Grief Update - Engine Rebuild

[Matthew Poxon]

yonex said:

Hi. Yes, JE 5.2 with steel rods, cross bolted and top hatted etc. I’ll dig out the spec. I’d like a better intake for mine.

That would be great if you don't mind, it does sound very similar to what I am doing with mine. I know John's 5.2s have a fantastic reputation.

Do you have any figures for yours?

Hopefully in a number of months time I will be able to tell you how the throttle bodies work out, it might be a nice bolt on upgrade for your engine if you are looking for an intake upgrade. I am keeping hold of my plenum just in case

[phazed]

I guess the throttle bodies are probably more efficient and you will probably get slightly more mpg then a triple plenum for instance.

With identical Camshafts I think you may get a few more BHP with the throttle bodies but slightly less torque.

Another tuppence worth, it all adds up!

[anonymous-user]

Matthew Poxon said:

That would be great if you don't mind, it does sound very similar to what I am doing with mine. I know John's 5.2s have a fantastic reputation.

Do you have any figures for yours?

Hopefully in a number of months time I will be able to tell you how the throttle bodies work out, it might be a nice bolt on upgrade for your engine if you are looking for an intake upgrade. I am keeping hold of my plenum just in case

At the moment it’s still not mapped, running on stock ignition It made 300HP and 350lb. 300lb from 2000 rpm. This was on JE dyno on break in and he said it compares well to others, especially the torque curve. I’ve been told to expect another 5-10 after mapping. It’s only covered 400 miles so we’ll see

[Matthew Poxon]

yonex said:

At the moment it’s still not mapped, running on stock ignition It made 300HP and 350lb. 300lb from 2000 rpm. This was on JE dyno on break in and he said it compares well to others, especially the torque curve. I’ve been told to expect another 5-10 after mapping. It’s only covered 400 miles so we’ll see

Are you still running the original 14CUX ECU on yours?

In my experience the JE engine dyno does read very differently to most of the rolling road dynos out there. This is a dyno read out from a Griff 500 engine rebuilt by John on his engine dyno. I know this car and I have seen it on a popular rolling road after the build pull over 310BHP.



I am not saying either one is wrong but as we already know there is a huge disparency of figures between dynos and the JE one definitely reads significantly lower than the dynos TVR folk usually use. JE one of course being an engine dyno should be the most accurate.

As many have said in the past you can only really compare cars on the same rollling road dyno on the same day.

[anonymous-user]

Matthew Poxon said:

Are you still running the original 14CUX ECU on yours?

In my experience the JE engine dyno does read very differently to most of the rolling road dynos out there. This is a dyno read out from a Griff 500 engine rebuilt by John on his engine dyno. I know this car and I have seen it on a popular rolling road after the build pull over 310BHP.



I am not saying either one is wrong but as we already know there is a huge disparency of figures between dynos and the JE one definitely reads significantly lower than the dynos TVR folk usually use. JE one of course being an engine dyno should be the most accurate.

As many have said in the past you can only really compare cars on the same rollling road dyno on the same day.

Absolutely right. It’s easy to make power on any given day with different environmental conditions or tweaking the fuelling, in practice neither are smart. JE said he had ‘a lot’ of cars on the system and I’ll take it from him, if he’s pleased then that’s perfect. IIRC a ‘good’ standard engine on his dyno makes 260/270 HP. At some point I’ll get it mapped somewhere, it’s stock 14CU at the moment. I’m tempted to go Emerald, but it’s not cheap. Also, what I have is actually very good, no real issues and it’s faster than a Griff needs to go with me inside The original engine covered 26K, head gasket failed and flooded the left cylinders. Crank snapped in three places. Split liners, not great. Had the block tested and top hatted. Then new everything. It’s been lightly ported, cleaned up as JE put it and the valves changed. I went with his advice rather and told him I wanted a strong engine, road based which could take upgrades in the future.

[Jhonno]

How much bonnet to filter clearance do you have? (May have missed it).

I would say with Powers Dyno, apparently their wheel figures translate to Joolz/SRR flywheel figures..

Interesting how large your tbs are, Cerb 4.2's run 40mm and can make 430bhp+ with ease (well, with a capacity increase underneath them). Wonder if something like that on an AJP would make a difference! (Slight OT).

Engine spec sounds nice! Will be interesting to see the end results. I shall keep an eye.

[stevesprint]

Matthew Poxon said:

Fully sequential is an interesting topic and one I have researched into a little. I was originally set on fully sequential, however JE advised against it saying it will add complication and expense for very little gain and Power have said the same thing. Dom did say if I want it then yes he will do it but he was concerned about the additional dyno time cost for little return. I did also speak to another ECU guru who said the same thing.

At this time I am going to take the advise and park the sequential idea and put it on the possible future projects list. I am trying to strike a balance between getting the car completed to a good spec first time but not at the expense of it turning into an unnecessarily long and complicated project. I will put this on the back burner along with items such as:

Wildcat heads
Roller Cam
Ceramic coated manifolds
Air ducts to the ITBs

I can always pick these up later as winter projects if a chose to do so.

Regarding the CPS I did look at a flywheel pick up as some others have done but I quite liked the idea of the reusing the dizzy gear as the sensor will be nice and accessible should it need replacing.

Matt
I respect JE and Dom’s honest opinions as most business owners in their position would just talk up the job to extract as much cash as possible, this is a good reminder they are both engineers at heart and we are very lucky to have available their parts they have designed & developed over the years. Isn’t JE’s workshop interesting, I could play in there for days.

I like your long term projects, it makes perfect sense delaying long complicated projects so you can get your Griff on the road for the precious summer weather, plus spreads out the expense and saves some fun projects for the long winter.

