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Urgent help,

I just swapped for a shaved head. Motor is a Mazda BP which was shaved 48thou. All gaskets were replaced with genuine Mazda, and new Durapro head bolts. Cams are stock, and bottom end was left stock. Cam timing was set.

After startup - had heaps of ticking noise - but just thought it was the lifters since they were (well some of them) were cleaned. I've dríven on it for maybe <50kms. On cold start the noise is LOUD and after driving the noise goes away, but under idle there's a silent (but audible) ticking noise.
Noise is still there as in the video. Just hoping that it is lifters, and not rod knock.



Edit: Checked the oil, no signs of coolant. Also, car wont start after trying to set ignition timing.

Ok, so now my car wont start.

I recently swapped a BP05 head into my NA8. I gave the head a port&polish, lapped valves, and it was shaved 48thou. Put in all new seals: valve stem seals, cams seals, Mazda head gasket, Durapro headbolts. BTW, the HLA's were soft/spongy, and i could not pull them apart to clean. Also did a coolant reroute with self made pipe and spacer.

Now, when I started it up, it gave a loud banging/ticking noise. I assumed it was the lifters, but it was loud and slow enough to possibly be rod knock? Listen to the video above. After taking it for a drive, the tapping quietened down significantly, but was still audible at idle. Also, the was a massive flat spot in power in lower RPM, and after around 4/5000RPM, there was a surge of power. I thought this was ignition timing.
On cold starts, it still gives said banging/ticking noise. I found injector #1 was leaking on the fuel rail side, so I replaced all 4 O-rings.

I took it for a drive to warm up to set ignition timing. After jumping the TEN and GND, idle dropped to ~200rpm, and somehow sustained itself. So I set to adjust the idle adjust screw, but idle did not change. So checking with timing light, it was much beyond 14* and even perhaps 18* (not 100% sure on value, but it was definitely quite a lot after 10*). So I moved the CAS, and the car stalled. I tried to start it, wouldnt start. Removed timing light, jumper between TEN&GND and still wouldn't start.

So I re-checked timing belt, spark, (tried to do injectors), tried multiple angles on CAS, compression was ~130 (most likely incorrect gauge) but nothing seems to be wrong. I'm at that stage where I'm so angry I tinkered with the car, and should have left it as is; I just want to get it running reliably.

Thanks,
Jordan

You have to go over everything.

One issue is that you dont have an accurate measure of compression or oil pressure, that would be the first step I would take.

Dann

You moved the CAS and the engine stalled and now won't start. Check the CAS and you may need to have one person start it (with a backup battery) and you slowly move the CAS until it starts. But check the wiring too.

G

What is your piston/valve clearance ?

NitroDann wrote:You have to go over everything.

x2

I don't think this is one you're going to solve over the internet. There are a few different possibilities, or combinations of possibilities. Whereabouts are you?

NitroDann wrote:You have to go over everything.
One issue is that you dont have an accurate measure of compression or oil pressure, that would be the first step I would take.
Dann

Dann, I checked timing and spark. It was giving spark on all 4 leads and iming was set according to miata.net, mx5 manual, and information on Cartalk. The tensioner had just enough left in it to tension the belt properly, and there are 19 teeth in between the two notches on the cam gears. I also confirmed it was at TDC with a screwdriver down the spark plug hole.
I cant really think of a way to test injectors; should I just get them cleaned?

manga_blue wrote:I don't think this is one you're going to solve over the internet. There are a few different possibilities, or combinations of possibilities. Whereabouts are you?

I'm in Ryde, Sydney.

Magpie wrote:What is your piston/valve clearance ?

I did measure valve clearance on the stock head using playdoh and verniers. I got 1.6mm of clearance - took off 48thou(1.2mm) so i thought I would be sweet with clearance.

gslender wrote:You moved the CAS and the engine stalled and now won't start. Check the CAS and you may need to have one person start it (with a backup battery) and you slowly move the CAS until it starts. But check the wiring too.
G

I did do this. I had dad crank the car over, while I moved the CAS, it wouldn't even begin to start.

You're too far away for me to help. I'll just talk about dealing with the knocking/ticking noises.

