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Wahey! It started up first go. Only idled and revved it up a little but no odd noises and good oil pressure.
Idle tuning needs some tuning, not a surprise as I'm on the spare head with stock cams, but it runs on all four and sounds well.
Fingers crossed the clutch cylinders will arrive tomorrow so I can get them installed over the weekend and retune / get some miles on it in the next few days.
Well luckily the clutch issue was only the slave in the end. Swapped it out and bled easily without needing to do any under dash olympics to change the master out which I was thankful for.
However I'm not going to make the trackday.
I started the car up and drove it round the block just to warm it up, check for leaks etc before taking it for a longer drive. When I started the car back up it wouldn't start. Really laboured cranking like the battery was going flat. The voltage while cranking was below 8v so I thought the battery was the issue. Went and bought a 063 lead acid locally and it started, still laboured a bit though, slow cranking speed again.
Thought this battery might just need bit of a charge. Took it for a drive all seemed fine at low speed stuff but I gave it some mild throttle and it just felt a bit flat.
Got it back into the garage and tried to hot start it and it wouldn't. Very laboured cranking.
I turned the engine over by hand and it was very stiff
Seems to be worse with temperature which suggests a clearance issue. Thrust bearing clearances were on bottom limit so could maybe be the culprit.
I've done a bit more poking this evening. The bottom end, with the cambelt removed from the cam pulleys seems to rotate as you would expect.
A little stiff around 90deg crank angle and easy to turn as you go over TDC. Feels normal, although it is cold(ish) (still a little warm) now.
When you put cambelt back on the cam pulleys it is really hard to rotate the engine from the sc pulley. Normally this is pretty easy because of the 2.5 pulley ratio.
Soooo I have a friend with a spare BP4W head- I am going to see if I can borrow / beg / steal / purchase that one.
I checked the lash on my head, nothing to suggest anything sinister. It wasn't noisy but there are some marks in the cams, not sure if they were there before or if they are new. I'll take the cam caps off tomorrow to see if there is any obvious munching on the cam journals or head running surfaces.
A head swap is something I should be able to turn around before the trackday. I don't really have anything to lose. If its the pistons I should see marks in the bores from above, but I measured the clearance several times. I don't see why this would be the case. Thrust clearances were also in spec, just on the tighter side of the spec, again no reason this would become an issue.
If it is the head I would have a hard job explaining why. Its a stock BP4W with some heavier valve springs - but no idea why this would be an issue for me when I've not heard of this issue for others.
Uh right so its been a fun day. Picked up the spare spare head from Nick.
Got home and compression tested the engine cold. Basically no compression to speak of on any cylinders. The winner was cyl 1 at 50psi. However the cranking speed was sloooooowwww. Really slow. cyl1 cyl2 cyl3 cyl4
Not great really. Then I leak down tested it. Interestingly cyl 1 was in the green, cyl 4 almost was, cyl 2 and 3 were poor. I listened in the intake and exhaust and they were fine. The air was coming up the oil drains in the head (rings) cyl1 cyl2 cyl3 cyl4
So I half expected to see carnage when I pulled the head, but not the case. Bores don't look to be an issue. Certainly no sign of the pistons seizing or damage.
cyl1 cyl2 cyl3 cyl4
Need to drop the oil to see what that looks like, but at the moment there doesn't seem to be anything up with the bottom end. I doesn't feel overly stiff.I'm in two minds as to pull the bottom end of the car at this point.
I think best case scenario at this point is:
> Starter motor / ground is not great and struggling to start the new motor over the honing and also stiffer springs.
> Low leakdown readings simply still need those cylinders to be broken in still.
> Lack of power is because of 2 of the cylinders still need breaking in and also the rich mixture, down in the low 10s.
Worse case is really is I have mucked up the break in and need new rings and a rehone. Not the end of the world but annoying. If the starting issue isn't the starter or a ground I struggle to see what that is. Maybe the head but I'm a little sceptical as I can't see any damage in there - still need to check the cam journals though.
