Engine failure - high speed running

[40 Deluxe]

Sounds like there a number of causes for this failure. From the looks of that rod I'd be concerned about the quality of the rebuild. Was the nut not tightened and vibrated off? Did someone strip the threads and just leave it that way? Pay attention to the other nuts and bolts as you disassemble. Try tightening them first to see if any are loose. 3,000 RPM is not too much for the stock oiling system.
Could you clarify what your coolant temps normally are and the max. is that you have seen? I noticed one place said up to 300 and another said 220. If it's running over 220, that's too high. Do you know what the piston to cylinder wall clearance was? You won't get an accurate reading now that the damage is done.

 

[Wick]

Too Hot. The last couple of times you drove it she should have smoked,look how wet the port looks. Piston down in hole has silver looking specks on top...not good. a Lot of carbon build up for 1000 miles. Looks like there was alot of blow by also.
By chance...you dident have drain holes drilled into your oil tray?
Wick

 

[1937pickup]

This may be too simple an explanation, but the coolant may be good to 300+ degrees but the materials and clearances in the engine are not. Materials break down at given temperatures. Pistons expand faster and to a greater degree than the block. The clearances area usually set up for temps between 165 and 220 F. You were likely running on the ragged edge before the high CR head. Once you installed the head you went over the edge. You must install a larger (more cores) or a second radiator to get the temps down under 220 deg. The limitation is not the coolant. The limitation is the engine and the temps it was designed to work at.

I think mcorrell is right, you are trying to operate way outside design parameters. You are dealing with a motor that's design is over 85 years old and has been in use for almost as long. The metal has been stressed and re-stressed over the years. Remember at the time of the casting they could barely spell metallurgy, nothing against the engineers, they did the best they could with what they had. You need to get the cooling under control, not the coolant. Just my two cents. Good luck.

 

[700rpm]

That's interesting, I was told that the original spec was 0.012"gap.

When you say your experience is .050" is necessary, what were you doing and what happened to indicate the necessity for that gap?

Sorry, it was too early here for me to try to be intelligent. My piston clearance is .005, not .050. My ring gap is .020 +or- .001. Sorry for posting bad info.

 

[MikeK]

Chalk up another victory for Evans Waterless coolant! Instead of running at a normal temp and inconveniencing you with a mandatory stop if you ever boil over, the stuff always runs very hot due to its low specific heat and because it doesn't boil it let you drive directly to total engine destruction. I'm running right out to buy some!

 

[Phil Brown]

All of the damage looks exactly like what we see on our high HP VW motors when they get into detonation, aluminum specs on top of piston,missing piston top (or part of it), Rings stuck in pinched ring lands, scored cylinder walls from overheated pistons that let oil up top that contribute to MORE detonation and lost ring seal, rod bearing pounded out and burned black from no oil. I know you said you only had 25 deg of timing in it and that's not much at all but that's some ugly damage.
Whats the spark plug look like that was in the #1 hole (the one with the piston top damage)
Phil

 

[Y-Blockhead]

You definitely had some detonation going on in #1 cylinder as witnessed by damage of the outer edges of the piston. Can't see the other pistons but #2 looks like it might have been detonating also.

 

[Tom Wesenberg]

Detonation and too high of coolant temps is what I see causing the damage.

Save that piston.........it would make a good "Hard Luck" trophy.

 

[johnneilson]

I am not so sure that No 1 had much detonation, it looks to me the top ring land broke away. Severe Detonation looks different. But it is too late now.

Even the absolute best parts can fail, this rod just needs a fork stuck in it.

These motors can handle quite a bit of abuse if properly clearance and lubricated. They do like to expose themselves when not happy though........

 

[Synchro909]

I think mcorrell is right, you are trying to operate way outside design parameters. You are dealing with a motor that's design is over 85 years old and has been in use for almost as long. The metal has been stressed and re-stressed over the years. Remember at the time of the casting they could barely spell metallurgy, nothing against the engineers, they did the best they could with what they had. You need to get the cooling under control, not the coolant. Just my two cents. Good luck.

X 2 on the cooling. A pretty car that doesn't go is as useful as fly screens on a submarine. IMO, you should increase your radiator capacity as a first measure to prevent this happening again. Either a larger radiator or add more tubes or fins to the size you have or fit another one hidden from view but still with good air flow. I'd like to see the temperature stay under 200F. An oil cooler might be worth considering too. Next, try increasing clearances in line with what the knowledgeable ones have posted above.

 

[ppower]

Thanks for everyone's posts. I will attempt to answer the responses.

 

[ppower]

PC/SR, "the car has travelled about 1000miles since the new pistons were fitted".


Could you tell us where the new pistons came from?

Tom Endy

I think that the pistons came from Snyder. They have GN cast into a tongue inside the piston.

