Anyone changed their own cam?
Discussion
As per the title - has anyone changed their own camshaft in a TVR RV8? Is it an engine out job or can it be done in situ?
My 4.0HC has done 69,000 miles now and I believe it's on the original cam - noticing it's starting to sound a bit "tappety" but more to the point the nice solid shove in the back as you accelerate through 3,000 rpm seems to have gone so I'm wondering if the cam could be on the way out...
I've changed plugs, leads and extenders - haven't changed coil and ignition amplifier yet - but she seems to tick over OK and does rev off-load but just under load seems flat and quite lifeless in comparison to what she did only a couple of thousand miles ago.
Phil
My 4.0HC has done 69,000 miles now and I believe it's on the original cam - noticing it's starting to sound a bit "tappety" but more to the point the nice solid shove in the back as you accelerate through 3,000 rpm seems to have gone so I'm wondering if the cam could be on the way out...
I've changed plugs, leads and extenders - haven't changed coil and ignition amplifier yet - but she seems to tick over OK and does rev off-load but just under load seems flat and quite lifeless in comparison to what she did only a couple of thousand miles ago.
Phil
You need to remove the valley pan because you will need new lifters as well.
Sadly cam wear does sound possible from what you describe, how's the inside of the cap and rotor arm tip?
Also when was the igniton timing last checked?
You probably have all these things checked but thought i'd mention.
Sadly cam wear does sound possible from what you describe, how's the inside of the cap and rotor arm tip?
Also when was the igniton timing last checked?
You probably have all these things checked but thought i'd mention.
Bassfiend said:
How much needs pulling off the top end of the engine? - Do you need to remove the plenum etc. to get access to the valley or can you just get away with the rocker covers?
As the valves operate via push rods the cam is located down in the valley between the two cylinder banks. You need to remove the entire plenum (upper and lower parts) in order to get to the cam followers. The rocker shafts also have to be removed in order to release the push rods.I also have a 4.0HC and decided to fit the V8Development's MC1 cam. This is a great compromise cam which preserves some top end performance but makes the driving at lower revs much much better.
I used two DTIs (Dial Test Indicator) to check precise alignment of the cam to the crankshaft but with the cam wheel supplied from V* Dev there turned out to be no need. I'm telling you this because there is a lot of info around giving advice to use DTIs.
I came across a few problems with corroded pipes when I got the plenum off, but appart from that the build was fairly straight forward. I did it over about three weekends. It is back breking - I ended up in A&E a week or so later so take care.
Mike
dog man said:
You need to remove the valley pan because you will need new lifters as well.
Sadly cam wear does sound possible from what you describe, how's the inside of the cap and rotor arm tip?
Also when was the igniton timing last checked?
You probably have all these things checked but thought i'd mention.
I'd forgotten about the followers so yes - you would of course need to remove the plenum.Sadly cam wear does sound possible from what you describe, how's the inside of the cap and rotor arm tip?
Also when was the igniton timing last checked?
You probably have all these things checked but thought i'd mention.
Cap and rotor arm were still clean and unburned a couple of weeks ago - haven't looked more recently than that - ignotion timing is a good point. Can't remember exactly when I last checked that but I *THINK* it was only a few months ago.
Cheers
Phil
MikeTVR said:
As the valves operate via push rods the cam is located down in the valley between the two cylinder banks. You need to remove the entire plenum (upper and lower parts) in order to get to the cam followers. The rocker shafts also have to be removed in order to release the push rods.
Yeah - I'd completely forgotten the followers ... I assume the hydraulic tappets are self adjusting and there's no need to shim them to adjust them?MikeTVR said:
I also have a 4.0HC and decided to fit the V8Development's MC1 cam. This is a great compromise cam which preserves some top end performance but makes the driving at lower revs much much better.
Hmmm ... the HC should already have the double valve springs shouldn't it? The Stealth or H404 sound tempting. 
