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Looks like my project will be taking an interesting turn. I can't seem to free up the rings in #4. My compression is down significantly in that cylinder and I was hopeful it would improve with use. It is amazing how well this car runs considering the issue. I did insert a camera and got a full view of the cylinder. All looks well with the exception of the high carbon buildup. I am still kicking around some ideas but I believe I am going to build another engine over the winter and swap them out in the spring. This will enable me to continue to rehab other systems of the car and keep it moving under its own power. I have another 4.5 in storage to use as the rebuild candidate. Stay tuned and as always, any input is appreciated!
Sorry to hear of this, Guy. I shouldn't be surprised that you already have a replacement engine....you da man! It will be fascinating to see your experience with rebuilding one of these engines.
All looks well with the exception of the high carbon buildup. I am still kicking around some ideas but I believe I am going to build another engine over the winter and swap them out in the spring.
Pull the plug on cylinder 4, and then spray copious amounts of Permatex Gasket Remover in there to soak around the rings. It dissolves carbon very nicely - might be enough to free up the rings on that cylinder.
Sorry to hear of this, Guy. I shouldn't be surprised that you already have a replacement engine....you da man! It will be fascinating to see your experience with rebuilding one of these engines.
Thanks Doug! I am actually not too disappointed. I have to do mounts, TB, oil pan and fuel lines so pulling the engine makes sense anyway. I am still having fun which is what this is all about
Pull the plug on cylinder 4, and then spray copious amounts of Permatex Gasket Remover in there to soak around the rings. It dissolves carbon very nicely - might be enough to free up the rings on that cylinder.
Hilton, I will try that, thanks! I have been filling the cylinder with some marvel mystery oil for a few times but still no love. I was also considering introducing a little water into the intake in the hopes of promoting some detonation to help free them up. For some reason, that method always scares me a bit but has worked wonders in the past
I can't take credit - I got it from other rennlisters (Jim Corenman and Imo000).
I've since used the stuff in a couple of cars. When it comes to removing carbon, the permatex gasket remover works better than the 3-bond foaming intake cleaner stuff my local parts place sells for carbon cleaning.
I can't take credit - I got it from other rennlisters (Jim Corenman and Imo000).
I've since used the stuff in a couple of cars. When it comes to removing carbon, the permatex gasket remover works better than the 3-bond foaming intake cleaner stuff my local parts place sells for carbon cleaning.
Good to hear some first hand feedback Hilton! Have you or the others had a look before and after to see the effect? How much smoke and crap out the exhaust when you start it up?
I was discussing the possibility of using Loctite or CRC gasket remover with Roger last week, and told him that I have used both and they each work really well on hard carbon ... but that I didn't know about using either down a plug opening, and then running the motor to purge the carbon.
Any comment on these? Likely they have the same/similar active ingredients.
Excuse the diversion Guy ... but thought you'd value the info too.
Last edited by Dave928S; 09-18-2014 at 06:21 AM.
Reason: added extra
Good to hear some first hand feedback Hilton! Have you or the others had a look before and after to see the effect? How much smoke and crap out the exhaust when you start it up?
I was discussing the possibility of using Loctite or CRC gasket remover with Roger last week, and told him that I have used both and they each work really well on hard carbon ... but that I didn't know about using either down a plug opening, and then running the motor to purge the carbon.
Any comment on these? Likely they have the same/similar active ingredients.
Excuse the diversion Guy ... but thought you'd value the info too.
Yes I had a cheapy ebay usb endoscope (which Andrew O posted a link about a couple of years ago).. The car was an Audi A6 30V V6 - I couldn't see the piston tops through the carbon. I went looking in the first place because oil consumption had gone up to around 1l every 2-3k kms.
I rigged up a short straw and some 3mm silicone vac hose to spray the gasket remover directly onto the piston tops - enough to fill the piston dish. Let it sit for an hour or so - the engine was warm, but not too hot to hold a spark plug in my hand.
There was a *lot* of thick thick white smoke on restart - I jumped in and drove it under load for a few km's and it was smoking under throttle for about 2km's. It was hard to start - turned over a few extra times before starting.
