htr
Well-Known Member
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- Central Otago, Southern New Zealand
My winter Workshop project - a more modified head for my K series Freelander 1.
I have interesting plans but I am wanting some guidance and advice. My aim is to enhance and improve the torque characteristics of the motor. I certainly don’t want it to guzzle more fuel or hamper it’s current performance. I hope to make it a bit more frugal on fuel and give it a more power. I’ve found that when passing it’s not very good at accelerating from about 80kmh in 4th, or pulling up a hill at 70kmh and trying to accelerate, even in 3rd gear
But first some back ground.
Some will recall when I acquired my FL1 in early 2014, an 1800cc K series five door which was a non-runner, and the process of getting it on the road again. I gained a lot of pleasure and knowledge in doing that, and I love to tinker with things which is just as well when we own a Land Rover!
At that time when I refitted the head I had taken the opportunity to do some minor mod’s to the motor which I believe collectively added to general reliability, economy and performance. The things I did were inspired by the article/s from the K Engine page, see this link. Not in any order of priority or importance, they include:
Since then I have acquired some useful spares including two complete motors, a standard 1800cc and a VVC one and a spare head. Except for the VVC the other heads are serviceable. The standard motor has been on my engine stand for over a year and it’s time I ‘got on with it’! It has one liner which requires to be resealed into the block, the head reassembled, refitted and away it should go. I have plans for that motor too - but another time.
I am familiar with the process of replacing a blown head gasket and have come to agree with many that it’s best to view the HG as a service item which needs replacing periodically. My coolant level has been fluctuating over the past few months and now I see coolant staining below the ex manifold - That time is very near. Other than that the car is running very well.
My project is to modify the spare head and then fit that to the car when I replace that HG. As before the work I’m considering is based on the suggestions from that K-Engine page. The work could include:
swapping the valves over as there are 2mm larger and according to that article they will fit the standard valve seats. [st’d inlet = 27.5 Vs VVC 29.5 & st’d Ex = 24mm Vs VVC 26mm]
Question #1 - Will the seats need to be recut and valves ground to suit?
Question #2 Will I have to trim the length of the valve stems?
I’ve the VVC intake plenum and throttle body as well so I could fit that too. Again I’d have to see how well the ports align and match for size. Will it give benefits?
Would there be a benefit in fitting the VVC inlet cam? Does it have a longer duration = more air/fuel in?
Would the st’d inlet cam work better with those bigger VVC valves [29.5mm]? OR would the VVC inlet cam with the st’d valves [27.5mm] be better with its longer duration?
I’m not looking for a high reving ‘race’ engine where power is developed at high revs. But making it breath better must help in improving torque and general performance & economy.
Other mod’s I’m thinking through which could help me but cost quite a lot: vernier pulls to optimise the timing - but I have to learn a lot more about the ins and outs of that. Having some extractors made which enhance torque in the low to mid range ie: long primary and secondary pipes…
I think I understand about porting and making things bigger… Larger airways are required in a high revving engine as there is a considerable amount of gases moving in and out. In a low revving engine those larger pathways would be a disadvantage as the gas movement would be slower? So would the st’d set-up work better in my situation, save for some minor resizing & reshaping?
I guess the question really is: would the ‘stock’ head, albeit smoothed out as above, be the best arrangement?
Here are some options below: In your opinion which is best and why?
Option #1
some modifications - valve guides & bosses trimmed, valve seat alignment smoothed, minor runner work, exhaust runners polished, better port size matching / alignment with their manifolds, valves un-shrouded 1.5mm and then blended into the combustion chamber, valves back trimmed 30º and edge rounded, valve insert lip removed, combustion chamber polished, VVC cam followers,
Option #1A
Fit VVC intake plenum and throttle body
Option #2
Stage 1 modified: Valve guides & bosses trimmed, larger VVC valves fitted [seats recut and valves ground, 30º back cut and edges rounded, Stem length checked], valve seat alignment smoothed, open up valve throats [inlet + 3mm? Ex + 2mm], runners to ports enlarged and concentric - exhaust runner polished, better port size matching/alignment with their manifolds, valves un-shrouded 1.5mm and then blended into the combustion chamber, valve insert lip removed, combustion chamber polished, VVC cam followers,
Option #2A
Fit VVC intake plenum and throttle body
Option #3
Stage 2 modified: Valve guides & bosses trimmed, larger VVC valves fitted [seats recut and valves ground, 30º back cut and edges rounded, Stem length checked], valve seat alignment smoothed, open up valve throats [inlet + 3mm? Ex + 2mm], runners to ports enlarged and concentric - exhaust runner polished, better port size matching/alignment with their manifolds, valves un-shrouded 1.5mm and then blended into the combustion chamber, VVC inlet cam fitted, valve insert lip removed, combustion chamber polished, VVC cam followers AND VVC intake plenum and throttle body fitted.
I have interesting plans but I am wanting some guidance and advice. My aim is to enhance and improve the torque characteristics of the motor. I certainly don’t want it to guzzle more fuel or hamper it’s current performance. I hope to make it a bit more frugal on fuel and give it a more power. I’ve found that when passing it’s not very good at accelerating from about 80kmh in 4th, or pulling up a hill at 70kmh and trying to accelerate, even in 3rd gear
But first some back ground.
Some will recall when I acquired my FL1 in early 2014, an 1800cc K series five door which was a non-runner, and the process of getting it on the road again. I gained a lot of pleasure and knowledge in doing that, and I love to tinker with things which is just as well when we own a Land Rover!
