Engine failure - high speed running

[Tom Foster]

I think the evidence now points clearly at the Evans coolant as the culprit here. Coolant that burns? Flash point +/-230 degrees, which you acknowledge exceeding, plus a little through a weld in the head, boom.
Fearless

[Rowdy]

You say the engine is mounted horizontally, does that mean as in aircraft the cyl's are flat with the earth. If so what mods did you make to the oiling system? Dry sump etc. Lack of oil could have contributed to the high heat and dramatic failure you experienced. Rod

[ppower]

Originally Posted by Tom Foster

I think the evidence now points clearly at the Evans coolant as the culprit here. Coolant that burns? Flash point +/-230 degrees, which you acknowledge exceeding, plus a little through a weld in the head, boom.
Fearless

No the crack was repaired and everything was fine for about 1000miles, until I held it at 75mph for about 10minutes

[ppower]

Originally Posted by Rowdy

You say the engine is mounted horizontally, does that mean as in aircraft the cyl's are flat with the earth. If so what mods did you make to the oiling system? Dry sump etc. Lack of oil could have contributed to the high heat and dramatic failure you experienced. Rod

The engine is mounted as in the Ford Model A with the axis of the crankshaft horizontal, so the troughs in the oil tray all contain the same amount of oil.

I did wonder if the gravity oil feed and the dip and splash oil to the big ends and the cylinders was inadequate for sustained 3000rpm running, but I have been reassured by earlier comments.

My remaining queries are:-

the correct ignition advance at 3000rpm (I am deaf so cannot hear pinking - I think you call it something else- I mean pre-ignition)

the correct piston skirt clearance - I only have .002" either side, but it increases to .005" front and rear.

Who sell the best pistons for my rebuild?

[Tom Wesenberg]

The common rule for spark advance is to pull the lever down just until no further increase in power or speed is felt, as long as the engine doesn't ping. Since you can't hear the ping, you might want to have someone else drive it like you do and see where they set the lever. You will have to use less advance when pulling hills or using a different grade of fuel, etc.

[Flathead]

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It got WAY too hot, your pistons have been through hell and didn't survive the trip. The rod most likely gave up when the piston seized. The cooling has to be improved, paint burning on the block is not good. I would not blame the old tech engine either, they didn't last this long by being crap. It is easy to fry a modern DOHC VVT blah, blah, blah engine at those temps too. You need to be careful with the timing advance also. I don't mean to rain on your parade but it is what it is. I hope you can work out a solution to this dilemma, it is a sharp looking ride.

[Mitch//pa]

3 pages of posts saying the engine was smoked from high temps...

so what actually do you think caused it

if someone cooked a new car under warranty it would be void from abuse.

thats why rebuilders use heat tabs

in this case the heat tab was the engine paint

[Phil Brown]

Originally Posted by ppower

The damage to the piston is similar to that I experienced 30years ago when I cruised a 1970 Jaguar XJ6 at 120mph on a German autobahn that was pre-ignition caused by the early design of piston. After the pistons were changed to a later specification the problem never recurred.

Here is a photo of all the plugs, unfortunately I cannot remember which was in number 1 cylinder.

What ignition advance do you think I should have been using?

The lower left one and the top one appear to have some aluminum specs on them but kinda hard to tell in the pics. As far as advance don't have a really know but would start with less (maybe 20 deg). Try and find a moderate grade to pull at steady pace and move the spark lever up and down one notch at a time you'll feel the motor change.It will make less power with too little and too much advance,you can feel it. Don't over look that detonation will skyrocket your water temps also so that might be a contributing factor as well. Are your high temps driving it into detonation that starts a vicious circle ?

[PC/SR]

The pistons are oblong and wider on one side than the other. That is why you get two readings. You want the small reading to be about .0035+ depending on the material in the pistons. The stock .002 clearance is not sufficient for modern pistons. Improved radiator/coolant may be worthwhile, but it is not going to cure insufficient clearances as noted by the burning below the water jacket. Before reassembly, do a lot of reseach on clearances. There are threads here about most any clearance on a Model A.
If the rebuilder used the wrong clearance the resulting heat and failure is on him, not abuse by the owner.

