Hello and question regarding my renault 688 powered skidsteer

[motzingg]

Howdy,

I'm across the pond in the USA and i've got a 1970-something case 1830 skidsteer powered by a 'Continental R688' which appears to be very similar to the late 60's estafette spec 688 1.1L/ 74 mm bore cleon-fonte motor. Continental imported the motors for industrial use, but aside from a different exhaust outlet location, they look pretty close to the automotive spec.

Nobody in America (well, nobody on the internet anyhow) knows anything about these engines, wants anything to do with them, and most of the tractor mechanic types who are used to big heavy cast iron stuff, say to yank it out and replace it with a motor that doesn't require metric tools to fix. Hence finding this forum and registering in hopes someone here might know more.

The motor has been good for me the last three years, the previous owner said it was rebuilt, until about 2 weeks ago when i was running it hard and suddenly noticed it smoking quite a bit. It appeared to be a loose hydraulic line dripping oil on the muffler, but after further investigation it was over a gallon low on coolant and when i filled it up, the coolant started blowing out the radiator cap. On further inspection the radiator was plugged, the cap was old and probably not holding pressure, and i removed the catch can last year because it didn't seem to be doing much of anything.

I diagnosed it to a blown head gasket, spent a lot of time learning the provenance and cross ref info for the engine and eventually tracked down an AJUSA head gasket set. Yesterday I pulled the head, cleaned everything up, replaced the gaskets, and got it all back together. Very cool little motor, smallest automotive engine i've ever worked on and over all a pretty simple and efficient design. Aside from the manifold gaskets being bonded to the head and taking almost 2 hours to scrape off... everything went really well and it was back together and running in time for me to clean up before dinner.


Now here are my questions:

1) When i first pulled the head, i noticed the two middle cylinder liners were a little 'wobbly'... I've never worked with wet liners before, but when i've heard of other engines using them, they are a heavy press fit. These appear to be a slip fit, is that correct? To make matters worse, i bumped the starter, not thinking about this, to clean the coolant out of the cylinders and further disloged the cylinder, it never came up, and the coolant still sitting in the block didn't end up in the oil, but my question is regarding the sealing at the bottom of the bore.

Since the engine was recently rebuilt, the oring should still be fairly pliable down there. I am hoping it will hold, my plan is to change and check the oil after the first couple good heat cycles, maybe even re-torque the head? Does this sound reasonable or is there something else i should do?

My 'last ditch' idea would be to fill the block only with coolant with leak-stop and let the engine get hot to cook it in there. If the engine has to come out, i don't think i will be putting it back in since it is not quite up to the task of running a skidsteer, and parts over here are hard to come by.


2) When i took the head off, the break-away (loosening torque) on the head bolts was low, very low, like less than 15 lbs on the bolts. Would this be normal for an engine that's overheated? Or would this be a sign of an incorrectly done rebuild. The engine was professionally rebuilt less than 60 hours ago, but once again since this is such an odd engine for USA, i'm worried that things might not have been done right.


Thanks for reading and any responses, sorry for the long winded post. If i get a chance later i'll add some pics for fun. I'm not sure if the skidsteer thing is common knowledge in Europe or if this is a novelty for you guys to see. Certainly fun for me to work on something thats so unusual for the type of things we usually see here.

 

[motzingg]

Despite having searched everything on this site for a few days, I saw this thread just now after posting:

Renault/Continental R engine 839-46

Hello, As i explained in the introduction section, I have a Toro Groundmaster 72 lawnmower with a continental R engine. I would appreciate any advice you Renault enthusiasts may be able to give me. A couple of years ago I picked up this old mower fairly cheap, it was great at the time after...

www.renault4.co.uk

That answers most of my questions. I'm still a bit confused on the sealing at the bottom of the block.

When i 'bumped the starter' the liner didn't pop up proud, just got a little more wiggly. My guess is that the paper shim gasket has torn, but am i correct that there is still a radial o-ring, and as long as the paper isn't too badly disturbed, it will possibly compress back down and hold?

At the end of the day, i guess the only way to find out will be to get her nice and hot, drain the oil, and hope there's no chocolate milkshake.

What a rotten design, why wouldn't they use copper shims for height and perhaps double up the o-ring? Or a press fit like any other sensible manufacturer.

