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Spin on oil filter adaptor


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Hi

I’ve managed to turn a minor oil leak from my spin on oil filter adaptor into a major one. As I await delivery of (yet another) seal kit, can I ask:

when replacing the copper crush washer under the head of the central bolt, one has to unscrew the floating centre piece. When it goes back on, how much should it be screwed back on? I can see that the central bolt has thread at bottom, then a gap and then a thread again. Does the floating piece need to be screwed on all the way to the gap between the threads as shown?

 

all advice much appreciated  I’ve already dumped two gallons of oil on the garage floor as I attempt to get it to seal. I thought I’d cracked it when I realised I had two of the large seals in the block but if anything with one seal it was worse  

 

thanks 

 

mark

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Hi Mark,

As I understand it the  “propeller “ nut should be floating in the gap in the bolt thread. The central boss of the adaptor needs to slide into the central recess against the spring and you must make sure it does as you assemble to the engine otherwise it will hold the outer rim away from the block and prevent a good seal. 
Dependant on whether you have an original Mocal adaptor or a copy there is a different clearance hole around the fixing bolt allowing the adaptor to tip as you do up the fixing bolt. 
Hope this is helpful,

Ian
 

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Hi Mark,

I was surprised how much torque the central bolt required before being completely dry. I was concerned to damage the soft copper ring initially but had to re-tighten quite a bit before dripping stopped.

Waldi

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I'm yet to fit mine but with the issues I've read about is it really worth all the effort over the original filter housing?

Plus mine was bought from Rimmers (before I knew better) which given the quality of their offerings so far doesn't fill me with confidence!

Andy

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The original filter housing is just a tin can that fits where it touches and therefore the oil seal groove may vary in depth and it will still seal. The adapter is machined to a certain size so on some engines it works fine, on others it leaks as the groove may be slightly deeper.

If you have a leaking one, get yourself a new rubber seal and some RTV. Clean out the groove removing all seals. Squeeze in RTV all the way round, put the new seal in on top and then install the adaptor just over finger tight. The aim is to squeeze the RTV evenly into the deeper recess. Leave overnight for the RTV to cure. Tighten the bolt just enough to form a seal. Test and if it still leaks, give it another tweek.

I have seen it reported that some adaptors have a sprung centre to alleviate this issue but I have not seen one.

Jerry

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When you seal the new holder against the block, you need to  ensure  that you get good filter thread engagement with the centre nipple. My Mocal adapter had less than 2 threads engaged and blew a filter off on a cold start. I was fortunate in that I watch the oil gauge closely after starting.

I had to machine up a new centre nipple with far more thread engagement.

 

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On 2/11/2022 at 11:23 AM, mark_smugglers said:

Thanks both. 
Mike that’s exactly what I found. Except after I’d hooked the extra one out it leaked more if anything!

And Ian that’s really useful. Thanks. 

Hi Mark,

I had a problem with the early Mocal spin on filter years ago with oil pissing out from the outer O ring seal. Mocal admitted to me that there was a problem with the early versions where they did not compress the O ring enough. I assume that this is where your oil leak is??? I cured it by turning back the center boss by .030" and recutting the center seal grove. Never had a problem since! Also I did away with the copper washer and used a Dow seal washer. That sorted out the dribble leak!

Bruce.

 

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You think you have problems.  Many years ago, I was waiting in the pitlane at Brands to go out and practice, and suddenly, the oil pressure disappeared.   I was wondering  WTF, when a marshal shouted into my window to turn off.     There was a LARGE oil puddle under the car,  which marshals HATE, 'cos it's a big clean up!

The centre boss that holds the adaptor to the block had fallen off, taking the adaptor with it, and of course all the oil from the sump!     Later examination showed a casting defect, that had survived many years of road use before I had it but then, probably as I had tweaked it tighter after my rebuild, had given way.     Never heard of anyone else suffering this!

But much later, I had to retire early from a hill climb, because of an oil leak in the same way as above, around the seal.    Simply replacing the rubber seal cured the leak.    I fear that many rubber products are inferior these days, harden and crack with use and heat, and cease to seal.  Nowadays I put a new one in every year.

John

Edited by john.r.davies
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The early adaptors were not spring loaded.

Some blocks had a deeper groove for the outer seal.  If, even with a thin o ring for the inners seal some of the adaptors did not compress the outer seal.  The solutions were to split an outer seal and fit it behind the seal or machine the adaptor.

The current adaptors have the centre section able to slide relative to the outer so that the outer seal can be properly squeezed to make the seal.

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15 hours ago, Red6 said:

Original set up on mine, 47 years and still working. Reading this thread I am thinking that some people have wasted their money just to get a worse set up.

I only changed after reading the original side mounted filter allowed old dirty oil to flow back into the engine! My spin on filter is soooooo much easier than all that mucky messing about cleaning out that Bowl and digging around in the groove with a spike trying to get the old sealing ring out! 

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6 hours ago, CP26309 said:

I only changed after reading the original side mounted filter allowed old dirty oil to flow back into the engine! My spin on filter is soooooo much easier than all that mucky messing about cleaning out that Bowl and digging around in the groove with a spike trying to get the old sealing ring out! 

I change the oil and filter myself every 1,000 miles or so and tend not to worry about spending 15 seconds getting the sealing ring out. The oil is never that dirty and is only really changed because it is hygroscopic and absorbs moisture over time. At least I am not pouring gallons of oil on my garage floor like some, but each to their own :lol:

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All sorted.

I spun the floating centre piece on until the propellor nut was floating between the two threads. Double checked I had just the one seal properly located and also made sure the adaptor was properly located in the groove. All in all, I’d say the product is fine but I’d put my experience down to user error!

Thanks for all input. 
 

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Had a similar problem on a TR6 purchased last year when I took off the oil cooler and put on a new filter conversion, oil pressure shot up to max on the gauge oil poured out. Turned out to be caused by an uprated pressure spring plus a washer underneath it. Fitted standard spring and all was well.

 

Rob

Edited by Robert Price
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