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Alan L Alan L is offline
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Join Date: Apr 2006
Location: New Zealand
Posts: 3,261
Hmm, I appreciate your suggestion.
I ponder this problem constantly - and found the thread on the other Pelicanite having same problem. Turned out his rubber CIS test hoses were pulsating.
Altho I wonder if his problem has actually gone away. (think he changed fuel heads in the end). The hoses by pulsing would certainly exacerbate the issue once started. But unless you are watching the airplate (or an installed CP gauge) it is hard to detect. (And intermittent). My piston is good and performs at least as well as the stock, if not better - having no imperfections. I notice the other pelicanite also had a scored piston. What I could not fix was minor scoring in the piston metering chamber. It is visble, but not to the touch. What I think may be happening is intermittent leakage down one of these 1 thou (guesstimate) channels past the head of the piston into the metering chamber. This may affect the CP, and flow to injectors in a minor way, at same time, causing the engine to bounce as it tries to right itself. It does not seem a common problem - in that others have not struck it, and we must have had all the CIS problems on this board by now.
The fact the other pelicanite who had this problem also had a damaged fuel head suggests this may be the cause. He had also polished the scores out of his piston. This would reduce the diameter , increase the clearance, by whatever depth the scores. The tolerance is about 0.5 thou. So, any reduction in diameter will exacerbate leakage past the head - which I suspect is the issue.
I have been thru some threads and found sources of refurbished heads, and PMd Lite 75 who has a head and WUR F/S.
I think I am going to have to take Brians advice and start swapping some (more) parts out.
AAargh. My bank balance.
Old 11-02-2008, 10:16 AM
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