Valve clearance gap?

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canada karl
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Joined: Tue Jan 06, 2009 3:50 pm

Valve clearance gap?

Post by canada karl »

Why do some say to set the valve clearance at .010 and others say it's better at .012 ???? Which is correct? :?
1976 530i. BMW 59 Triumph TR3A(rolling resto). 67 Triumph TR4A(salvageable). 86 900S Winter car
HB528i
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Re: Valve clearance gap?

Post by HB528i »

Intake .010 Exhaust .012 is what is used on b35 motors, not sure why
canada karl
Posts: 924
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Re: Valve clearance gap?

Post by canada karl »

I meant M30 motors.
1976 530i. BMW 59 Triumph TR3A(rolling resto). 67 Triumph TR4A(salvageable). 86 900S Winter car
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Mike W.
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Re: Valve clearance gap?

Post by Mike W. »

On early M30s, clearance was spec'd at .010-. 012. E28 era M30s were spec'd at .012- ,014. I'm not aware M30B35s had a different spec for intake and exhaust, I believe they're the same as E28 era engines, but it's possible.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter
HB528i
Posts: 74
Joined: Mon Dec 09, 2019 7:53 pm
Location: Huntington Beach

Re: Valve clearance gap?

Post by HB528i »

My b35 guru recommended it, 88 635CSi motor.
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keehn
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Re: Valve clearance gap?

Post by keehn »

If I can offer an additional suggestion:

Not aware if everyone here knows about ZDDP additives to motor oil. The elevator speech is that ZDDP additives assist flat tappets (our engines) by creating a thin anti-wear surface on metal parts that come in direct contact with one another. Essentially, the added heat caused by metal-metal friction causes ZDDP compounds to form an anti-wear coating at the site of the friction.

Here's an AMSOIL article discussing whether older engines need oil with ZDDP additives:

https://blog.amsoil.com/do-older-vehicl ... motor-oil/

I will most certainly be running ZDDP additives in Eleanor.

Mike
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528i-1981
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Re: Valve clearance gap?

Post by 528i-1981 »

I use a ZDDP additive and Valvoline VR1, which is high in zinc and phosphorous. The VR1 product sheet specifically says it's not for use in cars with catalytic converters. But the story is a little more complicated than that. Cats have been on US cars since 1975, and before the early 2000's, all oils had much higher zinc and phosphorus content. Oils were reformulated to lower zinc after cheaper catalysts were found in the early 2000's to replace noble metal catalysts, and zinc was found to foul these new catalysts. So if you have a 528i with an OEM-grade 3-stage catalytic converter, It doesn't seem that zinc will foul your catalyst.

I do think that lower zinc and phosphorus are not good for a flat tappet engine. But most of us change our oil frequently and put relatively few miles on our cars between changes.

I have found VR1 20W-50 to be quieter in the valvetrain than the conventional oil it replaced in my car, but to be fair I was running 10W-40 previously. For the record, my cat was deleted long ago.

-Eric
(oo=00=oo) Eric
1981 528i Manual
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Mike W.
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Re: Valve clearance gap?

Post by Mike W. »

More on issues with oil and cats. Sometime around 2000 manufacturers started using low tension piston rings in an attempt to get a tiny bit more MPG. In doing so oil consumption often went up, sometimes dramatically. A quart a thousand or more. At those levels cat damage can occur when using higher ZDDP oils, but if you're not burning oil, it's not a problem!
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter
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