So plan is to put it back together with a new starter, check the grounds, run a known good standard BP4W and drive it to see if the leak down improves on 2 and 3 particularly.
not an expensive task, run through coffee filters to collect any spares
Originally Posted by Tchaps
at the moment there doesn't seem to be anything up with the bottom end. I doesn't feel overly stiff.I'm in two minds as to pull the bottom end of the car at this point.
once the head is off it's easy to pull the bottom-end, before you do is it wothe pulling all belts and trying a spanner on the crank?
Dropped the oil - didn't have any filters but I cleaned out a large pale plastic washing up tub to help see anything.
The oil was slightly glittery (very very fine glitter) as you'd expect a new engine to be. No coppery bits or larger particles of anything. I have a magnetic drain plug and this had a reasonable amount of stuff attached, but when you felt them they were super fine, like a paste. Again I'm sure this is just normal as the rings try to seat. Nothing sinister found at all.
Turning the bottom end over by hand it is obvious the primary resistance is the rings of the pistons going up and down the bore. Going over the top or bottom the crank swings over lovely, easily and smoothly. I also felt the crank end play, so it has not managed to bind that up somehow.
I'm not going to pull the block at this stage. I'm going to load up the spare spare totally stock BP4W, and swap out the starter motor. If it is still slow cranking I will use jump leads to directly power the starter to try to rule out my accidentally breaking the main power feed or something like that.
Looking at the poor leak down values on 2 & 3 I think time would be better spent getting some miles on the engine on Wednesday and reviewing leak down and compression values then. If I don't see any improvements then I've probably mucked up the break in, will pull it and rering / fresh hone.
I increasingly thing the stiffness to turn over by hand could be the combination of fresh hone and stiff springs that I am just not used to. Certainly no sign of anything mechanically binding.
as to particles in the oil, it's almost impossible to clean a block after machining especially if you dont remove the oilway's brass end-plugs or cylinderblocks cylinderhead oil-feed restrictor so it's possible the bits you've found are reasonabally inocent
I use a dishwasher (partswasher) to clean components
at least engines are redily available & cheap in the UK...
as to particles in the oil, it's almost impossible to clean a block after machining especially if you dont remove the oilway's brass end-plugs or cylinderblocks cylinderhead oil-feed restrictor so it's possible the bits you've found are reasonabally inocent
I use a dishwasher (partswasher) to clean components
at least engines are redily available & cheap in the UK...
Rich.
They aren't really bits in the oil. You can't feel them between your fingers they are so small, and my understanding was that glitter was expected in the oil of a fresh engine, as the rings wear the hone peaks on the cylinder walls. Again the stuff on the magnetic drain plug was more like an oily paste - it felt like the ARP fastener lube between my fingers. Nothing that felt solid or 3D in any sort of macro sense.
I did my best with cleaning it out - the head I had all the oil plugs out, compressed air brake clean rags on sticks pipe cleaners down the small passages etc. The block is trickier because I've seen the main gallery plugs are horrible to remove (might be wrong, just what I've seen from others) but I did go through it as much as possible with a similar process as the head. Not saying I got everything but the symptoms don't really point to an oil issue I don't think. Good pressure, no horrible noises, bores in good condition.
Ring gaps are in a post a while back, think they were 0.45mm top ring and 0.5mm 2nd - which is basically the circle track / drag race spec. Its the 3rd from widest on the spec sheet and bear in mind I have only been gently street driving it. Don't really buy ring binding or end to end contact being the culprit. You can just slightly rock the pistons in the bores and see the rings move in the ring lands so they aren't stuck.
Also the fact that when I was comp testing it cold and the starter was really struggling shows the issue is still present when cold now. Maybe this is a sign the starter is just falling off a cliff, maybe not. I'll change it and test. Also the fact the car idles without much adjustment shows it can't really be too bad, and could well be a sign the starter has just gone a bit wussy on me.
