Lotus Elan and Lotus Elan Plus 2 Forums

Hi Guys,

From what I've read I believe it is recommended practice to thoroughly wash and scrub the cylinder bores with a hot water and laundry detergent mix using a nylon dish brush after any block has come back from a machine shop after boring and honing. The final test being whether a white rag remains white when rubbed across the cleaned bore.

Is this actually true or just folklore? What do you guys do?

I find it hard to believe that professional engine builders manually wash and scrub cylinder bores with laundry liquid prior to assembling an engine. Usually blocks come back from a machine shop looking brand spanking new having been chemically cleaned and furthermore I can't see this practice ever being used during OE engine assembly!

Any washing down with water will inevitably lead to light surface rusting even if the parts are dried very quickly afterward. I can't see this being good either.

Regards

Fine abrasive particles from the honing can be adhering to the walls. Removing them by washing and scrubbing and then re-protecting the bores to prevent rusting is well worthwhile. For long term storage I use CRC soft seal.

I am sure the best engine shops would do this before assembling a freshly bored and honed block

cheers
Rohan

What I used to do was scrub with water/detergent and then wipe down the bores with acetone using a lint free (probably overkill) cloth and finally coat with engine oil.

That's the bores sorted, but the rest of the block could be filled with all sorts of nasties. Ideally, all core plugs and oil way plugs should be removed so the block internals can the thoroughly cleaned. it should then be washed in a giant dishwasher A local (quality) engine builder should be able to do this for you for a small charge but it is well worth the expense. These use hot, soapy water but there is no issue with rust as they are too hot to touch and dry quickly.

This may give you an idea;

https://mobiloil.com/en/article/car-mai ... -an-engine

After all that I have some special paint for the inside of the engine block to keep that sealed up as well!

Kurt.

Fresh out of Bath Uni in 1980 I joined Ford as a management trainee, my first 3 month assignment was to quality control in the Dagenham engine plant.

One of my tasks was to strip down a Kent engine, clean everything to measure contaminants, all critical dimensions were measured & then the engine was rebuilt & it was dyno tested. If it failed the latter, I would have to strip down & rebuild it again...

Everything was washed down in alcohol & captured & measured, I can still see that swarf / particles in my minds eye, it was very small (smaller than a pinch of salt..). Blocks were washed down very aggressively after machining to make sure 99.x% of contaminants were removed, can't remember what the cleaner was, but looked almost like detergent & was definitely hot!.

BTW my engine passed first the dyno test first time

2cams,

I had a block bored by the engineers that I use, with an acid dip bath. Prior to boring, I always remove all core plugs and oil gallery screws. They usually have to be drilled out, but with care, that's not a difficult job, and well worthwhile, to clean out the oilways.

However, on returning to my workshop, with the block on the bench and some digging around, I noticed that there was still a hell of a lot of crud still present around the bottom of the bores. The block prior to boring, was on standard bores, so had never been worked on prior to this rebuild, and went out to +20 thou. I mention this, as it was obvious to me, that after nearly 50 years of use and sitting around, probably full of a rusty mix of coolant for a lot of that time, a large amount of silt and crap had compacted at the base of the bores, and an acid dip bath did NOT remove it.

I spent a whole day, with screwdrivers and home made tools, scrapping away through the core plug holes to remove this crud, ending up with a large pile on the bench. This mess took up a lot of volume in the block where coolant should have been, and I firmly believe that that is the cause of a lot of the overheating problems in twincam engines today.

Most professional engine builders, if any, would not spend the time cleaning a block out for a day, but home builders can, and should. It makes such a difference. This engine has spent thousands of miles gadding about in France, in 38 degrees of heat, with no issues whatsoever.

You have a chance when building your engine, to do it right. Be thorough and it will reward you.

Leslie

Totally agree Leslie, the crud in my block was above the rear core plug but a lot of scraping got it out; it seemed to me to comprise rust and also core sand. It runs nice and cool even with only the original electric fan. I had a few baby Elans in OZ in the 60's and 70's and never suffered with overheating, maybe no rubbish in the block yet.

Years ago, I had an over heating problem with a high performance Ford 289. Decided to go through the engine and had the block professionally cleaned. Upon getting it back, I decided to try cleaning around the bores through the core plug holes. Like Leslie, I cleaned out casting sand, rusty wire used in the casting process, and more crud and corruption than I thought possible. After the re-build, amazingly enough, I never had an over heating problem again. It is possible, that the block cleaning process from Ford's foundries is a bit less than satisfactory, though I never had that problem with the pre-cross flow engine in my S7.

