[Fot] Oil pressure and tolerance on valve clearance

[Marcel Van Mulders]

Someone told me, and it sounds logical, that the oil pressure relieve valve
is only there to  relieve the load on the oil pump etc. when the engine is
cold. And when the engine is at working temperature,the relieve valve is
always closed and no oil is bypassed. At the factory, this valve is adjusted
at about 70 lbs. If you see 80 lbs or more, either the valve is set too
high, or the gauge is reading false (this is not unusual).
A long time ago, I was working on a friends TR6 : I adjusted the valve when
the engine was hot, in an attempt to get "better" oil pressure. The day
after, he started the engine from cold : as a result his garage floor was
full of oil : the oil filter gasket was pushed out of place because of the
very high  pressure because the oil was cold now
Marcel
-----Oorspronkelijk bericht-----
Van: Fot [mailto:fot-bounces at autox.team.net] Namens Steve Yott
Verzonden: vrijdag 6 juni 2014 15:22
Aan: 'Greg And Alison Blake'; 'Tim Murphy'
CC: fot at autox.team.net
Onderwerp: Re: [Fot] Oil pressure and tolerance on valve clearance

Tim,
I would recommend 70 lbs. at 3000 rpm and at that point you don't want much
more as this would waste horse power.  As long as your main and rod bearings
are within bearing spec you should be able to achieve this by adjusting the
relief valve.  This is assuming you are running a 20-50 or equivalent weight
oil and it is up to temperature.

With the rocker clearance  this would be using a go/no-go at .001"... so if
you are adjusting for .014" then a .013" would go and a .015" would not go.
Many years back when I was working for Mercedes we actually had a three
finger tool for this purpose.

Are you running yet?????

Steve Yott

-----Original Message-----
From: Fot [mailto:fot-bounces at autox.team.net] On Behalf Of Greg And Alison
Blake
Sent: Tuesday, June 03, 2014 9:11 AM
To: Tim Murphy
Cc: fot at autox.team.net
Subject: Re: [Fot] Oil pressure and tolerance on valve clearance

I am at 80psi from 3000-6000.


> On Jun 2, 2014, at 9:54 PM, "Tim Murphy" <timmurph at fastbytes.com> wrote:
>
> What oil pressure is typical or desired for the TR4 engine?  When the
engine
> is up to temperature, at 3000 to 6000 RPM (typical racing revs) we are 
> running 50 PSI.
>
> I was just checking the valve clearance and again I've wondered why a 
> tolerance is never given for the clearance.  The only time I've ever 
> seen a tolerance given was for a 1975 Honda Civic 1200cc engine I 
> rebuilt and the clearance was +0.010 /- 0.001.  that made sense but 
> it's the only time I've seen it in a manual or any place else.  Does
> +0.001/-0.001 really make a difference or am I missing something here?
>
> The questions are mainly an engineering curiosity.
>
> Thanks,
>
> Tim Murphy
>
> 1961 TR4 #317
>
>
> [demime found a multipart/alternative section which it tried to parse 
> but could not find any section which it could render. Please send
plain text.]
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