Nic wrote: Thu Mar 28, 2019 11:04 am
drcarlos wrote: Thu Mar 28, 2019 8:26 am
Nic wrote: Wed Mar 27, 2019 8:58 pm
Engine was stripped down today.
Block has been rehoned recently, possibly done without removing it from the car. Water, oil pump and belt are obviously new. Piston rings have been changed, all the gaps are stacked on top of each other rather than being spaced equally. Spark plugs look like they have been running hot and haven’t been changed, ever. You can see the valves are looking pretty rough, one of the spark plug holes has been helicoiled. One HT lead just fell apart. It looks like it has two cats, first one is totally blocked, I’ll just rip the guts out of that one. Block is going to be checked for oval bores before going any further with it.
Good job we did pull it out!
When i fitted new rings and rebored one of my worn out race engines a couple of year ago I read up about piston ring ‘clocking’ as I had no idea about it. Each engine has its own specific design and putting them on with all the gaps aligned is undoubtedly why it’s burning oil (I guess you know that already though). Easy mistake to make though as I’d have probably done the same and I’ve no idea what caused me to look for it when I was building it up again.
If it’s that simple then win, but looking at the state of the head it’s obviously been neglected a bit!
It depends on how much they have removed from the liners. If it was using a dingleberry honer then they just remove polishing and don’t really take any material off. If it was jones using proper stones then you can actually remove a lot of material and the tan load (how much the rings push against the bore) can be reduced and you can get blow by.
I’d be surprised if the blocked cat wasn’t a big reason for the oil usage, you get a horrible burn in the cylinder with a high exhaust back pressure.
I’ve stripped engines with badly aligned rings and seen no difference in oil consumption but I’ve no idea how much of an affect it has, we just don’t assemble them any other way.
It’s amazing how little will destroy an engine but also how some engines take so much mis-treatment and soldier on.
Dave!