the .350" desired finish dimension and drilled about 0.3" deep.

Then with a little trepidation I chucked the new olde tyme slot drill in the Jacobs, brought it to bear on the drill rod with a little oil and started drilling. I was using my slowest back gear speed. No problem, the darn thing started to drill!

vtsteam · « **Reply #80 on:** May 23, 2014, 02:40:32 PM »

What I liked about this drill was that it faced the end as well as the sides of the hole, acting like a reamer and drill at once.

vtsteam · « **Reply #81 on:** May 23, 2014, 02:46:17 PM »

Measuring the bore. After hardening I had stoned all cutting edges, and the final drill was about a thousandth undersize -- but I figured I might gain that back when drilling the hole -- which worked out well. .350" was the target, and though not a critical dimension for this application, was nice to hit as intended. I'm now a great fan of making cutters like this for odd size bores. A lot faster than boring to size for a project like this. And it's repeatable for the future, in case I lose one of these little caps again. Just chuck it in the Jacobs and go.

vtsteam · « **Reply #82 on:** May 23, 2014, 02:48:26 PM »

After drilling out the bore, I turned down the outside to .475" without removing the rod from the chuck:

mattinker · « **Reply #83 on:** May 23, 2014, 02:49:26 PM »

Satisfaction ;--)

Regards, Matthew

vtsteam · « **Reply #84 on:** May 23, 2014, 02:55:14 PM »

Then cut it off a little long with a hacksaw. Sorry to say I've had problems parting in my lathe in the past, and I didn't want to take a chance on this part.

Unfortunately also my 4 jaw chuck was at it's limit turning the half inch rod. The jaws won't close much tighter, so I had to switch to the 3 jaw to face the ends. But that wasn't a critical operation.I left the cap about .01" long to allow fitting exactly for proper clearance on the actual valve. I chamfered the top end and finally ran the top and bottom over an oilstone to smooth them down.

vtsteam · « **Reply #85 on:** May 23, 2014, 02:58:12 PM »

vtsteam · « **Reply #86 on:** May 23, 2014, 03:13:53 PM »

Last operation was to harden and this time, temper the cap. Hardening was repeated the same way with the MAPP torch and cup of water.

But for tempering I wanted to go slowly and create an even temper, and it's kind f hard to control with a torch on such a small part. So I decided to try the electric toaster oven in our kitchen (with permission!). I figurd that would be a lot slower heating process, and more even. I set the temperature to 375 F and let it warm for 10 minutes.

When I thought things were up to temp I checked the broiler pan with a non-contact thermometer I got from Harbor Freight. I was shooting for a 399F light straw temper, but unfortunately, as I suspected, the oven was far from accurate (415 F) or consistent. It tended to overshoot quite a bit. So then I just dropped in the part, turned the stove up or down, by hand while checking frequently with the thermometer. That worked well and after ten minutes or so I pulled the cap out and saw a very light straw on the polished end. Done!

Sid_Vicious · « **Reply #87 on:** May 23, 2014, 04:25:35 PM »

Looks real good, you solved it nicely.

vtsteam · « **Reply #88 on:** May 24, 2014, 07:53:03 AM »

Thanks Matt, Sid!

Manxmodder · « **Reply #89 on:** May 24, 2014, 08:20:19 AM »

Well done Steve, I love the way you have approached and resolved the warped head and the missing valve cap.

Where there's a will there is a way

On the subject of using super glue to mount awkward workpieces such as the method you refer to in Tubal Cain's book,I have previously used this technique to reduce the thickness of crankshaft thrust bearing washers.
The washers being super glued on the bearing face to a piece of faced bar held in the lathe chuck and then skimmed according to dimensional requirements.

On the point of your concerns about the cam and follower condition,you could easily mount a mag based DTI on top of the engine block and check to see how the lift of that cam lobe compares with neighbouring ones.....OZ.

vtsteam · « **Reply #90 on:** May 26, 2014, 07:12:30 PM »

Thanks Manxmodder!

Good to hear you use the glue method for washers. It's a real handy thing to have in the arsenal!

I didn't use a magnetic base DTI to measure the lift, thought that's a great idea! kinda didn't want to know! I just wanted to see that one valve lift (exhaust #1 cylinder) to make sure there wasn't a broken lobe or stuck lifter, but more than that -- well this isn't a restoration, but a working tractor/bckhoe. It will probably see under 100 hours of use a year. But if it runs it will certainly pay its purchase cost back quickly -- machine time around here is about $150/hr. So for now, I just want t get it running.

This morning I cleaned the head and rocker arm assembly in kerosene (paraffin), and chased all the holes in the block and head, preparatory to re-,mounting. Then I scraped the deck and cleaned the cylinders as best I could. I'd squirt a little 30 weight around the pistons, and turn the crank by hand, then wipe the cylinders out again. i did that 5 times, and the oil came out clean.

When everything looked ready I set the head down on the deck and stopped to take a picture -- always a nice turning point to be adding things again, rather than taking them off.

Then I set the new head gasket in place

vtsteam · « **Reply #91 on:** May 26, 2014, 08:27:59 PM »

I decided to try the valve rocker assembly before actually torquing the head down in case there was a problem with cam or tappets in #1. I didn't want to squish the gasket in case I had to remove the head again. I wanted to turn the engine by hand and watch the valve openings.

