Lotus Elan

Engine oil: My leak solutions

PostPost by: Hawksfield » Sat Jun 18, 2022 3:36 pm

Hi all

I recently removed the engine from my S130 to cure oil leaks that had been evident for a long time, most importantly the rear crank lipseal. This had been fitted in 2000 when I had the crank reground. I always had a slight drip from the front pully even after fitting a new pully. Sump weeps over the years had also being cured from underneath just removing the sump, never really a long term success.
I decided that it was time to sort all these leaks and do a proper job with good sealants and gaskets.
I decided to look at alternate sump gaskets and seals with the engine on the bench which would give the best chances of long term seal. I looked at the fit of the Ford xflow gasket with black plastic half moon seal with spats at the ends that covers the cork gasket, I liked this idea as it was a ford upgrade but the seal has to be trimmed to fit in the alloy carriers. did a test fit and compared it to the original cork half moons. The compression by the sump pan is much less on the xflow black half moon seals than the cork, I thought this would be a possible future leak point. I ended up with the gasket kit "from Gaskets for Classics on ebay" that uses a plastic half moon that fits the carrier with the required height to give good compression from the sump and does not need trimming.
The timing chain case can leak around the back plate although mine in this case was not showing any signs of this However it did show signs at the joint of the two parts at the base adjacent to the sump gasket. The pully seal had a leak and I think in the past the timing case had not been centralised correctly, I decided I needed to find a way of doing this whilst fitting the front cover, I made up a centraliser from a new pulley seal filled with araldite and when hard made the lipseal rigid. This was fitted to the pully shaft with an old seal as a spacer whilst setting the backplate with sealant
and tightening the back plate holding bolt.

20211211_122459.jpg and
centraliser

20211211_122434.jpg and
front pully seal filled with Araldite


The rear seal of the crank looked ok as regarding scoring but to give it a new seal area I made up a new gasket using good quality gasket paper 0.30mm as apposed to 0.50mm moving the lip point 0.20mm closer to the block. it may not be significant but every little helps.

Timing cover procedure: was to use sealant "Permatex 80019" to both sides of the backplate gasket. fit back plate with bolt finger tight then fit front cover without chain and jackshaft sprocket. using all bolts finger tight, fit homemade centraliser and pully to centralise covers. the back plate cover then can be tightened fully through the gap in the timing case with a ring spanner, front cover can then be removed after allowing sealant to set so that sprockets and chain can be fitted and torque up back bolt.
Fitting the front cover using Permatex anaerobic 518 gasket maker and again use the centraliser to ensure that all is central, the centraliser only needs to entered into the access lightly not fully inserted as the final lipseal.

20211211_122254~2.jpg and
Centraliser in use


Sump rail gaskets: Permatex 8001 aviation No3 form a gasket maker
Sump half moon ends: Permatex 8115 black sealant
I left the above overnight before putting a light coat of Permatex 8006 high tack gasket sealant on the sump pan faces after checking straightness and correction, bolted down to manual specs. Engine has been in use since dec2021 no leaks as yet
20211214_101228.jpg and
left overnight before fitting sump


This is my effort to give long term absence of leaks from the sump area the remaining gaskets were installed with the same gasket sealants used above as required for each area.

I am pleased with the result and was worth the effort of removing the engine to the bench.

:D :idea:
John

+2s130 1971
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PostPost by: h20hamelan » Sat Jun 18, 2022 10:28 pm

hope not to impose, I was just reading this and though it pertinent

viewtopic.php?f=39&t=41344

for sure not all sealants are available in N America, or Canada!

Nice qualifying in F1 today, speaking of Canada.
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PostPost by: rgh0 » Sat Jun 18, 2022 11:50 pm

Its the attention to the detail of the fit and finish like your doing that stops the leaks. I am sure it will be "close" to oil tight :).

The front cover tends to move overtime due to thermal growth and pulley loads so its hard to get it to stay centred long term

cheers
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PostPost by: 2cams70 » Wed Jun 22, 2022 2:14 pm

Everyone has their own opinions on sealing a Twin Cam but just a couple of pointers from my experience:

rgh0 wrote:The front cover tends to move overtime due to thermal growth and pulley loads so its hard to get it to stay centred long term


Yes the design isn't good. You've got belt loads trying to pull the cover inward, you've got the lower sump bolts trying to pull the cover downward and you've got the three head to timing cover bolts trying to pull the cover upwards. Really the whole shemozzle should have incorporated a few dowel pins to positively locate everything on the front face of the block. Those three head to timing cover bolts I tend to torque to the lower end of the range because due to the softness of the cork gasket you are practically bending the head and timing cover toward each other by tightening them.

Those two countersunk screws securing the chain dampener to the inside of the cover. You need to put a low strength threadlocker on these to help prevent leaks. The thread has a direct passage from the inside where all the oil is to the outside.

I know a lot of people use Loctite 518 anaerobic to seal between the backplate and front cover. Personally I prefer Threebond 1215 Silicone as it's more flexible and doesn't set up as quickly. That assembly flexes quite a bit particularly at the point where the bolt for the belt adjustment strap passes through and when you need to tighten and untighten this bolt for belt adjustment. Silicone is a whole lot more flexible than 518 and I've also found that 518 once the two mating surfaces contact each other begins to set up very quickly and doesn't allow much time to get things aligned correctly. With silicone of course you do need to be careful of how much you apply and where you apply it but done correctly I think it's better here because it's better able to withstand things flexing over long term use.

The backplate to engine block gasket. I think the standard one is a bit thin for coping with surface unevenness. I cut my own using Mahle JV100 gasket material which is slightly thicker. I believe it has some "controlled swell" properties. Controlled swell paper contains SBR rubber which under the influence of oil helps the gasket to expand in a controlled way and fill irregularities. I don't bother with additional sealant.

Sump gasket. Thin smear of Threebond 1215. Tighten sump bolts in correct sequence (I've posted about this before) and don't be too keen to trim your cork half circle gaskets. They are designed to compress into the cover with a preload and if you trim too much you'll loose that preload. The Ford recommended sump bolt tightening sequence is designed to compress the half circle seals into their respective housings with the correct preload
1970 Ford Escort Twin Cam
1972 Ford Escort GT1600 Twin Cam
1980 Ford Escort 2.0 Ghia
Peugeot 505 GTI Wagons (5spdx1) (Autox1)
2015 Honda City 5spd.
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PostPost by: Hawksfield » Thu Jun 23, 2022 3:52 pm

2cams70
Can you repeat the tightening sequence again with bolt ID as I could not identify the sequence. I understood the numbers and letters but not which was which bolt.

Could be just me but I'd like to see it again.
Thanks in anticipation
John

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PostPost by: 2cams70 » Fri Jun 24, 2022 11:40 am

Hawksfield wrote:Can you repeat the tightening sequence again with bolt ID as I could not identify the sequence. I understood the numbers and letters but not which was which bolt.

Could be just me but I'd like to see it again.
Thanks in anticipation


First tighten in alphabetical order:
A to R: 6 to 8 lb.ft

Then tighten in numeric order
1 to 18: 6 to 8 lb.ft
Attachments
sump torque sequence.pdf
(757.97 KiB) Downloaded 39 times
1970 Ford Escort Twin Cam
1972 Ford Escort GT1600 Twin Cam
1980 Ford Escort 2.0 Ghia
Peugeot 505 GTI Wagons (5spdx1) (Autox1)
2015 Honda City 5spd.
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PostPost by: Hawksfield » Fri Jun 24, 2022 3:13 pm

Thanks 2cams70

The graphic makes all the difference
John

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