| Author |
Message |
    
Rich Cwik (66.2.65.178)
| | Posted on Friday, 03 January, 2003 - 12:07: |    |
Does anybody there remember reading an article about R-types overheating due to a blockage in the rear of the engine block (due to rust buildup) I have an r-type that runs quite cool( never over 75 degrees) but a friend of mine has one that can peg the temp gauge in 10 minutes-and it's got a new water pump and the gm 4-core radiator conversion,as well as twin electric fans added on. |
Jim Bettison (203.166.57.11)
| | Posted on Friday, 03 January, 2003 - 12:36: | |
Rich,
Where are you located? Are you a member of the RREC in UK? My reason for asking is that the RREC Bulletin (published for members) is in process of publishing an extensive article on matters related to overheating; the second part of the article is due in the next issue of the Bulletin.
The overheating you mention is a well-known phenomenon to be found in the B-series engines (basically, the engine fitted to the Bentley MkVI and R-type, the R-R Silver Dawn, the R-R Silver Wraith and the R-R Silver Cloud (first series) and the Bentley S1. The treatment to fix the problem is fairly extensive, but not heroic (as a surgeon might say), and for a case as bad as you have described will almost certainly involve removal of the engine and strip-down to get the waterways and water galleys clean. When one has gone that far, it becomes attractive to do checking/repair/refurbishment of other things - which I won't go into immediately - that will probably never be as cost effective as when done at the same time. The end result can be very rewarding, if done properly and completely.
The basic question is, How far is your friend prepared to go?
Look forward to your reply.
Jim Bettison.
(PS: I'm in South Australia) |
richard treacy (217.162.170.5)
| | Posted on Saturday, 04 January, 2003 - 03:25: | |
Is your friend using a genuine and new thermostat ? It should have a bypass valve integral otherwise the car will overheat. I never had an overheating problem with my R-Type in 400,000 miles except when the radiator was blocked once and the thermostat failed another time. |
Martin Cutler
Unregistered guest
Posted From: 211.30.112.172
| | Posted on Tuesday, 15 June, 2004 - 21:07: | |
My Mk Vi 4.5 litre has been slowly getting worse in the overheating department. I have a great gizmo that introduces compressed air into the hose pipe that you are running into the radiator. I got a lot of gunk out of my radiator, but failed to get the thermostat out of the block. I put it back together and noticed a good improvement in the temperature gauge, however, it is still not as good as it was 6 or so years ago when it first went back on the road. I am going to drill and tap the two holes in the top of the thermostat, and try to use a puller to get it out, as the thermostat seems well and truly stuck. I will do this AFTER I have purchased a replacement thermostat just in case I destroy it in the process. Then the plan is to stick the hose with 120 psi of compressed air into the block and see what comes out the other end, wish me luck! |
Bill Coburn
Grand Master
Username: bill_coburn
Post Number: 177
Registered: 4-2003
| | Posted on Tuesday, 15 June, 2004 - 23:07: | |
Through sheer ignorance when I 'did up' my first RR engine in a Silver Dawn, the thing would run hot if I looked at it. I pulled the whole lot out again re-stripped it to the bare block had it soaked in the local engine reconditioner's hot tank for a week which had not a schmick of an effect on it. Noting that the water passages in this 4 1/4 litre block resembled the bronchial passages of a committed smoker and that the stalactites and stalagmites were iron oxide I decided that good old brickies acid or more correctly hydrochloric acid was a suitable solvent. I made up plates for the hole where the water pump bolts on and one to cover the rear end. I put a bolt where the water tap normally resides and coated the newly bored and honed cylinders (complete with full length liners) together with the top of the block with thick impervious (to acid) grease. I levelled the block in a safe outside area and filled the thing with dilute acid right to the brim. And left it over night. Drained and flushed it the next day and got an incredable amount of rust and muck out. For the first time I was able to pull out the copper distribution tube that runs under the exhaust valve seats. Another fill that night and more muck emerged. Rigged up a globe on the end of some wire fed by a car battery. The globe would fit down the various holes in the top of the block and with a tiny mirror glued to the end of a knitting needle inspected the interior. Almost better than new. A few residual bits remaining and they came out after a third clean. After the umpteenth flush filled the block with a warm solution of good old carbonate of soda as a neutraliser. Did that twice then for good measure flung the block back in the hot tank. That block I swear was verging on surgically clean. Reassembled the whole lot and to this day the engine has never overheated. Mind you there has been religious attention paid to the antifreeze/anticorrode coolant properties. The 4 1/4 litre was the worst for this problem because of the restricted nature of the water passages. If a 4 1/2 has got to this stage - boy it must be crudded.
