Date: Thu, 9 Apr 1998 11:18:11 +0100 (WET DST)
From: George Windsor
Subject: Keeping cool in the Summer.
Dear all, As a fairly new Imp owner, after a lot of years since my last one anyway. I would like to ask a question. (or 2) Can someone please advise me as to the best cooling configuration for the uncoming Summer months.? 1. Is there any benifit to be had by blocking of the radiater by-pass pipe that seems to take water directly from the cylinder head to the Y joint and then straight back into the block.? 2. Will I get any benifit by removing the thermostat.? 3. I have currently got the heater bypass valve removed so the heater matrix is hot all the time, by keeping the heater running I am taking heat out of the system but the still hot water that returns to the Y joint then goes straight back into the engine and does not pass through the radiator. Is there any benifit to be gained by closing the heater pipes and making all coolant circulate through the block and then cycle through the radiator.? 4. Is the installation of a front radiator necassary for normal low mileage, sedate everyday driving.?
Sorry if I seem to be asking obvious questions but I would really like to know the optimum cooling configuration to avoid any further problems, having lost 2 head gaskets in the last 6 months.
Cheers George Windsor
Date: Thu, 9 Apr 1998 05:33:25 -0400 (EDT)
From: Donnelly Anne
Subject: RE: Keeping cool in the Summer.
Well, I'm no expert at all this stuff, but my car now has a 6 row radiator rather than the standard 3 row. It's (I think) a Jaguar rad, but has been fitted with the top and bottom from the Imp one. They had to open-up the bottom piece to get it to fit.
Since I had this fitted I've had absolutely no cooling problems even on long journeys - Newcastle to Sussex and Newcastle to Weston-Super-Mare.
HTH
Anne
To: imps@coollist.com
From: Bert Clewits
Subject: Re: Keeping cool in the Summer.
Hi George,
First thing to do is have the radiator checked for blockages in the pipes and clean the outside and check the condition of the cooling blades.
This and the standard cooling system should keep the imp engine cool even at 35degreesC at 110 km/H on motorways.
Are you sure the head isn't warped or the block, check the ignition timing, check the thermostat (best is to use a low 80degree one and not the standard 88degree winter thermostat). I hope you don't have false air entering the engine, as then any engine will run extremely hot. (check for white plugs, lean mixture)
If you have a solex carb check for a warped flange.
There can be many other reasons for a hot engine so I don't think altering the cooling system will help.
Hope this helps
Bert
Date: Thu, 9 Apr 1998 13:04:55 +0100 (WET DST)
From: Paul Waites
Subject: Re: Keeping cool in the Summer.
Hi George,
Yes the old headgaskets and cooling are the first problem that new impers get, (the second and third are waterpumps and kingpins)!!
In my experience a standard imp should cope perfectly well with the standard cooling system provided it is maintained in good order....
Flushing out the heater circuit by connecting a hosepipe and backfushing the lot is a good start. Always using good a good antifreeze will keep the corrosion at bay. The imp-club used to make a four row rad several years ago and I think that folk like Malcolm Anderson still do. I had my radiator rebuilt a few years ago at a local specialist and they put a modern high efficiency core in and this seems fine. I also reckon not to mess with thermostats and to make sure that there is no air in the system...
If your cooling system is o.k. and your heater is working fine and you are still getting headgaskets blowing then I would look a bit deeper into the cause, not wanting to alarm a new owner too much but it could be a warped head. I'm sure that some of our more expert engine people will soon be replying to you with more indepth solutions. (Keep your eye on the imp mag the issue of cooling is always popping up)
Hope this helps,
Paul.
____________________________________________________
Paul Waites
Biology Teaching Laboratories,
University of York.
e-mail: prw3@york.ac.uk (work)
paul@waites.demon.co.uk (home)
http: http://www.york.ac.uk/~prw3
tel: 01904 432835
Date: Thu, 9 Apr 1998 14:53:51 +0100 (WET DST)
From: kenneth barlow
Subject: Re: Keeping cool in the Summer.
Hey All. I have a problem with my cooling too. I have put in a recond engine (about 2000 miles ago, so it is run in) and I still have problems. The radiator has been profesonly cleaned out, rodded etc, the system has been flused, no pipes blocked, 78' thermo, and it still gets hot (going by the gauge) we think the gauge is faulty, its not the origonal, but it is matched to the sender. No brakes are sticking. Timing is 100%
Can any one help?
Kenneth
Date: Sun, 12 Apr 1998 07:03:00 +0100 (WET DST)
From: Gary Harding
Subject: RE: Keeping cool in the Summer.
George,
You have asked some very sensible questions. I shall try to answer them.
1. There is a minor benefit to be had by reducing the coolant flow though the bypass pipe. This pipe must not be blocked completely as the pipe allows coolant flow over the thermostat when the engine is cold and the heater valve is off. I have used an old rotoflex bolt cut to around 25mm in length and drilled a 4mm hole down the centre. The bolt is then inserted into the outlet stub pipe from the cylinder head (it will go).
With the bypass pipe back in position the bolt cannot move. I have this mod on all of my Imps with no apparent problems.
2. The thermostat does not reduce the coolant flow to any great extent. For all round use fit an 84 degree thermostat but it must have a small bypass hole and jiggle pin to work effectively in an Imp. Without the thermostat the engine will take longer to warm up with a great reduction in heater performance.
