EFI Testing - Dyno Day 6: 1.5:1 Ratio rockers
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Ah!! the old too much offset filling your pants issue!! 😁

Edited by Graham T on 8th Sep, 2019.

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Just for completeness, the wheels on the car are ET: -7
12 x 6b

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And the little wheels I tested with yesterday are 12 x 4.5 BFH x 34
So is that indicating ET: +34 ?

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yup +34 is a normal sort of mini offset graham.. what are those wheels off ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

’77 Clubman build thread
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Siamese 5 port EFI testing
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my front wheel offset is ET25, I have zero torque steer. When I made this change it had a HUGE positive impact on how the car handled. I was amazed the change going from et0. I would have gone bigger, but already tight on clearance with 13x10 front wheels

Team www.sheepspeed.com Racing

Edited by Graham T on 10th Sep, 2019.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
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jim ....out of dropping the track rod ends ,and changing wheels which do you think had the most effect ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I think the wheel offset

Team www.sheepspeed.com Racing

coolio

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

So, Dyno day 6 – 1.5:1 rockers: Where to begin?
There’s lots to get through here, so I think bite sized chunks.




Well, the first run of the day was with the setup “as the car came of the road”.

The only changes in setup since the July Dyno day were adding some fuel in parts of the map and increasing the boost duty at 5500RPM by 4 percent – Remembering what happened in Feb with a 20% boost duty increase, I thought I was erring on the side of caution. I only wanted 16PSI and it was at 14.7PSI for the last Dyno Run in July, so 4% sounds good.
Oh, and for overboost protection, previously I had it set for missing 1 ignition event in 60, which was way too aggressive, so that was changed to 1 event in 150.

So run one was going fine until 4000RPM when it hit 18PSI, the overboost protection cut in, dropping the rev’s by 200 and the boost by just under 2PSI, as far as driving the car was concerned (or at least being passenger), this just felt like a like “stumble” or mis-fire which occasionally happens, so keep on going, foot flat to the floor.
Boost built back up to 18PSI at 5500RPM and over boost protection cut in again, followed closely by Robert’s right foot jumping off the go faster peddle in an awful big hurry.
The engine was still pulling well and power was still building up, but Robert was not aware it was over boost causing the mis-fire rather than some nastiness happening that would melt the whole thing into a molten blob all over his rollers, so fair play for reacting to avert potential disaster.

The squiggle in the boost curve is the Rev’s dropping by 200RPM and the boost dropping.








So that’s:
193 BHP at 5444RPM and 17.8PSI
184 Lbs/ft at 4568RPM and 16.5PSI



Oh darn, I’ve got that decision to make again…
Drop boost duty or Turn off over boost protection.
Hmmm what to do????

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
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This graph compares Fridays run 53 with the last and best run from the July Dyno session.





Essentially from 300RPM Up, the engine is boosting at ~1 to 1.5PSI more than it was in July, but up to ~3950RPM, the Power and Torque are almost identical.


Also, MAF shows more air being ingested.



Additionally, you can just see at the bottom of the above graph that the AFR’s are marginally lean from 4250 through to 5000RPM, which could account for a little of the “Lose” of power in that region.

But I would have expected a slightly higher power leading up to the first over boost cut. Maybe around 7 or so BHP. Could this be a result of the high ratio rockers moving the power band up the rev range?


If I take the peak power from this run and compare to run 52 from July

193 BHP at 5444RPM and 17.8PSI
176.5BHP @5570BHP and 203KPa (~14.7PSI)

The boost increase is 3.1 PSI
BHP Increase is 15.5 BHP

I’d have expected that increase in BHP to be around 21 BHP, so again perhaps an indication of the power band moving up the rev range?
And if it had held on for a few 100 more RPM before overboost cutting in we might have seen the 200 BHP mark?

Edited by Graham T on 15th Sep, 2019.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

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Here is the SOT graph for Run 53.










Now onto the next run...

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Why the boost change and rocker change at the same time?

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
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On to the second run of the day.


It was decided to drop back to the same boost duty used for the July Dyno session. The whole idea of what I’m doing is to get comparative data and so, as I’ve have been trying to keep it around 16PSI, it seemed pointless doing another run on this boost duty just to try to get 200BHP, especially so early in the session.


So we looked at the log from run 53 and made a few fuelling adjustments lower in the rev range where the boost would not be altered by the change in boost duty. Mainly at 2500 and 3000 RPM.






176.6 BHP at 5345RPM and 15.9PSI
178 Lbs/ft at 4269RPM and 15.3PSI

Note in the above Graph I have added the outer Cylinder AFR trace – there is a reason…


Seems to be a fair amount of “missing” going on, right up through the rev range and from around 42500RPM it seems fairly flat.

2000 up to around 2900RPM its still pretty lean and again at 3800 through to 4800RPM, it’s too lean, whereas from 5400 through to the end of the run its getting progressively over rich again.

Also, the same boost duty cycle as July is making 1.3PSI more now than it did?




Some more fuelled added in the lean area’s and a few % taken out of the 5500 and 600RPM VE table cells.

And on to Run 55





174.1 BHP at 5539RPM and 16PSI
176.5 Lbs/ft at 4254RPM and 15.4PSI

So you can see that adding 2% at 2550 – 300 RPM made little to no difference, as well as the 3% addition at 4500RPM, but at 5500RPM to 600RPM, taking 3% out did lean it off slightly, but then the outers start reading 17 AFR??
And there was a definite misfire going on.

Oh dear!