I fastened the head down lightly, and bolted the rocker towers in. Number one cylinder valves appeared to work properly when i tried them, as did the rest of the valves. But I noticed that the #1 exhaust valve rocker arm was out of alignment with the new valve rotator cap:

vtsteam · « **Reply #92 on:** May 26, 2014, 08:32:16 PM »

I pushed it over toward the aluminum bracket, and it lined up properly then. There was a spring and a washer that kept it away from that bracket. This didn't seem right. Checking the other end of the rocker shaft, I saw that there were 2 washers on the end with the spring trapped between them -- that seemed to make more sense.

vtsteam · « **Reply #93 on:** May 26, 2014, 08:38:58 PM »

So it became apparent that someone during the life of this tractor had disassembled the rocker shaft, and then replaced the spring and washer in the wrong place. I verified this in the Ford Service manual.

But not only that, this particular rocker arm and pushrod was the pair that had varnish on the ball and socket joint -- they weren't shiny like the others in the assembly. I'm going to guess that this misalignment along with one other factor had caused the loss of that rocker cap long ago. The loss of the cap probably loosened caused a great deal of valve lash, and probably a very short exhaust timing.

That other factor was the fitting of the caps themselves, which was badly out of spec..

vtsteam · « **Reply #94 on:** May 26, 2014, 09:31:44 PM »

I removed the rocker arm assembly, pulled the cotter pin and rearranged the spring and washer in their proper locations.

With everything looking correct, it was time to fit the valve rotator caps. I assumed the three I had from the tractor originally were all correct -- I just needed to figure out which one went where. Wrong!!

Well, there was first a pause while I figured out just how I was going to be able to ensure the .002-.004" clearance they each had above the valve stems. I tried a few methods -- including Manxmodder's earlier suggestion of using a magnetic based indicator. But nothing I tried worked well enough to give me a consistent reading. The main problem was that the valve stem was recessed in the spring and there was nothing to compare its height to. Finally I realized that I could use a small 1/4" drive socket to serve as a spacer on top of the valve retainer. I could set my caliper end on top of that and measure the depth from the top of the socket to the valve stem, then subtract the socket height (.850") to get the height of the stem above the retainer. The depth of the caps needed to be .003" more than this height.

I got consistent readings using the socket and caliper method and started sizing the caps. Well surprise, surprise, they were WAY off!

None of these caps had been fitted properly to the valve stems. They varied from 20 to 50 thou too long. So with a fair amount of work grinding and checking many times with the calipers and finally when getting close, hand stoning them. I ground them all to .003" clearance for their respective valves.

I think that some prior owner had simply placed aftermarket caps on the valves, without fitting them. This in combination with the misaligned rocker arm may have spelled the loss of that #1 exhaust cap. I wouldn't be surprised if it (or pieces of it) are located in the oil pan.

Or perhaps the owner had simply lost the cap. I did wonder for a moment whether the warped head had been the result of the lack of a manual and/or torque wrench by this particular mechanic.

Well, no matter, that job done, it was time to torque down the head. The manual gave 65-70 foot pounds as the figure, and I followed the bolt torquing sequence in 3 stages. The I reattached the rocker arm assembly with the oil lines this time, and torqued it down to 45-50 ft/pounds,per the manual.

I blast cleaned the spark plugs, set the gaps, and screwed them into the head. It was beginning to look like a functioning engine:

vtsteam · « **Reply #95 on:** May 26, 2014, 09:45:00 PM »

(just broke 2000 posts here today)

to all!

RussellT · « **Reply #96 on:** May 27, 2014, 04:35:02 AM »

You can't leave us hanging there just when it's getting exciting.

It's looking good.

awemawson · « **Reply #97 on:** May 27, 2014, 05:03:25 AM »

Steve it's looking good

Presumably the 3 thou clearance to the valve spring retaining collets is just a minimum - I can't see that 10 thou more would make a jot of a difference as the cap just needs not to be resting on the collet, but only contacting the end of the valve stem.

Looking forward to seeing it running

vtsteam · « **Reply #98 on:** May 27, 2014, 07:43:35 AM »

RussellT sorry about that -- it was supper time and I had to cover the tractor up with rain threatening and put away the tools manuals etc. that I had scattered about!

Andrew it's the other way round -- the clearance is to the head of the valve stem. The cap rests on the valve lock/retainer, not the valve stem. When the rocker arm comes down it depresses the spring (through the retainer) in advance of contacting the valve stem head. This presumably frees the valve and allows it to rotate. the delay is short since the spec calls for .002" to .004" total clearance. What I found was .020" - .050". In other words the caps were too long, not too short (probably as received, rather than fitted). This would have added a fair amount to the normal valve lash of .014" - .016".

awemawson · « **Reply #99 on:** May 27, 2014, 10:50:32 AM »

Well you learn something every day !

Never come across that set up before, and I've pulled the odd engine apart in my time

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Author Topic: 1954 Ford 850 Tractor w/blown Head Gasket (at the very least) (Read 101921 times)