Swapped the spare spare unmolested BP4W head on and before I attached anything else did a leak down. All four cylinders were right at the top of green, virtually no leak down. I had sprayed a bit of WD40 on the cylinder walls before install just to lubricate for first start but still, was a very good sign. Also the cams were so much easier to turn over with the stock springs.
In the end I didn't swap the starter motor over - I felt that the issue was with the other head not the starter.
Built it all back up and comp tested it - 150 on 1, 2 and 4, 165 on 3. This was just a cold comp test and I didn't hang on the starter forever, the 150s were still moving but I didn't want to waste the precious battery and straight off the bat I could see we have comp now.
I did have a bit of a struggle starting it - turns out the cam position sensor wasn't close enough to the cam pickup. But then it cracked into life.
Only issue really seems to be the new exhaust manifold gasket is a pile of w***. I'll swap back to the old one tomorrow.
Also it now hot starts.
I'm not sure what was going on with that other head, will have to investigate when I have chance. It certainly seems to be the cause of the poor leakdown / compression. I'm not sure if this was me not cutting the seats correctly - I did lap them and they showed the strip of dull grey as they should - or if this is a pre existing issue with the head (no idea what). The car it came off had low compression also, but the head had been declared all good and tested by a machine shop.
On the slow cranking, maybe the springs were too much for the starter / battery with the added friction of the fresh hone. I didn't test the spring tension as installed (I need to get a spring tester, its on the list) but I'm interested to hear if any others have had issues / noticed similar issues when moving to a heavier valve spring, in my case a Supertech light double. There might be something else going on but they weren't any where near binding, this was with stock BP4W cams.
Or it could just be the starter is a little old, but can handle the stock springs no issue.
I had Wednesday off work before the trackday to get the car run in, tuned and prepared. Found a few little issues / leaks and sorted them out. Took it out on some drives to bed it in and also retune the fuelling.
The stock BP4W head wanted a fair bit more fuel in the lower load cells and idle (about 30%), and also idles between 15 and 20kpa lower despite the max lift being set at the same position my head vs stock head.
The stock head was also about a point richer at full throttle, at a very slightly higher kpa.
Well I made it to the trackday. It was damp and wet but was having a lot of fun. The car felt a little dulled performance wise, but I leaned out the WI fuelling to 12AFR and it seemed to wake up a bit. It still wasn't quite as eager between 6-7k as my old head though.
First, the success. The engine didn't use any oil on track at all. However last run of the morning I heard the engine start knocking. I got off the throttle and nursed it in but it was clear mechanically something was up with the engine. Had to get it recovered back home (5hrs in the truck wondering what I'd find) and tore the engine down today.
Still early days on the exact diagnosis but essentially I have spun rod bearing no2. It is the only rod that knocks. However I took a look at rod bearing 3 and it looks like s*** also. Looks like there was still shavings left in the block somewhere. I'm going to have a go at getting those main oil gallery plugs out this time, and to be honest I feel like a bit of a numpty for not trying to do that first time round.
Most of the bits of bearing seem to just be in the pan, there were a few small bits in the mouth of the oil filter. I've looked inside the oil pump and surprisingly it looks fine, somehow. The car still had plenty of oil pressure after it started knocking limping back into the pits. I am a little torn if I should replace it, simply because I know the general rule is to do that when this sort of thing happens, but it seems a little silly now I have seen inside.
Rod 2 has had it, the bearing bore is all chewed up, luckily I seem to be able to get hold of just the one rod to replace it rather than a complete set.
The crank could probably be reground for 0.25 or 0.5 bearings but I have sourced a good standard size crank, already crack tested and polished for a good price instead.
Then obviously needs new bearings.
So hopefully it won't be too long until I can break it again.
Just generally having a bit of a nightmare with it all really. I thought I'd done an alright job of cleaning it all out, obviously not.
I guess the two rays of sunshine is the lack of oil usage, and that I leak tested the engine before I tore it down again and literally it is above green on the gauge, virtually no leak down at all.
