Serp front cover bolt thread size/type...anyone know please?

[Pupp]

Need a couple of slightly longer bolts to mount my crank sensor bracket... anyone know the thread type and pitch please?

[spend]

According to Marki they area mix of 5/16 UNF & UNC on the front cover (he is normally very accurate).

He has a list of sizes & torques somewhere on his v8scimitar.co.uk site

Dave

[thenick]

Same here! I've made the bracket and attached the trig wheel and stuff so just need some longer bolts to sit in the threads better. I went down to the local motor factors and the guy gave me a length of threaded bar which he said should be cut to size and done up using locking nuts.

I'm not too keen on doing it this way though I must admit so if you do find some slightly longer bolts (about 10mm I think) then please let me know where to get them!

How's your install going? I'm just about through running the new wires so next up is trimming the length and attaching the new connectors I think to tidy up. By the way, what are you using for your tacho feed? I followed the black and white wire from the back of the rev counter and it ended up around the coil/dizzy area (can't remember what it was attached to). I guess i'm going to pull this back through the bulkhead and attach it to the ECU tacho driver because I can't find any evidence of one coming from the old ECU loom!

[Pupp]

thenick said:

Same here! I've made the bracket and attached the trig wheel and stuff so just need some longer bolts to sit in the threads better. I went down to the local motor factors and the guy gave me a length of threaded bar which he said should be cut to size and done up using locking nuts.

I'm not too keen on doing it this way though I must admit so if you do find some slightly longer bolts (about 10mm I think) then please let me know where to get them!

How's your install going? I'm just about through running the new wires so next up is trimming the length and attaching the new connectors I think to tidy up. By the way, what are you using for your tacho feed? I followed the black and white wire from the back of the rev counter and it ended up around the coil/dizzy area (can't remember what it was attached to). I guess i'm going to pull this back through the bulkhead and attach it to the ECU tacho driver because I can't find any evidence of one coming from the old ECU loom!

I'll check out Spendie's info and rustle up something from a local engineering merchant if I cannot find anything suitable (most of my stuff is metric)

Still early days for me, apart from the trigger wheel, I've spent far too long today cutting (well chewing) a 25mm hole in my Y piece (oo'er)...bloody stainless is a bugger when it's a 17mm drill bit with a wiggle followed by a selection of riffler files. Drag the welder out the pub tomorrow to sort the wideband boss and then figure how to mount my shiny new MSD coilpacks

Not thought as far ahead as anything too electrical... scared myself reading your purge valve thread but guess that can just be rigged to open at, say, 3k rpm or whatever using one of the spare prgrammable outputs? Or can the thing be rigged permanently open? I'll promise never to buy whale meat if that keeps the planet in equilibrium

[spend]

You only want the purge valve opening occasionally, its like having an air leak (unmetered air) so will bypass the throttle.. I think the normal scenario is once only after warm up, hitting 3000rpmish with full tps. After that if you are cruising the tank should be sucking instead of blowing so I don't think it is necessary again until you restart??

If you are in doubt a simple switch could be used to test. I don't think they 'purge' for a very long time (maybe <1sec) ~ often thought of linking a LED to see how long / when it is operated on the LR but never got round to it

Dave

[Pupp]

spend said:

According to Marki they area mix of 5/16 UNF & UNC on the front cover (he is normally very accurate).

He has a list of sizes & torques somewhere on his v8scimitar.co.uk site

Dave

Cheers for the info Dave...unfortunately the site seems to be off-line at the moment for reconstruction. Any other pointers?

[spend]

Try 'http://tvr3.dspen.com/ph/RV8 torque settings.pdf'

Dave

[thenick]

Hmm sounds tricky... Any ideas of how to get it to come on once in a while for one second??

How come non cat cars don't have them then? Mr Heath says that they were only a feature on cat cars so how do the non cats work?

Edited by thenick on Friday 28th December 14:06

[GreenV8S]

thenick said:

How come non cat cars don't have them then? Mr Heath says that they were only a feature on cat cars so how do the non cats work?

The catted cars have sealed filler caps; the non-cat cars have vented caps. The sealed caps are better as the vented ones can spill petrol under sustained high lateral G (despite the anti-surge flap).

[Pupp]

Right, the size is 5/16 UNC as Dave suggested... managed to source a couple about 10mm longer from a local industrial bearing factor at the first time of asking so guess they're common enough

[spend]

We'll see you in a couple of weeks then when you've finished trying to line the sensor up with the trigger wheel

Tip, buy a load of washers and cut slots in a lot of them so you can slip shims in. Once you know how many replace with real washers (otherwise you spend F ages putting combinations of washers on/off)

Dave

[Pupp]

spend said:

We'll see you in a couple of weeks then when you've finished trying to line the sensor up with the trigger wheel

Tip, buy a load of washers and cut slots in a lot of them so you can slip shims in. Once you know how many replace with real washers (otherwise you spend F ages putting combinations of washers on/off)

Dave

Hey, one step at a time fella... I've gotta suss the positioning for the TW first in relation to TDC. Given that there are only six possibles due to the bolt hole mounting pattern, I was thinking there *must* be an optimum that more or less achieves the required 90deg BTDC trigger point (any slight variance being dialled out on the ECU settings). Is the TDC mark and pointer on the motor (I know it won't be that accurate) at the top (it's peeing with rain and dark now so I can't be arsed to go look)? If so, and if not offset somehow, it seems to me the missing tooth must go roughly opposite the TDC mark on the damper as the sensor sits approx at 3 o'Clock... sound reasonable?

