Took it out this morning and it was doing a Laurel and Hardey performance. I could hear lash so assumed it was yet another lifter not pumped up. Anyway it didn’t go away after a few miles. limped back home and spark plug 4 lead cap is a little oily and so is the air filter close to it. I haven’t removed the plug yet as am now at work. I do remember when fitting the spark plugs that plug 4 seemed to tighten a little quicker than the rest, but convinced myself that I hadn’t cross threaded. Anyway it looks like this may have been the case? Type 4s 2 and 4 plugs are a nightmare with the tin distance and angle. Always seems like a bit of a guess I suppose all I can do is remove the plug and attempt to retighten it correctly. Knowing me, if I was in slight doubt I’d have tightened it up without usual full tightness…
Yep, as said before...a bit of hose pipe to guide the plug in and turn finger tight ensures you haven't cross threaded. Sometimes needs a bit of a zen state of mind but it's not a job to be rushed! Hope it's ok... Edit, prob best to clean up the plug hole before attempting to reinsert. Patience Grasshopper...
Ah well, spark plug was actually in soundly so that’s not the issue. Popping badly so I’ll start with the usual fuel, spark, air leaks etc
Came back from the Lakes on the very hot day. Cooled her down by easy country roads and 30mph for about 10 miles before turning engine off. I really couldn’t have done any more here. drove her 10 miles the following day and was totally perfect. 2 weeks later, so after standing, was planning on looking at valves adjustment as haven’t done them for some time. Adjusted none of them, just turned each to TDC and rocked the rockers to see if any rattled. Number 4 did have play, but was only rattle on lifter spring compression. As this had play, I fired her up and was a lashing sound from this cylinder. drove her 2 days later, today, lashing didn’t go away and progressively got worse at popping and backfiring. So could still be lifter not pumped up, but the effect is more dramatic than I’ve ever seen with lifters in the past. I’m guessing fuel starvation
I'm not sure rattling the rockers quite does it for checking hydraulic lifters are set up! If for example a loose seat was working it's way into the head you just wouldn't know. was it running ok when you did some cool down driving or was that due to feeling there might be something a bit wrong? Maybe air leak is more common than fuel starvation.
It was running great all holiday and on cool down. Plus 10 mile trip following day was running great. If Air leak I guess would be around carbs and carb manifolds?
Sorry, that wasn’t the way I was checking that the lifter setting was ok - rocking. I just went round and checked for rattle at TDC on each piston for prior knowledge as the following day was to be proper valve setting
I found that when an exhaust valve was permanently closed, caused by the clip and wavy washer breaking on a T1 at 60mph up hill, boy was there backfiring. It fired across the inlet manifold on my T1 and blew out the rubber joiner on the opposite side and disabled those two cylinders as well. Maybe your lifter has totally given up on being pumped up and collapsed. In your case with a T4 its probably firing sooty crud back through the carburettor and the air filter, leading to the dirt around the place. At least on a T4 the bolts holding the flywheel on will do a better job than dowel pins .. .mine were shaken out and the holes ovalled out by shaking.
Or the servo vacuum connections to the manifolds, or anywhere along the vac pipe or even the servo itself. If you have original carbs there is also a lot of pipework between them leading to the manifolds. Lots to go wrong there.
Well I think I need a Valium after that . Was popping madness again this morning, so I tightened the carb manifolds, replaced the split serve hose but this didn’t seem to help. I squirted carb cleaner in the icts and tick over gradually got better to the point where it test drove smoothly, lashing went and ran on all 4 cylinders. So what I think has happened is - after a 2 week sit one of the lifters has really, really refused to fill, so a valve on no 4 has sat there probably fully closed. This has caused caused pressure issues where oily vapour had been forced through LHS carb and it’s nearby servo hose T-piece. This Crud has clogged LHS carb and that, with none filled lifter, had caused shocking running. carb cleaner dissolved crud and lifter gradually fills and back to normal, Captain Kirk back in his seat. sound reasonable???
