Gilson chain drive tiller - engine and gearbox rebuild

[Krooza]

Hello, soon i am rebuilding the engine and gearbox on my 1978 Gilson chain drive tiller. I am starting with the engine. It was run on low oil by a previous owner. I had it working and i was using it for a bit, but it smoked like a freight train and i was planning to rebuild it soon. The last time i started using it it suddenly started making nasty noises, so i shut the engine down ASAP. The conrod bolts had come loose. I am going to rebuild it now, since it was needing it anyway. I am replacing the rings, all seals and gaskets, conrod and bearing cap, and the cam, and lap and adjust the valves. When i get to the rebuild i will document it in this thread.

This is actually my first engine rebuild, however I am not new to working on engines and equipment.

So my question is... Is there anything i need to know before the engine rebuild? Do you have any tips or tricks? Thanks in advance.

 

[GMB74]

Assess the engine carefully before actually buying any parts. An old engine like this that has been run low on oil is likely to be so badly worn out/damaged that it is unfeasible to rebuild. Some parts may not even be available.
Usually people just get a Predator engine (Honda clone) from Harbor Freight and are very pleased with the result.
I have an old log splitter from the 80's that is showing its age, and that is what I will eventually be doing.
If your goal is to restore this machine to original condition, I still would proceed with caution. You will have a lot of time and money in it when you are done.
Get a genuine Briggs and Stratton shop manual off ebay. They are not expensive and will have all the specs and information you will need for this adventure.

 

[Steve]

That engine has an aluminum bore. Do not hone it.

Check the front and rear crank bushings by removing the belt and the flywheel. Grab the front of the crank shaft and move it up and down. Grab the rear of the crankshaft and move it up and down. There should be no movement up and down. There should be some movement in and out. (Crankshaft end play)


Downloading a service manual will help.

 

[Krooza]

Assess the engine carefully before actually buying any parts. An old engine like this that has been run low on oil is likely to be so badly worn out/damaged that it is unfeasible to rebuild. Some parts may not even be available.
Usually people just get a Predator engine (Honda clone) from Harbor Freight and are very pleased with the result.
I have an old log splitter from the 80's that is showing its age, and that is what I will eventually be doing.
If your goal is to restore this machine to original condition, I still would proceed with caution. You will have a lot of time and money in it when you are done.
Get a genuine Briggs and Stratton shop manual off ebay. They are not expensive and will have all the specs and information you will need for this adventure.

thanks, it is definitely rebuildable

 

[Krooza]

That engine has an aluminum bore. Do not hone it.

Check the front and rear crank bushings by removing the belt and the flywheel. Grab the front of the crank shaft and move it up and down. Grab the rear of the crankshaft and move it up and down. There should be no movement up and down. There should be some movement in and out. (Crankshaft end play)


Downloading a service manual will help.

thanks, will check when i can

 

[Krooza]

I am waiting for parts, but does anybody know what model it is? it says nothing on the sticker, and for serial number it just says 616 - in a bit of a strange place.

 

[Krooza]

Opened the gearbox today, it was in much better condition than i thought. Still needs a reseal, and the shaft machined. I will take pics tomorrow.

 

[rzonk]

That engine has an aluminum bore. Do not hone it.

Check the front and rear crank bushings by removing the belt and the flywheel. Grab the front of the crank shaft and move it up and down. Grab the rear of the crankshaft and move it up and down. There should be no movement up and down. There should be some movement in and out. (Crankshaft end play)


Downloading a service manual will help.

Can an aluminum bore engine be bored?

 

[Steve]

Can an aluminum bore engine be bored?

Yes, just make sure your machine shop know what they are doing. Most of Mercedes engines produced in the last 20 years have aluminum bores. Even the AMG engines.

In this engines case, DO NOT hone the cylinder if you are just going to re-ring it. They finish the honing process with a heavy silicon paste to give it anti-wear properties. If you run a hone down there the engine will smoke and wear the cylinder very quickly.

Best to just wash the block and install new rings. Leave the cylinder alone.

 

[ray benson]

I am waiting for parts, but does anybody know what model it is? it says nothing on the sticker, and for serial number it just says 616 - in a bit of a strange place.
View attachment 400099

You might find some info here - snowblower and tiller parts.
https://gilsonsnowblowers.com/snowtillers.html#documentation

 

[Krooza]

You might find some info here - snowblower and tiller parts.
https://gilsonsnowblowers.com/snowtillers.html#documentation

Thanks, but i need the model number for that. maybe i need to email the guy who owns that website. If anyone knows its him.