[spend]

I wouldn't trust the alignment marks on the pulley... Sticking something down the no 1 plug hole should give a quick rough & ready check of the pulley alignment

Dave

[Pupp]

Right, just in case it assists anyone else using the John Eales kit...

After checking the pulley marks this afternoon and establishing they are accurate on mine (pure fluke maybe), it seems the JE trigger wheel/sensor combo cannot be set to achieve the Emerald default of 90 deg BTDC due to the pulley bolt hole arrangement. Again assuming the marks are accurate (and that the crank keyway, and damper bolt holes are always consistently arranged in relation to each other - perhaps hopeful given what others have found), trigger points of 60deg BTDC or 120 deg BTDC can be achieved (the emerald recommendation for optimum accuracy is in the range of 60 to 120).

I found it helped to mark the damper rim at 90 BTDC with a paint line, and simply deduced that point from the now known to be correct TDC mark by measuring a quarter of the circumference around the damper rim (mine has a circ of 485mm so 90 degrees of that = 121.25mm. Best way to measure this off, I found, was to carefully roll the thing along the edge of a flat surface with the required distance measured and marked off on the surface. Did it about 5 times and the results were consistent so good enough.

Once the 90 BTDC point was established, popped the pulley back on the motor, turned the engine until that point was lined up and then used a felt marker pen through the sensor mounting block to mark the tooth then being 'looked' at (it's pretty well impossible to see otherwise due to the small dia of the TW). With the pulley back off, and by counting from the marked tooth to the missing tooth (each being 10 degrees), it's possible to establish where the wheel needs to sit within the six possibles so as to get a sensible trigger point (in my case it was already at 120 degrees BTDC so just needed nipping up with some loctite and new bolts - the TW replaces the nuts on the back of the damper/pulley assy and is M8 threaded, mine had some sort of imperial fine threaded bolts and JE did tell me there were inconsistencies with these fastener sizes so maybe something to look out for).

[spend]

IIRC the JE trigger wheel is one of the smaller ones, some prefer the triggerwheels.com variety for this very reason.

I seem to recall some discussion where someone fitted the sensor on the other side of the front cover so it aligned with the TW from a different angle (ie oil filter side). If your TW is symmetrical you should also be able to flip back/front to alter the angles

Dave

[Pupp]

spend said:

IIRC the JE trigger wheel is one of the smaller ones, some prefer the triggerwheels.com variety for this very reason.

I seem to recall some discussion where someone fitted the sensor on the other side of the front cover so it aligned with the TW from a different angle (ie oil filter side). If your TW is symmetrical you should also be able to flip back/front to alter the angles

Dave

It is quite a bit smaller in dia than the damper body and it's not symmetrical otherwise that would be right... the teeth are proud on one side. It's not actually a problem when you get your head round it (assuming the ECU can be configured, which certainly seems to be the case), just made me think a bit more than is good in my hungover state

Edited by Pupp on Saturday 29th December 19:01

[Pupp]

Pupp said:

Right, just in case it assists anyone else using the John Eales kit...

After checking the pulley marks this afternoon and establishing they are accurate on mine (pure fluke maybe), it seems the JE trigger wheel/sensor combo cannot be set to achieve the Emerald default of 90 deg BTDC due to the pulley bolt hole arrangement. Again assuming the marks are accurate (and that the crank keyway, and damper bolt holes are always consistently arranged in relation to each other - perhaps hopeful given what others have found), trigger points of 60deg BTDC or 120 deg BTDC can be achieved (the emerald recommendation for optimum accuracy is in the range of 60 to 120).

I found it helped to mark the damper rim at 90 BTDC with a paint line, and simply deduced that point from the now known to be correct TDC mark by measuring a quarter of the circumference around the damper rim (mine has a circ of 485mm so 90 degrees of that = 121.25mm. Best way to measure this off, I found, was to carefully roll the thing along the edge of a flat surface with the required distance measured and marked off on the surface. Did it about 5 times and the results were consistent so good enough.

Once the 90 BTDC point was established, popped the pulley back on the motor, turned the engine until that point was lined up and then used a felt marker pen through the sensor mounting block to mark the tooth then being 'looked' at (it's pretty well impossible to see otherwise due to the small dia of the TW). With the pulley back off, and by counting from the marked tooth to the missing tooth (each being 10 degrees), it's possible to establish where the wheel needs to sit within the six possibles so as to get a sensible trigger point (in my case it was already at 120 degrees BTDC so just needed nipping up with some loctite and new bolts - the TW replaces the nuts on the back of the damper/pulley assy and is M8 threaded, mine had some sort of imperial fine threaded bolts and JE did tell me there were inconsistencies with these fastener sizes so maybe something to look out for).

Right, having done all this and convinced myself I needed to reference the ECU at 120deg BTDC by the measuring process described, it's now been suggested to me that JE toothed wheels are made to come up at 105 deg BTDC (or +/- 60 deg derivatives) assuming TDC is marked correctly on the pulley? Although I was pretty methodical when I went through this, I suppose it's possible I misgauged it. Anyone know for sure as I'd like to get the basic set up as right as possible from the off and a 15 deg difference is close enough for the engine not to tell me by either running or not?

[spend]

Do you think the TDC is that critical? as long as it is consistent it is a purely relative mark to crank position, the ecu is not like a cam, and software will just add digits to get a spark at the right time. Another reason the maps will all be different

Dave

[Pupp]

spend said:

Do you think the TDC is that critical? as long as it is consistent it is a purely relative mark to crank position, the ecu is not like a cam, and software will just add digits to get a spark at the right time. Another reason the maps will all be different

Dave

No, I appreciate what you're saying and understand the software will compensate... just want to know where I'm starting from 'though. Take it you don't know either