MikeTVR said:
I used two DTIs (Dial Test Indicator) to check precise alignment of the cam to the crankshaft but with the cam wheel supplied from V* Dev there turned out to be no need. I'm telling you this because there is a lot of info around giving advice to use DTIs.
OK - thanks...MikeTVR said:
I came across a few problems with corroded pipes when I got the plenum off, but appart from that the build was fairly straight forward. I did it over about three weekends. It is back breking - I ended up in A&E a week or so later so take care.
Ouch! Mines a daily driver so I'd need to do it in a weekend at the most... Phil
Edited by Bassfiend on Wednesday 22 September 14:44
Bassfiend said:
Yeah - I'd completely forgotten the followers ... I assume the hydraulic tappets are self adjusting and there's no need to shim them to adjust them?
Unfortunately you do have to shim the rocker pedestals. The Tappets are hydraulic but the pre-load is important to get right.I won't go into it now but have a read of this:
http://www.v8engines.com/engine-4.htm#preload
debaron said:
Unfortunately you do have to shim the rocker pedestals. The Tappets are hydraulic but the pre-load is important to get right.
I won't go into it now but have a read of this:
http://www.v8engines.com/engine-4.htm#preload
OK - so that URL is a scary one with all sorts of harbingers of gloom and doom...I won't go into it now but have a read of this:
http://www.v8engines.com/engine-4.htm#preload
It seems that you *CAN* get away with not shimming the rocker arms (at the expense of possibly a little too much clearance) and it could be done at a later date.
Anyone had theirs done at a garage recently and how much was it?
I've emailed a couple of garages but not expecting a reply too quickly given previous experiences ... haven't tried Neil Garners (although they have been excellent) simply because they're about 70 miles each way from me.
Phil
If it ever stops raining I will be at Langar on Sunday in my V8S. It's just had an engine refresh with rebore, new pistons and new cam / followers.
Its a bog standard 4 litre apart from the cam which is a realsteel DW268 I think.
I'll happily take you for a spin to see what you think.
In my opinion its in a different league now, 66000 on clock.
Its a bog standard 4 litre apart from the cam which is a realsteel DW268 I think.
I'll happily take you for a spin to see what you think.
In my opinion its in a different league now, 66000 on clock.
I didn't end up doing mine *YET* because I'm trying to isolate another "occasional" issue - sometimes I get what feels like one or two cylinders dropping out and if I pop the bonnet at that time the main (big) cat in the Y piece is usually glowing bright orange - when it's running normally the exhaust is just bloody hot rather than glowing...
...plus I have a leak in my radiator which I need to sort too!
:-(
Dave Batty had the car for a week and didn't think that it felt like it was exhibiting worn cam symptoms at this stage so I'm trying to get the other stuff sorted first.
Phil
...plus I have a leak in my radiator which I need to sort too!
:-(
Dave Batty had the car for a week and didn't think that it felt like it was exhibiting worn cam symptoms at this stage so I'm trying to get the other stuff sorted first.
Phil
Bassfiend said:
I didn't end up doing mine *YET* because I'm trying to isolate another "occasional" issue - sometimes I get what feels like one or two cylinders dropping out and if I pop the bonnet at that time the main (big) cat in the Y piece is usually glowing bright orange - when it's running normally the exhaust is just bloody hot rather than glowing...
Plug leads mate? I was loosing 1 cylinder and the manifolds were glowing, checked the leads but all looked ok, but on further inspection one was broken (had to give 'em a good wiggle). Replaced the set and the car goes like a bloody train again!
.Mark said:
Plug leads mate? I was loosing 1 cylinder and the manifolds were glowing, checked the leads but all looked ok, but on further inspection one was broken (had to give 'em a good wiggle). Replaced the set and the car goes like a bloody train again!
I guess it *COULD* be plug leads but it just seems so eratic - I'm wondering ignition ammp or coil at the moment...
Phil
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