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Old 02-12-2019, 07:43 AM   #1
ab1
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Default welch plugs that continue to blow

Ive been plagued by blown welch plugs for some time on my rebuilt b30 engine. the engine builder here in aus put a plate to keep them in place which worked for a year however they slowly pushed their way out and started to leak. its by no means a high perfmance engine probably pushing 200hp at the crank i would like to think with a k cam.

i have found that its time for a permanent solution

https://zeligsgarage.com/products/vo...-blue-anodized

i would like to check to see if anyone who has experienced this agrees that this is the correct method to solving this welch problem.

i presume that all red blocks share the same sized freeze plug. im aware that the later style was a cup and that this may cause an issue when it comes to effectiveness of the retainer.
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Old 02-12-2019, 01:44 PM   #2
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Do you have any pics of the plugs installed? When installed properly, they should look like this.



All B18/B20/B30/B21/B23 engines use 45mm core plugs. The cam/intermediate shaft plugs are different sizes. 42mm for the push rod motors and 50mm for the OHC engines.

Early B230 engines engines use 40mm welch plugs while late engines use 40mm cup plugs.
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Old 02-12-2019, 05:03 PM   #3
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I know Casey personally. He makes nice stuff!
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Old 02-12-2019, 11:37 PM   #4
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Loctite sleeve retention compound
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Old 02-13-2019, 01:20 AM   #5
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I'm also based in Melbourne.
If you need the contacts for some local Volvo guys let me know.
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Old 02-13-2019, 03:26 AM   #6
ab1
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engine builder has used stag to seal them and unfortunately not but i can tell you that they resemble the plug pictured above.

@jimmymelbs would you know of a local supplier of for these retaining clips i know its a bit of specialist part so fairly unlikely
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Old 02-13-2019, 03:34 AM   #7
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Before very recently I've only ever seen core plugs retained with bolts and washers overlapping the edges of the cup type plugs.
I'll see if I can find a photo.
I see no reason why the same method wouldn't work with the welch type plug pictured by hiperfauto, providing the plug is flush with the surface.
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Old 02-13-2019, 03:51 AM   #8
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Picture by bgpzfm142 on this page:
https://ozvolvo.org/discussion/7528/...rebuilt-engine

And on re-reading I notice someone by the name of ab1 started the discussion. I assume this is you?
My two suggestions are:
1) Swap to the cup type plug and add some overlapping bolts and washers as per above.
2) OR; make some completely covering retainers like the ones you want to buy yourself. Possibly one of the simplest fabrication tasks ever. Just a straight piece of 20mm wide steel with two holes in it should do the job.
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Old 02-13-2019, 08:07 AM   #9
ab1
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Correct that is me on the aussie forum

is it possible to swap to the cup style plug? i was informed by the engine builder that this was not something that is possible

as pictured by Bob as you mentioned above link to my thread on the other page for the straight 20mm to work would that require a cup style plug or would the dish type suffice
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Old 02-13-2019, 09:03 AM   #10
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Quote:
Originally Posted by ab1 View Post
is it possible to swap to the cup style plug? i was informed by the engine builder that this was not something that is possible
Firstly a disclaimer, I've not done this, but I assume there is a lip in the hole in the block that the dished welch plug sits against when you hit it? I'd carefully grind that lip off and then source some suitably sized cup type plugs. Perhaps a big risk though as you've them made irreversible changes to the block.


Quote:
Originally Posted by ab1 View Post
as pictured by Bob as you mentioned above link to my thread on the other page for the straight 20mm to work would that require a cup style plug or would the dish type suffice
I think either would work. The cup type is easy because it sits flush with the surface. For the dish/welch type you may have to space the 20mm strap away from the block if the plug sits proud of the surface, or place some sort of shim under it if the plug sits recessed. Re-reading your original post though, you say your engine builder put a 'plate' over them, is this not exactly what we are describing here? How did it fail?
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Old 02-15-2019, 08:58 AM   #11
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i have ordered the retainers as my OP linked

the original plate the engine builder used did not sit flush to the plugs and instead used a washer and another plug coupled on top to create pressure against the original plugs. whilst this stopped them form spontaneously bursting... they started to leak. the plate also could flex as it stretched the length of the block. we then suspected it was the non geniune plugs so swapped them for gen and didnt use the plate. 5 minutes after leaving the shop temp gauge through the roof again.
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Old 02-15-2019, 09:22 PM   #12
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If you haven't seen it, there's a long thread about cooling issues and plugs here:
http://forums.turbobricks.com/showthread.php?t=218895

IIRC, the rambling conclusion was that some blocks flex at high load/rpm, and the plugs pop out. I don't remember if there was anything definite to prevent problems.
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