Hi,
I currently have a 1242 16v FIRE engine and am looking towards installing some fast road cams. I have had a set of cams made and trial fitted them. They have made the car extremely lumpy but this could just be down to mapping. I have since removed them because of this.
However my question is, will the hydraulic lifters adjust to take up the slack of the reground cams? How does the hydraulic lifter work? Will correct mapping will this remove the seriously lumpy idle? How can I measure what duration the cams are?
I look forward to your responses. Ideally I am looking towards fitting these cams again in the new year. Further to this I have also heard rumours that the 16v conrods are only good for around 130bhp, is this true? The last trip to the rolling road gave engine 119bhp & 115lbft.
James
1242 16v engine with performance cam issues...
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James
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James
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Further to the above post I have done some more research. I have a few current problems.
Also should I move away from the standard Fiat valve springs?
- 1. I don't know the duration of the cam's I have. Is there any way that I can measure them so that I cam apply this to timing them in?
- 2. What is the best way to time the 1242 16v cams in as the are linked via gears and are only driven off of one pulley?
Also should I move away from the standard Fiat valve springs?
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Guy Croft
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James, you need to familiarise yourself with the rules in 'What's New' in top level GC Q&A which state:
Referring to Vendors:
Do not to refer to any vendor (company, person selling parts and services, based UK or anywhere else) 'by name' (or in such a way as they can be identified either indirectly or directly) unless you are saying 'they supplied something' or are going to pay them a compliment.
Do not make critical or remotely damaging comments of any kind about the quality of any firms or individuals' products! Every firm gets things wrong from time to time and yes, there are some bad apples in this business but they definitely don't want to see it published on the internet at GCRE.com, and if they do they will get very annoyed with me.
There are legal and ethical considerations in this regard and it is always possible to write a post in an interesting and factual way without 'naming names'.
If you are let down by a supplier, what you should always do first is take an issue back to the supplier in writing, if there is no satisfaction then, you should go to a lawyer, not to the internet. Just be careful please.
Now don't be upset - because it's not the first time someone did not know about the rules here and won't be the last! No harm done. I have deleted the name of the firm from whom you got the cams and yes I'd expect product support to come from them. I won't get over-involved in this because they are not cams supplied by me.
But I'll tell you this:
You can't guess at these setups. A hydraulic lifter runs with zero running clearance, and the build-up in contact pressure between the lifter and cam profile - as the cam comes into the lift phase - ensures a smooth transition from base circle to lift.
If you're running reprofiled cams with hydraulic lifters you have to be sure that the lifter (merely a piston in a cylinder fed by oil pressure) can accomodate the reduction in base circle, because if it cannot, there is going to be a clearance between lifter and cam that will upset all the cam characteristics. If you have reprofiled cams you have got to be absolutely sure that they will work with standard lifters, which, I'm afraid, really means ONLY buying from top-notch firms like Kent and Piper who take the matching of their parts very seriously.
Me - I don't like hydraulic lifters - I don't believe in using them with any competition cam. And any non-standard cam is a comp cam.
Go to solid lifters if you can, and yes the engine definitely needs checking for fuelling, there is no guarantee that there will be enough fuel going in with the increased airflow from any cam swap. This is true of all premapped engines.
As for cam timing, I figure I can time up most setups but I have never seen the valvetrain on that motor so post some pictures so I can see how both cams run off one drive.
GC
Referring to Vendors:
Do not to refer to any vendor (company, person selling parts and services, based UK or anywhere else) 'by name' (or in such a way as they can be identified either indirectly or directly) unless you are saying 'they supplied something' or are going to pay them a compliment.
Do not make critical or remotely damaging comments of any kind about the quality of any firms or individuals' products! Every firm gets things wrong from time to time and yes, there are some bad apples in this business but they definitely don't want to see it published on the internet at GCRE.com, and if they do they will get very annoyed with me.
There are legal and ethical considerations in this regard and it is always possible to write a post in an interesting and factual way without 'naming names'.
If you are let down by a supplier, what you should always do first is take an issue back to the supplier in writing, if there is no satisfaction then, you should go to a lawyer, not to the internet. Just be careful please.
Now don't be upset - because it's not the first time someone did not know about the rules here and won't be the last! No harm done. I have deleted the name of the firm from whom you got the cams and yes I'd expect product support to come from them. I won't get over-involved in this because they are not cams supplied by me.
But I'll tell you this:
You can't guess at these setups. A hydraulic lifter runs with zero running clearance, and the build-up in contact pressure between the lifter and cam profile - as the cam comes into the lift phase - ensures a smooth transition from base circle to lift.
If you're running reprofiled cams with hydraulic lifters you have to be sure that the lifter (merely a piston in a cylinder fed by oil pressure) can accomodate the reduction in base circle, because if it cannot, there is going to be a clearance between lifter and cam that will upset all the cam characteristics. If you have reprofiled cams you have got to be absolutely sure that they will work with standard lifters, which, I'm afraid, really means ONLY buying from top-notch firms like Kent and Piper who take the matching of their parts very seriously.
