[TR] [EXTERNAL] Re: Ideas, anyone?

[Reihing, Randall S.]

Don't know for sure on TR4's but some engines source their oil pressure from the rear cam bearing, not the oil pump, mains or rod bearings. Where does the TR4 source it's oil pressure? If it comes from the rear cam bearing and if that clearance is excessive it could result in a very low pressure at idle with hot oil. Oil pumps are volumetric flow pumps not necessarily pressure pumps, so you might be fine if the oil pressure gauge senses it's pressure indication from the rear cam bearing. Just a thought.

Randall Reihing
1959 TR3A
________________________________
From: Triumphs <triumphs-bounces at autox.team.net> on behalf of andrew uprichard <auprichard at uprichard.net>
Sent: Wednesday, May 13, 2020 7:34 AM
To: 'Alex & Janet Thomson' <aljlthomson at charter.net>; triumphs at autox.team.net <triumphs at autox.team.net>
Subject: [EXTERNAL] Re: [TR] Ideas, anyone?


Thanks for al the suggestions.  Gauge is good, have tried a new oil pump.   I think the next step is to plastigauge the bearings and check the rocker shaft, as suggested.  Then I guess the engine will have to come out. Sigh…..



From: Alex & Janet Thomson <aljlthomson at charter.net>
Sent: Wednesday, May 13, 2020 5:58 AM
To: 'andrew uprichard' <auprichard at uprichard.net>; triumphs at autox.team.net
Subject: RE: [TR] Ideas, anyone?



Was the crankshaft cut down by a previous owner for use with undersize bearing shells? I saw this happen in a Nuffield tractor once. Great oil pressure at startup but diminishing quickly as the oil thinned out.



Alex Thomson



From: Triumphs [mailto:triumphs-bounces at autox.team.net] On Behalf Of andrew uprichard
Sent: Tuesday, May 12, 2020 5:54 PM
To: triumphs at autox.team.net<mailto:triumphs at autox.team.net>
Subject: [TR] Ideas, anyone?



Having (I think) sorted out the problem with the TR4, I took a recently-finished TR3B out for its second inaugural drive.



The first inaugural drive went pretty well, but once the engine temp came up, the oil pressure fell like a stone – and here we are talking around 40psi at 3000rpm and almost nothing at (what was hot) idle. Adjusting the pressure with the screw on the oil filter head did nothing.



I checked everything over, even pulled the oil pan and checked all the bearings (one main and 4 rods) – all perfect.  I really didn’t find anything, and the specs on the oil pump looked good, but I ordered a new pump as well as a new spring for the Purolator oil filter head (the valve itself is no longer obtainable).



So today when I first took it out, the pressure was almost too high – around 90 at 3000 rpm.  But as soon as the engine warmed up, it again dropped to scary levels. No leaks, no oil in water or vice versa.



I am running out of ideas here.  Could it be a bad oil filter head?  Anything else?



Andrew Uprichard

Jackson, Michigan
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