Rocker arms and push rods
Discussion
Hi All got a quick question on rocker arms has any one fitted the steel ones I have heard mixed reports, power offer the steel ones as an upgrade but I was told the alloy ones are lighter and better .There is a chap on ebay offering a full set of hd steel ones and shafts for £120.00 as mine are looking abit worn on the shafts I was going to swap them but dont know which to get, also has any one fitted the adjustable push rods with oil filled lifters are the tvr push rods heavy duty as standard or will the heads have to be modded to take them as I dont fancy modding them on the engine cheers Jason
This will cause a raction but here goes.
One of the best mods you can do to one of these engines is to fit steel rockers solid lifters and adjustable push rods.
the main rason for this ---- to quieten the bloody engine down.
The hydraulic lifters can deal with a certain amount of clearence , if the clearences are over the maximum or below the minimum then you have to shim the rocker shaft pillars. Depending on the clearences being under or over the max that the lifters can cope with you have to add or remove set shims.
Of course you have to add or remove shims to all the pillars they have to be the same thickness, and this is the problem.
This would work if you start off with all the valves at the same height, unfortunatly unless you are very lucky they will not be.
Take the rocker shaft off the head and place a straight edge across the valve stems you will notice that the clearences are all over the place, you have major problems.
If you took the heads in to the average workshop they would simply grind the valve stems to all the same height, this could be a serious mistake as you have lost the csae hardening on the contact point between the valve stem and the rocker.
Doing the mod mentioned solves this inherent problem and you get proper valve clearence on all valves something you rarely get with the standard set up.
so you get a quieter --" non ticking " engine but you get a smoother engine .
So go for this mod its well worth it.
By the way its simply poor build quality not making all the valve seats the same deapth or because you have bought an overtuned lump of alliminum with oversized valves that could well be banging their way deeper into the heads, far too much support material has been cut away to accommodate these large valves.
sorry for the ramble
Steve
One of the best mods you can do to one of these engines is to fit steel rockers solid lifters and adjustable push rods.
the main rason for this ---- to quieten the bloody engine down.
The hydraulic lifters can deal with a certain amount of clearence , if the clearences are over the maximum or below the minimum then you have to shim the rocker shaft pillars. Depending on the clearences being under or over the max that the lifters can cope with you have to add or remove set shims.
Of course you have to add or remove shims to all the pillars they have to be the same thickness, and this is the problem.
This would work if you start off with all the valves at the same height, unfortunatly unless you are very lucky they will not be.
Take the rocker shaft off the head and place a straight edge across the valve stems you will notice that the clearences are all over the place, you have major problems.
If you took the heads in to the average workshop they would simply grind the valve stems to all the same height, this could be a serious mistake as you have lost the csae hardening on the contact point between the valve stem and the rocker.
Doing the mod mentioned solves this inherent problem and you get proper valve clearence on all valves something you rarely get with the standard set up.
so you get a quieter --" non ticking " engine but you get a smoother engine .
So go for this mod its well worth it.
By the way its simply poor build quality not making all the valve seats the same deapth or because you have bought an overtuned lump of alliminum with oversized valves that could well be banging their way deeper into the heads, far too much support material has been cut away to accommodate these large valves.
sorry for the ramble
Steve
tgriff said:
This will cause a raction but here goes.
One of the best mods you can do to one of these engines is to fit steel rockers solid lifters and adjustable push rods.
One of the best mods you can do to one of these engines is to fit steel rockers solid lifters and adjustable push rods.
You have to accept that once you go to solid lifters, you have to adjust the valve clearances regularly. Hydraulic lifters are 'fit and forget' items. If you have other reasons for going to solid lifters to suit your engine spec then this is a price you may be willing to pay, but I don't think it makes sense for a normal road car.
My tuppence worth;
My view on this would be, steel rockers are heavier than the std ones, but they are stronger with less chance of the contact pad breaking off (mainly cos its all one and the same, if one of my customers asked me about fitting them, my first question would be...do you do a lot of track days? The steel ones (IMHO) would be better suited if you did.
As for adjustable pushrods, good idea (in theory) but has a lot of drawbacks.
If the car is just for cruising around with the occasional hooning, probably best to leave the std setup on it unless of course you just HAVE to spend some money on it!
Jamie
My view on this would be, steel rockers are heavier than the std ones, but they are stronger with less chance of the contact pad breaking off (mainly cos its all one and the same, if one of my customers asked me about fitting them, my first question would be...do you do a lot of track days? The steel ones (IMHO) would be better suited if you did.
As for adjustable pushrods, good idea (in theory) but has a lot of drawbacks.
If the car is just for cruising around with the occasional hooning, probably best to leave the std setup on it unless of course you just HAVE to spend some money on it!
Jamie
If all Griff owners opened their bonnets and listened to their engines when hot more than 40% of them would hear a ticking to some degree or other. The cause will be as previously mentioned.
These engines were indeed start and go unfortunatly TVR have seriously modified the original engine especially to the 500 units.
so again the mod is very worthwhile, and yes you have to check the tappet clearence but thats a good thing.
Steve
These engines were indeed start and go unfortunatly TVR have seriously modified the original engine especially to the 500 units.
so again the mod is very worthwhile, and yes you have to check the tappet clearence but thats a good thing.
Steve
Well I like the idea of solid lifters when I swap the cam I will go down that route as I dont want new lifters with my old cam.I am going for the steel rockers as I have had a set of ally ones and it ticking on overun when it gets hot has returned ,sweet as a nut when cold .What about the push rods I was going to get a set incase I have a worn one but which fit the tvr heads the supplier qoutes moding the heads to get the heavy duty ones in any one tried them.on anouther point point rover dont bother with setting pre load tvr dont bother setting it, I did last time but might bin the shims and see how it goes maybe the extra tightness may keep it sweet when hot. The back of the cam has got to be in the same place on all v8,s only the front of the lobes are diffrent when the lifters are compressed and the pre load is not there.The standard setup works very well on range rovers etc thousands of miles and no ticking any thoughts. Cheers Jason
jasoncook said:
might bin the shims and see how it goes maybe the extra tightness may keep it sweet when hot.
That's just increasing the preload isn't it? I'm not sure what that would do. There is a school of thought that you want to run very low preload, to minimise the scope for the lifters to pump up.
Hi,I would just like to say that I had a very tappety motor in my 400se,took the advice from fellow ph"ers (cheers green v8s) and adjusted the pre-load,renewed rocker shafts and changed one worn rocker and she"s quiet as a mouse now. ps the cam and hyd followers were 2000 mile old so all in good nick. all the best simon
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