As far as assembly and start-up. This is a small car engine install and for folks who are used to bigger engine bays, they may get frustrated as it can be backbreaking work being bent over so far.  There are a few things that must be followed and you may want to pass this along to your mechanic.


1.    The engine hangers are on the generator bracket and transmission housing. The easiest method is to raise the rear end of the car and install the engine and transmission as one uint, at least for first timers.  The carbs should be removed to install the engine if they are using this method.
2.     The front driveshaft seal must be replaced or you will puddle transmission fluid on the floor forever more.

3.     Engine only installs can be done but more finesse is required. Raising the front of the car to allow the transmission to swing into the tunnel ( I have both front and back raised). Otherwise the tail will hit the floor of the shop.
4.     Use a 10/30w oil. Your call on a new filter, I would not bother until the next oil change. After the rebuild there may be a few crumbs of aluminum swarf washing out with all the thread repair that has been done but it will collect in the pan.
5.     Fuel pump and filter still need to be worked out, the OEM set up is less reliable than an electric after market pump. An after market Mitsuba pump can be used but you will need to make a mounting bracket for the mitsuba fuel pump.
6.     The generator needs to be tested. At this point, the best thing is to run it in the car with the voltage regulator hooked into the system.
7.   First time start, bump up the idle to between 1000-1200 RPM to start.
8.       Try not to run the engine at idle for extended periods of time. There is high fuel supply to the pistons at this low rpm which lowers cylinder lubrication and fouls plugs. I don’t suggest that no idle is acceptable, just not for 10-15min at time.
9.       Piston to sleeve tolerance is very tight. For the first 600 miles, do not install the thermostat and do not run the engine over 6.5K. This is frustrating,but the alternative is a stuck piston and severe engine damage. The engine will run cool, but at is better than the opposite. Until the water pump function can be confirmed it is best to err on the side of caution. The engine will run a wee bit rougher but it is not worth putting the thermostat at this stage. Diehard carb mechanics may want to convince you otherwise, if so, install a cold thermostat for sure.
10.   Re-check exhaust bolt tightness after a few hours of driving or they will loosen and fall off.

Many restorers insist that building Honda s600 engines may take several years to complete.  I can tell you they do not know what they are doing or not giving your project the time it deserves.  Restoration suits a particular breed of mechanical artist, they are meticulous, they are analaytical, they are smart in decisions. Once you have found a potential restorer, based on reputation or references, look around their shop, is it clean and organized, or are there boxes of unfinished and partial projects and parts everywhere?  Are parts labelled, bagged and tagged.  Disassembled engines in progress should be broken down into bins, labelled with engine serial numbers and sub assemebly names, every sub assembly, every part, every fastener should be bagged and tagged and labelled.  That is why Sharpies and zip lock bags were invented.  If your potential candidate restorer is not doing this, walk away.


Before you engage a restorer, ask the restorer to see an in progress engine to explain the process to you.  Bad restoration can cost you thousands of dollars in lost parts, damaged rare castings, and imporper cleaning and assembly.  Be very cautious of restorers who use restoration to keep there mechanics busy between oil changes, they don't care about your restoration, they are not qualified to touch your engine, and the mechanics most likely have little or no training in engine restoration.  Would you want your engine to be used to train?


A restoratin shop MUST be clean and organized.  You should be able to walk in to the restorers shop and locate your engine and parts instantly, after all it is your investment they are working on.  Honda s parts are rare and difficult to replace.  If the general public can walk in and out of the restoration shop what stops your parts from becoming souvenirs?  If parts are strewn everywhere, what prevents a mechanic from throwing your precious OEM fasteners away with the pile of used oil filters?  If multiple projects are going on, how do you know a rush project does not borrow parts from your bench?  The shop shold treat your project as an investment, your investment into the Honda s engine, and their investment into reputation.

JP did the restoration on Chatham engine in just over three months working part time.  He supplied almost all of the photos on these pages, he kept me informed and involved every step of the way.  Problems became solutions, decisions that impacted budget were discussed, and the engine turned out to be a jewel.  Thanks JP for doing a super job on the Chatham engine.


Arrival in JP's Shop:  March 29, 2012

Completion of Engine: July 3, 2012

Elapsed build time: 3 months 5 days

Suppliers:  Ortmann, CMSnl, Eurasia, Spread-tool, private 





















The installation of the crank into the block is very peculiar for the Honda s600.  The later s800 had a slight conical shape in the liner to make this process a little more tolerant to the level of skill of the mechanic.  The s600 requires a high degree of skill, and finess to put the crankshaft into place.  


All parts have been cleaned and prepped for the assembly.  Ring end gaps are set based on the bore size. The rear liner had a small amount of play  and was stabilized prior to the assembly


All items are test fitted to ensure assembly will run flawlessly.


The crank is assembled and new oversized pistons and rings attached, here a ring is used to compress the rings for assembly into the block.


The classical assembly of the crank shaft into the block is with a pair of scissor jacks, allowing a controlled of two pistons at a time into the liner.  THis takes some finess as the compressed rings have to be guided into the liners.




I had purchased several starter clutches and had several starter motors from my spares collection, so I had a choice in parts.  The starter motor did not need to be rebuilt, and several of the starter clutches were functional, so we chose the best.


Typically the starter clutch, pins and often the face plate receive wear, I have borrowed these photos from John to look at the pices of the starter clutch:




 Spare parts are available from Ortmann, Eurasia and Spread-tool.  There are size differences to these pieces depending on the production time of the engine, but the following links will give you a start to finiding the spares.

Starter clutch roller bearings lat type:

Starting clutch plate:


Roller and springs:




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Some S600 photography courtesty of Karin Johnston