Jim F Posted January 9, 2016 Report Share Posted January 9, 2016 Hi, I'd appreciate any advice I can get on this... I took the rocker cover off my 2.5 PI motor the other day to check tappet gaps and I was surprised to see deposits on my rocker arms, (see the attached images). These deposits are a dark brown (or dark red) and are fused to the rocker arms. Any clue what could be causing this? Could it be nitration? And what would be the cure? Thanks for the help. Jim Quote Link to post Share on other sites
peejay4A Posted January 9, 2016 Report Share Posted January 9, 2016 Looks nasty. If it's the oil reacting with combustion gases then I'd say a compression check is your first port of call. Quote Link to post Share on other sites
Jim F Posted January 9, 2016 Author Report Share Posted January 9, 2016 Yep - owned TRs for decades and I've never seen this before. Quote Link to post Share on other sites
barkerwilliams Posted January 9, 2016 Report Share Posted January 9, 2016 Jim, Is the crankcase breather coupled up and unblocked? If you have a catch tank fitted is it trapping the brown water from the crankcase? Alan Quote Link to post Share on other sites
Geko Posted January 10, 2016 Report Share Posted January 10, 2016 (edited) Head cracks or head gasket failure? Deposit on/color of the plugs could give a hint. Edited January 10, 2016 by Geko Quote Link to post Share on other sites
GT6M Posted January 10, 2016 Report Share Posted January 10, 2016 If no loosing water, then its not a HG problemo but if alot of short journeys, or oil no up to temp, then its condensation. coupled wid olde oil with water / contaminants init. generally see this on engines been stood for ages in cold conditions Scrap yard cars are a good source if ye ever look into rocker boxes. Even newer cars / engines get this if left a while M Quote Link to post Share on other sites
RogerH Posted January 10, 2016 Report Share Posted January 10, 2016 From the two little pics it appears to be only on the centre body part of the rocker. This is the coolest part of the head assembly so it could be a condensation affect. What sort of mileage, trip lengths do you do. What oil do you use. Is oil coming out of the rocker oil holes at the top Do you have an oil cooler Roger Quote Link to post Share on other sites
john.r.davies Posted January 10, 2016 Report Share Posted January 10, 2016 Looks to me like the first stages of Black Gunge.. That's down to a combination of neglect, no oil changes, consequent wear and excess blow-by. Condensation (as Roger says) > rust > deposit of carbon and wear particles and corrosion. But if you have had and used the car some time, and are the sort of owner who actually checks tappet gaps, I doubt if the proceeds of neglect can have started. Yes, compression test it. Blow-by may have carried lots of moisture into the engine. John Quote Link to post Share on other sites
Jim F Posted January 10, 2016 Author Report Share Posted January 10, 2016 Thanks for responses. Oil is valvoline VR1- still available with the right zinc levels. Trips tend to be 30+ minutes, but rarely more than an hour at higher speeds, (70+). Crankcase breather replaced about a year ago and working ok, and plugs look somewhere between ok and lean. I agree - the deposit pattern seems to indicate that the oil is coming through the rocker oil holes and them, as pressure is reduced and there's access to oxygen, the deposits form out of the oil. And the deposits are hard! No evidence of head gasket failure - I'll do another pressure test to see what i'm getting. Quote Link to post Share on other sites
LGFromage Posted January 10, 2016 Report Share Posted January 10, 2016 To me there is a lack of oil throughout and it appears that the rockers have been running dry. A check of wear in the rockers would be useful. Tim Quote Link to post Share on other sites
stillp Posted January 10, 2016 Report Share Posted January 10, 2016 Dried up gasket cement? Pete Quote Link to post Share on other sites
Peter Cobbold Posted January 10, 2016 Report Share Posted January 10, 2016 (edited) "....deposits are hard" - rust? Test by breaking a bit off and seeing if its magnetic Peter Edited January 10, 2016 by Peter Cobbold Quote Link to post Share on other sites
Jim F Posted January 25, 2016 Author Report Share Posted January 25, 2016 I thought I'd provide an update - I found combustion gases in the coolest so off came the head and I'm waiting to hear back from the machine shop. Maybe the deposits are in some way related to head gasket - one can only guess. Anyway rocker shaft being replaced and the rocker arms are being checked out for excess wear. Took the opportunity to check cam lift using dial gauge and no sign of weak after 11 years so that's reassuming, (though why I have a FR89 cam in a TR5 I'll never know...), double checked my pulley TDC marker against real TDC ... While I'm waiting for the head to return I'm wondering how I could check cam timing ... I could use the dial gauge to see the cam profile change as I rotate the crank, and I can see the piston position relative to the bore, so is there a way I could double-check cam timing. Any suggestions? Thanks Jim Quote Link to post Share on other sites
john.r.davies Posted January 26, 2016 Report Share Posted January 26, 2016 (edited) "Equal lift on Overlap" At the end of the four strokes of the cycle, tha exhaust valve is closing but still open, slightly, as the intake opens for the new cycle. This is the "overlap". Because Triumph used a "Symmetrical" camshaft, when No.1 is at TDC on the firing stroke, No.6 will be at the point described, and both the valves will be open equally. This test is best done with two dial gauges on the named valves. or rockers. Turn the crank until they are both open equally and check that No.1 is at TDC. Job done. JOhn Edited January 26, 2016 by john.r.davies Quote Link to post Share on other sites
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