coverworks08

coverworks08

Member
hi would like some advise please, i have 3.5 high comp v8 in my series...not sure of the mileage and no problems or strange noises...it starts and runs very well, when i had efi removed and a fitted another manifold with Weber carb my valley gasket was replaced and i saw the cam is worn and there is a very slight oil leak from one head.i want to get another cam ...what is the best way forward....replace it with standard cam?what other work should i do to the heads?thanks rob
 
Piper 285 camshaft for more power and torque.

New Tappets

New Pushrods

Rockers

Pedestals

Stem seals

Headgaskets

Valley gasket



Maybe some mild head porting?
;)

etc etc ;)
 
I often wonder if cams are something of a dark art.
It's understandable that the 3.9 spec item has a different profile to the 3.5, but why doesn't the latter engine use the same cam for both carb fuelled versions & the EFI ?
 
norseman said:
I often wonder if cams are something of a dark art.
It's understandable that the 3.9 spec item has a different profile to the 3.5, but why doesn't the latter engine use the same cam for both carb fuelled versions & the EFI ?
Click to expand...
Both the cams have different profiles that’s why, so matching the engine and perceived use of the vehicle.
Basically, it’s all about fast opening and slow closing of the valves, then the amount and method of delivering the fuel, then removal of the exhaust gases, so the basic carburettor will require replacement jets and an EFI modifications or replacement of the ECU, of course the exhaust system will have to be replaced with a free flowing item.

I been there and done it with a car I own which is fitted with a 2.0 Ford Pinto engine, and gained 55bhp at the wheels which made a big difference to the standard 98bhp factory spec, I fitted Piper, 270 fast road cam kit, so no need to replace the valve springs if I had use a 285 cam plus maybe fitting a big valve head.
 
Thanks for the explanation Discool. My 3.5efi had only covered 40k when bought ten years & I seriously considered having a cam change to a 'mild road' or similar, but you know what they say about good intentions :rolleyes:
 
norseman said:
Thanks for the explanation Discool. My 3.5efi had only covered 40k when bought ten years & I seriously considered having a cam change to a 'mild road' or similar, but you know what they say about good intentions :rolleyes:
Click to expand...
That’s the cam to have if you have, a factory cam with a slight improvement plus there’s no other changes required, it’s also recommended for an auto.

My 3.5 cam start ticking after 100,000 miles which was replaced by a main dealer for £1,000 as one wanted to touch LR V8s back then :( if you have the time without any pressure and it’s warm it looks an easy and interesting job to do, after it’s only nuts &bolts:D

The 3.5 is much smother running than the 3.9 so don’ t ruin it...
 
You need something with low down bhp and torque as you're never going to be needing peak power high up the rev range in a series or wanting a high top end as over 60mph you'll be starting to want to slow down. My engine is from a P6B but no idea what cam it has. I've got Kent 885's in both the TVR's (4.3 and 5.0) but these are different animals. If I was changing my cam in the Series 3 I'd want a stable idle and low down grunt. If I had an extra 10 or 20bhp/torque I doubt I'd be able to tell much difference.
 
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My old 3.5 had 4.6 heads and cam with four into one manifolds, I can say it was very thirsty and went quite well but doubt if it was much better than a standard 3.5.
A good fast road cam will give more power higher up without ruining the bottom end, head work will improve power but more power means more fuel burned, mine was returning less than 15mpg on a good day
 
I’m in the process of rebuilding my 3.5 atm and I too have had to replace the cam, followers, etc.
Under advisement I went for the 3.9efi cam. Sadly it’s not running just yet, so I can’t vouch if it’s that different
 
Which cam did you go for? I' averaging 11-12mpg but only doing doing less than 1000 miles so not an issue. Sounds glorious, on a par with the TVR (well one of them, the other is significantly louder)
 
I've fitted a 3.9 cam to a 3.5 but couldn't tell you if it was an improvement over a 3.5 cam....the fact it ran on 8 cylinders instead of 6 and 1/2 with the new can fitted made it great :)
 
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