[colin1928]

ppower the gravity feed and dipper oil system works well up to about 4000 rpm
and has been proven in some high performance engines more than a few times
Ignition time will vary slightly from engine to engine but 24deg BTDC is very retarded IMO and will cause high cylinder and exhaust temps how do your exhaust valves look ?
Most of the std B Model distributors centrifugal advance I have seen have 18deg BTDC at idle and 32-34deg at around 2000-2200 rpm
My latest engine likes 36deg at 2400 rpm

[dave in australia]

Originally Posted by ppower

Who sell the best pistons for my rebuild?

Try JP Pistons down here in OZ. With the current GBP - AUD exchange rate, they will be a very high quality, but cheap set of pistons. They do custom pistons as well. I had to get a custom set for my Durant D60, due to a previous engine rebuild, and they fell in and run without a problem. I am also getting them for my A engines.

http://www.jp.com.au/JPPistons.html

[mshmodela]

Maybe put a cosworth in that babe...

[PC/SR]

"The engine is mounted as in the Ford Model A with the axis of the crankshaft horizontal, so the troughs in the oil tray all contain the same amount of oil."

The Model A engine was not mounted horizontally. It had a 3 degree tilt to the rear so oil could flow back and excess oil flowed into the overflow pipe that directed oil to the front of the dipper trey for the rods.
As I think about this more, I think that mounting the engine horizontially so that all chambers received the "same amount of oil" was a mistake. You will note that the dams in the valve chamber are of different heights to control the oil levels. All that is needed is to oil to the main bearings and camshaft tubes, which are not very high, plus some splash to cool the valve stems. All else goes to the dipper trey. Mount the engine so there is a slope to the rear so excess oil goes to the dipper trey.
All excess oil, and there must be excess oil, must flow to the overflow tube into the dipper trey and this is mandatory. The #4 piston would be the last to receive any overflow, if any, and that probably explains why # 4 blew. My guess is insufficient oil to #4 because the horizontal mounted engine did not flow sufficient oil to the dipper trey. Once oil is in the dipper trey it must flow to the rear, ie, to #4, which a horizontal engine or dipper trey will not do.
If you are going to run over 3000 rpm regularly, I suggest you open up the dippers per the attached (I hope) photos. I actually open them a bit more than shown in the photos, which were a test. Its easy with a dremel tool.
I also suggest you open up the oil pump to flow more oil if you are over 3000 regularly. This involves turning down the shaft and opening up the the inlets and the outlets. There is a website on this and I am sorry I cannot find it right now. More oil flow will get more oil to the valve chamber and overflows to the dipper trey to the rods if the engine is sloped to the rear. This must be done to protect #4. The overflow from the valve chamber is the only source of oil to the dipper trey.
My conclusion is that your engine failed because of insufficient piston clearance (.002 is not enough as stated above) and insufficient oil flow to the dipper trey because of the horizontal engine. If properly set up, 3000 should not be a problem, but I would not run a stock set up engine at that speed very long. As your test shows, about 10 minutes is max.
Take care of these things and see how coolant and ignition timing work out. Coolant and timing are not your primary problem, although it is nice to think so because they are easy to deal with. Oil and clearances are the problems and that is going to take some work but you are going to feel good when you get it right. I do like the car, and putting an A in it intrigues me. Good Luck and Best Wishes.

[ppower]

Originally Posted by colin1928

ppower the gravity feed and dipper oil system works well up to about 4000 rpm
and has been proven in some high performance engines more than a few times
Ignition time will vary slightly from engine to engine but 24deg BTDC is very retarded IMO and will cause high cylinder and exhaust temps how do your exhaust valves look ?
Most of the std B Model distributors centrifugal advance I have seen have 18deg BTDC at idle and 32-34deg at around 2000-2200 rpm
My latest engine likes 36deg at 2400 rpm

Thanks for this post. It contains the information I was seeking

[ppower]

Originally Posted by dave in australia

Try JP Pistons down here in OZ. With the current GBP - AUD exchange rate, they will be a very high quality, but cheap set of pistons. They do custom pistons as well. I had to get a custom set for my Durant D60, due to a previous engine rebuild, and they fell in and run without a problem. I am also getting them for my A engines.

http://www.jp.com.au/JPPistons.html

Thanks for the recommendation of JP Pistons. Does anyone else agree or argue that I should consider a different manufacturer?

