I finally got my car IVA'd and registered! Drove it home for the first time on Friday, was absolutely awesome to finally drive it on the roads!! Everything was running well with no problems, on Saturday after about 8 easy mile it's started developing this knocking sound, gutting! Can anyone point me in the right direction as to what's causing this?

After this started , it's been hard to start, and I had to get towed off the road...

Engine is a:
1.6 16v 4age
Race/rally cams
Jenvey throttle bodies
Omex 600.
All this was running well when it was set up on the rolling road and for 80 or so miles on Friday.

Video....



Thanks

Sounds like the top end to me. Hard to tell on a video though.

Got an oil pressure gauge? Low oil to the top end?

Always hard to tell from a vid... but could be dry cams/tappets/followers.

I think you need to take the cam cover off and see whether there's oil supply (and I wouldn't keep running too much).

The oil pressure had been fine, about 10 psi at idle and around 40psi when driving....

I took the cam covers off this evening just before I recorded the video, everything in there looks ok, there's definatly oil getting to the cams and it's still clean...

I'm trying not to run it, I only did for the video... I realise it's hard to diagnose from a video or even without taking it apart...

I'm starting to think of getting it recovered to a localish mr2 specialist, just as I'm pretty busy the next few weeks and I just want to drive it...

[Edited on 17/8/14 by stripe]

10 psi at idle and 40 psi running is very low, mine runs 30 psi at idle when hot and 60 to 70 psi when running above 3000rpm when hot and is higher when cold , so I'm guessing low oil pressure is the issue engine will need inspecting and possible rebuild I'm afraid..

I does sound like your oil pressure is low - 30psi and 70 are more the norm.

16 valves have the shim on top of the cam bucket - I wonder whether you may have "spat" one out causing the clattering sound.

I'd be checking that first [and just checking the valve clearances anyway]. Then, I'd get a known gauge to confirm the oil pressure after checking the oil level and viscosity [I run 10/50 synthetic]. I'd also change the oil filter in case it's causing a restriction.

There may even just be some gunk holding the bypass valve in the oil pump open, but that's pretty unlikely. Oil pumps can be changed with the engine in place, but it's a prick of a job separating the silicon seal on the sump and windage tray. If you do that, it's simple to drop out a big end and main bearing cap to check the bearings while you're there.

How many miles does it have on it - they're normally very robust, and street driven ones over here regularly get 300,000k's on them.

I've just re-read your original post. If the cams have been changed to something more serious, I'd be putting money on it spitting a shim unless the head was re-shimmed by someone who knew what they were doing.

at the moment I cant remember what oil is in there, I would have to go and look what it says on the tin...
would it make any difference to the oil pressure running an oil cooler as well?

I've spoken with a guy from Rogue Motorsport who are nearish Birmingham who specialise in MR2's and he wasn't overly concerned about the oil pressure, he was saying that if your down at 2.5/3 psi at idle then your low, but it does sound that I'm lower than a lot of you guys so its something to check out.
oil pump was changed when the cams were, so about 100 miles now...


shims looked ok and in place when I took the rocker covers off last night, I haven't measured the shim gaps, but it sounds like the knocking is coming from lower down the head...

Checked your cambelt not slipped also all cam timing alignments - also ignition timing ?

Not easy on video.. good luck

[Edited on 18/8/14 by johnemms]

sounds like a big end bearing gone to me.

Didn't play vid but 10 psi and 30 psi is very low for 4age engine so I agree with last person poss big ends or main bearings is likely ..

Sounds the same as my 4age when it spun a big end

The more people I talk to about this the more people seem to think it's the bottom end. When you take the spark plugs out and try and turn the engine by hand it doesn't turn as easily as it should....

As I'm short on time, it's looking like im taking the expensive route and taking it to someone who knows these engines... I don't want to have it in bits for weeks/months...