Tapping noise??? - Toyota Nation Forum : Toyota Car and Truck Forums

***MR2Jedi*** · 09-27-2008, 03:24 PM

Awhile back, I blew my head gasket on my '91 MR2 Turbo USDM 3sgte.
I replaced the headgasket, installed 1 new piston (#3) that was pitted , all new rings and rod bearings. The #3 con rod bearing showed some wear, so I changed them all.I cleaned up the head, and did a visual inspection. Turned both cams, everything seemed fine.I put it back together and there was this tapping noise coming from the front of the engine.Kinda sounded like it coming from #1 cylinder.

So I pulled the head AGAIN and I had the machine shop check it out. All the valve guides and seals needed to be replaced. And I had the valve seats ground.A slight warpage but restraightenable-which they did with some resurfacing. I put it back together-AGAIN and
I still have this tapping noise that seems to be coming from the front of the engine. It sounded like it might be the oil pump, so I replaced it with a new one. Cranked it back up and the noise is still there. Though it seems to be lesser.
I'm at a loss as to what this may be.
Any ideas ? It's driving me crazy!!!

MR2 Turbo77 · 09-27-2008, 09:46 PM

yeah i would have said the oil pump. try to see if its a knocking sound or a clinging sound like somthings jumping around in there.....cause somthing could be loose with in like somthin simple. or it may b the crank/shaft.....but somthing mayhave fallen in orhad been misplaced when doing the gaskets n heads. it happens once n a while. hope i helped on got the brain fluids moving

MR2 Guru · 09-29-2008, 03:56 PM

Are we sure its not a leak of some sort? Exhaust Manifold, Turbo-to-manifold, failed seal on gutted TVIS plates?
The turbo-to-manifold gasket makes a horrific tapping-type noise when blown, and often sounds internal.
Its always good to try the simplest explanations first if possible.

tHa kNiGHt FaLL · 09-29-2008, 07:42 PM

start w/ frequency... does it follow RPM or CAM speed...?

***MR2Jedi*** · 09-29-2008, 07:50 PM

Hhhm? Good question. I would say RPM speed..

MR2 Guru · 09-30-2008, 02:39 PM

A leak will also change with RPMs, so do try to eliminate those as a possibility.

***MR2Jedi*** · 09-30-2008, 03:16 PM

Quote:

Originally Posted by MR2 Guru

A leak will also change with RPMs, so do try to eliminate those as a possibility.

I've got a full schedule at work this week, but I will pull the exhaust mainifold sometime later in the week, check the ex. manifold for warpage and at the very least, replace the gasket.(turbo one too) Thanks Harry and Drew.

tHa kNiGHt FaLL · 09-30-2008, 08:43 PM

Quote:

Originally Posted by MR2BAD

I've got a full schedule at work this week, but I will pull the exhaust mainifold sometime later in the week, check the ex. manifold for warpage and at the very least, replace the gasket.(turbo one too) Thanks Harry and Drew.

did you replace the cam followers when you had the cams re-ground...?

***MR2Jedi*** · 09-30-2008, 10:26 PM

I didn't have the cams reground. And what are Cam followers?

***ModifierMR*** · 10-01-2008, 07:27 AM

Ok here is a stupid question, You seem like you know what you are doing, but I have to ask cause sometimes we all forget: Did you remove the shims/buckets from the valves, if so did you label them and put them back in the right order

what am I saying, of course you did. lol

***MR2Jedi*** · 10-01-2008, 12:09 PM

I labled each shim with a permanent marker. But it was the machine shop that rebuilt the head with new valve guides, seals, resurface and set valve clearance.
I've listened to the engine again and I think the noise IS coming from the exhaust side. I'm going to remove the Exhaust manifold and check it for warpage. If it's warped. I'm either gonna resuface to straighten or replace it. And of course, a new gasket.

tHa kNiGHt FaLL · 10-02-2008, 06:46 PM

cam followers are the "buckets" that sit on top on the valves... lol

i guess when i read that you "turned" both cams i somehow thought you meant you had them machined.

***MR2Jedi*** · 10-02-2008, 11:27 PM

Oh, OK. I haven't heard them called that before. No, I meant I just turned them on the head to make sure all the valves opened , closed and sealed completely. But I can see how that could be thought of that way.

Kuma85 · 10-13-2008, 06:06 PM

if its a clicking sound and it gets faster if you rev the rpms, you should check out the lifters. probably worn.

***MR2Jedi*** · 10-13-2008, 07:18 PM

Problem has already been identified and fixed. Part of it was a bad oil pump and also some warpage in the exhaust manifold.(as per MR2 Guru)
Head and components were thoroughly checked out and rebuilt by the machine shop.