ticking?
Drifting
Joined: Jul 2002
Posts: 1,944
Likes: 20
From: The only Corvettes in Highett Victoria
Oil change???
Have you changed your oil recently? I mean the brand and/or rating of your oil. If you are using an oil with an SG rating, it probably contains enough ZDDP to protect your cam/lifter interface from wear. If, however, you are using an SJ or SM oil, then they do not contain enough ZDDP to protect your cam and it has probably worn to the extent that the lifters have "dropped" and the tappet clearances have opened up. This is one cause of the ticking sound.
I hope this is a wrong diagnosis, but if it's correct, then your engine needs to be pulled apart and all of the bits of metal from the worn camshaft will have to be cleaned out. Then you will need to put in a new camshaft and lifters. If you ante up to put in a roller cam and lifter kit at this stage, then you can keep using an SM rated oil.
Regards from Down Under
aussiejohn
Thread Starter
Holley HP EFI w/TPI
Joined: May 2009
Posts: 553
Likes: 0
From: Kanata ON
Headers, no, I have the 69 style sidepipes.
Oil change, not recently, although I did notice the oil level was low and added some Mobil one synthetic (10w30) that I had in the garage.
How can I tell if it's a worn camshaft?
Oil change, not recently, although I did notice the oil level was low and added some Mobil one synthetic (10w30) that I had in the garage.
How can I tell if it's a worn camshaft?
Drifting
Joined: Jul 2002
Posts: 1,944
Likes: 20
From: The only Corvettes in Highett Victoria
You have answered your own question. Mobil One is not suited to engines with a flat tappet camshaft. It does not have the minimum required amount of ZDDP. Looks like a re-build and a new camshaft and lifters are coming up.. You MIGHT be lucky if you drain ALL of the oil out, including the filter, and fill up with an SG rated oil and a new filter. Good luck!
Regards from Down Under
aussiejohn
Thread Starter
Holley HP EFI w/TPI
Joined: May 2009
Posts: 553
Likes: 0
From: Kanata ON
Valve clearance, no, but I have noise from both heads, and it doesn't seem to be specific to one area.
I will check this weekend.
Hydraulic lifters, don't know, this is my first SBC powered car.
It's a 1970 Corvette engine AFAIK.
I will check this weekend.
Hydraulic lifters, don't know, this is my first SBC powered car.
It's a 1970 Corvette engine AFAIK.
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Thread Starter
Holley HP EFI w/TPI
Joined: May 2009
Posts: 553
Likes: 0
From: Kanata ON
Moon,
You have answered your own question. Mobil One is not suited to engines with a flat tappet camshaft. It does not have the minimum required amount of ZDDP. Looks like a re-build and a new camshaft and lifters are coming up.. You MIGHT be lucky if you drain ALL of the oil out, including the filter, and fill up with an SG rated oil and a new filter. Good luck!
Regards from Down Under
aussiejohn
You have answered your own question. Mobil One is not suited to engines with a flat tappet camshaft. It does not have the minimum required amount of ZDDP. Looks like a re-build and a new camshaft and lifters are coming up.. You MIGHT be lucky if you drain ALL of the oil out, including the filter, and fill up with an SG rated oil and a new filter. Good luck!
Regards from Down Under
aussiejohn
Ok, I've drained all the oil, new filter and put in Mobil 1 15w50 synthetic (from the flat tappet thread).
Jerome
Le Mans Master
Joined: Oct 2000
Posts: 6,362
Likes: 30
From: Oak Harbor WA
Remove the valve cover and have a look at the engine at idle. Are all the rockers moving the same distance up and down? You may need to do this a bit quick to keep the oil mess to a minimum.
If you carefully apply a little pressure to one does the noise go away?
A few things to look for: a broken valve spring, no oil coming out of the pushrod, a stud that is pulling out
If you carefully apply a little pressure to one does the noise go away?
A few things to look for: a broken valve spring, no oil coming out of the pushrod, a stud that is pulling out