The rings in number 2 piston were only a little tight and number 3 piston was OK. I checked the piston gap and it is .008" front and back and .005" on both sides.

All the other big ends and main engine Babbitt bearings are OK.

 

[ppower]

Sounds like there a number of causes for this failure. From the looks of that rod I'd be concerned about the quality of the rebuild. Was the nut not tightened and vibrated off? Did someone strip the threads and just leave it that way? Pay attention to the other nuts and bolts as you disassemble. Try tightening them first to see if any are loose. 3,000 RPM is not too much for the stock oiling system.
Could you clarify what your coolant temps normally are and the max. is that you have seen? I noticed one place said up to 300 and another said 220. If it's running over 220, that's too high. Do you know what the piston to cylinder wall clearance was? You won't get an accurate reading now that the damage is done.

All the other nuts were tight and fitted properly with split pins. I have found the stray nut and the thread has been pulled out of it.

The engine normally runs at about 220 degrees. Once after a fast run I checked the coolant temperature with a digital thermometer and it was 285degrees.

Piston clearance are detailed in my previous post

 

[ppower]

Too Hot. The last couple of times you drove it she should have smoked,look how wet the port looks. Piston down in hole has silver looking specks on top...not good. a Lot of carbon build up for 1000 miles. Looks like there was alot of blow by also.
By chance...you dident have drain holes drilled into your oil tray?
Wick

I was surprised by the amount of carbon. There are no holes drilled in the oil tray.

 

[Tom Wesenberg]

#17 second picture, what is the white stuff in the coolant chamber?

If you built a racing engine, the first thing I'd start with is a crankshaft with counterweights.

Your rings have enough clearance, but what's the skirt clearance, if 2 and 3 aren't too damaged to get an accurate measurement?

 

[ppower]

Chalk up another victory for Evans Waterless coolant! Instead of running at a normal temp and inconveniencing you with a mandatory stop if you ever boil over, the stuff always runs very hot due to its low specific heat and because it doesn't boil it let you drive directly to total engine destruction. I'm running right out to buy some!

Following your post I checked the Evans site for the technical information which I studied before I bought the waterless coolant; it is no longer there and instead I found this http://www.norosion.com/evanstest.htm. I know it is written by a competitor, but it is very damming. perhaps I should try a water wetter.

 

[ppower]

All of the damage looks exactly like what we see on our high HP VW motors when they get into detonation, aluminum specs on top of piston,missing piston top (or part of it), Rings stuck in pinched ring lands, scored cylinder walls from overheated pistons that let oil up top that contribute to MORE detonation and lost ring seal, rod bearing pounded out and burned black from no oil. I know you said you only had 25 deg of timing in it and that's not much at all but that's some ugly damage.
Whats the spark plug look like that was in the #1 hole (the one with the piston top damage)
Phil

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?

 

[ppower]

#17 second picture, what is the white stuff in the coolant chamber?

If you built a racing engine, the first thing I'd start with is a crankshaft with counterweights.

Your rings have enough clearance, but what's the skirt clearance, if 2 and 3 aren't too damaged to get an accurate measurement?

The white in the second picture is a broken cylinder line insert.

I am not looking for a racing engine. The Ford engine, was a quick cheap fix when the original engine (one of only five remaining) boke its centre bearing. I now love the torque, but don't want more revs.

The piston crown clearances are listed above in #33. The skirt clearances are .005" front and rear and .002" on both sides.

 

[Ron W]

The parts and clearances in your engine is only a distraction. Your basic mistake is assuming that the Evans coolant will compensate for a radiator that is too small. The Evans transfers less heat, not more. Thier site says, " Vehicles running under normal operating conditions, should show no change or a slight increase in temperature." As others have said, you need more cooling capacity to keep the engine at it's proper operating temperature. Ron W

 

[ppower]

The parts and clearances in your engine is only a distraction. Your basic mistake is assuming that the Evans coolant will compensate for a radiator that is too small. The Evans transfers less heat, not more. Thier site says, " Vehicles running under normal operating conditions, should show no change or a slight increase in temperature." As others have said, you need more cooling capacity to keep the engine at it's proper operating temperature. Ron W

I ran the car for several years with this engine using water as a coolant and it ran hot, but not unacceptably hot. I switched to Evans coolant when a stitch weld in the combustion chamber opened up, and for two years it ran OK until the crack became too larger and the engine started to ingest the coolant producing an impressive smoke screen. I then re stitched the crack and fitted new piston and bearings. Everything was fine. I then fitted the high compression head, and until I drove for a sustained period at 3000rpm had no problems. I will be returning to water coolant, but I want to ensure that when I rebuild the engine on a new block, all the clearances are correct.