312-8 with K301 - Can't keep intake valve adjusted

[TC10284 113]

Alright, so I'm having a problem that is strange to me, but probably not you experts. 

 

312-8 with K301. Clicks badly when running. I have adjusted the valves already multiple times. Exhaust valve stays in check. Intake valve, I have adjusted it at least three times now to 0.009, which is right smack in the middle of 0.008 and 0.010. I spin the engine over by hand four times and recheck clearance each time. It's good each time I check when I spin over by hand. When I start it up, it still clicks horribly. I open the valve cover again to find it way out of spec again. I've done my best to make sure the tappet bottoms out before adjusting.

 

I'm frustrated with it. It runs good, just clicking badly. 

 

Here's a couple pics and video. 

https://photos.app.goo.gl/FYGCCUomCYbTGofT9

 

[Fordiesel69 271]

It would appear the adjustment bolt is stripped and slipping down into the tappet.  From the video it does look like the intake valve is openining and closing correctly.

 

1.)  Tighten the adjustment bolt in (clockwise) until it bottoms out.  Paint one of the flats and then count approx the amout of turns out to get the proper adjustment.

 

When it loosens up again count again and you will have the answer.

[TC10284 113]

I will try this. Is there a way I can get a replacement bolt if that's what is stripped? 
Can I use some kind of glue or something that will hold it in place better or is that a bad idea? 

[Fordiesel69 271]

You may be able to rinse it with carb cleaner and put some red loctite, then adjust it, let it sit 24 hrs and hopefully it will hold.   It will be a big maybe 

[RED-Z06 2,567]

Good news is..good used tappets are very affordable and its extremely rare to have one fail.

 

Bad news is, they are pretty much the first thing that goes into the bare block.

 

https://www.ebay.com/itm/204598457694?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=F_u84YYiRGO&sssrc=4429486&ssuid=Z0V4Uge1Tf6&var=&widget_ver=artemis&media=COPY

[Rick3478 438]

I've seen valve seats come loose, which can make strange things happen.

[TC10284 113]

Will this bolt come all the way out if I remove the valve spring?

 

And to replace the tappet, I basically have to disassemble the entire engine? 

Edited May 4, 2024 by TC10284

[Fordiesel69 271]

The engine needs to come cometely apart to get the tappet out unfortunatly. 

[TC10284 113]

1 hour ago, Fordiesel69 said:

The engine needs to come cometely apart to get the tappet out unfortunatly. 

 

Does the bolt come out fully? 

[lynnmor 7,799]

19 minutes ago, TC10284 said:

 

Does the bolt come out fully? 

Good question and I don't have the real answer, but I see where you are going with this.  The tappet body is made from a real hard steel and may have no damage with the bolt being the only problem.  The unknown is the condition of the cam and the tappet surfaces where they meet.