Afterwards I could see the valve cutouts and top of the pistons clearly, although there were a few small spots of carbon on the piston still, but not enough to bother treating again. Oil consumption was much improved afterwards (about 1l per 5k kms), so I'm guessing some of the rings came unstuck.
I'd previously used Threebond Engine Conditioner - it resulted in much less white smoke than the gasket remover. I didn't have an endoscope however to compare before/after.
Lastly - for reference, here's the gasket remover I used:
MSDS says its mostly methylene chloride. I noticed that the USA also has a VOC-free version which is mostly water, so probably doesn't do the job as well.
MSDS says its mostly methylene chloride. I noticed that the USA also has a VOC-free version which is mostly water, so probably doesn't do the job as well.
Paint stripper.
I might play around with some , using my series 3 LR as a crash test dummy
Thanks for the detail Hilton ... that's great information. The MSDS on each of these shows they both have the same amount of Methylene Chloride as the main ingredient, and so also should do the job.
Looking at the MSDS sheets it's OK on aluminium ... but as its effectively a paint stripper should obviously be kept away from such surfaces in the engine compartment.
I know Greg Brown has also been looking for an alternative to chipping off rock hard carbon, after finding water was less than brilliant at removal.
I'll start a separate thread on carbon removal once I've done my GTS .. which will be in the next few weeks .. with some before and after scope views.
I can't take credit - I got it from other rennlisters (Jim Corenman and Imo000).
I've since used the stuff in a couple of cars. When it comes to removing carbon, the permatex gasket remover works better than the 3-bond foaming intake cleaner stuff my local parts place sells for carbon cleaning.
I don't think I suggested using it in-situ, I haven't tried that-- just on disassembled parts. My concern would be washing the lubricant off the cylinder walls, but I am watching with interest. I assume an oil change would be advised afterwards?
I don't think I suggested using it in-situ, I haven't tried that-- just on disassembled parts. My concern would be washing the lubricant off the cylinder walls, but I am watching with interest. I assume an oil change would be advised afterwards?
I changed the oil immediately afterwards just in case. I also haven't done this to a 928 yet - although the A6 had an alloy block too.
Interestingly, my local auto pep-boys equivalent now stocks this stuff: http://www.nulon.com.au/products/Aer.../#.VBrykRY0-K8
The instructions include using it to clean the piston tops of carbon by spraying directly into the cylinders - the MSDS on it tells us nothing about its composition however.
Tried a few things to help free the rings including water injection, seafoam, and even some gasket cleaner. Drove very spirited afterward but no dice. This cylinder is just not coming around.
On a positive note, I tested my spare M28 engine today at 180, 190, 200, 200, 200, 200, 190 and 190 (cold w/oiled cylinders). That's much better than the high of 170 that I got out of the current engine in the car.
Looks like I have a winner. I am gonna break it down a bit over the next couple of weeks and decide how far to go with it.
On a positive note, I tested my spare M28 engine today at 180, 190, 200, 200, 200, 200, 190 and 190 (cold w/oiled cylinders). That's much better than the high of 170 that I got out of the current engine in the car.
Looks like I have a winner. I am gonna break it down a bit over the next couple of weeks and decide how far to go with it.
So whats the plan? Rebuild the spare? Or drop it straight in and rebuild the original engine?
Tried a few things to help free the rings including water injection, seafoam, and even some gasket cleaner. Drove very spirited afterward but no dice. This cylinder is just not coming around.
On a positive note, I tested my spare M28 engine today at 180, 190, 200, 200, 200, 200, 190 and 190 (cold w/oiled cylinders). That's much better than the high of 170 that I got out of the current engine in the car.
Looks like I have a winner. I am gonna break it down a bit over the next couple of weeks and decide how far to go with it.
Those are great cold compression numbers Guy.
It should go like stink when you're done.
Not dead.....just decided to MOVE. Had to put the 928 project on ice while I marketed by house and made a short move 6 miles away. The best part is a BIGGER garage!. Here is one of my babies in the new garage. Parked in the short bay temporarily
So, as soon as I unpack the hoard of parts I should be able to get to work on the engine swap. I drove it over to the new house, trouble free. Best 7 cylinder car I have ever driven
09-16-2014, 11:25 PM
