Low compression

[Phil Waterman]

Hi Malcolm

What RPM was the engine running during your spark test? What type of timing light pickup? Induction or direct connection to spark plug?

Running engines in on the test stand I have seen the same apparent intermittent spark using an induction pick up. Seems to smooth out at around 1000 RPM, never have tracked down the actual cause of the intermittent nature of indicated spark. Wonder if it is just slightly lower voltage at idle.

Because of the phantom problems with stored vehicles, I try not to get to excited about rough running, hints of missing, etc. generally I wait till I've run through a tank full fresh gas before doing tune-ups etc.

Please keep us posted on your mechanical detective efforts.

Cheers Phil

[Tony Wheeler]

Originally Posted by Malcolm Towrie

I also did a wet test on the bad cylinders and saw very little difference, a few psi higher. In fact I was surprised by how small the difference was.

That's great news Malcolm. It means all pistons/rings/bores are in excellent condition. Once you've fixed the leaky valves (or head gaskets) you can expect at least 95 psi all round, which would point to the motor having been rebuilt. If that's the case you'd expect the valves to have been reground already, so it may be something simple like head gaskets or valve clearances. Fingers crossed! You'll know more when you pull the intake manifold off.

[Malcolm Towrie]

Originally Posted by Phil Waterman

Hi Malcolm

What RPM was the engine running during your spark test? What type of timing light pickup? Induction or direct connection to spark plug?

Running engines in on the test stand I have seen the same apparent intermittent spark using an induction pick up. Seems to smooth out at around 1000 RPM, never have tracked down the actual cause of the intermittent nature of indicated spark. Wonder if it is just slightly lower voltage at idle.

Because of the phantom problems with stored vehicles, I try not to get to excited about rough running, hints of missing, etc. generally I wait till I've run through a tank full fresh gas before doing tune-ups etc.

Please keep us posted on your mechanical detective efforts.

Cheers Phil

Phil,
It was an inductive light. Engine wasn't idling because I can't get it to idle down (I forgot to mention that), so throttle screw was holding rpm over 1000. I was planning to try another light last night for confirmation but that's when I couldn't get it to start. I'll try it today. It starts OK cold.

Malcolm

[Malcolm Towrie]

Originally Posted by Tony Wheeler

That's great news Malcolm. It means all pistons/rings/bores are in excellent condition. Once you've fixed the leaky valves (or head gaskets) you can expect at least 95 psi all round, which would point to the motor having been rebuilt. If that's the case you'd expect the valves to have been reground already, so it may be something simple like head gaskets or valve clearances. Fingers crossed! You'll know more when you pull the intake manifold off.

What are the chances this engine has adjustable lifters? Is that a "mandatory" thing to install on a rebuild?

Malcolm

[Lynn Eades]

Adjustable lifters are not mandatory, just a bit of a minefield it seems.
There are problems with soft ones (probably not your problem) but there are also problems with them not holding a setting (the screws move in the lifter.- could be your problem?)
If she won't start from hot, then I would go to the coil. This might be your cause of the erratic spark? I say this because f.h. coils give a lot of trouble, even NOS ones. Of course there are plenty of other things to make her hard to start from hot. The coil is just a very likely one.
It sounds like the carrier could benefit from someone going carefully through a tune up.(Your problems may well resolve them selves with valve clearance.

Now that you mention it, it makes sense that she doesn't idle down to a nice smooth 450 rpm

[Malcolm Towrie]

I checked spark again today with another induction timing light. Same findings, #1 barely sparking, 2 missing occasionally, rest OK.

I checked for spark on a couple of the "good" cylinders when trying to start hot today, and there was none. Like you, Lynn, I suspect coil, maybe condenser.

I also found the 6V terminal studs on the remote coil stripped so the wires weren't very secure. And the clamping screw on the dizzy was loose so the points drag had rotated the breaker plate as far CW as it could go (looking from rear to front). Based on an old dizzy I have at home, that's retarded about 5 degrees cam so 10 degrees crank assuming clamping screw is normally set around the middle. But these are side issues.

So the plan is to pull the dizzy, coil and wires and go over them. (The plugs checked OK on the tester at 140 psi.)

Malcolm

[Malcolm Towrie]

Another update regarding no sparks on the Canadian carrier when hot. I got the divers-helmet dizzy, remote coil, radio suppression doohicky, and wires off. I've got more questions than answers.