 

[malcolm]

The later engines (not 688) changed from paper gaskets to rubber O rings. With the 688 paper gaskets you have to be very careful. When removing the head leave one bolt nearly tight and knock the head sideways to break the seal. And don't turn the engine without clamping down the liners.

If they did replace the paper seals recently you might get away with unseating them. The only way to tell is to run the engine and see if the oil turns to mayonnaise. You will find out very quickly. If the oil goes bad then you have the pain of replacing the liner seals. They are still available. I've not written up the job but https://www.renault4.co.uk/forum/media/albums/blanche-the-1990-savanne.200/ was about exactly this.

 

[motzingg]

Malcom, thanks for the reply and thanks for providing a wealth of info on the site.

I guess at this point, all i can do is hope for the best.

would love to take the time to do a proper rebuild but the middle of summer on the farm is not a great time to be down on the skiddy

 

[motzingg]

Checking back to close the loop,

Some pictures of the job as promised:

Here is the engine in situ for anyone who wants to know what it looks like to have a 60s compact car motor in a 70s American skid steer!


Getting after it, I noticed the break away torque on these head bolts was very low, I've noticed that especially on aluminum head/iron block engines that get overheated, or they weren't torqued all the way, who knows.


Head gasket blown out between the two middle cylinders, into the water jacket.. Other than that everything confirms the previous owner saying it was rebuilt a few years ago.




Back together and running, all in the job took about 6 hours over 2 days, most of that time spent scraping the ex/int manifold gaskets, haha! Really not bad all things considered. Nicely designed simple little motor.

 

[motzingg]

So now the follow up questions: (and I apologize for writing a novel)



Everything went together pretty well, the only thing I struggled with was getting the head set on the block square, with the intake and exhaust already installed it was a bit of a fight to find the locating dowel and clamp everything down while keeping track of the pushrods and everything else. Having to perch in the cab of the skidsteer, hold myself in place, and set the head down in the hole. I’m hoping that it all went together clean but seems to be sealed up and working. The seals at the bottom of the cylinders seem to be doing the trick, I’ve run it for about an hour cumulative since the rebuild and not a hint of water in the oil!



Also, I should mention, in between my wife calling me in for dinner, running to the store, and rushing to get done before dark, I forgot to put the oil drain plug back in, poured 2 quarts of oil on the ground, and started it up and ran it for a good 30-40 seconds before realizing my mistake. After doing hundreds or maybe thousands of oil changes in my life, this is the first time I’ve ever actually screwed this up. Good thing these engines appear to be pretty tough, I don’t think I spun a bearing or anything like that.



After assembly, the engine starts better than it ever has. I think the carb may have been leaking air at the base gasket or something. Running however, its very rough, feels like its not hitting right on all cylinders.



In addition to that its developed a terrible oil leak at what appears to be the ‘front’ (opposite of flywheel) main seal. This might have been leaking before, but its much worse now. Made worse by overheating? Running dry of oil? Is there anything else up in that area that I might have forgotten or messed up with the HG job?



The radiator cap was definitely bad, which I think is what lead to all these problems in the first place. A new 16# cap seems to have solved the issue for now. At some point, I might replace the very old and busted up radiator with a modern one with an electric fan, but it’s a ways off.





So I have a few things on the agenda before I put it back to doing hard labor around the farm, I don’t want to have it die out in the field or do worse damage.



First of all, the rough running and clatter, possibly a slight difference in HG thickness or just the general vagaries of reassembly might have set my valve adjustment off? This is on my list. It really sounds like a periodic ‘rocker hitting tin’ type clatter, anything else that might be causing this? Doesn’t sound like a rod knock to me. Is there any chance the gasket could be far enough off that a piston could be tapping the edge? I noticed the gasket was notched for the valves, could a valve be catching the gasket? Having only one locating dowel, it was dicey going together.





Second, the ‘front’ main seal… is this something that can be replaced without dropping the oil pan? Its actually very easy to get to with the engine in the machine, but if the pan has to come off, its easier to pull the engine. Is there any chance that something else in the area (appears to be coming from behind the crank pulley/ timing chain cover) could be leaking?



Third, as I’ve never done it, I was thinking it would be good to check the ignition timing and distributor advance. Any suggestion of what the base timing should be set to, keeping in mind this engine gets worked hard. Its not unusual for me to stall it a couple times when I’m running in the dirt.