The dizzy gear cam sensor is a cunning idea, simple to fit anytime and I assume accurate enough for the ECU to know the stroke while the crank sensor tells the ECU the exact crank angle. Do you know where the dizzy gear black top sensor cover is from???

You’re going to have a very special engine and I look forward to seeing your ITBs.

Good Luck
Steve

Edited by stevesprint on Sunday 9th June 22:39

[Classic Chim]

Cam sensor,,,,, this is enthralling.
Better than a thriller

Keep it up superstar


Some car


It’s not the end it’s the journey getting there that matters most. Takes your time Matthew.

Great read this is turning out to be.

[Dougal9887]

Sorry to be a killjoy but one of the big benefits of moving away from the dizzy ignition is the high degree of accuracy afforded by a crank sensor compared the the sloppy distributor drive via cogs and chain. It would serve as a get-by if you needed cam angle, which is only needed for sequential and it's marginal benefits. Better gains will be had from a highly accurate crank sensor and I doubt you will ever have to change it. Most used are the GM type and they're very reliable.
Accessibility isn't actually too bad.

Dougal.

[phazed]

That is a very good point.

If you have taken out a well used front end, there is loads of backlash in the camshaft due to the stretch of the chain.

[stevesprint]

phazed said:

That is a very good point.

If you have taken out a well used front end, there is loads of backlash in the camshaft due to the stretch of the chain.

I assume that's the reason why sequential systems have both, crank sensor and cam sensor.

[Matthew Poxon]

Dougal9887 said:

Sorry to be a killjoy but one of the big benefits of moving away from the dizzy ignition is the high degree of accuracy afforded by a crank sensor compared the the sloppy distributor drive via cogs and chain. It would serve as a get-by if you needed cam angle, which is only needed for sequential and it's marginal benefits. Better gains will be had from a highly accurate crank sensor and I doubt you will ever have to change it. Most used are the GM type and they're very reliable.
Accessibility isn't actually too bad.

Dougal.

Hi Dougal,

The build will still feature a crank sensor and coil packs to allow the ECU to control the ignition timing. For the time being I the car will not utilise a Cam Position Sensor as I will be running semi sequential based on the recommendation from TVR Power and JE. I may choose to look at fully sequential in the future by adding in a dizzy gear driven CPS.

The trigger wheel and sensor bracket will be supplied by TVR Power, Dom supplies a very nice kit for his ECU packages. It is shiny and made in the UK to naturally I am all over it



The ignition system is a shameless copy of what ChimpOnGas uses on his LPG Chim. From what I understand the ignition system needs to absolutely spot on for LPG and CoG has perfected and developed his over a number of years. The setup will easily be sufficient for petrol setup

[Matthew Poxon]

I was tempted to reuse the flywheel from my old engine but after reading ChimpOnGas's thread a while back on his new steel billet flywheel I was sold. One of the last items Dom needs to be able to commence the build arrived from TTV Racing.

[QBee]

Very shiny tin hat Matthew - you expecting abuse incoming???

[Dougal9887]

Matthew Poxon said:

Hi Dougal,

The build will still feature a crank sensor and coil packs to allow the ECU to control the ignition timing. For the time being I the car will not utilise a Cam Position Sensor as I will be running semi sequential based on the recommendation from TVR Power and JE. I may choose to look at fully sequential in the future by adding in a dizzy gear driven CPS.

The trigger wheel and sensor bracket will be supplied by TVR Power, Dom supplies a very nice kit for his ECU packages. It is shiny and made in the UK to naturally I am all over it



The ignition system is a shameless copy of what ChimpOnGas uses on his LPG Chim. From what I understand the ignition system needs to absolutely spot on for LPG and CoG has perfected and developed his over a number of years. The setup will easily be sufficient for petrol setup

Got you! That crank sensor bracket does look good .
Although you're not going sequential, and I'm with you on that one, have you considered timed and in pairs? Have a look at the post under Chimaera - Megasquirt and Shunting, not for the Megasquirt or shunting but regards pairing. It makes an interesting read.

[Matthew Poxon]

I popped in to see Dom today and to drop off a few more parts for the build.

The block has now been top hatted. The crank, pistons and rods are ready to be balanced but we are just missing the blanking grub screws for the cross-drilled crank. The screws are not a standard size but Dom is going to get some made up.



I had a good chat with Dom and Jason today, Dom seems to be genuinely quite excited about the build and has suggested a few improvements. I am looking forward to seeing the build progress.

One of the improvements is ceramic coating pistons, the same as used on the Power's pro stock bike and then the Power's black edition 5.0 Speed Six engine. This will prolong the life of the piston and reduce the rattle you sometimes get from forged pistons on a cold start.... let's not overlook the fact that it is also pretty damn cool


https://www.facebook.com/dompowersperformance/vide...

Edited by Matthew Poxon on Saturday 22 June 00:03

[hoofa]

Yes go for the ceramic on the pistons , I had mine done and some other stuff on the skirts

[Matthew Poxon]

hoofa said:

Yes go for the ceramic on the pistons , I had mine done and some other stuff on the skirts

That's the one Nigel, gold on top and black on the skirts. How is yours coming along? The quality looks incredible from the pictures I have seen.

[stevesprint]

hoofa said:

Yes go for the ceramic on the pistons , I had mine done and some other stuff on the skirts

Matt
Yes go for the ceramic on the pistons , I wish I had mine done and some other stuff on the skirts

[mk1fan]

Thought Dom was a well seasoned expert. Even I know the pistons go 'in' the engine. And the other way up