360R / 420R Expansion Tank leak

[ChrisC]

My 360R suffered a minor persistent  leak from the expansion tank connection to the T piece hose.   It was only a few drips but was very annoying.    The problem was the difference is size between the T piece, which was 19mm and the expansion tank at 15mm, the 19mm silicon hose just would not seal on the expansion tank.    I solved that it a straight silicon reducer 13mm to 19mm, so the hose was snug on the expansion tank, almost didn't need a hose clamp.    

Recently I had my 360R upgraded to a 420R, which relocates the expansion tank, and guess what, the leak returned, problem is there is no space for a straight reducer this time.  So after a lot of searching I have found a solution.   A 13mm to 19mm 135 degree reducer from do88 

https://www.do88.co.uk/product_info.php?cPath=1272_1285_1287_1366&products_id=9987&osCsid=34e994116b6c21d0edfe42238b5dc6f2

So if you have this annoying problem, try one of these.   I hope it helps

Chris.

[Jim 123]

Great solution and detective work Chris. On my Sigma the issue is totally seasonal. I get maybe 1 drip that sits on the LH horn upper casing when the car is parked up for a few days and the air temp goes down below about 8 degrees. I'd bet that most cars with this configuration have the issue but the coolant weep is so minimal that it goes unnoticed.

[ChrisC]

Yep should about what mine does.  So looks like Sigmas should also be including as well.   I will add mine only does it when parked up for a couple of days.  

[Jim 123]

Sigma ditto

[sjl1]

Hi Chris

from your recent threads it looks like you have had both the dry sump and cam upgrades to bring your 360 to 420 spec? Would be interested to read your thoughts on the outcomes, is the power increase very noticeable etc

thanks

simon

[ChrisC]

Hi Simon 

At the moment that’s a bit of a loaded question.   My car has a persistent oil leak, which has rather spoiled the last few driving days before the salt came, and the SORN was applied.  My comments are based on the assumption that this will be fixed and I have no reason to assume otherwise.

Caterham sell two kits which officially turn a 360R into a 420R and they change their records, the badges and stamp the service records, however there are a couple of additional items  you might like to consider if your doing the upgrade.   First is sump protection, the plastic wedge is the correct spec for a 420, but a cheaper R500 version is also available.    Next is the oil filter housing, replacing the oil water unit cooler, it seems to me the 420R oil is over cooled, and having two oil coolers has to be over kill.  Finally the crank case breather is blanked on the 420, but they just cap the original plastic breather during the upgrade, this was one of the areas my car leaked from.   If you do all that the only difference will be a digit in the VIN code.

So the burning question, is it worth it.  For me I knew I had made the correct decision as soon as the engine started.  It’s difficult to explain unless you have had old school cars which have had cams changed.  There is a urgency/aggression even at idle that just isn't there with normal product car engines.   Don’t get me wrong I would not want it in my tin top, but in the Caterham it just feels right.  The power is definitely a step up,   I found myself thinking that’s fast, then realising I wasn’t flat.   Using it to the fullest is not going to happen that often, and I am looking forward to a set of ZZRs on my next track days.   Don’t get me wrong the 360R is great, but the engine does last a little character.

hope this helps

Chris

[sjl1]

Thanks Chris, interesting to hear your experiences of the upgrade. Whilst the cam upgrade sounds very successful, the dry sump sounds less so.

i have had two precious caterhams, a k series and a sigma and have done a Caterham cam upgrade on both very successfully. I completely agree with you point about standard Duratec lacking something. Definitely lacks urgency at top end. Not saying the car is slow, it isnt, engine just lacks a bit of character

I think the mocal water/oil cooler on the 360 is a recent addition but was surprised they didnt remove it when adding new oil cooler? Actually think the mocal unit works well, oil never goes over 85 unless on track when i have seen 90’s but never over 100 and this is when absolutely caning it. Also surprised you didnt get the nylon wedge as part of upgrade given that the 420 has it.

Am now thinking of having the cam upgrade done first and see how i get on, hmmm

[ChrisC]

At the moment the dry sump upgrade is proving to be problematic, but I have not doubt it will be resolved.    Its not as if the parts begin used are unproven.    I actual think the dry sump is an essential part of the upgrade, given how low the wet sump (see the Monkey video).   I have also had the flat floor adjusted for this and the stance is so much better.   As for the additional parts, well, the picture of the kits on the parts website didn't show them, so I had assumed they wouldn't be fitted, but the information was a bit difficult to extract from them at the time.     It seems there aren't a lot of cars upgraded from 360R to 420R spec (at the moment), given it cost £2000 more than doing the same at purchase time.   However I think upgrading my car was cheaper than selling and trying to buy an equivalent spec car. 

I actually like the water/oil cooler idea, apparently they also have the benefit of warming the oil faster, so it's loss is not without sadness, however I might be able to see/fill the screen wash bottle now ;-) 

Obviously the cams are then thing that's adding the character that was missing from my 360R, but I actually wanted the dry sump upgrade first, because I want to use ZZRs during track days, and started to get worried about oil supply.   I figured, and this is how it was sold to SWMBO, adding a dry sump to a 360R would not add value to the car, where as converting it to a official 420R will add value, offsetting the cost should I sell it.   As you can tell I am glad I did, because its added an X factor. 

 

[ChrisC]

Oh and just to say I have a wet sump, used but no damage or scratches for sale, which will offset the costs a little.