My phone has died so I'll post pictures of the fun tomorrow. I got some video from the track so I'll upload that too.
Pre teardown leak down test results. I had to check the gauge still worked I didn't believe them at first
Then onto the carnage Plug had caught a fair amount of small but sharp metallic slivers, and this larger part. and this bigger bit was on there too, probably bearing backing Lots of larger chunks of bearing in the front of the pan. Crank rod journal no2 - the top shell still stuck on there, it took some persuasion to come off. Top shell of rod 2
Got the front main gallery plug out. Wasn't too bad. Drilled it and tapped it to M10, then used some studding, a socket and nut to pull it out.
The brass was a little tough too drill but I took it slow and it worked out. I think my drill bits are a bit dull and need a sharpening.
I am going to get the main alignment checked at the machine shop, just to be sure it isn't a contributor to any stiffness and cranking speed issue. I checked the main bearing bores for ovality with the ARP mains torqued up without the bearings with my dial bore gauge and they were spot on as far as I can tell.
I am going to take the shim out of the oil pump, put it back down to stock 60psi. I have shimmed my pump twice over the course of the last few years and both times I have found it seems to increase the sensitivity of oil surge under braking. If you compare my Llandow and Anglesey videos on track you will see that at Llandow, even though I do get a little oil drop at the end of a braking zone (might even just be the drop in revs) its no where near the same as the drop I was seeing at Anglesey, which was almost as soon as I do any braking the pressure is dropping. Both runs are with oil topped off to the full line in the sump. Maybe there is more oil in the head because of the extra pressure and so less in the sump. I'm also not sure if it was a contributor to the bearing failure. The bearings look scored rather than wiped (debris more likely) although obviously rod bearing 2 is just a car crash so hard to tell exactly what the initial failure was.
I've read lots of threads on the oil surge on braking, a number of respected builders on here that can build an engine that lasts more than 400miles not seeing the brief surge as an issue, but I'm going to follow my nose on this one, as I didn't see any oiling issues from just 60psi at the mildly elevated rpm limit I was running. Whichever way you cut it I can't see reduced oil pressure and more the potential for air bubbles being a good thing if I can very simply minimise it at the levels of braking I achieve in the car, which isn't anything mind bending. I'm on mild track tyres and run no aero at all.
I also noticed when I was running the engine in on 10w40 break in oil, rather than my usual 10w50 that oil temps were lower on the road. I had swapped back onto the 10w50 for the trackday. Looking at the clearances I'm going to be running with the new crank (about 2thou on mains, 1.7thou on rods) and comparing to both stock clearances / oil recommendation and this useful bit of info from Driven Racing Oils https://aaoil.co.uk/driven-racing-oi...ing-clearance/ I think that the 10w50 might be thicker than I need. I'm going to have a chat with Millers oils about it too, but it might be that a 10w40 would be a better choice for my clearances and usual oil temps and possibly free up a little power. I do need to consider the sc gearbox oiling in this too though. Its something I haven't really investigated before. I moved to 10w50 on a UK suppliers recommendations when I first started doing trackdays with my old M45 because of high oil temps before I got the cooler setup dialled in.
don't forget the rear plug (& theres the head's oilfeed restrictor / anti-drain valve also) - bottlebrush time then...
Originally Posted by Tchaps
The brass was a little tough too drill but I took it slow and it worked out. I think my drill bits are a bit dull and need a sharpening.
sharp helps but a straight flute drill with brass specific rake angles can make life so much easier (& less 'grabby')
as to oil, I was taught not to go too high with pressure as this saps power (to create and as resistance) and can also damage bearing surfaces - maybe this was to frighten over excited apprentaces but whitemetal bearings were still sort of common repair work ~30 years ago.
admittedly you want enough pressure & flow to 'float' the journal (bearing shell being secondary to the 'hydrodynamic-wedge' of the oil) but if you have wide clearances theres little to restrict oil escaping the bearing.....
