Electric water pumps.

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suffolkpete
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Re: Electric water pumps.

#21 Post by suffolkpete » Tue Dec 15, 2015 1:56 pm

Join the queue behind me ;)
1974 Rover 2200 SC
1982 Matra Murena 1.6

zipgun
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Re: Electric water pumps.

#22 Post by zipgun » Tue Dec 15, 2015 3:04 pm

Modern cars with electric water pumps only have about 1/2 a pint of coolant :)

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JPB
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Re: Electric water pumps.

#23 Post by JPB » Tue Dec 15, 2015 3:26 pm

zipgun wrote:Modern cars with electric water pumps only have about 1/2 a pint of coolant :)
I found this when I was running the MK7 Golf Diesel as a daily car, the problem was that the rest of the coolant was sloshing around on the floor thanks to the heater pipe, whose vibrating about in an unprotected hole where [the pipe] came through the bulkhead had left me with only around the half pint or so remaining in the expansion tank.
Also, I've driven a mini 380 miles with even less than that in its system and it was only slightly wrecked when it got us home. Ah, the joys of basic minis, only equipped with speedometer and fuel gauge so no need to worry! :lol: Wretched thing was so hot that its bonnet was starting to sweat..
:oops:
J
"Home is where you park it", so the saying goes. That may yet come true.. :oops:

History
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Re: Electric water pumps.

#24 Post by History » Tue Dec 15, 2015 8:56 pm

I know that a Stag engine can be made reliable. But any engine that requires careful maintenance and maybe careful use is IMO not a good bet.
Here's a list of design short comings.

Water ways in block too small because the engine was originally 2.5 litres. It was bored out to 3 litres using some of the cooling jacket space.

Over long timing chain.

Cylinder head studs not perpendicular to the block face causing side ways load on head gaskets causing fretting as engine cools down or heats up.

Because of the extra con rods on the crank pin. The crank pin is wider and the main bearings too narrow for the power produced.

The above has never been truely sorted except the timing chain being converted to duplex.

I have heard many discussions over the water pump. Some say that if the water pump was belt driven then the belt could break. Which to me is daft because in 50 odd years I have changed many belts because they are worn but very few because they broke. In other words proper servicing. Which is exactly what the Stag fans promote.

The Rover V8 was fitted to many types of cars and vans. The Stag engine was only fitted to the Stag.

One reason the Rover V8 wasn't fitted to the Stag was that it was in short supply.

The Truimph 2000 Mk2 saloon was developed from the Stag not the other way round. The saloon was also meant to have the Stag engine.

OHC engines aren't harder to work on than OHV engines just a different layout. The Stag layout is not good.

Hart Racing tuned a Stag to 260bhp. However racing cars are serviced every race say 200 miles.

A small block GM V8 does go in but the USA Stag guys prefer a Ford Windsor V8.

A comment from the USA was that if Truimph had introduced the Stag with the 2.5 straight six it woukd have given extra time to develop the engine better which ironically is exactly what MB did with the SL, the Stags main competitor. The Stag engine was never bench tested to 1000 hours at max RATED power which is the norm. Another test not done was wide open throttle under load till destruction. A good design will make about 100 hours before the engine blows. The very best I have heard is 450 hours. Max rated means say 100bhp at 5000 rpm and no more. The destruction test is the max power the engineers can screw out of the engine. The weak point on a lot of engines is the main bearing area of the block. A good way is to have the head bolts go down as far as the main bearings. This puts the block under compression which greatly strengthens the block. Examples are XJ6 Jag. Rolls Royce V8 and V12 Merlin and Rover K series. Long head bolt design.

Truimph engineers must have known the engine wasn't right but still allowed it to be sold.


To be fair the Rover V8 has its faults. Such as liners coming loose if engine gets too hot. Quality control. Feeble out put at 160 bhp. 3500 cc should make 200bhp. However I have come across std Rover V8s that are quiet smooth and powerful but not many. However as with the Stag engine a proper rebuild sorts the Rover out, cheaper as well.


Bob.

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TerryG
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Re: Electric water pumps.