[Bob Bidonde]

PPower,
Find someone who has race engine experience and have him look at the damage. Try the Secrets of Speed Society for example. It may not be the cooling system that caused the failure. Poor lubrication could be the culprit.

[ppower]

Originally Posted by PC/SR

"The engine is mounted as in the Ford Model A with the axis of the crankshaft horizontal, so the troughs in the oil tray all contain the same amount of oil."

The Model A engine was not mounted horizontally. It had a 3 degree tilt to the rear so oil could flow back and excess oil flowed into the overflow pipe that directed oil to the front of the dipper trey for the rods.
As I think about this more, I think that mounting the engine horizontially so that all chambers received the "same amount of oil" was a mistake. You will note that the dams in the valve chamber are of different heights to control the oil levels. All that is needed is to oil to the main bearings and camshaft tubes, which are not very high, plus some splash to cool the valve stems. All else goes to the dipper trey. Mount the engine so there is a slope to the rear so excess oil goes to the dipper trey.
All excess oil, and there must be excess oil, must flow to the overflow tube into the dipper trey and this is mandatory. The #4 piston would be the last to receive any overflow, if any, and that probably explains why # 4 blew. My guess is insufficient oil to #4 because the horizontal mounted engine did not flow sufficient oil to the dipper trey. Once oil is in the dipper trey it must flow to the rear, ie, to #4, which a horizontal engine or dipper trey will not do.
If you are going to run over 3000 rpm regularly, I suggest you open up the dippers per the attached (I hope) photos. I actually open them a bit more than shown in the photos, which were a test. Its easy with a dremel tool.
I also suggest you open up the oil pump to flow more oil if you are over 3000 regularly. This involves turning down the shaft and opening up the the inlets and the outlets. There is a website on this and I am sorry I cannot find it right now. More oil flow will get more oil to the valve chamber and overflows to the dipper trey to the rods if the engine is sloped to the rear. This must be done to protect #4. The overflow from the valve chamber is the only source of oil to the dipper trey.
My conclusion is that your engine failed because of insufficient piston clearance (.002 is not enough as stated above) and insufficient oil flow to the dipper trey because of the horizontal engine. If properly set up, 3000 should not be a problem, but I would not run a stock set up engine at that speed very long. As your test shows, about 10 minutes is max.
Take care of these things and see how coolant and ignition timing work out. Coolant and timing are not your primary problem, although it is nice to think so because they are easy to deal with. Oil and clearances are the problems and that is going to take some work but you are going to feel good when you get it right. I do like the car, and putting an A in it intrigues me. Good Luck and Best Wishes.

Thanks for your logical and reasoned explanation, I will now go out to the garage to consider the oil flows with the benefit of a greater understanding.

Also thanks for the kind comments about the car. It is certainly now more fun than when the 1500cc engine was fitted, but the purists still frown at it. I promise them the original engine will be restored and refitted for the car's hundredth birthday party!

[Rex_A_Lott]

I am curious which side of the engine faces forward, the carburetor side or the other side? I agree with most of the advice you have been given. One other thing you might consider is some bafflles/swinging gates to try to ensure the oil pump always has oil surrounding it.
Good Luck!

[CarlG]

Originally Posted by Rex_A_Lott

I am curious which side of the engine faces forward, the carburetor side or the other side? ...

I don't think he ever said that the engine was transverse. He did say that it was mounted horizontal (flat) as opposed to a 3 degree rear tilt, as in a model A.

[Ron W]

PC/SR Has hit on an important issue. The engine must be inclined. Oil runs front to back in the valve chamber (which feeds the mains) and dipper tray. No cooling plus no oil equal a cooked engine. Ron W