Broken Crank Shaft

Broken Crank Shaft

Author
Discussion

sean ie3

285 posts

103 months

Wednesday 9th June
quotequote all
I'd definitely choose the 4.7 upgrade as, I think conrods, gudgeon pins and pistons could be damaged with this sort of failure.

MattPlaneCrank

71 posts

5 months

Thursday 10th June
quotequote all
gruffalo said:
To answer some of the points on here I had my 4.5 converted to a 4.7 by STR8SIX, it was mapped at Powers and Dom said it is the most powerful AJP8 they have ever had in for mapping.

Mine came off the rollers there with 435 BHP at the wheels, the guessing is on this being around 475+ at the flywheel and 410lbft of torque, the torque curve is almost flat from 3000rpm to 7000rpm.

The engine is a dream to drive, still completely mental but now less dependent on revs in order to deliver its push, the torque is infectious, I have the beating of mates Telsa Model 3 Performance track set up car every where from 20 to 120 and above 90 I leave him for dust, quite level to 90mph, with the Cerbera slightly in the lead.

Byker28i on here had his engine shipped to STR8SIX re built and shipped back, there are standard maps available for the 4.7 but you get the best out of it by getting it mapped, Jools (Kits and Classics) or powers can do this for you but they will require the car and for it to have been run in first.

The loom is the same as is everything else but you will need bigger injectors which would come with the engine.
I know this is a bit off the topic of Thomas's broken crank (sorry Thomas I feel the pain in your crankcase and your wallet) but which ECU are you running and do you have cats in place to achieve your impressive performance figures? scratchchin


gruffalo

6,660 posts

193 months

Thursday 10th June
quotequote all
MattPlaneCrank said:
gruffalo said:
To answer some of the points on here I had my 4.5 converted to a 4.7 by STR8SIX, it was mapped at Powers and Dom said it is the most powerful AJP8 they have ever had in for mapping.

Mine came off the rollers there with 435 BHP at the wheels, the guessing is on this being around 475+ at the flywheel and 410lbft of torque, the torque curve is almost flat from 3000rpm to 7000rpm.

The engine is a dream to drive, still completely mental but now less dependent on revs in order to deliver its push, the torque is infectious, I have the beating of mates Telsa Model 3 Performance track set up car every where from 20 to 120 and above 90 I leave him for dust, quite level to 90mph, with the Cerbera slightly in the lead.

Byker28i on here had his engine shipped to STR8SIX re built and shipped back, there are standard maps available for the 4.7 but you get the best out of it by getting it mapped, Jools (Kits and Classics) or powers can do this for you but they will require the car and for it to have been run in first.

The loom is the same as is everything else but you will need bigger injectors which would come with the engine.
I know this is a bit off the topic of Thomas's broken crank (sorry Thomas I feel the pain in your crankcase and your wallet) but which ECU are you running and do you have cats in place to achieve your impressive performance figures? scratchchin
No Cats, ACT balanced headers and large bore exhaust with their quiet back box. 1mm skim on heads to increase the compression ratio quite a bit of work in the heads to create a more turbulent air path into the combustion chamber to improve the mixing of fuel and air, Green injectors as they have a finer spay pattern and are higher capacity.

ECU is the MBE 9A9b including knock sensing.

Last time it was at SRR it showed 435bhp at powers a few weeks later 395 Rear Wheel but it was running very very rich the new ECU and wideband lambdas have sorted that, the before and after numbers on TVR Powers RR were 395 rear Wheel vs 435 rear wheel so if we add that extra 40 bhp to the SRR figure that is where the 475 estimate comes from.



Edited by gruffalo on Thursday 10th June 11:08

MattPlaneCrank

71 posts

5 months

Thursday 10th June
quotequote all
500 would be a nice round number wouldn’t it?

gruffalo

6,660 posts

193 months

Thursday 10th June
quotequote all
MattPlaneCrank said:
500 would be a nice round number wouldn’t it?
Yep, not sure it is achievable, I have thrown lots of cash at it but not completely sure it is achievable.

500 would be nice but I do feel it would be willy waving. Any time other than summer I have to be careful not to get carried away with the right foot even in 3rd on the motorway, I have had some huge power slides at 80 in 3rd on a dry but cool road even with top grade tyres.

thomas.moeller

Original Poster:

83 posts

179 months

Thursday 10th June
quotequote all
gruffalo said:
Yep, not sure it is achievable, I have thrown lots of cash at it but not completely sure it is achievable.

500 would be nice but I do feel it would be willy waving. Any time other than summer I have to be careful not to get carried away with the right foot even in 3rd on the motorway, I have had some huge power slides at 80 in 3rd on a dry but cool road even with top grade tyres.
550Hp : https://www.pistonheads.com/gassing/topic.asp?h=0&... but don't believe all you read smile

MattPlaneCrank

71 posts

5 months

Friday 11th June
quotequote all
So Thomas are you going for the 4.7 conversion? Powers seem very busy at the moment, my car is there having a new clutch and a few other bits done and they have a backlog of work so if you send your engine there it won’t be quick!
Also what sort of real 0-60 does 400+BHP give you?

thomas.moeller

Original Poster:

83 posts

179 months

Friday 11th June
quotequote all
MattPlaneCrank said:
So Thomas are you going for the 4.7 conversion? Powers seem very busy at the moment, my car is there having a new clutch and a few other bits done and they have a backlog of work so if you send your engine there it won’t be quick!
Also what sort of real 0-60 does 400+BHP give you?
My first option is still to get an upgrade, but as you point out Powers and Str8Six are very busy and it is difficult to convince them to do a pre-2000 engine. I was advised to try to contact Simon Wood. I think he is with Lotus now, but I have not been able to get hold of him. I don't have his email address, so if any has it, please share it as a private message.

