Noisey Tappets

[1975ToyotaCrown]

I have a 4MU engine in our 1979 Toyota Crown that has noisy tappets under acceleration, is it possible to adjust tappets by oneself without any trouble.
I have a rebuilt 4MU engine thats close to replacing this engine but would like to have the noisy bits quietened.

[wilbo666]

The tappets can be adjusted with a set of feeler gauges, a 10mm? ring spanner and a flat blade screwdriver.

They should be adjusted hot.

I don't recall the clearances off the top of my head, but I think they have been listed before on the forums... (if the same as 5me), I'm sure someone will pipe up with them



Cheers
Wilbo

[allencr]

... has noisy tappets under acceleration, ...

I don't think it does! Any noise from excess valve lash is going to happen all the time, whether at idle, accelerating, WOT or backing down and it will happen under a full load, no load, no fuel or no spark. It will be 100% steady in time/sync with the engine RPM, and will not miss, skip or be random.

Like marbles rattling around in a tin can when accelerating from a low RPM in too high a gear?

[jeffro ra28]

what allencr is saying is spot on if its a NON hydraulic lifter.

[af300e]

Sure it's not pinging??

[driftedmz20]

I have a 4MU engine in our 1979 Toyota Crown that has noisy tappets under acceleration, is it possible to adjust tappets by oneself without a any trouble.
I have a rebuilt 4MU engine thats close to replacing this engine but would like to have the noisy bits quietened.

ever considered if its under load then it could be a bearing....namely a bigend that is on its way??

my 1G did that and gradually got worse until you could hear it all the time.
just something to look for coz if they let got it does some serious damage! kinda fun at the same time tho

maybe replace if you can

im not too sure on those types of engines if you can drop sump and replace from under. someone can confirm that tho

maybe time to put rebuilt one in??

[af300e]

If the noise is under load it is generally not bearings. They normally make noice when unloaded. (I have experienced this first hand).

If it is occuring when the motor is laboured, it really sounds like it might be pinging.
What mods are there?
Any mods that you think may have caused it?
Are you running it on 98?

I had an old merc, 500,000km and although it had little carbon in the cylinders, it would ping under load on 95 octane fuel. 98 fixed it.
The same motor spun a big end at around 480,000km. I thought it was tappets as it started as a very light noise (different to pinging though).
Turned out to be a big end bearing (I rebuilt it, ground up).
Big end noise only occurred when the motor was unloaded between gear changes, this is commonly the way it manifests.

[Darola]

hey there mate... if your replacing the motor anyway.. just use a thicker oil or add 1lt of gear oil mixed with normal engine oil and that will make it quiter

Ed

[1975ToyotaCrown]

Hi Guys, Thanks for the advise, its a standard 1979 4MU Toyota Crown engine and its differently the tappets just have to open the bonnet to hear. I've bought a 4M motor manual today and will give the tappets an adjustment soon then maybe give the thicker oil a go depends on how much quieter it is. I'm still waiting on the gasket kit for other engine now so hopefully I'll have it back together in a month. I'll also give the higher octane fuel a go, the only problem is I filled the tank 2 days ago and that normally lasts a month.

[allencr]

Hi Guys, Thanks for the advise, its a standard 1979 4MU Toyota Crown engine and its differently the tappets just have to open the bonnet to hear. I've bought a 4M motor manual today and will give the tappets an adjustment soon then maybe give the thicker oil a go depends on how much quieter it is. I'm still waiting on the gasket kit for other engine now so hopefully I'll have it back together in a month. I'll also give the higher octane fuel a go, the only problem is I filled the tank 2 days ago and that normally lasts a month. I live in a small country town in Qld Australia.

IMO, whether you live in a small town or not, try to get a knowledgeable and/or trustworthy opinion Before you start throwing solutions at symptoms of unknown origin.

[af300e]

IMO, whether you live in a small town or not, try to get a knowledgeable and/or trustworthy opinion Before you start throwing solutions at symptoms of unknown origin.

It's true, all our diagnoses are based on what you have said, rather than actually hearing/experiencing the prob.

Having said that, if you have mechanical knowledge and a manual, go for broke on the valve clearances.

[1975ToyotaCrown]

Trustworthy options thats what this forums all about, sourcing technical advise from other Toyota owners.

[af300e]

Maybe allencr has had dealings with sites such as DC where knobs argue measurements with you after you have just run a ruler over the item in question?

What I mean is, not all forums are as reliable in their tech content as this one.

In any case, I don't think he meant to seem abrupt.

[1975ToyotaCrown]

I spent most of today giving the 4MU engine a valve adjustment, I even took off the bonnet to make life easier.
I took the newer rocker arm adjusting screws out of another 80,000 klm 4M motor and fitted them to the older 4MU rocker arms then also gave the timing chain tensioner an adjustment as per the 4M Crown repair manual.
The engine now only has a very slight tick under load so tomorrow I'll change the oil and add a bottle of that Nulon engine quieter also I'll drain the fuel and replace with the higher octane stuff. Lets see I have 1 x 20lt and 3 x 10 litre jerry cans and a 55 litre plastic garbage bin I can put the fuel in then I'll see if that also makes an improvement.
Thanks for the advise to date, its greatly appreciated.
Owen.