Rover V8 Rebuild
Discussion
Right just spent the day cleaning the dimantled bits. I looked at the whole engine and it looks like the following is needed:
cam
tappets
about half the pustrods(therefore full set)
time chain
cogs
Now where I'm struggling is the rocker assembly. There is some wear on the shaft but the rockers seem not to bad with only the very, slightest of wear on the pads, the dome bits are all fine with no cracks or ridges etc.
- On this basis I'm thinking of just two new shafts but am I better buying a new full assembly.
Valve springs are they worth replacing? There seems to be little wear to the valve stems/guides so I thought I'd leave then. Would replaceing the springs upset the valve seating...
Anyhow it is only a 8.13cr 3.5l so I don't wont to keep spending on it.
Also are there any benefits to be obtained by replacing the cam with a high compression 3.5 or a 3.9 cam. I understand the low compression cams were for emisions and thus not the most efficient?????
Thoughts please people, if anyone is a V8 parts supplier I'll happily put the parts your way to ensure better quality....
cam
tappets
about half the pustrods(therefore full set)
time chain
cogs
Now where I'm struggling is the rocker assembly. There is some wear on the shaft but the rockers seem not to bad with only the very, slightest of wear on the pads, the dome bits are all fine with no cracks or ridges etc.
- On this basis I'm thinking of just two new shafts but am I better buying a new full assembly.
Valve springs are they worth replacing? There seems to be little wear to the valve stems/guides so I thought I'd leave then. Would replaceing the springs upset the valve seating...
Anyhow it is only a 8.13cr 3.5l so I don't wont to keep spending on it.
Also are there any benefits to be obtained by replacing the cam with a high compression 3.5 or a 3.9 cam. I understand the low compression cams were for emisions and thus not the most efficient?????
Thoughts please people, if anyone is a V8 parts supplier I'll happily put the parts your way to ensure better quality....
On this basis I'm thinking of just two new shafts but am I better buying a new full assembly.
You would probably be OK just getting two shafts.
Valve springs are they worth replacing? There seems to be little wear to the valve stems/guides so I thought I'd leave then. Would replaceing the springs upset the valve seating...
I'd definitely replace the springs, replacing them will not upset the seating and it is always smart to check fitted length to ensure they are working to their optimum.
Anyhow it is only a 8.13cr 3.5l so I don't wont to keep spending on it.
Also are there any benefits to be obtained by replacing the cam with a high compression 3.5 or a 3.9 cam. I understand the low compression cams were for emisions and thus not the most efficient?????
I'd consider checking with somebody like Rimmer Bros in Lincoln if they have some higer CR pistons available, I bought some from them a few years back for a Triumph, they were about 10 quid each. It may be comparable in cost to just buying new rings. Low CR engines are basically to allow engines to survive on poor quality petrol, if you want performance and economy a higher CR would be beneficial. You can achieve this by skimming the heads. You must ensure the pistons are a solid type not a split skirt type or the engine will not be able to be thrashed. As regards the cam I think you are better off going to a real expert like Kent Cams and getting a kit that is proven.
You would probably be OK just getting two shafts.
Valve springs are they worth replacing? There seems to be little wear to the valve stems/guides so I thought I'd leave then. Would replaceing the springs upset the valve seating...
I'd definitely replace the springs, replacing them will not upset the seating and it is always smart to check fitted length to ensure they are working to their optimum.
Anyhow it is only a 8.13cr 3.5l so I don't wont to keep spending on it.
Also are there any benefits to be obtained by replacing the cam with a high compression 3.5 or a 3.9 cam. I understand the low compression cams were for emisions and thus not the most efficient?????
