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TR6 Oil usage - TR6

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Mike_Roe

Mike_Roe

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Hello all, newly rebuilt TR6 engine is using a quart every 300 miles. Smokes on startup, especially after sitting a bit. No valve seals, but shop said guides were in spec. Original pistons, new rings, cylinders just honed, but ring gap was greater than spec at install. Here's what I'm thinking: guides are leaking, so install seals, one or more oil rings might be upside down, ring gap is allowing blow-by. Thoughts? Suggestions? What brand rings should I get? Any advice would be appreciated, thanks in advance! Mike
 
Sure sounds like valve guides. As far as the rings, 300 miles isn't really enough, IMO, to judge.
Was it an economic decision to go ahead with those pistons and rings despite the gap ?
 
Sounds like an awful lot of oil for just going past the guides. Does it by any chance have an auxiliary oil feed to the rockers?

How big was the gap?
 
How many miles on the cylinder head?
I think for sure the real problem is in the rings or ring gap.
Have you done a dry/wet compression test yet? that's the best way to seperate rings from guides.
 
Hi all. Good discussion and very helpful. I have about 2500 miles on the engine since rebuid. I can confirm the oil is not leaking out and the oil pan is tight. I had an auxiliary oil feed and separator, but took them off as a first step in diagnosis. Engine had about 250,000 miles before rebuild, didn't really want to take apart but oil pressure got quite low.

I pulled the plugs and did a compression test last night. Got 160 psi on the first cylinders(1-4), 175 on the rears (5&6). Plugs had oil on the threads, rearmost ones had the most. Did not appear to leakdown very quickly, but I don't have much experience with that.

I'm thinking guides still, but oil control rings might in upside down (or faulty), especially on rear cylinders. My logic is the rear cylinders showed slightly higher compression and more oil on threads, therefore more oil is in these cylinders causing them to seal slightly better. Thoughts?

It's got Deves rings now, might go with Grant on rebuild. Head is coming off, just a matter of time. Thanks for the discussion and let's keep it going! I will post findings and root cause when I get it. Mike Roe
 
well if there is no evidance of oil driping then its got to be buring it, good luck on pulling the head and keep us posted

Hondo
 
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