Thanks in advance for any advice!

 

[motzingg]

Attempting to answer some of my own questions here (and for posterity)

I did find the continental manual through another post on this site, also found the pics of Malcom's gordini engine and realized that as fitted into the cars, these engines dont have a front main seal. Pictures being worth a thousand words:




So my engine is there on the left, with a V-belt and water pump driven off the 'front' which is of course the rear in the Renault 4 and also in my skidsteer.

As i'm trying to source the automotive parts rather than paying ski-high prices for the 'tractor' parts, do you guys know if there were any auto applications for the rear pulley drive motor? Worst case, i'll pull it apart and measure and try to source a generic lip seal. It does look like it will come off with the tin cover so thats good.

So the question that is applicable: Does the timing chain cover come off without breaking the oil pan seal?

 

[motzingg]

Ah yes and one more...

the continental manual says to do a re-torque after 5 hours. I think i'll do it along with setting the valves at 1 hour, should i do it again at 5?

Is the procedure just to crank on them up to 50 ft lbs again? Or should i back them off half a turn and bring them up to 50?

 

[motzingg]

Found this picture on ebay, appears to be a standard lipped shaft seal, and the cover held on with a conventional flat paper gasket.

Should be something i can measure and order from a generic bearing and seal shop.

 

[Andy McGhee]

Ah yes and one more...

the continental manual says to do a re-torque after 5 hours. I think i'll do it along with setting the valves at 1 hour, should i do it again at 5?

Is the procedure just to crank on them up to 50 ft lbs again? Or should i back them off half a turn and bring them up to 50?

A lot of R4 owners with 688-engined cars do it this way:
- Torque the bolts in the correct sequence
- Set the valve clearances
- Run the engine until the engine fan kicks in (I know your set-up is different)
- Let the engine cool down completely (the French RTA manual says at least 2 hours)
- Back off bolt 1 by 1/4 of a turn and then retorque it to the recommended figure
- Same procedure for the remaining bolts - following the correct order
- Check valve clearances again

It sounds from what you say that the gasket failure might have been caused by loose head bolts.

 

[motzingg]

Andy, thanks for the reply. Since this engine was rebuilt ~3 years ago - less than 100 hours of run time probably- by someone in the USA where these engines are incredibly rare, my guess is that the re-torque was not done. A fellow was in the process of a full restoration on this machine, had the engine rebuilt, and had a heart attack before he ever heard it run, so when i took over and finished the project, this was something i never knew to do.

The breakaway torque was probably less than 15 ft lbs, but the engine was also 1 gallon low on coolant and overheated badly enough to seize, so its a chicken-and-egg type situation.

I saw .006-.008" on the valve lash adjustment. I can say by feel some of them were closer to .020, hopefully the retorque and lash adjustment gets my smooth running engine back.

 

[malcolm]

We don't have that seal on the Renault 4. We have a weird set up where the pulleys are driven from the flywheel end. Where the engine was used in transverse engined cars after 1984 (super 5, 9,11 etc) they had the pulleys on the same end as your engine. They use a normal main seal. It's the first time I've seen photos of one of the engines over there. Yours doesn't look like any of the cars so it might have been modified in the US.

The valve clearances are quite small. 0.15mm inlet and 0.2mm exhaust. Definitely worth checking after you have the cylinder head off.

For rough running there is a breather hose that connects to the bottom of the carburettor. That should have a 1mm hole size restrictor in it which is often left out when the hose is replaced. Blocking that hose completely is good too. Otherwise it's a simple engine. Worth checking the points and timing https://www.renault4.co.uk/tech-points.htm

 

[motzingg]

You are referring to the Vacuum advance hose going to the distributor needing a restrictor? I will check that, definitely can fabricate something or maybe even scrounge up a random carb jet that will jam in there.

I saw this excellent article as well

Mechanical Advance Wear and Pinking

We would call it 'ping' or 'knock' over here... funny how that is. I will do a full service on the distributor and check the advance, this could well be the problem and contributed to the overheating.

 

[malcolm]

It's not the hose to the distributor. There is a hose that goes to the bottom to the carburettor or inlet manifold. That needs to be restricted (like the factory did) or blocked. Otherwise the air/fuel mixture gets too lean.

