Engine Balancing
Discussion
notaping said:
Just under 53k.
Probably due a refresh by now anyway.Mine got rebuilt at 50K mile mainly because the head gaskets were starting to let coolant weep up the head bolts so failing in an unspectacular way, removal of the heads showed they were really quite rotten and well past their best.
When the bottom end was pulled apart there was meat left on the bearings but again showing early signs of wear, the same for the oil pump, early signs of wear the bores and basically everything while not knackered it was all showing its age.
I opted for STR8SIX to rebuild mine as a 4.7 with and much reliability enhancements as possible added in, the result a powerful and really strong AJP that is such a pleasure to drive, the extra grunt of the 4.7 is very noticeable.
notaping said:
...I've tried to find a more detailed photo of the 4.5 manifolds, but unsuccessfully.
Perhaps another PH'r with a 4.5 can confirm this.
....
Gordon
Hi again Gordon Perhaps another PH'r with a 4.5 can confirm this.
....
Gordon
I've had a look on my 4.5 and have found a set of 3mm Allen screws threaded into the base of each Throttle Body Port.
I thought that if I injected summat (by hand) into one of these threads
that I could try and see if it comes out below the throttle valve.
I have a set of 4 Vacuum Guages, which I bought to tune my Suzuki, but never used.
I think I'll link them up, to sets of pairs of opposing Throttle Bodies and see if I can get any consistency.
Any opinions ?
Ta !
PJ
Edited by Mr Cerbera on Wednesday 26th August 21:51
If you look back earlier in the thread to the photo I posted of the 4.2 manifold you'll see there are similar Allen screws on the common rail linking the intakes. My initial thought was that these points must be to attach instruments to the individual intakes to finely balance them, but try as i might, I could not budge any of them. I was also slightly concerned that in removing them I might be introducing air leaks behind the throttle valves if I couldn't seal them tightly again.
Not knowing what the original thought process was by the engineers who designed these manifolds - I don't really know what these screws are for. Maybe intended for gauges, or maybe just for access as part of the manufacturing process - then sealed for good.
In the end I just opted for the easy option and removed the vapour recovery tubes - allowing me to balance the banks like a big V-twin.
But, if you manage to remove the Allen screws then potentially you could get vacuum readings for each cylinder. You would need to find an adapter to fit the vacant hole, and screw right down through the common chamber to block any effect from the other cylinders on that bank. However, even if you manage that and get individual reading for each intake - what then. There is no easy adjustment between cylinders on the same bank. You need to start messing with blead screws on the butterfly valves etc. Not for me !!
I would start by just removing the vapour recovery hose from each bank and using 2 gauges from your set of 4 try to balance the engine. If you find this method works for you but you require further refinement - then I would attack the Allen screws. For me though, this seemed like too much work for too little gain.
The vapour recovery hoses on my car are simply held on with jubilee clips - so really easy to remove. The vacuum gauge hoses should slide straight on.
If you do manage to remove any of the Allen screws - I would be interested to know what you find.
Gordon
Not knowing what the original thought process was by the engineers who designed these manifolds - I don't really know what these screws are for. Maybe intended for gauges, or maybe just for access as part of the manufacturing process - then sealed for good.
In the end I just opted for the easy option and removed the vapour recovery tubes - allowing me to balance the banks like a big V-twin.
But, if you manage to remove the Allen screws then potentially you could get vacuum readings for each cylinder. You would need to find an adapter to fit the vacant hole, and screw right down through the common chamber to block any effect from the other cylinders on that bank. However, even if you manage that and get individual reading for each intake - what then. There is no easy adjustment between cylinders on the same bank. You need to start messing with blead screws on the butterfly valves etc. Not for me !!
I would start by just removing the vapour recovery hose from each bank and using 2 gauges from your set of 4 try to balance the engine. If you find this method works for you but you require further refinement - then I would attack the Allen screws. For me though, this seemed like too much work for too little gain.
The vapour recovery hoses on my car are simply held on with jubilee clips - so really easy to remove. The vacuum gauge hoses should slide straight on.
If you do manage to remove any of the Allen screws - I would be interested to know what you find.
Gordon
Thank You, Thank You, Thank You,
Such a full reply at whatever time that was. I presume that the case was empty
Yes, although I only had a brief go, the Allens defied my attempts, with two different keys, so I will follow your suggestions on the Vapour Recovery Hoses
and research further into the construction of the throttle bodies at a later date.
Thanks, once again
PJ
Such a full reply at whatever time that was. I presume that the case was empty
Yes, although I only had a brief go, the Allens defied my attempts, with two different keys, so I will follow your suggestions on the Vapour Recovery Hoses
and research further into the construction of the throttle bodies at a later date.Thanks, once again
PJ
https://docs.google.com/document/d/1f77vGGQkTiFgk-...
For 4.2 AJP Engines.
Reset adaptives, and clear faults via software.
With the idle screw, set the idle to ~1200rpm - this is to reduce the chance of stalling, when tuning the 2 banks.
Driver's side: moving only the throttle pot, and not the idle screw, adjust until the adaptive is showing 0, or as close to 0 as you can get it. Note that the throttle pot number does not matter at this point, only that you get the adaptive set to 0, or as close as you can, via the throttle pot (not idle screw).
In theory: now showing
Throttle 21 adaptive 0
Passenger side: moving only the throttle pot, and not the throttle bar, adjust until the adaptive is showing 0, or as close to 0 as you can get it. Note that the throttle pot number does not matter at this point, only that you get the adaptive set to 0, or as close as you can, via the throttle pot (not the throttle bar).
