Hey Guys...
Here's an interesting one....
Looks like TM1 broke a ring last night during his run.... (Eventually, been expecting it since the seize a while back...) Compression is way down, LOTS of blow by, and pretty much impossible to start, even on the 220v starter... Right, so not much interesting there, but....
Here's the interesting bit:
While I was piddling aboot wif him, I quickly rebuilt the IP and installed a new element... 10min well spent as it has been long overdue anyway... I thought, what the hell, lets give him a wind over and see what he does, just for S&G....
I wound him up good and well on the starter for a few minutes, allowing the air to bleed out the IP lines (Man, a 100% duty cycle rated starter is great!!)... When I dropped the compression release, there was the "usual" sound of first firing, then knocking of note... as if he was starting on ether.... I pottered around a bit, checked IP timing, checked that there was no solvents in the lines etc, then wound him over again to see what happened... Same again, first compression stroke a nice sounding diesel event, then getting less and less as knocking got worse and worse...
Now, TM1 has a crank vent that feeds into the air intake - when I pulled the vent out of the intake, there was major ring bypass in progress.... The unburnt and partially burnt ventings that are being fed into the intake are causing him to pre-ignite as they get compressed.... Again, of interest, there has been no evidence or indication of a runaway while he was running...
Anybody else had similar??
Keep it smoking....
Cheers
Ed
Edit: Here's one for everybody to chew on.... Something was plaguing me, something I might have missed.... I took another look at the IP pump and timing on TM1 (rebuilt the pump again, just for good measure in case I missed anything)...
Interesting times....
It looks like something is squiff with the IP cam... When I set the timing to around 20 degrees BTDC, the pump bottoms out ... This is quite unusual, because I used to be able to set him up to around 25 degrees BTDC with no bottoming before...(A hint guys: when you set timing, turn the flywheel over SLOWLY and CAREFULLY by hand and feel for pump bottoming or other resistance, it could save you some $$$ and tears).
I have run a quick check on TDC marks on the flywheel by watching for the valves going "on the rock" and things are pretty much ok in that department, so flywheels haven't shifted, nor has the cam gear lost a tooth and moved either... The only thing that seems out of place is the IP timing, to the tune of about 15 degrees by a rough guestimate...
I pulled the IP plunger and had a look at roller et al... All seems fine in that department... This situation seems "quite unusual" and, barring an incident many years ago on another CS type engine, where a cotter pin snapped and allowed IP timing to vary at random this seems strange to say the least.... Looks like I will have to pull a flywheel and see whats happening behind the governor housing when I get a chance... Oh, and the major knocking saga? Looks like that with the injector timing being so retarded, the combustion chamber volume was filling up with unburnt fuel (WMO - Thanks to 220v starter and extra long cranking capabilities), compression ratios went up, and any vapors present decided to ignite a little before they should (euphemistically speaking of course....thump, crack, hammer, hammer!)
Who knows? But a quiet tear down of the governor side to poke around and have a look at seems to be the order of the day! (Any forecasts as to what I will find?)