Was converting my car running standalone megasquirt from distributor+wires to COP. I didn't do enough research on properly driving the coils and I ended up with a bent rod, a destroyed piston, a broken oil squirter, and a little bit of damage to the bottom of the bore.
Here is a picture of the bent rod. You can see where the skirt got destroyed in 1 spot, but there are 2 others just like it covered by the rod.
Here is a picture of the corresponding bore. Is this block still usable or do I need to start searching for another bottom end?
It might be the way digital cameras take photos but the bore's finish has me more worried than the nick at the bottom. Looks really, really coarse.
As long as you can fit a new squirter (boss not damaged), I'd get up in there with a die grinder, or even just a rattail file for the main course and some sandpaper for dessert, and round all the edges of the bore chunk so it doesn't shave the piston, and run it. Depending on how the block is built there is a very small chance that the bore was knocked out of round, which WOULD be a problem. I can't think of a simple way to check for that though. Maybe slide a piston ring down the bore (you can use a piston to keep it square) and check to see if you can see light past it?
I was involved in repairing an engine that had a Very Long Stroke where the wristpin was almost visible at BDC. The problem was whoever built the engine did not bevel and round off the bottom of the bore, so the pistons were shaving themselves on the sharp edges. The oil was filling up with aluminum powder at an incredible rate, it'd look like nail polish after 15 minutes of runtime. Details matter...
Can't comment on your specific application, but Honda d16 blocks that are being turbocharged frequently have their blocks notched in that exact place so they can run thicker rods.
The notch likely isn't a problem, unless there are cracks radiating out from it. I would probably pay the dough to have that cylinder crack checked and measured by a pro.
And I agree about grinding it smooth if there are no more serious issues.
I would notch blocks more than that BUT!!!
i would want to have the block magnafluxed.
i would also want to look at the mains as with a bend rod like that you have put a ton of force against the mains. I would want to know that they are still in line and still in round. I would also have the crank inspected.
I also don't like the finish of the cylinder walls. Looks to rough but as others have noted it could be a lighting thing with the camera.
If it all checks out just take a grinder to the area to radius all the edges to release stress points. While you are there I would clean up the inside of the block of all casting slag and casting lines to promote oil drain back to the pan.
The block is a VW 1.8 16v. The wall with the notch is very thick and I didn't spot any cracks in the area. The cylinder walls are very smooth it is just the lighting in the pic. I had a flashlight pointing down but my camera wouldn't focus unless I had flash turned on.
As soon as the rod bent I shut the engine off since I have a bright red low oil pressure warning light on my dash. All of the rod bearings (which have ~500 miles on them) look brand new still. I can check the mains, but I am very confident that there are no issues with the crank.
What wheel should I use on my grinder to smooth the notch out?
Carbide burr in a die grinder, or even a cutting bit in a Dremel will do. (Not a stone or a disk)
Iron cuts really easily, it's self lubricating because of the carbon/graphite/whatever it is that stains your skin when you file it.
Don't re use the bearings. Any of them. The block needs inspection not just at the notch but at all the points where the loads were transmitted back to it. Shutting it down the way you did is not really relevant with respect to this.
I have raced a 16V Scirocco so I know what you're dealing with.
What are your plans for the use of the engine?
I'd replace the main & rod bearings and any bent rods, etc.
Then once the crank is back in the engine I'd spin the crank.
Measure the drag with a torque wrench.
Does it rotate smoothly?
If not then it could be bent.
If it spins OK install each piston/rod and spin the assembly after each install.
As long as everything spins smoothly I'd run it.
I believe that VW 16V cranks are forged steel.
jimbbski said:
I have raced a 16V Scirocco so I know what you're dealing with.
What are your plans for the use of the engine?
I'd replace the main & rod bearings and any bent rods, etc.
Then once the crank is back in the engine I'd spin the crank.
Measure the drag with a torque wrench.
Does it rotate smoothly?
If not then it could be bent.
If it spins OK install each piston/rod and spin the assembly after each install.
As long as everything spins smoothly I'd run it.
I believe that VW 16V cranks are forged steel.
The car is an 88 16v scirocco. I already disassembled it down to just the bare crank, and spun it by hand with the pulley. It was spinning smooth all the way around without any binding. I also used a pry-bar and checked for any side to side movement and didn't have any so I think the crank is still straight. It is forged and known to hold up to some serious abuse. I got all new bearings and I will be replacing them just for the peace of mind.
Also spoke to a local engine builder and he told me that there shouldn't be any issue using the block as long as I smooth the edges to prevent the skirt from being damaged.
shawkur16v said:
Was converting my car running standalone megasquirt from distributor+wires to COP. I didn't do enough research on properly driving the coils and I ended up with a bent rod, a destroyed piston, a broken oil squirter, and a little bit of damage to the bottom of the bore.
I was curious when I first read this, about how this is caused by improperly driving the coils. That is a hydrolock problem, I'd say, probably because you had the intake runner full of gasoline from a stuck open injector, and you sucked it down into the cylinder immediately on the engine starting.