Based on the fact we have been getting more misfires than normal, we pulled the spark plugs to take a look see thinking that possible one had given up entirely.



Only 3 in the photo because the last one is still in the car. But perhaps time to jump up to some 8’s.

Robert had 4off BPR8ES and so he cleaned them up and set the gaps to 0.6mm and I put them in the engine.

We also added a bit more fuel in both of the rev ranges that were lean, and left the fuelling as it was at top end Rev’s albeit a bit too rich still.


Run 56




174.7 BHP at 5502RPM and 16PSI
180.8 Lbs/ft at 4369RPM and 15.4PSI

So Peak torque is up slightly but it’s still missing badly at the top end and the missing is starting lower down the rev range now.
There is also an inexplicable hole in the power at just before 4750RPM.

More fuel still required at 4500RPM.

This seems to indicate that the missing is not the plugs.
Checked settings for over boost, rev limiter and traction control, just to make sure there was not an erroneous setting causing an issue.
Nope nothing I could see.
Checked wiring on Coil pack. All seemed OK.

We swapped the BPR8ES’s back out with a new set of 7’s I keep in the car – or at least 3 new ones, so 1 old one went back in, in cylinder 3 (just because so far the missing appears to be on the outer Cylinders. This was to make sure that Roberts “stock” 8’s were not duff…
But made no other changes to any settings.

’77 Clubman build thread
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Siamese 5 port EFI testing
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Run 57



174.7 BHP at 5450RPM and 15.9PSI
178.8 Lbs/ft at 4332RPM and 15.5PSI


So fairly comparable to the previous, but with the miss fire happening slightly later.





One last run for the day and a decision to drop the boost to base (ie turn off the boost controller), hoping to eliminate some sort of ignition mis-fire due to boost pressure…

At the same time Robert asked me to see if I could video the run with my phone (and in the dark..) to see if there were any sparks flying around from the HT leads.


Run 58






142.5BHP at 5492RPM and 9.5PSI
139.3 Lbs/ft at 5250RPM and 8.9PSI

Still lean at 4500RPM
Still missing badly starting around 5450RPM.


https://youtu.be/fhVljyifsqo

Not particularly exciting but you can hear at the very end of the run the “missing”…

You can see there are no signs of sparks whizzing around and at that point still no clue as to what the problem could be.

That is until the rollers finished running down and the noise abated enough we could hear it idling: Then we knew what was wrong…

’77 Clubman build thread
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Up until this point the engine was not left idling after the run was finished, and even if it had been, what I heard was not going to be heard over all the rest of the noise of the fans, rollers winding down and the exhaust extraction system when sat in the car with ear defenders on.

No chance this small CLACK, CLACK, CLACK was going to be heard.













Ahhhhhh – Well that’s a bit embarrassing!!!

Could the incompetent Mechanic who installed the rockers not have tightened the lock nut?


I have not yet measured that gap between valve stem and rocker (which I can only do on the photo), but erm, I’d guess there’s not going to be a lot of space for the exhaust gas to pass out of the cylinder when that opens.

So I think that actually makes the results we got, at least on the later runs not as bad as they looked originally.

142.5BHP at 5492RPM and 9.5PSI on 3 and 1/3 Cylinders.

Edited by Graham T on 15th Sep, 2019.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Measuring the photo in PDF, I am estimating that the rocker was around 6.8mm off of the valve stem, with a 0.017” clearance that would mean very roughly 6.4mm of “extra clearance”.


Lobe lift of the SW5 is, I think, 0.281” (7.137mm)
1.5:1 rockers should give peak lift of 10.7mm ?

less the 6.4mm “extra clearance”.

So the exhaust valve for Cylinder 4 would have been opening around 4.3mm?

I’m not very good with all this cam related stuff, so if I have this wrong, someone please correct me.

Regardless, this has somewhat screwed up the results we got from this Dyno session, so I guess I will have to have another attempt a bit later in the year before I make a decision to stick with the 1.5:1 rockers or go back to 1.3:1.

Anyhow, we got the rocker adjusted back up fine and hopefully tight this time (if it was actually me not tightening it in the first place) and so I was able to get home without issue.
Once I got a bit closer to home I decided to see if it truly was the rocker which had caused the issues and did a quick first gear flat to the floor run.

Yep – no “missing” at all, right up to 6300RPM

Next steps:

Check the rest of the clearances.
See if I can check the valve spring rates in-situ with the measuring equipment Robert has loaned me.

if the springs are weak, Could valve bounce be an issue and contributed to the lock nut not locking?
And could valve bounce also explain why I’m not making power higher up the rev range?

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

brilliant write up Graham !

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Edited by Graham T on 15th Sep, 2019.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

So I have made up some stops to stop downward movement at the right point and a lever assembly to get some pressure on.

Results are:
230 Lbs for the max valve lift with 1.5:1 ratio rockers

and

190 Lbs for max lift with 1.3:1 ratio rockers.


I have done this on 3 sets of springs.

The only spec's I have for the springs installed is:
180Lbs
which would have been with the original 1.3:1 ratio rockers installed.

Edited by Graham T on 15th Sep, 2019.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Tonight I decided to take the head off and check valve installed height ready to buy some new springs and if needed shims.

Small set back!



I’m thinking that piston did not look like that the last time I saw it…









You can just see on either side a slight amount of burring.







I’ll clean it up proper tomorrow and take a better look.



Valve:






I guess I’m also going to need to check the pushrod is straight.

Edited by Graham T on 17th Sep, 2019.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
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Doh!

Obviously, check if the valve is bent, also check guide clearance.