2000 Head replacement

#21
A 1977 MGB has less power than earlier ones, just 84bhp I think, so a Rover 2000 TC should be rather quicker. Contemporary road tests showed 0-60mph times of 14.0sec for the 1977 B GT (Autocar), 11.9 sec for a 2000 TC (Motor). I agree with Demetris' plan of attack. Retarded valve timing, caused by gradual stretch in the timing chains, might prove to be the reason for the poor performance.
 
#23
Agree with the post regarding giving it a good run. Better on a dual carriageway than around the streets. Our SC exhaust clearances were a bit tight. Luckily we had to take the head off for the oil leak problem, so sorted them at the same time. We bought a Lotus Elan that had been stood for a year. Comps went up 20psi after a good blast up the motorway for about 20 miles and back. When we got our SC it was dead as well. Timing was a couple of degrees out retarded. Sorted that and it made a world of difference. Don't be tempted to over advance the car though, as you could risk breaking the rings. Four pots aren't a racing car, but when sorted go quite well for what they are.
 

cobraboy

Well-Known Member
#24
We bought a Lotus Elan that had been stood for a year. Comps went up 20psi after a good blast up the motorway for about 20 miles and back.
The Lotus twincam seems to be particularly prone to valve sealing issues when laid up. Like the Rover it has an alloy head with seat inserts. My Elan which I have had now for going on forty years barely starts and runs after a prolonged 'rest'. After owning it for so long I just take it with a pinch of salt. When out on the highway it will chug along for a few miles, unwilling to rev at all, then gradually it will clear and then start to come back on song.
The Rover V8's I have had do not seem to be as affected, perhaps because they get run on a more regular basis. Or perhaps it is the bucket and shim set up on the four pot, in common with the Lotus that leads to issues.
 

Demetris

Well-Known Member
#25
A good run, or worse an Italian tuning with closed tappet clearances, wrong ignition timing and / or mixture strength will cause damage rather than improve running. If you are sure that everything is within the specs, go for it though!
 
#26
Timing is set correctly at 6 degrees BTDC points set at 0.016in and plugs set 0.025. New jets fitted in the HS8 carbs and airflow is set equal on both carbs, choke and throttle set as per White Rover repair and operation manual idle at 750rpm. Only thing not checked is valve clearances.
Regards Terry H
 
#27
might be worth moving the distributor round a bit ,mine runs better way in advance of the 6 degree mark , might be chain wear , plus my brakes were binding a little and the wheels needed tracking too.
 
#28
Just a thought. did you check you are getting advance on the timing when revs go up. If you have a strobe that can be altered to the setting you want, set it to what the advance should be at the given revs. I think the TC should advance to around 25-30 deg at about 25-2900rpm. with the vac advance connected. Standard timing is 6deg as you say at idle and I think if you reconnect the vac it should increase that to around double, 12deg. Should be in the workshop manual if you have one. It's not really super critical, as long as you are getting late twenties advance at 3000rpm ish, the car is doing what it should be. If you aren't getting as much the performance will be affected. Give it a go. Nothing lost. The SC advance is different.
 
#29
I did check to see if the vacuum advance was working with a vacuum pump on the carb end of the pipe with the connection on the carb blocked off so I could operate the advance by using the pump manually and it was working correctly.
Regards Terry H
 
#30
Hi Terry, if you don't have a suitable timing light, a way to check if the advance weights are not seized up in the dissy is just remove the cap, grab hold of the rotor arm and turn it. You should be able to feel the springs working against you. If the rotor is solid, the advance weights could be seized. If it flops around, the springs could be broken. Easy to fix, but will make a hell of a difference to performance if it's not working correctly. Cheers, Rob
 
#31
Yep did that with the rotor and there is resistance. I do have a good timing light though it is getting a little grubby now could do with a good clean. Haven't managed to get a run in yet but will do before the weekend and then retest the compression.
Regards Terry H
 

jp928

Well-Known Member
#32
Check the cam timing - if off spec you can adjust for chain stretch with the vernier inside the top chain wheel. IIRC the TC had its timing retarded 4d compared to the SC.
 
#34
Just came back from a short run on the M4 both ways from Newport to Magor as we still have Covid restrictions. Total 20 miles at 65-70 MPH all the way, started with half a tank of petrol with a shot of Red X in the fuel to clean everything out. I found that when cold I couldn't pull of without pulling the choke out, when warmed up on acceleration the car ran well. Holding at any speed with foot feathering throttle there seemed to be a slight stutter/misfire, more so on drag down hill, if I wasn't listening for things I probably wouldn't have noticed it and when I put my foot on the throttle there was a slight hesitation. I have to say that at 65-70 MPH revs at 3000-3500 RPM there is a need for overdrive, why wasn't it fitted to the Rover P6. Haven't checked the compression yet will do that as soon as I can. I did notice a rattle from the nearside front when the wheel hit a bump, sort of like a hazelnut in a empty tin, if you can imagine that. Didn't sound metallic. I checked the front hubcap but all nuts were in place and tight.
Regards Terry H
 

chrisw

Well-Known Member
#35
They did experiment with fitting an overdrive unit - I have one in the shed - however, they could never get it properly balanced.
 

harveyp6

Well-Known Member
#38
I did notice a rattle from the nearside front when the wheel hit a bump, sort of like a hazelnut in a empty tin, if you can imagine that. Didn't sound metallic.
Check the front shock absorber mounting rubbers, paying particular attention to the lower mount, making sure that the splitpin is in the correct hole. (ie the pin is horizontal)
 
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