I may have written that lot badly
your oil surge thoughts, it's possible that theres a large volume of oil staying / trapped in the cylinderhead, worth investigating this and maybe looking at the drainage tubes in the head & block? I know several speciallist engine builders that pay attention to this as oil drainage & crankcase breathing can both fight for the drain tubes.....
Ha ha I don't feel like a 'great mind' atm to be honest 'I don't know how many times I've seen people 'build' engines without removing all plugs & caps to clean out the gack ' ohh man right in the feels
Yes need to tackle the rear plug too. Was your plan to remake the head oil restrictor on a lathe, or did you source one from Mazda?
I am wary of the removing the restrictor pill for the head, not being able to get hold of another or having to reverse engineer it and get my new friendly machine shop to do one for me.
I saw about the rake angles from researching brass - I haven't really touched the stuff before (with a drill etc). Interesting stuff. I didn't find my bits grabby, probably because they are dull. It just seemed to cut better with a lot of pressure and a very slow drill speed (pulsing the trigger on my hand drill), just like I found with stainless.
My number one theory would be excess oil in the head with the additional oil pressure. I guess you could mitigate with either a smaller head restrictor, improving drainage or statically overfilling the sump. Not sure if others have seen this but I have seen this trend twice now. Increasing the oil relief valve pressure increased oil surge sensitivity. The previous time I did this I took the shim out and oil surge behaviour returned to normal. Normal for me is virtually no surge with oil at F mark on dipstick, with surge starting to become noticable if oil is at L mark.
Messing around with the head restrictor I'm not particularly confident on. I don't really want to find I have under oiled the head with an expensive failure.
I already run an additional vent pipe from the front of the sump up into the baffled section of the valve cover to help relieve the additional blowby additional hp inevitably brings, which should reduce the load on the oil drains.
Overfilling would be simple but I'm not sure if I would end up with negative effects when just running the engine at lower rpms on the road. Excess windage, oil frothing etc.
The old 60psi setup seemed to work well, and I am trying not to introduce to many variables that would require engine disassembly to resolve. Just want to get it running again.
On the oil viscosity vs clearances vs temperature - I think I am going to end up with 0.0018" clearance on mains, which is a little over the top stock tolerance of 0.0014" but not massively. Rods are going to be top of stock clearances at about 0.0016" - I do need to double check these in the rods and mains, this has been calculated by measuring the bearing bores in the rods and block, measuring the crank journals then measuring the thickness of the bearing shells separate from one another, matching them all together to provide equal as possible clearances across all the mains and rods. Good side of this technique is the dial bore gauge does not mark the shells. Bad side is the multiple measurements being added up and calculated gives rise for increased error. So I do need to give it all a final measure when I assemble, and I will use these in discussion with Millers to see what they recommend. But no point in running a higher viscosity and higher pressure if the internal geometry and loading does not require it, sapping power, possibly providing un optimised lubrication.
But this is a sideline to making sure I don't send swarf through it again. 10w40 or 50 makes no odds if its full of shrapnel.
Ha ha I don't feel like a 'great mind' atm to be honest
well, your build shows you were at one point
Originally Posted by Tchaps
ohh man right in the feels
lol, wasn't aimed at you but....
Originally Posted by Tchaps
Was your plan to remake the head oil restrictor on a lathe, or did you source one from Mazda?
not done yet get easily sidetracked and too many other projects / distractions / new ideas etc.
I'm torn with making a fixed restrictor and just buying a standard one, with the drysump there'll be plenty of oil capacity but don't want the head to fill as it can be messy & have oil consumption issues (or leaks?) I know Ford / Cosworth BDA series and Vauxhall XE engines commonly have a smaller restrictor - not a 'one-way' / anti-drain valve fitted for this reason.
suppose the mazda item is designed around a road engine that is presumed to spend most of it's time at low / mid rev range not redline and the drainage should be adequate there...
Ha ha well hopefully I get it right this time. There is hope, the old engine did well and would have carried on longer had I not split the pistons.