If anyone got any "strings" to pull or could put in a word for me at either Powers or Str8Six I would be grateful.

Who else do the 4.7 Conversion?

Alternatively, I'm looking into a rebuild if I can get parts and finally there is the option to buy another engine. The last one seem to be a rather expensive option since I would have to import it in to EU which will add 10% customs duty + 25% VAT.

Another problem is getting the Engine to UK. I spoken to more than 10 companies and so far none of them will go to UK after Brexit. Too much paperwork and waiting time they say.

MattPlaneCrank

71 posts

5 months

Friday 11th June
quotequote all
Hi Thomas, we use Uniserve to move goods between UK and EU all the time. There’s no duty or delays if you complete the paperwork correctly.

MattPlaneCrank

71 posts

5 months

Friday 11th June
quotequote all
Having said that you don’t have a deferment account which won’t help…..

Jhonno

4,034 posts

108 months

Friday 11th June
quotequote all
thomas.moeller said:
MattPlaneCrank said:
So Thomas are you going for the 4.7 conversion? Powers seem very busy at the moment, my car is there having a new clutch and a few other bits done and they have a backlog of work so if you send your engine there it won’t be quick!
Also what sort of real 0-60 does 400+BHP give you?
My first option is still to get an upgrade, but as you point out Powers and Str8Six are very busy and it is difficult to convince them to do a pre-2000 engine. I was advised to try to contact Simon Wood. I think he is with Lotus now, but I have not been able to get hold of him. I don't have his email address, so if any has it, please share it as a private message.

If anyone got any "strings" to pull or could put in a word for me at either Powers or Str8Six I would be grateful.

Who else do the 4.7 Conversion?

Alternatively, I'm looking into a rebuild if I can get parts and finally there is the option to buy another engine. The last one seem to be a rather expensive option since I would have to import it in to EU which will add 10% customs duty + 25% VAT.

Another problem is getting the Engine to UK. I spoken to more than 10 companies and so far none of them will go to UK after Brexit. Too much paperwork and waiting time they say.
Drive it over to APM in the boot of your daily?

Byker28i

35,621 posts

184 months

Friday 11th June
quotequote all
The AJP isn't that big when stripped...



Byker28i

35,621 posts

184 months

Friday 11th June
quotequote all
gruffalo said:
No Cats, ACT balanced headers and large bore exhaust with their quiet back box. 1mm skim on heads to increase the compression ratio quite a bit of work in the heads to create a more turbulent air path into the combustion chamber to improve the mixing of fuel and air, Green injectors as they have a finer spay pattern and are higher capacity.

ECU is the MBE 9A9b including knock sensing.

Last time it was at SRR it showed 435bhp at powers a few weeks later 395 Rear Wheel but it was running very very rich the new ECU and wideband lambdas have sorted that, the before and after numbers on TVR Powers RR were 395 rear Wheel vs 435 rear wheel so if we add that extra 40 bhp to the SRR figure that is where the 475 estimate comes from.



Edited by gruffalo on Thursday 10th June 11:08
475 is easily understandable from the figures we saw at SRR early 2020 rolling road day.

Byker28i

35,621 posts

184 months

Friday 11th June
quotequote all
thomas.moeller said:
My first option is still to get an upgrade, but as you point out Powers and Str8Six are very busy and it is difficult to convince them to do a pre-2000 engine.
Which is strange as that's when most cerberas were built? Worth pointing that out?


Robscim

748 posts

223 months

Friday 11th June
quotequote all
Jhonno said:
Drive it over to APM in the boot of your daily?
This!!

Give Andy a call - he's very busy I know (he has mine in for a rebuild too!!) but speak nicely with him and discuss your options.

Then (as above) chuck it in the back of your daily and have a road trip to Liphook!! driving

Just don't try to jump me in the queue!!! hehe

Cheers

Rob


thomas.moeller

Original Poster:

83 posts

179 months

Friday 11th June
quotequote all
It seems like I finally manage to find someone willing to take the job smile

I was recommended to go for the 4.5 red rose conversion instead of the 4.7. Apparently, the 4.7 got more torque at low revs, but the 4.5 revs up faster (does that make sense?) spin

Could it be that the 4.5 is more agile and gives you a faster car in the middle range? Do anyone got any first hand experience?

My son use to do a lot of karting and here it was not always the engine with most BHP being the fastest on the a narrow track


itsallyellow

3,617 posts

187 months

Friday 11th June
quotequote all
The 4.7 is more drivable, has more power and has more torque.

There is not one thing a 4.5 does better than a 4.7.

I have lots of experience of both engines. I now have 4 cars with 4.7 AJP’s and one with a 4.5

Mike

FarmyardPants

3,698 posts

185 months

Friday 11th June
quotequote all
thomas.moeller said:
Could it be that the 4.5 is more agile and gives you a faster car in the middle range?
Quite the opposite, as Mike/itsallyellow says. If it’s mid range grunt you’re after, 4.7 is the way to go.

I would see this as an opportunity. Coming from a 4.2 the increase in torque will be a revelation.

DuncanM

4,333 posts

246 months

Saturday 12th June
quotequote all
Gruffalo your Cerbera sounds incredible! Smiling from ear to ear reading about it smile.

OP, good luck with your repair smile

Byker28i

35,621 posts

184 months

Saturday 12th June
quotequote all
itsallyellow said:
The 4.7 is more drivable, has more power and has more torque.

There is not one thing a 4.5 does better than a 4.7.

I have lots of experience of both engines. I now have 4 cars with 4.7 AJP’s and one with a 4.5

Mike
Mike knows what he's talking about.

Some figures from the last rolling road day in 2019, specifically to put numbers to upgrade options
https://www.pistonheads.com/gassing/topic.asp?h=0&...