Me - I don't like hydraulic lifters - I don't believe in using them with any competition cam. And any non-standard cam is a comp cam.
Go to solid lifters if you can, and yes the engine definitely needs checking for fuelling, there is no guarantee that there will be enough fuel going in with the increased airflow from any cam swap. This is true of all premapped engines.
As for cam timing, I figure I can time up most setups but I have never seen the valvetrain on that motor so post some pictures so I can see how both cams run off one drive.
GC
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James
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sumplug
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James.
The 16v head is very hard to port on this engine and i know of one tuner who cut the head up to find where to port. You say you have had cams reground?? Not from billet?
The hydraulic lifters severely restricts the altering of the cam and the head is extremely hard to change to solid lifters. PM me if you want and i will let you know the man who knows this head inside out.
Andy.
The 16v head is very hard to port on this engine and i know of one tuner who cut the head up to find where to port. You say you have had cams reground?? Not from billet?
The hydraulic lifters severely restricts the altering of the cam and the head is extremely hard to change to solid lifters. PM me if you want and i will let you know the man who knows this head inside out.
Andy.
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Julian
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Hi James, good to see you here as well.
The hydraulic lifters in the 16v head do allow for a little variation in the base circle but not much. We have managed to create an improved cam profile but it is pretty subtle.
As you already know the move to solid lifters on the FIRE 16v head is pretty much a dead end so you are effectively stuck with a relatively mild profile or totally reengineering the head.
I have heard some people say they have successfully converted the lifters to solid but I have yet to see anyone illustrate how they can accurately set the clearance. If you can't set the clearance accurately then you may as well have stayed with the hydraulic setup.
Guy - if you haven't looked at the 16v head before I suggest you take a look. It is a slightly odd setup that has definitely been optimised to do the job it was designed for, unfortunately that means it is production spec with virtually no scope for serious improvement.
Incidentally if anyone does manage to convert one of those 16v heads (in a realistic manner) I will be at the front of the line to shake them by the hand and buy them a well earned drink.
I'm pretty convinced that the most realistic option is to simply use the 8v head, you can't get the same peak flow without really working the head but you have much more scope for improvement elsewhere especially in the cam profile. The only other alternative is cast your own head or convert one from another engine (neither of which is cheap or easy).
The hydraulic lifters in the 16v head do allow for a little variation in the base circle but not much. We have managed to create an improved cam profile but it is pretty subtle.
As you already know the move to solid lifters on the FIRE 16v head is pretty much a dead end so you are effectively stuck with a relatively mild profile or totally reengineering the head.
I have heard some people say they have successfully converted the lifters to solid but I have yet to see anyone illustrate how they can accurately set the clearance. If you can't set the clearance accurately then you may as well have stayed with the hydraulic setup.
Guy - if you haven't looked at the 16v head before I suggest you take a look. It is a slightly odd setup that has definitely been optimised to do the job it was designed for, unfortunately that means it is production spec with virtually no scope for serious improvement.
Incidentally if anyone does manage to convert one of those 16v heads (in a realistic manner) I will be at the front of the line to shake them by the hand and buy them a well earned drink.
I'm pretty convinced that the most realistic option is to simply use the 8v head, you can't get the same peak flow without really working the head but you have much more scope for improvement elsewhere especially in the cam profile. The only other alternative is cast your own head or convert one from another engine (neither of which is cheap or easy).
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James
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Thanks for the replies,
I spoke to my Cam supplier last night and they informed me that the 1242 16v has 2mm of tolerances within the hydrolic lifters and that my cams are within this. Apparently the cams were re-ground by a small specialist, but I haven't been given a name, apperently a trade secret, however I was told that they would be suprised if Guy didn't know who they were.
I know C&B make a cam kit for the 1242 16v but i'm guessing that these would be billets, so within the tolerance's of the lifters.
From speaking with my supplier last night I think it is possibly a timing issue but from reading articlies on cam timing using different methods I think I will be stuck without know the duration etc of the cam. If they are similar to his 1242 8v cams then it could be close to 290degrees.
If I installed them using the standard Fiat timing and then used a vernier pulley would this make life easier?
I spoke to my Cam supplier last night and they informed me that the 1242 16v has 2mm of tolerances within the hydrolic lifters and that my cams are within this. Apparently the cams were re-ground by a small specialist, but I haven't been given a name, apperently a trade secret, however I was told that they would be suprised if Guy didn't know who they were.
I know C&B make a cam kit for the 1242 16v but i'm guessing that these would be billets, so within the tolerance's of the lifters.
From speaking with my supplier last night I think it is possibly a timing issue but from reading articlies on cam timing using different methods I think I will be stuck without know the duration etc of the cam. If they are similar to his 1242 8v cams then it could be close to 290degrees.