The remote coil says it's a "Standard, 6V, no external resistance required" coil. Lots of oil sloshing around inside. Primary side resistance is 1.4 ohms. I subjected the primary side to a steady 6.4 volts. Current was 4 A, dropping slightly as the coil heated up. I was hoping for a sudden drop in current as the temp rose, but it got up to 70C and was still flowing close to 4 A. So the primary coil is good, I guess.

I also measured the voltage between the secondary coil terminal and the -ve primary coil terminal during the above testing and it also stayed steady at 6.4 V. So the secondary coil didn't go open circuit as it heated up.

BUT the secondary coil resistance is 11 kilohms which seems high. I'm used to seeing around 7 kilohms. Is that a concern?

Also, the wires between the dizzy caps and the the plugs are solid core so their resistance is low as expected, <0.5 ohms, but the wire between the coil and the dizzy is carbon core, with a resistance of 11 kilohms. Is that a problem?

The capacitor is an oldie. It's a Ford piece stamped "6 45", so it may be 71 years old! It tests OK, but it's rated 1 microfarad (confirmed by DMM), which is 3-4 times more than it should be by any standards. I suspect someone used a noise suppression cap by mistake. I'll change it, but I don't think it explains no spark when hot, as I heated the cap with a heat gun while meggering at 500V and it didn't die.

The drivers side points, which initiate the spark, are badly "peaked", with the peak visibly holding the points apart. That can't be good. The points open time on a flathead is so short, I'm wondering if that is the problem?

I need to check if the original ballast resistor that flatheads had in series with the 6V coil is still in the circuit. Or did carriers not have this?

I hooked the radio suppression box doohickey up in series with the coil and passed 4A through it to see if it was reducing voltage to the ignition. It passed with flying colours. No voltage drop, no heating up of caps or inductors.

Sp I'm still wondering what is causing the no spark when hot. If I don't find anything, I guess I need to check voltage drop when cranking to confirm the ignition is getting decent voltage.

Any suggestions appreciated.

Malcolm

[Mike K]

Originally Posted by Malcolm Towrie

Also, the wires between the dizzy caps and the the plugs are solid core so their resistance is low as expected, <0.5 ohms, but the wire between the coil and the dizzy is carbon core, with a resistance of 11 kilohms. Is that a problem?









Malcolm

Hi

I would get rid of that carbon core wire and replace it with a copper cored wire , same as you have for the spark plug leads . Mike

[Malcolm Towrie]

An update on the running problems: the distributor shaft was quite badly bent. It had 0.010" runout at the cam. Since the points gap is only 0.014-0.016" this seriously messed up the dwell and timing with big changes on a cylinder-to-cylinder basis as the shaft did a full rotation. The points being set too wide didn't help.

With a good, used shaft with 0.002" runout, and the points set at 0.015", dwell was right on the money and she's purring now.

Malcolm

[rob love]

Good for you.

When you say "distributor shaft" I take it you are talking about an 8BA engine with the distributor up top? Seems like it would take a lot of force to bend the shaft on either a crab or a divers helmet distributor mounted on the front of the engine.

[Malcolm Towrie]

Originally Posted by rob love

When you say "distributor shaft" I take it you are talking about an 8BA engine with the distributor up top? Seems like it would take a lot of force to bend the shaft on either a crab or a divers helmet distributor mounted on the front of the engine.

No, this is a divers helmet distributor. And it doesn't take much force at all to bend it when all the parts are stripped off. I chucked the small end in a lathe and measured 0.060" runout at the journal on the other end. It only took a few taps with a soft hammer to get it straight to within 0.002". It's pretty spindly in the middle as you can see but I was surprised how easy it was to straighten. I cleaned the shaft up thinking maybe it was cracked but I couldn't see any.

Some rough handling would have bent it easily.

I bet the last person to set the points must have struggled.

Malcolm

[Lynn Eades]

I think somewhere back there Malcolm confirmed it was a divers helmet type.
How to bend a shaft in one of those, I don't know.
As it was the centre cylinders and one half of the firing order rotation, I think I was headed in the right direction as far as a misfire goes, but can't see really why it had matching low compressions, when comp test pointed toward valves.

Good news that it is sorted!

[Malcolm Towrie]

Lynn, I should have got into the ignition problem in a separate thread to avoid confusion as it was a totally separate problem. The low compression hasn't gone away!

That shaft wouldn't bend in service but throwing it in a box and then throwing other parts on top of it would bend it easily, based on how easily I straightened it.

