Engine failure - swap compatibility?

[Skifey]

Long time no speak everyone!

A lot has happened in the last 3-4 months hence the thread going dead. I'm going to have to do a proper big write up and update but long story short; the whole head was rebuilt, got a new clutch and flywheel, new leads, new coils, new starter and more.

Engine was put back in the car and everything reattached. I went to go start it - eagerly anticipating that huge beaming moment of joy - and it cranked and cranked and cranked... but didn't start. I thought it might be the fuel since it had been sitting there for 5 months so I drained it using the fuel pump to push it out of the fuel feed line and replaced it with fresh 98. Cleaned the newly fouled plugs and went for gold again. Nothing.

I've since checked
- The CAS sensor, coils, leads, spark plugs and harness; I've definitely got spark
- The fuel lines, tank and pump; I've definitely got fuel happening because the cylinder tops were wet. I haven't checked for injector pulse though!
- I've done a compression test with the throttle closed, engine cold (obviously) and got 125/125/100/113 across cylinders 4/3/2/1 respectively.
- I've checked the timing hundreds of times; cylinder 1 at TDC. Photos below.

Could my low compression be causing this?

Has anyone got ANY idea at all as to why this thing isn't running? I'll be active here again on this thread so questions I'll be able to answer quickly.

[RS2000]

Are you sure the inlet is timed correctly? Looking at your bottom photo, which seems to be taken square on, it looks like the inlet sprocket has to be rotated 1 tooth clockwise? The 'E' at approx. 4 o'clock should line up with the raised portion of the tin plate rear cover. The 'I' on the exhaust sprocket looks good.

For future reference, another check is to count the belt pitches between the marks/slots at 12 o'clock on both sprocket teeth outer side faces, before removing the belt.

[Ross]

To my eye, RS2000 is right, I count 20 teeth across the top, should be 19.
But I would have thought it should still run, just poorly.
Mine ran when I was one tooth out on the exhaust.

[Skifey]

Are you sure the inlet is timed correctly? Looking at your bottom photo, which seems to be taken square on, it looks like the inlet sprocket has to be rotated 1 tooth clockwise? The 'E' at approx. 4 o'clock should line up with the raised portion of the tin plate rear cover. The 'I' on the exhaust sprocket looks good.

I thought I had it perfect but I lined the E on the sprocket up with the E on the plate, not the raised portion. Oops. Looks like I'll redo the timing and try that!

But I would have thought it should still run, just poorly.

I would've thought so too :/

I'll redo that and get back but in the meantime does anyone have an opinion on the compression? Would those numbers (granted that the engine was cold and throttle was closed) actually STOP the engine from igniting and thus running?

[Skifey]

Just went out and rotated the crank to check the timing. I tried to take the photo as square on as my camera would allow ... I think I'm good and I count 19 across the top unless I'm starting from the wrong tooth?

[ManiacLachy]

From the first pictures I thought you were mis-aligned too, but that latest photo looks good, and I count 19 teeth between the gears. Are the cams at TDC though? The locating pin should be in the vertical groove.

Sorry about the quality here, Autozone don't want to make it easy to user their photos, but you can see what I'm talking about.

Edit: actually, the quality is quite good on our forum background

You can just see the pin in the exhaust cam here.


And here's a naked VVT intake cam, clearly you can see the pin, it should be at the 12 o'clock position


Sorry, not sure about the compression affecting startup, but those numbers don't look great IMO.

[StanTheMan]

the other thing to remember is that when those marks are where they are . you need to be at TDC with No1 Cyl.

take a look at tour timing mark on the harmonic ballancer. it should be pointing at 0.

you can also make sure with a screw driver that the No 1 cylinder is right at the top of its stroke.

tthe cam lobes should be pointing towards the outside on No 1 cylider
specifically for
intake at about 180
Exit at 0

[RS2000]

I've no idea what cold compression figures should be, but I'd think it would start. The readings may be fine when the engine's hot.
BTW, the throttle should be open, not closed when testing compression.
Have you re-connected all electrical connections & earths? Checked fuses? Haven't disturbed crankshaft position sensor?

[RS2000]

Looking at the crank timing marks in the 2nd photo (first post), you are at TDC on no.1 cylinder, but easy to confirm with a screwdriver as Stan says.

[manga_blue]

Am I right in assuming this is a BP4W engine? If so then does it have a crank timing plate bolted in behind the harmonic balancer? The most common (and embarrassing) reason for BP4Ws to fail to start after a rebuild is that someone installed that timing plate back to front. It fits easily either way but the engine only works with it the right way.

[StanTheMan]

Are you talking about the trigger plate?


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[manga_blue]

Are you talking about the trigger plate?


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That's the one.

[manga_blue]

While I think about it, have you tried hooking up a timing light to see where it is actually firing?

[StanTheMan]

Mine started initially, then decided to be intermittent. I changed just about everything. CAS, installed COP's , installed 36-2 trigger wheel intsallaed Crank angle sensor, installed cam sensor, revmoved CAS....in the end I think I accidentally changed maps. couldn't be too sure....but she fired up. In my case it was definitely a lack of spark. but to this day I still don't really know what the problem was. but shes been fine since

[bruce]

I'm hoping to see the words 'It's alive!' soon.