At that time when I refitted the head I had taken the opportunity to do some minor mod’s to the motor which I believe collectively added to general reliability, economy and performance. The things I did were inspired by the article/s from the K Engine page, see this link. Not in any order of priority or importance, they include:
- flowing the oil pump
- fitting the strengthened bottom oil rail,
- removing and welding splatter from the ex manifold & front pipe,
- de-cat pipe fitted,
- removed the plastic ‘flash’ from the inlet manifold,
- removing the thermostat and fitting a PRT to the top hose,
- some head work including un-shrouding the valves by 2mm,
- trimming the back of the valves themselves [ a 30º ‘back cut],
- trimming back the lower side of the valve seats to remove the step, or lip, due to misalignment of the seats to the casting,
- trimming down the valve stem boss and the valve guide and opening up the runners by maybe 1mm or so as well as slightly enlarging the inlet/ exhaust ports,
- built a cold air feed for the motor and swapped out the st’d air filter for a K&N Apollo one.
Since then I have acquired some useful spares including two complete motors, a standard 1800cc and a VVC one and a spare head. Except for the VVC the other heads are serviceable. The standard motor has been on my engine stand for over a year and it’s time I ‘got on with it’! It has one liner which requires to be resealed into the block, the head reassembled, refitted and away it should go. I have plans for that motor too - but another time.
I am familiar with the process of replacing a blown head gasket and have come to agree with many that it’s best to view the HG as a service item which needs replacing periodically. My coolant level has been fluctuating over the past few months and now I see coolant staining below the ex manifold - That time is very near. Other than that the car is running very well.
My project is to modify the spare head and then fit that to the car when I replace that HG. As before the work I’m considering is based on the suggestions from that K-Engine page. The work could include:
- replacing the valve guides [ I know the current ones are worn]
- unshroud the valves by 1.5mm [and blend those areas into the head],
- put a 30ºback cut to each valve,
- remove the ‘knife-like’ edge and put a round edge on the valve,
- - except for that blending, the work will be by a specialist head workshop,
- As before I’ll trim down the valve guide protrusion as well as the ‘boss’ around the guide,
- correct alignment issues at the bottom edge of the valve seats,
- remove, or round off the ’step’ where the valve insert sits in the head,
- polish the combustion chamber surface,
- polish the exhaust throats, runners and port areas,
- Fit the VVC Cam followers which are the later type
- minor valve throat, runner and port resizing.
- I’ll check to see if there is a difference in the Inlet port size and the Exhaust manifold pipe size and match up more closely if possible.
swapping the valves over as there are 2mm larger and according to that article they will fit the standard valve seats. [st’d inlet = 27.5 Vs VVC 29.5 & st’d Ex = 24mm Vs VVC 26mm]
Question #1 - Will the seats need to be recut and valves ground to suit?
Question #2 Will I have to trim the length of the valve stems?
I’ve the VVC intake plenum and throttle body as well so I could fit that too. Again I’d have to see how well the ports align and match for size. Will it give benefits?
Would there be a benefit in fitting the VVC inlet cam? Does it have a longer duration = more air/fuel in?
Would the st’d inlet cam work better with those bigger VVC valves [29.5mm]? OR would the VVC inlet cam with the st’d valves [27.5mm] be better with its longer duration?
I’m not looking for a high reving ‘race’ engine where power is developed at high revs. But making it breath better must help in improving torque and general performance & economy.
Other mod’s I’m thinking through which could help me but cost quite a lot: vernier pulls to optimise the timing - but I have to learn a lot more about the ins and outs of that. Having some extractors made which enhance torque in the low to mid range ie: long primary and secondary pipes…
I think I understand about porting and making things bigger… Larger airways are required in a high revving engine as there is a considerable amount of gases moving in and out. In a low revving engine those larger pathways would be a disadvantage as the gas movement would be slower? So would the st’d set-up work better in my situation, save for some minor resizing & reshaping?
I guess the question really is: would the ‘stock’ head, albeit smoothed out as above, be the best arrangement?
Here are some options below: In your opinion which is best and why?
Option #1
some modifications - valve guides & bosses trimmed, valve seat alignment smoothed, minor runner work, exhaust runners polished, better port size matching / alignment with their manifolds, valves un-shrouded 1.5mm and then blended into the combustion chamber, valves back trimmed 30º and edge rounded, valve insert lip removed, combustion chamber polished, VVC cam followers,
Option #1A
Fit VVC intake plenum and throttle body
Option #2
Stage 1 modified: Valve guides & bosses trimmed, larger VVC valves fitted [seats recut and valves ground, 30º back cut and edges rounded, Stem length checked], valve seat alignment smoothed, open up valve throats [inlet + 3mm? Ex + 2mm], runners to ports enlarged and concentric - exhaust runner polished, better port size matching/alignment with their manifolds, valves un-shrouded 1.5mm and then blended into the combustion chamber, valve insert lip removed, combustion chamber polished, VVC cam followers,
Option #2A
Fit VVC intake plenum and throttle body
Option #3
Stage 2 modified: Valve guides & bosses trimmed, larger VVC valves fitted [seats recut and valves ground, 30º back cut and edges rounded, Stem length checked], valve seat alignment smoothed, open up valve throats [inlet + 3mm? Ex + 2mm], runners to ports enlarged and concentric - exhaust runner polished, better port size matching/alignment with their manifolds, valves un-shrouded 1.5mm and then blended into the combustion chamber, VVC inlet cam fitted, valve insert lip removed, combustion chamber polished, VVC cam followers AND VVC intake plenum and throttle body fitted.