If I installed them using the standard Fiat timing and then used a vernier pulley would this make life easier?
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Guy Croft
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James
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Julian
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James,
Can't help with the cam situation but I can say that vernier pullies are an absolute necessity as soon as you move away from a stock engine and especially stock camshafts.
The timing belts for these engines are not the strongest of items (I don't mean they snap or tear but they are somewhat elastic) and this can throw the static timing off relative to what the engine experiences under load. Vernier pullies can be used to good effect to correct the offset if you want to get clever. Ultimately though it means losing out somewhere since it can only be correct in one situation but at least you can choose where that is rather than idle (assuming that is where it is correct to begin with under static conditions).
Can't help with the cam situation but I can say that vernier pullies are an absolute necessity as soon as you move away from a stock engine and especially stock camshafts.
The timing belts for these engines are not the strongest of items (I don't mean they snap or tear but they are somewhat elastic) and this can throw the static timing off relative to what the engine experiences under load. Vernier pullies can be used to good effect to correct the offset if you want to get clever. Ultimately though it means losing out somewhere since it can only be correct in one situation but at least you can choose where that is rather than idle (assuming that is where it is correct to begin with under static conditions).
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James
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Julian,
Would a good quality vernier pulley accept the standard belt etc?
James
Your reference to price deleted. Discussion of price is totally forbidden on this site except in Sales & Wants. Read and abide by 'Content of Post and Referring to Vendors' in 'What's New? Top level GC V/W
GC
Would a good quality vernier pulley accept the standard belt etc?
James
Your reference to price deleted. Discussion of price is totally forbidden on this site except in Sales & Wants. Read and abide by 'Content of Post and Referring to Vendors' in 'What's New? Top level GC V/W
GC
Last edited by James on December 12th, 2006, 10:17 pm, edited 1 time in total.
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Julian
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Julian
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Now that I am the laughing stock of the workshop I will pass on a few gems.
The cam pulley on the FIRE 16v is not located by a traditional keyway. To adjust the timing you simply fit the official Fiat cam locking tool, slacken the retaining bolt adjust the angle and then tighten again.
The same trick can be used at the other end of the head to adjust the chain gear that synchronise the two camshafts.
In short - no real point in a vernier pulley.
The best you would really aim for is a lightweight pulley and gear set.
The cam pulley on the FIRE 16v is not located by a traditional keyway. To adjust the timing you simply fit the official Fiat cam locking tool, slacken the retaining bolt adjust the angle and then tighten again.
The same trick can be used at the other end of the head to adjust the chain gear that synchronise the two camshafts.
In short - no real point in a vernier pulley.
The best you would really aim for is a lightweight pulley and gear set.
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James
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Julian
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This would definitely be a matter of custom fabrication. No two ways about that one.
I am not aware of anyone that makes a custom belt - we use Gripper belts by preference and that is because of the warranty that comes with them! Some models of the Fire engine do have heavy duty belts available as an option but I don't think the 16v is one of them.
Removing weight from the valvetrain has a similar effect to removing weight from the flywheel and crankshaft. It reduces the energy "wasted" in just turning the engine internals. There is still work to be done so energy will always be lost in this manner to some degree and taking too much out is detrimental to the strength of the engine. You can spend a fortune on exotic materials for very little improvement but generally the standard pulley (or in this case pulley and gears) are an easy win as they tend to be quite heavy. The pulley would be the easiest but likely not cheap as no-one (that I know of) makes one as standard, I suspect the gears would prove prohibitive. You would also find that the hydraulic lifters are a much larger consideration as they are far and away the biggest limiting factor in the head design.
This part of the tuning process, although an essential part, is not something you should be persuing while there are still other more productive avenues to follow. As part of a complete package it would be an integral part but since the timing adjustment (far more important) is there as standard it is far less important to focus on the mass until you know exactly what you are going to do.
I am not aware of anyone that makes a custom belt - we use Gripper belts by preference and that is because of the warranty that comes with them! Some models of the Fire engine do have heavy duty belts available as an option but I don't think the 16v is one of them.
Removing weight from the valvetrain has a similar effect to removing weight from the flywheel and crankshaft. It reduces the energy "wasted" in just turning the engine internals. There is still work to be done so energy will always be lost in this manner to some degree and taking too much out is detrimental to the strength of the engine. You can spend a fortune on exotic materials for very little improvement but generally the standard pulley (or in this case pulley and gears) are an easy win as they tend to be quite heavy. The pulley would be the easiest but likely not cheap as no-one (that I know of) makes one as standard, I suspect the gears would prove prohibitive. You would also find that the hydraulic lifters are a much larger consideration as they are far and away the biggest limiting factor in the head design.
This part of the tuning process, although an essential part, is not something you should be persuing while there are still other more productive avenues to follow. As part of a complete package it would be an integral part but since the timing adjustment (far more important) is there as standard it is far less important to focus on the mass until you know exactly what you are going to do.
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