I'd consider checking with somebody like Rimmer Bros in Lincoln if they have some higer CR pistons available, I bought some from them a few years back for a Triumph, they were about 10 quid each. It may be comparable in cost to just buying new rings. Low CR engines are basically to allow engines to survive on poor quality petrol, if you want performance and economy a higher CR would be beneficial. You can achieve this by skimming the heads. You must ensure the pistons are a solid type not a split skirt type or the engine will not be able to be thrashed. As regards the cam I think you are better off going to a real expert like Kent Cams and getting a kit that is proven.
get the heads checked for true/pressure tested while you have them off! skimmed a bit, fit some vitesse or p6 pistons to up the compression, a 3.9 cam would be a cost effective upgrade, tin head gaskets to maintain compression, but a composite valley/inlet gasket is a must! the tin ones are a bugger to seal properly, and the outside row of bolts only want about 25lb ft torque, the four closest to the exhaust ports! are you keeping the twin sus/strombergs or having a weber/holley setup? i have a tool for priming the oil pump if you want one
>> Edited by v8 westy on Sunday 4th January 22:37
>> Edited by v8 westy on Sunday 4th January 22:37
Fish said:
Right just spent the day cleaning the dimantled bits. I looked at the whole engine and it looks like the following is needed:
cam
tappets
about half the pustrods(therefore full set)
time chain
cogs
Now where I'm struggling is the rocker assembly. There is some wear on the shaft but the rockers seem not to bad with only the very, slightest of wear on the pads, the dome bits are all fine with no cracks or ridges etc.
- On this basis I'm thinking of just two new shafts but am I better buying a new full assembly.
Valve springs are they worth replacing? There seems to be little wear to the valve stems/guides so I thought I'd leave then. Would replaceing the springs upset the valve seating...
Anyhow it is only a 8.13cr 3.5l so I don't wont to keep spending on it.
Also are there any benefits to be obtained by replacing the cam with a high compression 3.5 or a 3.9 cam. I understand the low compression cams were for emisions and thus not the most efficient?????
Thoughts please people, if anyone is a V8 parts supplier I'll happily put the parts your way to ensure better quality....
Hmmm... what's wrong with the pushrods? Case-hardening worn off the ends I presume?
Performance cam... if it gives you more valve lift you'll need valve pockets in the pistons, which even the stock Rangey 3.9 pistons don't have.
The wear in the rocker shafts will be compensated to some extent when you reshim the rocker pedestals (because you WILL reshim, won't you ?
) though you could investigate the old cheap and cheerful dodge of turning the shafts through 180 degrees and using the other 'side'.... I can't recall whether the RV8 lets you do this, however. A duplex timing chain conversion is worthwhile (makes a nice noise, too!). So are composite head and valley gaskets, updated rocker cover gaskets and an uprated oil pump spring.
Valve springs: measure the free length and if ALL within tolerance, probably not worth changing. If some or all are out by varying amounts, change them.
I used Rimmer Bros for all my V8 spares when I did a rebuild on the 390: if you can do all the spannering yourself then, say, £500 will go a looooong way on parts and machining...
Fish said:
Just got all the bits and am putting it back together. Made a cockup already, put the RH head on the Left and vice versa. I'm going to leave them that way round but is there any potential real problems I could create.
Looking forward to driving the thing now...
As long as any threaded holes you need for alternator bracket etc. are in the right places on each head....
RichB said:
are there any benefits to be obtained by replacing the cam with a high compression 3.5 or a 3.9 cam.
When you chaps talk about low and high compression cams you obviously don't mean that the cam affects the comp. ratio, so what do you mean? Rich...
The V8 was produced with various compression ratios (from about 8:1 to 10.5:1 IIRC) and the cam profiles vary depending on that. The cam timing was optimised to make best use of, say, the quality of fuel that could be used, and to alter the torque curve. Changing the cam would make a difference, but whether it would be an improvement...
RichB said:
When you chaps talk about low and high compression cams you obviously don't mean that the cam affects the comp. ratio, so what do you mean? Rich...
The static ratio is not changed by the cam but the dynamic ratio is.
SCR is stroke, Bore, distance the piston is down the hole at TDC, thickness and diameter of compressed head gasket, combustion chamber, dome or relief’s in piston.
DCR is all of the above except that the stroke is not what you expect it to be.
On the inlet stroke you are reliant on the vacuum caused by the piston going down and atmospheric pressure, to fill the cylinder. You have also created momentum in the air flow which you want to take advantage of therefore the inlet valve does not close until some time after BDC. The stroke used for the compression calculation is where the piston has risen to at the point the inlet valve closes.