Malcolm

[Malcolm Towrie]

An update: due to the low compression test pressures reported at the beginning of this thread, we just pulled the engine to find the cause. I've only got the heads and intake manifold off so far, but checking each valve when fully open, I can see damage to the exhaust valve seats of the 4 low pressure cylinders. That seems to be the culprit. The other exhaust valve seats look ok, so I'm not sure why these particular seats went bad. Tappet clearance too tight and holding the valves off the seat perhaps?
The cylinders are 0.015" over and a bore gauge check of the bores just above the pistons at BDC and at the TDC wear "ridge" shows wear in the 0.002 to 0.003" range for all cylinders, so acceptable, IMO. But even the 4 "good" cylinders only had 85 to 95 psi results instead of 110 psi, so I think the bores need honed and new rings installed.
The valley shows a depressing amount of sludge on all surfaces. And the oil pan has a good layer of black sludge on the bottom. We use a 15W40 diesel oil in most of our vehicles. This is a high detergent oil and I suspect it is bad news in this type of application as the detergent dissolves the stable sludge deposits and circulates it around the engine. We should be using a non-detergent oil on these old engines.
I also found a water pump with the bearings almost seized, front crank seal rope packing installed so tight, it had burnt the paint on the timing cover, causing a severely scored front pulley sleeve, and a crack in the block around the rear boss for the oil cooler supply, due to overtightening the fitting. I'm not sure how to repair that. All in all, a typical 75 year old engine.
Malcolm

[Lynn Eades]

Malcolm, What model is the engine? What casting numbers if any? Does it have domed pistons? What cylinder heads does it have? What bore size? (just checking)

[Richard Farrant]

Originally Posted by Malcolm Towrie

The valley shows a depressing amount of sludge on all surfaces. And the oil pan has a good layer of black sludge on the bottom. We use a 15W40 diesel oil in most of our vehicles. This is a high detergent oil and I suspect it is bad news in this type of application as the detergent dissolves the stable sludge deposits and circulates it around the engine. We should be using a non-detergent oil on these old engines.

Hi Malcolm,
A mistake people often make is getting an old vehicle of unknown history, draining the oil and refilling with a detergent multigrade oil. Most of these old WW2 era engines (and earlier) had either no filter at all or a bypass filter, which was tapped of the oil gallery and returned to sump. Detergent oils keep dirt and carbon in suspension so with a full flow filter system it is quickly cleaned. The older mono-grade oils had no detergent in them and the sludge formed in the sump mainly, so it was flushed out on oil changes. If you get hold of an unknown engine and it has a bypass filter, or none at all, go for a non-detergent mono-grade as blended for vintage vehicles. Actually the Classic / Vintage mono-grades in the UK do now have a very slight detergency in them as I am informed by the oil companies, but they do not scour out all the old sludge like a multigrade does.
Hope I am not teaching you to suck eggs, but I am sure there will be readers who are not aware.
regards,
Richard

[Malcolm Towrie]

Originally Posted by Lynn Eades

Malcolm, What model is the engine? What casting numbers if any? Does it have domed pistons? What cylinder heads does it have? What bore size? (just checking)

Lynn, yes, it has domed pistons. CR is 6.12:1.
Stock bore size is 3 1/16", 3.0625". This one is 0.015" over so 3.0775".
It's the 85 HP, 221 cu. in engine. I'll get some casting numbers.

Malcolm

[Malcolm Towrie]

100% agree with you, Richard. Ever since seeing fresh Shell Rotella T 15w40 (a very popular diesel oil loaded with detergent) turn black within a few miles on one of our Ferrets, I've had my doubts about the wisdom of using this oil in our old engines.

And since then, I've seen how much sludge accumulates in the oil pans of these old engines. In fact, I suspect the oil pans were made so deep just to provide a nice quiet place for particulates, varnishes, etc. to settle down into out of the way to somewhat compensate for the lack of filtering. Dissolving this stuff back into a high detergent oil is bad news.

Malcolm

[Jim Burrill]

HD oil issues - My Humber Mk4 Armoured car had an engine rebuild at the shop in the UK. With less that 50 hours of run time, we burned up no4 Main bearing.

The final understanding was that during the engine rebuild, two oil channels (which has a freeze plug type cap on one end, and a bolt on the other) was not opened and cleaned out.

We put HD oil in for our running in.

Apparently, it dissolved the sludge and circulated it to the oil sump/pan. The pick-up for the oil pump has a metal wire filter. That was completely sludged over. The resulting oil starvation caused #4 piston main bearing - a poured babbet bearing - to melt.

