My twincam has turned into a Harley

PostPost by: CrisinColorado » Thu Jun 27, 2024 2:34 pm

Tall deck 1700, removeable water pump front cover. Leaks like a screen door in the rain. Most concerned about a leak along the top of the front cover. I noticed that the spacer between the block and head only has a gasket on the top side, between the head and the spacer. Should there be a spacer as well on the bottom side between the block and spacer?? There might be some non-visible sealer material, can't tell.

It's leaked since built, I need a course of action plan. Do I start with new front and matching rear 'tall' deck covers?
What else ?

Thanks in advance for the advice & hand holding.

Cheers,
Cris
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PostPost by: CrisinColorado » Thu Jun 27, 2024 10:15 pm

Error in original post:
Should there be a GASKET as well on the bottom side between the block and spacer??

(changed spacer to gasket)

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PostPost by: StressCraxx » Thu Jun 27, 2024 11:53 pm

One gasket between spacer and head, one gasket between spacer and timing cover.
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PostPost by: rgh0 » Fri Jun 28, 2024 12:34 am

i have never built a tall block with a spacer so this is just my thoughts

I would cut a paper gasket from a suitable gasket material ( similar to whats used on the back plate to block join) and use that with Lotitie aviation gasket sealer on the bottom and use the standard cork gasket with the same sealer on the top.

I would avoid using 2 cork gaskets as it would be difficult to get them to both compress evenly the same amount.

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PostPost by: 2cams70 » Fri Jun 28, 2024 12:57 am

The spacer to cover joint is an ideal location for using sealant instead of a gasket as it's a close fitting rigid joint. You won't know if there's sealant until you take things apart
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PostPost by: CrisinColorado » Fri Jun 28, 2024 4:26 pm

Thank you all very much for your thoughts & input.

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PostPost by: StressCraxx » Fri Jun 28, 2024 4:59 pm

I helped build one a tall block motor for one of my friends with a Europa. We had similar leak issues using one gasket on top of the spacer and sealant on the bottom. The issue was there was insufficient compression of the gasket and no compression of the sealant. The total stack after tightening the bolts left us with no compression of the gasket or sealant at all. I completely overlooked this. I should have realized it because fluid sealing systems are part of my industry work.

So we used two cork gaskets and non-hardening Permatex No. 2 sealant. The total stack height of spacer and two uncompressed gaskets was 0.050" greater than the gap between the head and front cover. That combination gave us a decent seal. That combination worked much better with just slight seepage after a year. When my friend replaced the water pump 4 years later, he did the same but used Permatex "Right Stuff" and said that worked better than the Permatex No. 2.
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PostPost by: 2cams70 » Sat Jun 29, 2024 2:28 am

StressCraxx wrote:I helped build one a tall block motor for one of my friends with a Europa. We had similar leak issues using one gasket on top of the spacer and sealant on the bottom. The issue was there was insufficient compression of the gasket and no compression of the sealant. The total stack after tightening the bolts left us with no compression of the gasket or sealant at all. I completely overlooked this. I should have realized it because fluid sealing systems are part of my industry work.

So we used two cork gaskets and non-hardening Permatex No. 2 sealant. The total stack height of spacer and two uncompressed gaskets was 0.050" greater than the gap between the head and front cover. That combination gave us a decent seal. That combination worked much better with just slight seepage after a year. When my friend replaced the water pump 4 years later, he did the same but used Permatex "Right Stuff" and said that worked better than the Permatex No. 2.


Steve at Lotus Marques here in Australia can supply a variety of different thickness head to block cork gaskets to suit the specific application. This is probably a better solution than stacking up multiple gaskets. I agree with you that silicone of the appropriate grade is a better sealant here than shellac based ones like Permatex No. 2. Be aware though that silicone such as "Right Stuff" is most definitely not the "Right Stuff" unless you apply it properly. Personally I use Threebond 1215 silicone.
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PostPost by: StressCraxx » Sat Jun 29, 2024 4:36 am

2cams70 wrote:
StressCraxx wrote:I helped build one a tall block motor for one of my friends with a Europa. We had similar leak issues using one gasket on top of the spacer and sealant on the bottom. The issue was there was insufficient compression of the gasket and no compression of the sealant. The total stack after tightening the bolts left us with no compression of the gasket or sealant at all. I completely overlooked this. I should have realized it because fluid sealing systems are part of my industry work.

So we used two cork gaskets and non-hardening Permatex No. 2 sealant. The total stack height of spacer and two uncompressed gaskets was 0.050" greater than the gap between the head and front cover. That combination gave us a decent seal. That combination worked much better with just slight seepage after a year. When my friend replaced the water pump 4 years later, he did the same but used Permatex "Right Stuff" and said that worked better than the Permatex No. 2.


Steve at Lotus Marques here in Australia can supply a variety of different thickness head to block cork gaskets to suit the specific application. This is probably a better solution than stacking up multiple gaskets. I agree with you that silicone of the appropriate grade is a better sealant here than shellac based ones like Permatex No. 2. Be aware though that silicone such as "Right Stuff" is most definitely not the "Right Stuff" unless you apply it properly. Personally I use Threebond 1215 silicone.


Completely agree, Sir!
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