You need to do a full compression test. Firstly dry to get an initial figure then with some oil in the bores to see if any loss of compression is due to pistons or valves. If adding a little oil improves a low compression reading then usually you have a ring problem, otherwise you have a valve leak.

You probably need to take the cam cover off again and try to gauge how well each HLA is working. Turn the engine by hand and check that each HLA is firm against the cam when in the valve shut position. It's a PITA job because the HLAs all lose a little oil just sitting there and it gets really hard to work out if one is working or not. A couple of times I've had to repeatedly remove and refit the cam cover so I can spin the engine to run up fresh oil pressure. Don't spin it with the cover off unless you want to lubricate your garage - I know this.

The problem with cleaning HLAs is that there's usually a risk that some HLAs won't work at all after you've cleaned them. I've done lots, I'm very meticulous but I still find that 1 or 2% fail completely after the clean. Some simply do not like being dismantled. I've given up HLA cleaning because of this.

There's normally enough clearance between valves and pistons, even with 48 thou off, that they won't touch. The real issue is that it is possible for inlet and exhaust valves to foul each other during assembly. This is especially true if you put in HLAs that are full of oil. Normally I put in cams with all the cam and crank alignment marks in the correct position and do not turn them until the timing belt is on and they've had overnight to squeeze out any surplus oil from the HLAs. Is it possible that you've bent or chipped a valve by tightening down the cams while the HLAs are too fat with oil or else by turning the cams individually?

As a last check I'd try to get a look at each valve spring to make sure none are broken. Starting the car with overfull HLAs can damage them too.

For the sake of future searches this may be of some help..

I know there is a bleeding procedure but Ive always fitted HLA's empty and let them clack until they self fill.


Honestly a lot of the time the only answer to this stuff is to just test everything and then pull it all apart, less heartache pullin git apart, replacing the damaged part and moving on then there is doing a million stupid little things looking for a placebo (ie 100 different oils for HLAs F*** my life... omg.)

Dann

NitroDann wrote:I know there is a bleeding procedure but Ive always fitted HLA's empty and let them clack until they self fill.

I think if we combine the two then we get the right procedure. I reckon it should be:
1. Put the HLAs in empty but lightly oiled on the outside,
2. Set the crank at somewhere vaguely around BDC
3. Put the cams in as close as you can to the alignment mark and tighten them up. Don't turn them.
4. Leave the job for a few hours
5. Position the cams accurately but still without turning them other than small movements to get position right
6. Bring the crank up to TDC
7. Fit the timing belt
8. Hand turn the crank to see all works
9. Start it and listen to it clack for a minute or two

If you agree, Dann, then I'll post it in the tech guides.

That's how I do it, but without waiting because aint nobody got time for that.

Also not BDC, halfway between where all pistons are a few inches from the top. At BDC you have just moved 1 and 4 from the head and 2/3 are at it instead. It's almost totally inevitable that the cam will move as you fit it and push some valves open in a random spot. Even if this doesnt happen because you are experienced, halfway is just as safe

Dann

Yeah, you're right about BDC. Should be about half way.

So! The car runs. I had a mechanic mate come over and help, who found the problem straight after pulling the rocker cover off. I really did think I set timing properly - and I kinda did. However,

Intake Cam



Exhaust Cam



The reason for this happening is: when I first set timing, I put zipties over the belt and camgears so I didnt have to re-time the car. When I went to reinstall, I obviously didnt align the pins and gears properly. The car was trying to crank over with the intake cam 180* from where it should have been. The loud knocking noise has gone away, but still has quiet lifter tick (not that it matters).
Lesson learnt.

Cam gears and cams from the other engine head were installed. Any ideas of how to get the sheared pin out, or are they garbage?

Thanks for your help guys.

just go get a second hand head from a 90-96 1.8 323/laser. same gears, cams and lifters.

Glad that's fixed then. I gave up on the zip ties and not loosening the tensioner = creates more trouble than it's worth. The belt often skips at the crank end anyway while you're trying to get the cam pulleys back on. Basically it's safer to fit the cam pulleys properly without the belt on, then line it all up properly to slip the belt on.