The 24 Hours of Lemons Forums → Lemons Tech → Why do we keep throwing rods?
You had detonation issues.
Notice the out of round head gasked fire rings? That's a good sign of excesive cylinder pressure.
Cast pistons have been know to crack ring lands from a single solid ping, I somehow doubt that you could hear any pinging over the racket of racing.
You will see flecks of clean aluminum on the piston top/head when detonation does it's thing. Sometimes they leave cleaned shockwave patterns. I've never seen detonation take out a skirt. Not saying it's not possible. The top ring appears to be in one piece. Detonation usually takes out rings. That could be detonation flecks on the broken piston, could be junk bouncing around in there too. What's the spark plug look like?
You had detonation issues.
Notice the out of round head gasked fire rings? That's a good sign of excesive cylinder pressure.
Cast pistons have been know to crack ring lands from a single solid ping, I somehow doubt that you could hear any pinging over the racket of racing.
Nope, that's the shape they are right out of the box
Dave, can you post some detailed pics of the bottom of the piston when its out. Also, look at the cylinder bore for signs of the piston chatering.
Woody can post those. The wrist pinned showed no sign of failure. The piston is not scalled at the pin. Just broke away. The pictures I just sent to woody, shows the cylinder walls after the piston was removed. The bore went oval trying to accomadate the semi broke piston for a few revolutions before the violence began. The oval means I can see into the water jacket in 2 vertical lines on each side with a larger hole near the bottom of the stroke. This point may not have been the actual bottom, but where the rod finally seperated.
You had detonation issues.
Notice the out of round head gasked fire rings? That's a good sign of excesive cylinder pressure.
Cast pistons have been know to crack ring lands from a single solid ping, I somehow doubt that you could hear any pinging over the racket of racing.
Man, I worried about that, but the plug, and head color as removed looked good.
More expensive components would fix this? More expensive pistons? Its just that I cant find anybody who race these other than drag racing, and thats a different animal. I need better rods, bolts, and pistons than they run.
We have alot of lipstick ( kinda) on this pig.
We really detuned it from the first 300 laps as far as the rev limiter also. From 5,000 or 5,250 to 4,500. It should run to 6,000 for what parts were in there.
Seriously, I think your reverse of the /6 e30 BMW idea is a good one. Put an M30B35 with Getrag manual trans in there. 208 hp all day long, and then some. One of the many things Cerveza does right is using that engine.
hell, if you want to do BMW power, stay in class C, and use ONLY parts with a Ford part number, use a 524td mill, it was sold in Lincoln Continentals and Mark VII for at least one year. Those mounts make any little six (m20 engines) a straight bolt in to a Fox body...
fyremanbill wrote:Dave, can you post some detailed pics of the bottom of the piston when its out. Also, look at the cylinder bore for signs of the piston chatering.
Woody can post those. The wrist pinned showed no sign of failure. The piston is not scalled at the pin. Just broke away. The pictures I just sent to woody, shows the cylinder walls after the piston was removed. The bore went oval trying to accomadate the semi broke piston for a few revolutions before the violence began. The oval means I can see into the water jacket in 2 vertical lines on each side with a larger hole near the bottom of the stroke. This point may not have been the actual bottom, but where the rod finally seperated.
Ok, looking more and more like a mechanical piston failure. The piston tops look good...no heat or detonation, and a little rich. If the pin and whats left of the pin boss in the piston look ok, it looks like it just came apart. Does anybody make a forged piston for that engine?
I think the Ford Tempo Silverlite pistons we used were the wrong call. The last time we had one come apart (Chuckwalla) we spun it up to a much higher RPM before it just fell apart. Like 7000rpms or something.
The only answer is forced induction. I do still have Anton's Tbird 3.8 blower sitting here.
I have solved your problem.
Weisco makes a 94.00 mm (3.700) forged (all of their stuff is, at least for cars) Toyota 22R piston.
It uses a 22mm pin, so have the rods bushed to fit and now their full floaters instead of pressed.
Compression height is 1.533", so you can mill the piston a little to get your 1.500" or leave it a little tall and raise the compression.
p.n K509M94
http://www.wiseco.com/Catalogs/SportCom … atalog.pdf
I have solved your problem.
Weisco makes a 94.00 mm (3.700) forged (all of their stuff is, at least for cars) Toyota 22R piston.
It uses a 22mm pin, so have the rods bushed to fit and now their full floaters instead of pressed.
Compression height is 1.533", so you can mill the piston a little to get your 1.500" or leave it a little tall and raise the compression.p.n K509M94
http://www.wiseco.com/Catalogs/SportCom … atalog.pdf
Adding 22r Toyota parts I see no fail here.
With oil pressure guages, even mechanical ones there is so much damping of the pressure that you won't see brief drops down to zero.
Mount a decent sized gauge with a decent sized feed line ( plumbed with safe hoses ) where you can see it.
After doing this with several cars and seeing wild pressure swings and drops to 0 in corners we went to using oil accumulators on all of our engines.
The electronic gauges are crap and the capillary tubing with most mechanical gauge sets is too small to read quick changes.
Well, we ran all weekend with the bone stock junkyard motor with no problems at all. Sure we turned the rev limiter way down to 4000rpm, but we also did nothing to this motor except change the oil. Its came out of a junkyard Fairmont with 47,000 miles on it.
Now the question is, do we trust this stock Ford built bottom end and swap on the higher compression head with the 2bbl carb for next spring's Sear's Point race, or leave it be? I think we are down about 50hp from our racy souped up motor, to less than 100 at the rear wheels.
Trust the ford lower end with better head
chinacharged it.
We are going to analyze the oil after this race and see how much bearing material is in it. I know when I overhauled our original 99,000 mile motor the bearings in the big ends and mains were starting to come apart.
Well, we ran all weekend with the bone stock junkyard motor with no problems at all. Sure we turned the rev limiter way down to 4000rpm, but we also did nothing to this motor except change the oil. Its came out of a junkyard Fairmont with 47,000 miles on it.
Now the question is, do we trust this stock Ford built bottom end and swap on the higher compression head with the 2bbl carb for next spring's Sear's Point race, or leave it be? I think we are down about 50hp from our racy souped up motor, to less than 100 at the rear wheels.
You thinking you found the little old lady car that only drove it to church on sunday ?
I think you should put fresh tape on your tail lights and race it as is for C Class Victory!!!
Then swap on the top end cause you're gonna need it in B.
I only know that we would not be competitive in B without a blower, 3-6 side draft carbs, or a V8 swap.
I am not assuming anything about the motor we have in there now. We were just tired of blowing up and spending money so we went with the low budget/low effort solution. We will likely do a compression test and more at least before the next race. We'd do a head gasket and look in the bores, but we'd easily lose a 1/2 point of compression going from the old Ford stamped metal to the modern head gasket, and we have barely 8:1 compression to begin with.
You can always add the oi l accumulator for the price of one T fitting or oil cooler pancake,, short hose and 12 inof pipe. Phil has said that value add but it is still less than 50$ actual cost.
The 24 Hours of Lemons Forums → Lemons Tech → Why do we keep throwing rods?