In theory: now showing
Throttle 22 adaptive 0
It would be boring and unrealistic for both to be the same (perfect) straight away.
You now need to balance the 2 banks (throttle numbers) , so that they match. You only use the throttle bar for this leaving the idle screw, and throttle pots alone. You are adjusting the passenger side, to match the driver's. Once both banks are showing the same throttle numbers, you need to test, that when opening the throttle, the adaptives stay relatively low on both sides, and also (arguably more importantly), that they trim in the same direction.
Perfect theoretical world:
Idle 1200
Bank1 21 adaptive 0
Bank2 21 adaptive 0
In reality you will need to make micro adjustments on the pots, and bar, but do not touch the idle screw yet, you are always working towards matching the passenger side to the driver's, not the other way around.
Once micro adjustments are made, and you are happy that the throttles both trim the same way (important!), you can finally reduce the idle, with the screw, I recommend 1000rpm.
By separating the task into two, as advised above, you are making the job much easier, and won't get yourself into a mucking fuddle. I might update this in the future, with pictures etc.
For 4.2 AJP Engines.
Reset adaptives, and clear faults via software.
With the idle screw, set the idle to ~1200rpm - this is to reduce the chance of stalling, when tuning the 2 banks.
Driver's side: moving only the throttle pot, and not the idle screw, adjust until the adaptive is showing 0, or as close to 0 as you can get it. Note that the throttle pot number does not matter at this point, only that you get the adaptive set to 0, or as close as you can, via the throttle pot (not idle screw).
In theory: now showing
Throttle 21 adaptive 0
Passenger side: moving only the throttle pot, and not the throttle bar, adjust until the adaptive is showing 0, or as close to 0 as you can get it. Note that the throttle pot number does not matter at this point, only that you get the adaptive set to 0, or as close as you can, via the throttle pot (not the throttle bar).
In theory: now showing
Throttle 22 adaptive 0
It would be boring and unrealistic for both to be the same (perfect) straight away.
You now need to balance the 2 banks (throttle numbers) , so that they match. You only use the throttle bar for this leaving the idle screw, and throttle pots alone. You are adjusting the passenger side, to match the driver's. Once both banks are showing the same throttle numbers, you need to test, that when opening the throttle, the adaptives stay relatively low on both sides, and also (arguably more importantly), that they trim in the same direction.
Perfect theoretical world:
Idle 1200
Bank1 21 adaptive 0
Bank2 21 adaptive 0
In reality you will need to make micro adjustments on the pots, and bar, but do not touch the idle screw yet, you are always working towards matching the passenger side to the driver's, not the other way around.
Once micro adjustments are made, and you are happy that the throttles both trim the same way (important!), you can finally reduce the idle, with the screw, I recommend 1000rpm.
By separating the task into two, as advised above, you are making the job much easier, and won't get yourself into a mucking fuddle. I might update this in the future, with pictures etc.
ukkid35 said:
In an ideal world would it be better to follow that procedure at 2k rpm?
As 2k rpm is probably the most used rpm, not withstanding the issues with overheating etc
I get what you're saying, 1200 is antisocial enough for me, especially if (and you should) run it through a fan cycle. I do make the point, to make sure you test the throttle opening, which I do up to 2500rpm, making sure the adaptives trim the same way. As 2k rpm is probably the most used rpm, not withstanding the issues with overheating etc
This is key for me, and although we will all have our own versions of this procedure, I have always found it quite easy, by separating the two objectives (0 adaptives first, then balance).
Further to this, I'd urge people to buy a better balance bar linkage, I bought from Ondrives, but seem to remember you buying nice rose jointed ends from ebay, for a lot less £?
Another significant improvement, is replacing the internal throttle cable, for a stainless, thinner one. This then has hardly any friction at all, and removes any jerkiness.
DuncanM said:
For 4.2 AJP Engines.
Reset adaptives, and clear faults via software.
Awesome - makes total sense and thanks for sharingReset adaptives, and clear faults via software.
DuncanM said:
Further to this, I'd urge people to buy a better balance bar linkage, I bought from Ondrives, but seem to remember you buying nice rose jointed ends from ebay, for a lot less £?
Peter Essling makes a very nice one which I have but have yet to fit - I couldn't find a picture of it but details are here and this is a photo of my one
Juddder said:
Peter Essling makes a very nice one which I have but have yet to fit - I couldn't find a picture of it but details are here and this is a photo of my one
Ooh that looks lovely, and will be of huge benefit 
I'll link my howto for swapping out the inner throttle cable, as it's cheap, easy, and makes a big difference.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
DuncanM said:
Juddder said:
Peter Essling makes a very nice one which I have but have yet to fit - I couldn't find a picture of it but details are here and this is a photo of my one
Ooh that looks lovely, and will be of huge benefit I'll link my howto for swapping out the inner throttle cable, as it's cheap, easy, and makes a big difference.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
And I think the first upgrade I did to my Cerb was an Essling rose-jointed throttle link bar, wonderful piece of kit.
Edited by Imran999 on Tuesday 19th March 23:02
Imran999 said:
Duncan, it was fun reading that old post again, a bit of garage teamwork despite being 3000 miles apart :-)
And I think the first upgrade I did to my Cerb was an Essling rose-jointed throttle link bar, wonderful piece of kit.
Yes! Just what this forum is all about And I think the first upgrade I did to my Cerb was an Essling rose-jointed throttle link bar, wonderful piece of kit.
Edited by Imran999 on Tuesday 19th March 23:02
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