In closing I must have a shot at the first responder to Rich's question. The inference is (correct me please if I am wrong) is if you are not a member of the RREC ( a club that I have the utmost respect for) - go find the solution somewhere else unless of course you join. I keep appealing that our mission (what a dreadful word) surely is to preserve the cars not preserve the Clubs. I am not remotely interested in the owners just the cars. There will be no more so look after what we have got! |
Alan Padgett
Unregistered guest
Posted From: 172.185.54.91
| | Posted on Monday, 02 August, 2004 - 07:39: | |
In my 40 odd years of playing with the Mk Vl and R Type blocks, it is almost inevitable that the rear cylinders will be very choked with silt and rust formation. I have used special sharp tools to chip away at the adherences and solidified corrosion but taking great care not to damage the water jacket. The use of rust removal by chemicals like Phosphoric Acid is not my idea of a solution. The fact that the water jacket can too easily be eroded away to a danger point is a symptom of the huge mileage these cars have done but a terminal matter if the walls get too thin.
See how much loose rust you can remove and then use a proper water additive to prevent further errosion ( see the relevant R-R Service Bulletin ) Then try the engine with a new radiator core and see the result.
Alan |
Richard Treacy
Grand Master
Username: richard_treacy
Post Number: 267
Registered: 4-2003
| | Posted on Monday, 02 August, 2004 - 08:48: | |
That was Bill's first R-R project. Midnight Blue Silver Dawn SDB94. Canberra 1971. Kind of like going over a Silver Spur today in age terms.
The result was stunning. |
Bill Coburn
Grand Master
Username: bill_coburn
Post Number: 212
Registered: 4-2003
| | Posted on Monday, 02 August, 2004 - 08:53: | |
Well Alan I wish you luck. I would have done this treatment to I suppose some twenty engines and there has never been the slightest indicator of damage. The removal of corrosion products from these blocks is harder than trying to perform a personal haemorrhoidectomy. The products are very hard and so strongly bonded to the metal that 'chipping' away will often break off some of the original metal. The acid (muriatic) is very dilute and very slow acting. In fact if you do it in Winter it is very difficult to get any reaction. I have not used phosphoric acid for removal as I understand that the action here is to convert the iron oxide to an inert phosphate which remains stable. This doesn't get over the problem of removal it simply protects the barnacals that are already there. Although I have not done this work for many years I remember that I was given a rather nice crystalline acid to use, that certainly put paid to any fear of block damage. As I recall (the memory is not the best these days) it was an ammoniated citric acid and is/was used in bottle washing plants which can't use anticorrosive additives for health reasons but their mechanisms can get very crudded with corrosion. As to using a new radiator on a dirty block I am sure the manufacturers of radiator cores would be delighted. The main reason cores 'block'is that bits of the barnacles break off from inside the block and are pumped up to the header tank where they lodge usually very firmly in the radiator tubes. The only way to remove these is to remove the top and bottom tanks and 'rod' the tubes out. Not infrequently the barnacles are so firmly wedged that vigorous rodding breaks the wall of the tubes and you have a new problem. If you have any suspicion about the cleanliness of the block when fitting a new radiator core, you should rig up a suitable filter on the top of the engine to protect the latter. Finally, once having got the block clean it should last forever using the correct additives. I have always been amazed at how clean blocks have been on everyday cars that have always had antifreeze etc in them but with no TLC on them. As to concerns about acid damage I now recall a desperate action by an owner in the town who inherited a rather neglected Mini Moke. The interior of that engine was almost jammed with rust. The obvious solution ws to replace the unit given the cost and availability but the youthful owner observing my practice decided he would do it his way. He drained the cooling system and filled it with dilute hydrochloric acid and ran the engine for an hour. That fixed the problem and the little thing is still running. That procedure however I would not recommend! |
Kim Stapleton
Yet to post message
Username: kim_stapleton
Post Number: 1
Registered: 5-2003
| | Posted on Monday, 06 September, 2004 - 18:48: | |
Guys if anyone has done large amounts of research into overheating it would have to be Lloyd Missen. He has a Silver Dawn and can now tell you the temp in about 12 different parts of the block.
But seriously he has done a lot of work on his Dawn in regards to overheating and would be a good resource.
Cheers,
Kim |