Author Topic: Flat head hit and miss engine???  (Read 8811 times)

Online Kim

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Re: Flat head hit and miss engine???
« Reply #150 on: March 26, 2023, 05:11:46 AM »
Congratulations on getting your first run there Brian!
I'm sure you'll get the details worked out.  And I'll be following along  :ThumbsUp: :popcorn:
Kim

Offline Admiral_dk

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Re: Flat head hit and miss engine???
« Reply #151 on: March 26, 2023, 12:24:52 PM »
First Pop is always good  :ThumbsUp:  - it's first a little later one realize that 'I want more' ....

If it is possible to destroy the ring on the Ports - there is a good chance that the same will happen to a O-Ring .... any sharp edges that needs to be removed ?

Per            :cheers:

Offline Brian Rupnow

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Re: Flat head hit and miss engine???
« Reply #152 on: March 26, 2023, 02:01:24 PM »
Admiral dk--this is what I have to explore today. Right now I'm not sure what I'm going to do. I'm thinking of putting the viton ring on the piston, compressing it in a sleeve, then sticking it in the freezer for an hour or two. If that works, then pop the ring and piston out of the freezer and drop it into the cylinder, past the ports. Then as ring thaws it will regain it's normal cross section. I haven't heard of anyone doing that, but if it works it's a very cheap fix.

Offline Brian Rupnow

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Re: Flat head hit and miss engine???
« Reply #153 on: March 26, 2023, 02:49:45 PM »
I don't know how well you can see this, but---the ring that was used to break in and get the initial runs on the engine is on the left. A visual inspection of it doesn't show any cuts or missing pieces from going past the ports in the cylinder when the piston and ring were installed. The ring on the right is a brand new, never installed viton ring. It appears to be larger in cross section than the original ring. Measurement with a vernier caliper shows that the new ring has a cross section of 0.072". The "old" ring has a cross section that measures "0.063" cross section.  The only thing that I can think of is that I had reamed the i.d. of the cast iron cylinder, but not honed it. The roughness left from the reaming operation has worn away the outside of the ring, and thats what happened to my compression. Later today I will install the piston with the new ring on it and see how that affects my compression.


Offline Brian Rupnow

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Re: Flat head hit and miss engine???
« Reply #154 on: March 27, 2023, 09:08:31 PM »
Today was disaster day. While cranking the engine over to start it with my electric drill, the rod cap bolts came loose, the rod cap came off and jammed against the inside of the crankcase, and bent the crankshaft as a result. Flywheel is now very wonky, which is one of the things I wanted to avoid. I believe the concept of a flathead hit and miss engine is valid, but everything now comes to a halt. I have other things to do that aren't part of my engine building exercise, so I will be away from the forum for a while. This is not the result I wanted to achieve, but it is what it is. I will probably pick up with this build at a later point.---Sorry guys.---Brian

 

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