3. Removing the heater valve will improve water flow to the heater but you will have no control over the heater!
4. If you feel you need to make all these modifications then almost certainly you will need to re-core the radiator. I've found they tend to loose their efficiency after around 5 years but usually soldier on for another 5 years or so. If in any doubt about the radiator then get it re-cored. Some of the Imp specialists run an exchange scheme but your local Serck Marston can do the job. Best to go for a 3-core high efficiency core. Once you have done this you will wonder what all the fuss is about.
I hope this has helped.
Gary Harding
Date: Sun, 12 Apr 1998 07:02:55 +0100 (WET DST) To: imps@coollist.com From: Gary Harding <101562.1150@compuserve.com> Subject: RE: Keeping cool in the Summer. Reply-To: imps@coollist.com
Kenneth,
Cleaning the radiator, never mind how professionally, will not work. The core must be replaced, use a 3-core high efficiency core.
Gary
Date: Sun, 12 Apr 1998 05:38:11 -0400 (EDT)
From: Nickcleak
Subject: Re: Keeping cool in the Summer.
In a message dated 12/04/98 05:02:21 GMT, you write:
> 1. There is a minor benefit to be had by reducing the coolant flow though
> the bypass pipe. This pipe must not be blocked completely as the pipe
> allows coolant flow over the thermostat when the engine is cold and the
> heater valve is off. I have used an old rotoflex bolt cut to around 25mm
> in length and drilled a 4mm hole down the centre. The bolt is then
> inserted into the outlet stub pipe from the cylinder head (it will go).
> With the bypass pipe back in position the bolt cannot move.
I have done exactly the same and it does help the heater flow . Another mod i have done is to fit a small electric water pump to the heater water pipe , it flows quite a lot of water through the heater especialy at low rpm , you all know the rush of heat you get from the heater when you rev the engine ....
well it's like that all the time now when in traffic etc ... when you switch the engine off you are able to extract heat from the heater for another five to ten minutes which is also useful . Another side advantage... In my Clan a fan belt flew off once ... i was able to carry on for 15 miles without overheating at reduced speed just due to the circulation provided by this little water pump !
Nick ...
Date: Tue, 14 Apr 1998 05:51:05 +0100 (WET DST)
From: Gary Henderson
Subject: Re: Keeping cool in the Summer.
Hi again
All my comments recently about cooling are based on my Mk 1 with its original 1964 core!!! The fins are still pretty good. The only time it ever seemed to flag was when the fan had ingested a bit of rag or similar off the road, coating the core with a layer of felt.
Cheers
GaryH
From: Gary Henderson
Date: Tue, 14 Apr 1998 03:18:06 +0100 (WET DST)
Subject: Re: Keeping cool in the Summer.
Dear George
The radiators used to block up from new, due to aluminium swarf 'growing' as it corroded in the cooling system environment. Once the radiator has been dismantled & the core has been rodded-through, be careful to avoid any swarf in the water-jacket (e.g. from head planing etc) & this should never be a problem again.
DON'T do away with the bypass, unless you like replacing exhaust valves regularly!
The cylinders tend to have crept down in the block a little over time - this means the top of the block will need a skim (if not done already) so the head gasket actually is squeezed hard against the cylinders.
My Mk 1 Imp has to gain 200 m altitude (a solid haul at about max gradient to hang in with 3rd gear) every day and is then stopped after only about 1/4 mile of level running. It has done 33000 miles since head was last off for any reason. At times when waterpump was dodgy, it did this with the pressure-cap released without any loss of coolant. OK, Wellington isn't classed as tropical but we have seen 28 deg C for some of these journeys.... With the Mk 1 I find more problem with slow warm-up, and I know the thermostat is OK!
Hang in there & remember that it CAN all work as intended!
Best regards
GaryH
Date: Wed, 15 Apr 1998 20:41:40 +0100 (WET DST)
From: Nickcleak
Subject: Re: Keeping cool in the Summer.
> the top of the block will need a skim (if not done already) so the
> head gasket actually is squeezed hard against the cylinders.
yes , so many people skim just the head when it overheats but neglect the block completely , it's just as important and a 100% overheating cure is guaranteed until it runs out of water for one reason or another next time !
exactly the same as with any modern alluminium engine ...
Nick ...
Date: Thu, 16 Apr 1998 07:25:42 +0100 (WET DST)
From: Gary Henderson
Subject: Re: Keeping cool in the Summer.
Hi Nick
A few modern ones are through-bolted which should help. (There are so few AR K-series here that I don't know if it helped them ...) Could be interesting retorquing or undoing those long whippy bolts though!
If desperate, on finding the edges of the water-jacket higher than the cylinders, even careful levelling with a large flat file (using the tops of the cylinders as a reference plane) would be better than just reassembling it & hoping. Don't gouge into the iron bits & make sure to get all the swarf out though!
Cheers
GaryH
Date: Sat, 18 Apr 1998 07:11:20 +0100 (WET DST)
From: Gary Harding
Subject: RE: Keeping cool in the Summer.
Don't forget though that the absolute minimum amount of material must be removed from both cylinder heads and block to minimise the increase in compression ratio. The Imp is already at 10:1 which is high for the design of engine and ignition system.
Gary