Jump to content

Core plugs on front of engine


Recommended Posts

My CP engine has 2 core plugs on the front side. The parts manuals only show one plug. I replaced one, but am not sure about the other: is it the flat spherical type as currently installed or the cup type?

Thanks,

Waldipost-13554-0-29328000-1522488519_thumb.jpgpost-13554-0-25182600-1522488507_thumb.jpg

 

Link to post
Share on other sites

Thanks Ed.

I prefer the cup type, as it provides a larger seal area, especially when the bore is not 100%.

Will go with that.

Regards,

Waldi

Link to post
Share on other sites

Hi Waldi ~

 

In days of old when I was an apprentice mechanic we used to cover the back of the cup type core plugs with a coating of solder

to prevent corrosion taking place. (This was in respect of core plugs fitted in the cooling system).

 

Tom.

Link to post
Share on other sites

Hi Tom,

That would have been a good approach especially in the days where more water was added and corrosion inhibitors as in modern coolants not as common as today.

Basically it provided cathodic protection, as long as it was not covered with chalk (CaCO3).

Regards,

Waldi

Edited by Waldi
Link to post
Share on other sites

Hi Tom,

That would have been a good approach especially in the days where more water was added and corrosion inhibitors as in modern coolants not as common as today.

Basically it provided cathodic protection, as long as it was not covered with chalk (CaCO3).

Regards,

Waldi

When I re-built my engine after 44 years of use and came to remove the old core plugs. I was surprised at how thin they were caused by corrosion. They would not have lasted much longer before leaking even though I had used Distilled water since new and quality anti-freeze with tri-annual changes. Therefore if you have the block out, change the lot in my view, especially if they have been in for a good few years. I am also not certain as to the quality of my replacements as 2 of them have leaked from the inside edge through cracking but luckily they were the easy to get at ones!

 

 

Bruce.

 

Bruce.

Link to post
Share on other sites

Just to complete the story:

I removed the old dished core plug, to find the bore had a recess, so only a dished plug will fit.

It was, as expected, pretty corroded.

So I guess on the front of a CP engine (and maybe also on others), there is one (deep) cup type core plug and one dished ("flat") plug. All plugs I needed for block and head were in the set I bought from Moss, all fitted well.

Regards,

Waldi

 

 

post-13554-0-68712000-1522777407_thumb.jpg

post-13554-0-45616800-1522777416_thumb.jpg

Link to post
Share on other sites

Hi Ed,

I technically prefer the cup type, the likelihood for leakage is smaller since it does not have a line contact but a wider band.

All other plugs in my engine are cup type, not sure why this one is not. As always, there probably is a reason for it.

Regards,

Waldi

Link to post
Share on other sites
  • 2 years later...

Thank you for this thread...I’m just encountering the same problem on my TR250 engine build.   I have the cup type and also have the recess...I’m thinking of carefully grinding down the lip of the cup one the ensure it is flush (or slightly below) the face of the block so the gasket and front engine plate fit correctly over it...it is the right diameter plug but not the right depth.

Any thought on this approach?  Don’t think I want to wait 2 weeks for a new dished one...

Cheers

Tush

Link to post
Share on other sites

Hi Tush,
I would not cut the plug, it’s sealing principle relies on the elastic behaviour, which the “skirt” provides, like a very stiff spring. Also not worth taking chances given the amount of rework needed if it starts leaking. Just my 2cts.

Best regards,
Waldi

PS: good to see you on the forum every now and then, I watched several of your video’s when I was wondering “how others did it”, so thanks for that effort!

 

Link to post
Share on other sites

Thank You for the reply.   I'll see how long it will take to get the other style to me....

I figured it could work as there will be at least 1/2 of the edge of the cup to still seal along with a little RTV around the edge....plus the plug would be held in with the gasket and front engine plate....you are right though, I would hate to have to take it back out again.   I am planning on doing my engine break in prior to putting the body back on but I am not sure a 20 minute break in time would be sufficient to know if it was leaking or not....

As an aside, I have sent the Vendor I purchased this plug kit from to see if anyone else has reported issues with the fitment....this kit was marketed as a TR250 kit so I don't want others to run into the same issues...

 

Cheers

Tush

Edited by M. Pied Lourd
Link to post
Share on other sites
10 hours ago, M. Pied Lourd said:

Thank You for the reply.   I'll see how long it will take to get the other style to me....

I figured it could work as there will be at least 1/2 of the edge of the cup to still seal along with a little RTV around the edge....plus the plug would be held in with the gasket and front engine plate....you are right though, I would hate to have to take it back out again.   I am planning on doing my engine break in prior to putting the body back on but I am not sure a 20 minute break in time would be sufficient to know if it was leaking or not....

As an aside, I have sent the Vendor I purchased this plug kit from to see if anyone else has reported issues with the fitment....this kit was marketed as a TR250 kit so I don't want others to run into the same issues...

 

Cheers

Tush

I sense a YouTube video on engine build coming this week!

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.