We had a machine shop remove all the babbet bearings and switched to cap bearings.

We are better off having cleaned the oil journals, but some $4,000 poorer for having to pull the engine and the rebuild.

So.... no more HD oil for my stuff!

[Malcolm Towrie]

Jim, based on a similar bad experience I had, I'd be more inclined to blame the shop than the oil.
I had a local shop do machining on a Chevy engine. As normal, they hot-tanked the engine first. But, like your shop, they didn't remove all the gallery plugs and flush/brush the galleries out. Luckily I noticed when I got it back. I removed the plugs and found a large amount of sludge behind them that had been softened to a semi-liquid by the caustic cleaning solution. I shudder to think what that stuff would have done to the new bearings as soon as the oil started circulating.

Malcolm

[Malcolm Towrie]

Originally Posted by Malcolm Towrie

Lynn, yes, it has domed pistons. CR is 6.12:1.
Stock bore size is 3 1/16", 3.0625". This one is 0.015" over so 3.0775".
It's the 85 HP, 221 cu. in engine. I'll get some casting numbers.

Malcolm

Lynn, I couldn't find any casting numbers, strangely enough. This is a 24 head-stud engine.

[Michael R.]

On Canadian produced engine blocks found in universal carriers MK-I* and MK-II*, the engine block casting number is displayed on the shoulder over the water pump. Viewing from the front of the block, the 'left side'. The number '81' casting plate may appear as '87'. (see image of two examples)

Serial numbers on Canadian produced engine blocks found in universal carriers MK-I* and MK-II*, the number being displayed on the exposed portion of the intake manifold deck. Viewing from the front of the block, the 'right side, rear corner'.

Serial number format is 'TLXXXXXF'. There may be multiple 'F' letter strikes after the normal sequence, as well as the inspector stamp and additional letters or symbols, the more common upper case letters being 'E' and 'V'.

The complete serial number example displayed belongs to the engine found in the restoration thread for the carrier in Israel, with thanks to Mr. Berko. Of note, that is a MK-I* carrier, upgraded to MK-II in the UK and given a British cast data plate, with a MK-II* engine block.

See: http://mapleleafup.net/forums/showpo...7&postcount=70

[Malcolm Towrie]

Thanks, Michael. I found the "81" but only because you told me where to look. The cast number is almost illegible.
I didn't find a serial number of any kind. I did find a brass plate identifying a rebuild by RCEME in 1951.

I've got 9 valve/guide assemblies out and two pistons so far. Everything looks in good condition.

Malcolm

[Lynn Eades]

Thank you Michael R, for educating me on carrier engine numbers.
Malcolm, I am trying to get to the bottom of your low compressions (in the apparently good cylinders)

Ford did 3 different piston tops:
the flat top piston is for the early 21 stud engines.
There are two left:
The first is a sperical top. The profile when looked at from the side is a gentle curve going up one side over the center and back down.
The other is what Ford called a "Combination" When observed from the side it appears that the climb is a constant flat, coming to a point at the top and straight down the other side.
These pistons are not interchangeable.
The sperical one Part no 78C-6199-A
There are a couple of combination pistons.
If you look inside the piston skirt and you should find a number like 01T-6110-A

Cylinder heads. Some types fit both sides but mostly there is a left (6050) and a right (6049)
They may be hard to see, but as far as I know, they are all identified with part numbers
Those numbers above are the base number. All have prefixes and some have suffixes.
Your engine could/ should be wearing heads with:
81A-6049-A (or 6050)
81T-6049
C91A-60xx- B1

On compression ratios:
At sea level a comp. ratio of:
5.4:1 = 99psi
5.6:1 = 102psi
5.8:1 = 105psi
6.0:1 = 108psi
6.2:1 = 111psi
6.4:1 = 114psi
6.6:1 = 117psi

The above is all drawn from Ford service bulletins.
The whole point of my post is so that you can check that the combination of pistons and cylinder heads is a match.
In 42 the valve line changed. (design) Early heads could be relieved to fit the later blocks. If these heads were fitted to an early engine, they would have a lower than std. C.R.
Food for thought.

[Malcolm Towrie]

Thanks for the good info, Lynn. I'll check out what pistons and cylinder heads I have.

But I found something else interesting. I only managed to get one exhaust valve/guide assembly out. (The others are stuck in the block, apparently a common problem with flathead Fords.) Looking at the seats with the valves fully open, I flagged this exhaust valve as OK. (It's on one of the "good" cylinders.) But check out the photo taken after I cleaned it up. It's far from OK. It's blackened and pitted. Compare it to the photo of a good intake valve face. I'm beginning to think the whole low compression issue is down to bad exhaust valves.





