MX5 V8
Moderator: phpBB2 - Administrators
MX5 V8
Hey,
I bought Andy's old MX5 V8 last October and after a couple of running issues Andy told me about this forum.
The car is a mk1 MX5 which a JRV8 3.5 Rover engine. Just had it on the rolling road today and it made a measly 164bhp. Every fuelling/ignition reading was perfect, any suggestions will be really welcome!
I bought Andy's old MX5 V8 last October and after a couple of running issues Andy told me about this forum.
The car is a mk1 MX5 which a JRV8 3.5 Rover engine. Just had it on the rolling road today and it made a measly 164bhp. Every fuelling/ignition reading was perfect, any suggestions will be really welcome!
MX5 4.6 V8
Previous of many SD1's back in the day!
Previous of many SD1's back in the day!
Re: MX5 V8
What is the spec of the engine? 164 bhp is more than many, but less than some.southernd wrote:Hey,
I bought Andy's old MX5 V8 last October and after a couple of running issues Andy told me about this forum.
The car is a mk1 MX5 which a JRV8 3.5 Rover engine. Just had it on the rolling road today and it made a measly 164bhp. Every fuelling/ignition reading was perfect, any suggestions will be really welcome!
Note that RV8 cams - especially 'wild' ones - can have a pretty short life. And the engine can appear to run ok, but be well down on maximum power.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
Hey Dave,
It was option 3:
http://www.jrv8.co.uk/engines/
285 cams if I remember and a pretty extensive rebuild. Built for around the 200bhp mark. It's done very few miles since rebuild, less than 10k from what I can see. I've yet to do a compression check but there's zero that sticks out as an issue. Torque wasn't that high either.
It was option 3:
http://www.jrv8.co.uk/engines/
285 cams if I remember and a pretty extensive rebuild. Built for around the 200bhp mark. It's done very few miles since rebuild, less than 10k from what I can see. I've yet to do a compression check but there's zero that sticks out as an issue. Torque wasn't that high either.
MX5 4.6 V8
Previous of many SD1's back in the day!
Previous of many SD1's back in the day!
Does it really feel short of power on such a light vehicle? I know we all want more.southernd wrote:Most likely I'll try and get hold of an experienced Rover V8 mechanic. If the engine proves no good I'll look at getting a 4.6 short block, a bit of work but more powerful from the start
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
If the heads are stock and unmodified you can put as much cam, carb and compression as you like on it - It will not do 200BHP - for stock heads 168BHP is about as much as you could ever expect.
ETA
Graph shows as expected with stock deads - flow stops after 5500. Lift the valve as much as you like and put as much carb behind it as you please - the air will not get past the restriction in the throat.
Spend £4-500 having the throats opened up and some decent seat cut and it should see 225BHP.
ETA +
The torque increase from 2500 would be what you would notice most with the head works.
Andrew
ETA
Graph shows as expected with stock deads - flow stops after 5500. Lift the valve as much as you like and put as much carb behind it as you please - the air will not get past the restriction in the throat.
Spend £4-500 having the throats opened up and some decent seat cut and it should see 225BHP.
ETA +
The torque increase from 2500 would be what you would notice most with the head works.
Andrew
4.5L V8 Ginetta G27
They didn't tell me much to be honest, I got the print out you see
If anyone remembers the MG Maestro, it feels like that. Yes it's nippy, it will move if you spank it but nothing like a V8 should. I'm not a BHP snob, it's not something I normally chase but for a V8 it just doesn't have much umph.
They are Vitesse cylinder heads, I'll Google them in a mo. Looking at the invoice/list of work the compression was raised to 9.75:1 and a hurricane camshaft, the rest was pretty much a full rebuild.
If anyone remembers the MG Maestro, it feels like that. Yes it's nippy, it will move if you spank it but nothing like a V8 should. I'm not a BHP snob, it's not something I normally chase but for a V8 it just doesn't have much umph.
They are Vitesse cylinder heads, I'll Google them in a mo. Looking at the invoice/list of work the compression was raised to 9.75:1 and a hurricane camshaft, the rest was pretty much a full rebuild.
MX5 4.6 V8
Previous of many SD1's back in the day!
Previous of many SD1's back in the day!