Model Engine Maker

Help! => Mistakes, muckups, and dangerous behaviour => Topic started by: Chipmaster on April 14, 2020, 06:13:25 PM

Title: Converted an inlet valve into an 'ex-valve'
Post by: Chipmaster on April 14, 2020, 06:13:25 PM

I couldn't get my twenty plus year old model Gardner O Type to run yesterday. I hadn't run the engine for almost a year and it seemed to be lacking compression The inlet valve was leaking so I removed and dismantled the combustion chamber / valve block and reground the valve but that failed to do the trick. Close inspection revealed wear to the valve face so I thought I'd re-face the valve in my lathe holding the stem in a chuck and the top slide set at 45 degrees. All was going well, I was on the home straight then the tool dug in and bent the 1/8" diameter stem somewhat.

Here are a couple of pictures of the old bent valve and the replacement made by soldering the head onto the stem -  1/8 diameter silver steel,

(https://live.staticflickr.com/65535/49773882471_d72e56f2ab_z.jpg) (https://flic.kr/p/2iQmaar)IMG_1254 (2) (https://flic.kr/p/2iQmaar) by Andy (https://www.flickr.com/photos/116764188@N08/), on Flickr

(https://live.staticflickr.com/65535/49774211322_b22cc714eb_z.jpg) (https://flic.kr/p/2iQnQVh)IMG_1256 (2) (https://flic.kr/p/2iQnQVh) by Andy (https://www.flickr.com/photos/116764188@N08/), on Flickr

There is a happy ending - the engine has been running well this afternoon.

Andy

Title: Re: Converted an inlet valve into an 'ex-valve'
Post by: kvom on April 14, 2020, 06:26:48 PM

Quote

bent the 1/8" diameter stem somewhat.

 :Lol:

Title: Re: Converted an inlet valve into an 'ex-valve'
Post by: Roger B on April 14, 2020, 06:29:40 PM

Glad you've got it working again  :ThumbsUp:  :ThumbsUp:  :wine1:  I guess that the original valve had been hardened a bit by running.

I tried several times to repair cracked tubular exhaust manifolds on my competition cars but they always cracked again  :( I finally realised that they were at red heat in a carbon rich atmosphere from the exhaust and were being hardened  ::)  :toilet_claw:

Title: Re: Converted an inlet valve into an 'ex-valve'
Post by: Chipmaster on May 28, 2020, 10:04:12 PM

Here's a video of the repaired engine. I used the 'slo-mo' option on my iPhone and was impressed, particularly by the sound track.

https://www.youtube.com/watch?v=iQhagWin-KI

Andy

Title: Re: Converted an inlet valve into an 'ex-valve'
Post by: crueby on May 28, 2020, 11:03:11 PM

Runs great! The slo-mo is pretty cool too!