4 litre down on power.

[stevo.elan]

hi all, i have a 96 400 chimaera which is down on power. all is well untill 4000rpm and she just dies away. is this pos a cat problem?

[v8 racing]

Hi what sort of power loss do you have? is it a misfire or just low on power? rotor arm could be a cause amongst many other things

[stevo.elan]

the car picks up well untill 4000rpm then it runs out fo grunt, there is some poping and farting from the front end of the exhaust(no clear back firing) and there is no miss fire. the rotor arm has been change with the plugs and leads.

[GreenV8S]

Perhaps a cam, what mileage is it?

[stevo.elan]

50k

[GreenV8S]

That's a pretty good life for a cam. Not saying it's definitely that, but it's a distinct possibility. Unfortunately there's no foolproof way to check the cam without opening things up.

Is this something that has happened suddenly, or has been a gradual thing over thousands of miles?

[poorpeet]

Eeeek! Mines done 87K on the original cam! I wonder if I still have a cam or just a bumpy tube!

[Podie]

GreenV8S said:

That's a pretty good life for a cam. Not saying it's definitely that, but it's a distinct possibility. Unfortunately there's no foolproof way to check the cam without opening things up.

Wouldn't it show up on a rolling road graph? - a big drop off in the power?

[trackcar]

poorpeet said:

Eeeek! Mines done 87K on the original cam! I wonder if I still have a cam or just a bumpy tube!

My 4 litre has done 109k miles on original cam and clutch they *can* be hardy things if treated well.

[targarama]

I recall laughing at a mates' 4.0L HC needing a new cam at 25k a few years ago. Then about 6 months later mine needed doing at 29k ish. My car was treated gently. From what I recall the Rover V8 doesn't deliver as much oil to the rearmost rockers/cam assembly as it could.

I think mine cost around £700 to change (front chassis crossmember needs unbolting to slide out old one).

[Colin L]

Mine has done 118,000 miles now and still on orginal cams, no work done other than giving a good engine flush to clean out the oil pump.
Put out 278BHP at a rolling road last year.

So good servicing is always a good thing, mine had a problem like that once have you checked the airflow meter, but best to go for a full health check.

We could have our own we club of the 100,000 Chimaera's.

Colin L

[GreenV8S]

Podie said:

Wouldn't it show up on a rolling road graph? - a big drop off in the power?

The drop-off would be apparent, but I don't think that would prove it was caused by a worn cam. The cam that was in mine when I bought it was knackered by 25k miles. The replacement was still fine 25k later when I had the rest of the engine replaced. The new cam and engine was still fine 100k miles later. I suspect a lot of it has to do with the way the cam is bedded in, and oil changes and quality etc. They can last a long time, but it also seems quite common for them to wear out at relatively low mileages. If the power tapers off gradually at the top end with no obvious running problems, and this has developed gradually over many thousands of miles, I would suspect a worn cam.

[TJW]

Colin L said:

Put out 278BHP at a rolling road last year.

Standard...

I highly doubt that is standard, most prob some tvr factory prototype or something?

[stevo.elan]

the dyno shows a good output up to 4000 then it tails off. the max it recorded was 158bhp at the flywheel
oh and i've only just got her.

>> Edited by stevo.elan on Thursday 6th April 17:20

[Mad Mitch]

Sorry to hear you are having probs so soon mate. Doesn`t sound like a cam problem to me. Have you had the cat/exhausts checked ??ie restricted ?? Also check fuel pressure and ensure also there is enough fuel and no line /filter blockage.....

[trackcar]

a graph with the AF ratio would be cool .. when my S did simiar stuff (down to 130bhp though!) it was low fuel pressure causing the problem, just correcting that one fault netted 68bhp extra!

[stevo.elan]

all good advice guys thank you. i'll start with the cat before i strip it down to the cam. i've worked on this engine before on a p6 so its not to daunting.

[BIG COL]

TJW said:

Colin L said: Put out 278BHP at a rolling road last year. Standard... I highly doubt that is standard, most prob some tvr factory prototype or something?

OR


some sort of irish mist/Bullshit in front of the RR screen

[V8 Archie]

Recent murmurings I've heard would make it sound that you could be running very lean. Not enough fuel to ignite in the cylinder so it get's pushed int the exhaust and hey presto! Pop bang.

[vixpy1]

trackcar said:

a graph with the AF ratio would be cool .. when my S did simiar stuff (down to 130bhp though!) it was low fuel pressure causing the problem, just correcting that one fault netted 68bhp extra!

Yep, seen a couple with this.. running silly lean afr's at the top end and making bugger all power..