 

[motzingg]

Malcolm,

would it be this one? (red arrow)


There is a black plastic fitting near the fuel inlet, it has several hose barbs sticking off of it, but only one of them seems to do anything when i cover it with my finger, aka, ported to inlet vacuum. The other outlets are seemingly blocked?

The hose routes back into the inlet manifold.

It wasn't hooked up when i bought the machine and i just guessed at the connection, other than that i don't see any other untapped vacuum ports.


Based on the sheet metal plate with 3 studs, i'm thinking this carb is meant for an automotive style air cleaner, currently its hooked to a 'tractor style' one with a large rubber hose. I don't have anything hooked up for PCV either, the port on the valve cover is just open, but its on my list to fit a small filter.

 

[angel]

In addition to Andy McGhee's procedure of torquing head bolts, Renault recommended another retorque after 600-1000 kilometers of driving (can't figure out what would the equivalent of operation hours be).

Did the clatter you describe go away after resetting rocker arm clearance? If not, it may be caused by the timing chain slapping against the guide on the timing chain cover, if there is one on your cover (looks rather different from the Renault one).

 

[AdamWilkes]

The 'rocker hitting cover' noise is possibly exactly that - mine did that after I over-tightened the rocker cover a little. I think it may have squashed over the years, too - I loosened the bolts a little and noise went away

 

[motzingg]

Its been a busy summer and it took me until last weekend to get back into this. I've used the skiddy a couple times for small jobs but mostly trying not to run it hard.

I pulled the valve cover and noticed that the front (rear in a normal engine) most stud on the valve cover was noticeably loose.

I started doing the valve adjustment then i thought better of the stud being loose, went to torque it back down and it went from righty tighty to righty loosey. Pulled out all the threads in the head. So either it was loose when i put it back together and the forces slowly stripped it out, or it stripped out awhile ago, or something else dumb happened but anyhow it is what it is.


When i checked the rocker clearance, the front few rockers were over .050" like over a MM!! I snugged them down and test fired it just to see if that resolved the rough running and sure enough it did.


M7 helicoils are available but not exactly common this side of the pond. The only time i ever see m7 on anything its Peugeot, Motobecane mopeds, is it a french thing?

It looks like there is plenty of clearance to just tap it out to an M8 and use some lower grade allthread. Fine pitch on a high stress application into cast aluminum just seems like a bad idea all around. My plan for when i get back on this is to pull off the whole rocker assy and tap that one hole out to m8x1.25 and screw in a ~150mm ish long piece of 8.8 all thread, run a nut and washer down on it to hold the rocker shaft, and drill the hole out in the valve cover and secure it with a nut.

sounds reasonable? I could tap out to a M7 helicoil but it just seems like more work to put the bad design back in. Once i get it all apart and take the rocker shaft off i'll look everything over and make sure i'm not missing anything.


thanks again everyone who's chimed in and helped me sort this out. Hearing it run smooth with the rockers snugged up makes me feel good that nothing deep in the engine is hurt too bad.

 

[AdamWilkes]

Just to say that a Helicoil insert generally seems to make a fixture stronger than original in aluminium as the aluminium doesn't suffer the friction of tightening any more and the actual aluminium part has a larger surface area than new. The aluminium just sits there whilst the helicoil does the hard work, and the result is better than new.

 

[motzingg]

Yeah I just don't like m7 in general, the pitch is too fine and the threads don't have enough root cross section into soft aluminum casting.




M8*1.25 worked perfectly! The vacuum in the picture along with just going slow and clearing chips kept everything nice and clean.

Also you guys were right about the rockers hitting the cover, adjacent to the hold down nut, the top of the cover had pulled down and was running the rocker arm.

I used a large drift and a block of wood to punch the cover back into shape.

All the rockers adjusted and retorqued the head, she runs better than she ever has. Settled down to a beautiful low idle. It would never idle that low before. I think the bolt has been stripped since I got it and has been working it's way out of the head making the rocker lash worse and worse.


Time will tell on the front (rear) main seal leak. I might have slightly overfilled the oil, and running it on a hill plus the uneven firing order might have been too much and pushed it out or wrecked the seal. Either way it's not terribly hard to fix. I might also put in a new radiator with an electric fan just for an extra measure of overheating protection. The radiator it has now doesn't have a cowl and is in bad shape.