...just been through this with a Mini block.

Pull the freeze plugs

Put it in a molasses bath for a week - did a great job of removing the rust from the water galleries.

Then steam cleaned it (oil plugs removed).

Finally, wait for the Missus to go shopping and get it in the dishwasher, with 2 cleaning tabs

Back out let it dry from the retained heat and then WD40 on the bores as they start to rust before your eyes.

Then some time with the blow gun down the galleries, then lots of time with the gun cleaning brushes and cellulose thinners. Also coppper wires and strips of an old shirt dipped in thinners - keep pulling through the galleries, and change your rag, until it comes up clean

Keep rubbing the bores with clean rags until they come up clean

Job done

Hi ' just like add another item I found very good for cleaning . It's a pressurised wax oil gun . I used cellulose thinner in the gun instead ' the nozzle is 4 mm with lots holes around it . 120 psi from compressor , it goes in all oil galleries . Blows liquid thinner from nozzle at high pressure in all directions, works a treat.
Cas

There are some great suggestions above.
I would add: Don't clean the engine bores with brake clean or solvent-there will be oil in the pores of the metal left over from the machining process and you need it. Years ago I was working for a Volvo dealer and we had a run of failures of engines rebuilt in our shop by a superb (English) mechanic. It was finally determined that he was washing the bores thoroughly with solvent before assembly and removing the oil in the pores of the bore walls. Once he stopped that we had no more problems.

At the other extreme-I have an old English sports car that I rebuilt the engine on-I did as above and also did what I usually do, soak the bores and the piston rings in oil during assembly. The problem was that the rings provided (by Venolia pistons ) were chromed... Ten thousand miles later I finally gave up all hope of the rings bedding in and replaced them with Hastings cast iron rings. I did some research on the net and found that leading US engine builders were putting NO oil on the bores or rings during assembly! I followed their lead, although I did spray a light coat of WD40 on the bores and after a very brief bedding in period the rings are sealing and the engine is better than it has ever been. This is an Aston Martin engine so this was no small undertaking.

Thanks Guys for your suggestions. I'm fairly confident the coolant passages and oil galleries are OK because I made a point of removing all the plugs and cleaning everything out thoroughly before handing over the block to the machine shop for acid dipping and reboring. The main lot of crud was in the coolant passage behind the cylinder drain plug at the LHS rear of the block after it was removed. I assume it all collects there being the lowest point. The cylinder block would probably have been water tight even without the plug! - had to dig it all out with a screwdriver and run a tap down the thread to clean it up.

My main concern is just the bores after reboring. In the past I've used a garden hose in the backyard and a bucket of hot soapy water but because of the light rusting that almost immediately occurs it got me thinking - is this really necessary??

I think I'll do it anyway for peace of mind. I guess it depends a lot on the process (if any) the machine shop uses to clean the block after it's bored. I'll wait for one of those hot 40+ degrees C summer days we have here in Australia and hope the bores don't stay wet for too long!

Further to what I wrote above. I have recently removed the engine from one of my Sprints. I call it my workaday car, because it is not perfect and I do not mind so much if it receives another stone chip through much usage, 40k odd miles since restoration by Mick Miller. I was fed up with all the oil leaks and I knew that the valve guides needed replacing again, so bit the bullet.

Now this car travelled to Classic Le Mans in 2010 and for a 3 week sojourn [spelling] around France, when the mercury most days hit 40 degrees. It never missed a beat and the standard radiator and cooling system coped admirably with the heat. At that time, the car had travelled approx. 11k miles since restoration.

I am fairly diligent on servicing, and change the coolant every 2 years, but I had noticed, in subsequent years, that the cooling system and fan has had to work a little harder, and that the engine was running a little hotter, and during this engine rebuild I was looking for the reasons why. The pictures probably explain everything and confirms what I have found in the past. Almost half the water capacity of the block taken up with shite!

"What are the white deposits?" I hear you all cry Well, I am assuming, I know, that it is limescale, as where I live, the water is extremely hard, and I have mixed the coolant with tap water. In future, I shall always use distilled water for the mix.

The good news is, that after 40k miles, the bores of the block do not show the slightest bit of wear, no lip, and still have honing marks, and I shall just fit new rings as a matter of course.

Leslie

When I had the engine out of mine i found the rear water jacket plug was badly corroded, and slight weep. So I changed all the plugs. As part of that I removed a significant amount of rusty sand like material from within the block that had built up in a similair locations/fashions to yours.

It running a little cooler according to the gauge but I think that's the air holes i added to thermostat or slightly poor connection to the temp sender that any rear change in temp.