#25 Post by TerryG » Tue Dec 15, 2015 11:03 pm

As bigger fan of the rover v8 as i am, i wouldn't fit one to a stag.
Every engine has it's weak points. The rover v8 is no exception.
The 3.5 doesn't drop liners, only the larger bore 3.9/4.0. 4.2, 4.6, 4.8, 5.0 and 5.2 do when repeatedly over heated. Treat the radiator like a service item and they are fine.
Cam shafts / followers are a serious weak point so are chains. cam lobes wear terribly, worse on engines that have been neglected. cam chains stretch and throw the timing out.
The oil pumps on pre-serpentine engines are a bugger to prime and their flow characteristics are pants.
Oil sludging is a major problem for all of them as they start getting up in miles. This makes the already marginal oil flow worse. It is known as the black death amongst owners.
On engines with electronic ignition the placement of the module on the side of the distributor is really daft as they overheat and fail frequently. you can move them without much effort and everyone i know with a frequently used rv8 has.

On the other hand they are really cheap, sound amazing, are really easy to tune, after market parts are abundant and not expensive and supposedly you can bore and stroke them to 5.7 litres should you so desire.

edit: 3.5 and earlier 3.9 and 4.2 14 bolt engines suffer with premature head gasket failure due to uneven loading and lousy gasket design. later 10 bolt engines are fine.
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.

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JPB
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Re: Electric water pumps.

#26 Post by JPB » Tue Dec 15, 2015 11:22 pm

Bob wrote:Cylinder head studs not perpendicular to the block face causing side ways load on head gaskets causing fretting as engine cools down or heats up.
That only happens when people who haven't checked the sequence tighten down the head(s) in the conventional way. If the following sequence is used, then the studs will pull the head tightly down in the correct position, then the bolts are tightened down to tension the head correctly across its surface from side to side:
stud 4 stud 2 stud 1 stud 3 stud5
bolt 9 bolt 7 bolt6 bolt 8 bolt 10

4 and 9 are at the chain end, if however someone assumes that they must cross stitch the head, then either two or three studs will never be tight as they can't bottom once each stud's opposing bolt is tightened, so then and only then will the head effectively shuffle about as the engine temperature changes. Otherwise, the whole point is that the 45 degree angle that allows studs and nuts all to be accessed from the exhaust manifold side of the head is a clever solution to making the head narrow enough in the versions with only the two valves per chamber. Weird, but clever. German sourced chains tend to be reliable and there's no way to fit duplex chains to the V8 versions of this engine unless you carve out your own chain case, make some new tensioners and turn up a new set of bespoke pulleys.. The bottom ends are fine, journals are at least small enough on these to avoid the starvation that killed so many of the large journal OHVs used in 1500s and Spitfires as the oil pump keeps pace perfectly. I can't remember ever having encountered crankshaft problems in any Ricardo engine of any capacity that had been serviced in accordance with the schedule, sure & that's important in any vehicle though.
J
"Home is where you park it", so the saying goes. That may yet come true.. :oops:

rich.
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Re: Electric water pumps.

#27 Post by rich. » Wed Dec 16, 2015 2:52 pm

or buy an mx5 :lol:

sierra3dr
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Re: Electric water pumps.

#28 Post by sierra3dr » Wed Dec 16, 2015 5:28 pm

@Bob (History) there is an article in a recent Classic car buyer about the Stag. It mentioned the chain tensioner was one of the issues on the V8 amongst others

History
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Re: Electric water pumps.

#29 Post by History » Wed Dec 16, 2015 8:38 pm

Cam chain tensioner problems are bad news on an interference engine.

Forgot to mention the Stag engine revs higher than the Rover. The Stag final drive is relatively low geared. The Rover engine needs higher ratio. And also the position of the temp sensor only works on one head the other head could be in trouble. When OHC heads warp it puts the cam shaft brgs out of line. This if not corrected it can lead to chaim chain failure. JIWS do a chain specifically for automotive use. High quality.

What other engines fit.

How about a BMW engine. The rear axle arrangement on the Stag is similar to some BMWs so the whole drive line could be used.

I like the Stag and should one come way at a reasonable price. To me the Stag engine is flawed but because I only drive 3000 miles a year using 2 cars the problems won't manifest themselves. I not really fussed about what engine is in the car as long as its sensible. Its the shape that attracts me. Red one please.

Bob.

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gazza82
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Re: Electric water pumps.

#30 Post by gazza82 » Thu Dec 17, 2015 3:47 pm

History wrote:Cam chain tensioner problems are bad news on an interference engine.
I have a small collection of belt and broken valves to back that up! It seized, stripping a section of teeth and when the belt got to the next gear wheel, it stopped turning the cams .. but not the pistons! And that was only on the starter motor!! :cry:
"If you're driving on the edge ... you're leaving too much room!"

Retirement Project: '59 Austin A35 2-door with 1330cc Midget engine and many upgrades
Said goodbye: got '98 Alfa Romeo 156 2.0 TSpark to 210K miles before tin worm struck

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