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Maximum clearance between camshaft housing and journal.

Posted: August 20th, 2016, 10:36 pm
by Piotrek125p

I am looking for info about maximum clearance between Fiat TC camshaft journal and camshaft housing and maximum ovalness of camshaft housing that we can use without oil pressure losses in service.

I have a set of an OE camboxes.
My camboxes.
20160820_131835.jpg (141.54 KiB) Viewed 2228 times
My intake cambox is in excellent condition, housing hasn't any damages, scratches etc. and it's diameter are all in OE spec.

My exhaust cambox from Argenta with distributor mounting hole is in worst shape than intake cambox.
My exhaust cambox
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It has a minor housing damages, typical for Fiat TC camboxes. A overhauling method for it is clearly explained in a New GC workshop book and I will do it according to GC advices but I am not sure what is the maximum clearance for cam housing and journal. My exhaust cambox housing are out of OE spec for 0.03-0.04mm spec. (housing from photo has 46,250-46,265mm diameter) that give me a clearance about 0,065 - 0,085mm according to OE data.

I want to avoid an oil pressure losses in service and any annoying sound (knocking etc.) from cambox in service, so GC please give a detailed advice about a clearance for this important thing.

With best regards.

Re: Maximum clearance between camshaft housing and journal.

Posted: August 21st, 2016, 3:03 pm
by Guy Croft
I've gauged loads of cams, they wear faster than the housing, esp on nose and center journal - that's how it works, the harder part wears quicker..

I've never gauged a housing in my life though by feel I can tell when there is a problem..

I've never had an oil-pressure problem either!

If the housing is outside design limits what you going to do? Buy a new one?

if you're worried about oil pressure put a hardened 2mm washer under the oil pressure relief valve spring, stop measuring and get the engine built is my advice. It's old, we all know that...


Re: Maximum clearance between camshaft housing and journal.

Posted: August 22nd, 2016, 7:40 pm
by Piotrek125p
I have a supplier who has a many of this type of camboxes and I think I could choose a better part that mine. I thought that this is a really important part of Fiat TC, but I am fully trusted to your words GC and I will make a overhaulings ops according to your book and build my engine with it.