Different cams will have different points for inlet closure therefore the cam does effect the compression.
My engine has a SCR of 10.28:1 but a DCR of 7.9:1.
To run on super unleaded without pinking you should aim for about 7.5 for engines with iron heads and 8 for ali heads.
Try here for more info and a download of the DCR calculator http://cochise.uia.net/pkelley2/DynamicCR.html
Steve
[quote=fish]
Sensors on the inlet manifold are temp sender and an otter switch what does the otter switch send to?
[quote]
Sensors are water temp sensor for the ECU (the sensor with a posh plug) and a separate water temp sensor for the gauge. Otter switch is completely different, this is the switch that turns the fan(s) on and will be fitted to either the top hose, swirl tank or radiator.
Sensors on the inlet manifold are temp sender and an otter switch what does the otter switch send to?
[quote]
Sensors are water temp sensor for the ECU (the sensor with a posh plug) and a separate water temp sensor for the gauge. Otter switch is completely different, this is the switch that turns the fan(s) on and will be fitted to either the top hose, swirl tank or radiator.
The 'otter' switch on the manifold (Bosch thermotime switch) runs independently of the ECU and turns the little cold start injector on the plenum on and off if its hot, its off, if freezing cold - full-on.
If the engine is from an SD1 then yes unleaded is OK if its a P6 lump then mabye not.
Matt
If the engine is from an SD1 then yes unleaded is OK if its a P6 lump then mabye not.
Matt
fish, Two questions on the rebuild, it should be fired up at the weekend 
Sensors on the inlet manifold are temp sender and an otter switch what does the otter switch send to?
me, Not an otter, choke warning according the parts book. part No. 545010, gasket 236022 typed int search at johncraddockltd but for some reason it states 4cyl???. i can scan the parts book if you want?
fish, Early V8s circ 1980 low comp are okay on unleaded aren't they??????
me, yes but the timming may need changing to avioed pinking, but the seats and valves are fine
>> Edited by seaton on Wednesday 21st January 18:21
Sensors on the inlet manifold are temp sender and an otter switch what does the otter switch send to?
me, Not an otter, choke warning according the parts book. part No. 545010, gasket 236022 typed int search at johncraddockltd but for some reason it states 4cyl???. i can scan the parts book if you want?
fish, Early V8s circ 1980 low comp are okay on unleaded aren't they??????
me, yes but the timming may need changing to avioed pinking, but the seats and valves are fine
>> Edited by seaton on Wednesday 21st January 18:21
Fish,
Have you polished up the valve seats? The reason I ask is that if the engine has previously been run using leaded, then the seats will retain some lead and thus you could get away with UL most of the time (search for "memory effect" should explain what I'm on about). The MGOC have a 'long-term' test car using just UL (IIRC it is an early metro without hardened seats). They keep running the car and occasionally check the valve seats.
Alternatively, find your nearest "bayford thrust" garage selling genuine 4*
Edited to add: See www.leadedpetrol.co.uk
>> Edited by Sheepy on Thursday 22 January 13:38
Have you polished up the valve seats? The reason I ask is that if the engine has previously been run using leaded, then the seats will retain some lead and thus you could get away with UL most of the time (search for "memory effect" should explain what I'm on about). The MGOC have a 'long-term' test car using just UL (IIRC it is an early metro without hardened seats). They keep running the car and occasionally check the valve seats.
Alternatively, find your nearest "bayford thrust" garage selling genuine 4*
Edited to add: See www.leadedpetrol.co.uk
>> Edited by Sheepy on Thursday 22 January 13:38
fish said:
I've since spoken to Noble Motrosport in Chesterfield who will be doing the re needling, on a rolling road and the unleaded/leaded depends on the number on the heads. Mine is early and on checking I will be using Leaded well LRP in it......
Shame would have preferred unleaded.
Shirley you can get basic U/L heads from someone like V8D for less than £300 a set here, got ot be worth the expense in the long run
. Its not as if you get a lot of gallons to the mile with V8 lndies do you, they've got to pay for themselves fairly quickly dependant on the mileage, do the maths and see. Harry
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