If penetrant doesnt loosen up the stuck valves, I'll have to make up the c-clamp tool to get them out.

Malcolm

[Malcolm Towrie]

Well, live and learn. I've only checked one rod bearing but I found it way too loose in the rod bores. (Two rods install on one bearing.)That's normally a recipe for disaster as if the bearing spins in the bore, it will damage the rod, bearing and crank. But turns out its normal for flathead Fords. They have "floater" rod bearings. Unlike typical rod bearings which are locked tightly in the rod bore. they ride on an oil film in the rod bore as well as on the crank journal. Trouble is the bearing I checked is 0.020" oval (2.030" at split line, and 2.010" 90 degrees around) so it's too snug in the 2.220" rod bore. The fix is to "massage" the bearing to make it round again. Sounds fiddly.

Also, anyone any idea what the recommended torque is on the rod nuts? The manual doesn't say. They're secured by cotter pins so on disassembly, I found the torques all over the map depending how much the previous rebuilder had to over-torque them to get the cotter pins in. I guess I'm looking for a minimum torque.
Malcolm

[Malcolm Towrie]

I finally got the last 2 exhaust valves out of the block. What a pain they were. The problem is the early style V8's have mushroom-tip valves. You can see this in the photo below. The two parts below the valve are the split guide. So the guide halves are fitted on the valve stem with the larger end next to the valve head, the spring is installed on the narrow end of the guide, and the smaller horseshoe shaped retainer fits over the mushroom part of the stem to retain the compressed spring.
The lifter/tappet, just to the right of the valve, is fitted into its block bore just above the camshaft.
The whole valve assembly is then fitted into the block from the top side. The guide is a snug fit in a bore just below the valve seat. The guide is then pulled down into the lifter valley against spring pressure and the larger horseshoe shaped retainer is fitted into the narrow groove in the guide. When released, the spring pushes the guide and the retainer back up into its bore. The second photo shows the installed valve assembly, upside down.

The problem is that the guide can seize into its bore after many years of service, or after many years of non-service for that matter. And you have to get the guide out to get the valve out because of that mushroom tip. Damn you, Henry Ford. I couldn't free up two of the guides despite making a c-clamp tool to press them out. I ended up removing the smaller retainer, which releases the spring, pulling the valve head out as far above the block as it would go, cutting the valve head off, driving the now-accessible guide halves down into its bore with a brass punch, cleaning off the rust/varnish build-up at the top of the guide bore, slathering on WD40, and finally getting the guides out of their bores.

So the 8 intake valves came out easily. Of the remaining 8 exhaust valves, 2 came out with the c-clamp tool, 4 came out with the c-clamp and some serious prying., and the last 2 needed the drastic treatment.

If your planning on rebuilding a Carrier engine, put a few hours by for this job.

Malcolm

PS torque on connecting rods is 35-40 ft-lb.

[Malcolm Towrie]

There are 4 really bad exhaust valve seats in the block, corroded and pitted. My local machine shop agreed they should be replaced, but he couldn't do it because modern seat removal/replacement tooling is designed to hold cylinder heads, not a whole block.
I decided to use the welding technique to remove the bad seats because i could do that at home, and buy replacement seats, figuring i could make up the simple tooling required to install them. I hit some snags.

The seats came out no problem by fitting a slightly loose 1/8" thick washer inside the seat bore and MIG welding it to the seat. This shrinks the seat and loosens it in the block so I was able to tap the seat out using a brass punch on the underside of the washer. One photo below shows the block with the seats removed, and the other shows the removed seat.

The first snag was the seat counterbores in the block were 0.005" out of round, varying from 1.625 to 1.630". This seemed a bit much considering the press fit of the seat in the block is 0.005" interference. The other snag was the new seats were 0.010" over nominal size on the outside diameter, which I found out is normal. The supplier assumes you will be cutting the counterbores 0.010" oversize to clean them up. Another minor problem was the new seats are 1/4" thick, when nominal size is 7/32".

So now I need to find a machine shop who can bore out the counterbores in the block to 1.635" ID so that I get the right press fit for the 1.640" OD seats. Parry Automotive in Orillia may be able to do this.

Malcolm

[Frank v R]

which vehicle is this engine from?

[Malcolm Towrie]

Hi, Frank,
It's the Mk I Universal Carrier, formerly known as Al's Carrier.