Nah I don't think its overthinking. I would have thought they would design the restrictor around the pressures, usage rpms and viscosity. You start playing with those you are going to have knock on effects, its just whether the effect begins to turn up negative consequences.
I do find it a little odd though as its not like shimming the pump is a rare thing to do, infact seems to be recommended in most cases for a track build or if running external coolers etc, and I haven't heard everyone screaming to high heaven about surge. I dunno I'm just going to follow my nose on this one.
I'd think maybe your dry sump system would help the oil control, draw the oil down from the head, hoover up blowby. Also will remove the oil surge on the brakes simply by virtue of the way those systems operate. My guess would be the system would be a lot less sensitive to any over oilling, but under oilling could obviously still be an issue. I'd be tempted to just run the stock restrictor and use the scavenging for all its advantages. (I've never played with one, I am just thinking here)
I have found some Mazda oil gallery plugs here in the UK which is a relief.
I got the rear plug out this afternoon, and this has even less room behind it than the front before the nearest child runner to the main bearings.
This lack of depth was going to be a problem for me in trying to install a threaded plug. I would have to leave outer face of the plug either inset or flush to the face of the block to avoid gearbox or water pump fitment issues, while not going so deep not to partially block the child gallery behind. It looked very tight, particularly trying to do this with a taper plug.
I looked at getting my machine shop to make me up a batch after taking some measurements off the ones I removed, but just being able to order the Mazda part is easier.
I got some micrometer calibration sticks (thanks for the tip Zed) and calibrated all my micrometers. The 25-50 and 50-75mm both needed a tiny bit of adjustment, about 0.005 to 0.01mm.
I wanted to do this because measuring the thickness of the shells individually out of the block and rods and measuring the rod and main bores separately involves using more than one micrometer, and if they aren't calibrated correctly it will throw the calculated clearance out.
I sense checked my calculated clearance by dummy loading one of the mains with the shells and checking with my dial bore gauge. The two figures were spot on the same so happy about that.
As I think I have mentioned rod journal 4 and main journal 5 are a little bit bigger than the rest, about 0.06mm / 0.012mm respectively, I was going send the crank into the engine machine shop to have the two journals ground / polished down, but I was concerned that with such a small amount of material to remove it would be easy to overshoot.
I ended up working out that my mains clearances were going to be a little bit tight anyway to where I wanted them, down at about 1.5thou, so I have got a pack of 0.025mm oversize shells coming. I will probably run half and half std size and 0.025 over on mains 1, 2 and 3, then run full 0.025over on main 4 to give me even clearances of about 2.2thou on all mains. If that ends up looking a bit wide I will just run half and half on main 4 and run std on 1,2,3. Either way I can adapt to the slightly larger main 4.
The rods I can mix and match shells to bring them all to between 1.8 and 2 thou. This sets up the mains and rods up with very similar clearances, and according to the info I linked previously spot on for 10w40 for over 104degC temps. I may well continue to run the 10w50 just to protect for the track oil temps up to 120degC, but atleast I know it is all setup to be ballpark matched to it.
I think I have also found a replacement block oil restrictor pill - part RF01-10-305-A. There was one listed on ebay, for a Mazda 626, but on a bit more investigation looks like it is used across a load of Mazda models. We shall see when it arrives and I get a mic on it.
I'm going to remove the current restrictor from the block anyway. It's exactly the sort of thing that could hide a load of nastiness behind it. Worse case if the part above isn't correct I will have to reverse engineer it and get the parts machine shop to make me a new one. Will be a bit annoying but not insurmountable.
Also I have decided not to send the block into the machine shop for line honing. Instead what I have done is ordered a 500mm engineering straight edge, and will check for alignment using a 1 thou feeler gauge around the circumference of the mains.
I was worried the engine machine shop would just hone it anyway regardless and end up mucking up either clearances or bearing crush by removing too much material.
08-12-2021, 12:31 PM
2
) to clean components
)
' ohh man right in the feels 
get easily sidetracked and too many other projects / distractions / new ideas etc.
