Clatter Cams

[TooTall Paul]

Does anyone have the lift durations between the clatter cams and normal 4.5, or any info on the differences.

Cheers Paul

[trackcar]

get in touch with either tvr craft or jamie at castle race engines if you're thinking about cam swaps paul .. both have their own versions of diferent cams and may be able to give you some info.

[Cyclone1]

trackcar said:

get in touch with either tvr craft or jamie at castle race engines if you're thinking about cam swaps paul .. both have their own versions of diferent cams and may be able to give you some info.

If I was keeping the beast then this would be my next upgrade

Jules.

[TooTall Paul]

Hi

Just thinking this morning about the different cams, i have a pair of clatter cams in the garage and was just wondering if there was a big difference between the two

[TT Tim]

Anyone want to post the part numbers for various cams on here?

I now have some 'spare' cams but I haven't got a clue what they are, but they do have numbers stamped on them.

Is there a OE TVR listing out there somewhere?

Tim

[TooTall Paul]

TT Tim said:

Anyone want to post the part numbers for various cams on here?

I now have some 'spare' cams but I haven't got a clue what they are, but they do have numbers stamped on them.

Is there a OE TVR listing out there somewhere?

Tim

I only know the difference between the two, by the spanner hex on the clatter cam.

[350matt]

You could always contact somoeone like Kent, newman or piper cams and get them to measure the parts , they should be able to reverse engineer the profile fairly easily for a nominal sum. I heard it rumored that Newman did the original cams in any case

Matt

[cerbhead]

TT Tim said:

Anyone want to post the part numbers for various cams on here?

I now have some 'spare' cams but I haven't got a clue what they are, but they do have numbers stamped on them.

Is there a OE TVR listing out there somewhere?

Tim

My road cams (2001) are marked RD3 and according to my measurements and assuming equal lift at TDC have 41/73/61/29 timing with 13.5mm lift on both valves. The race cams I have have '101' etched on them which is lobe centre angle (RD3 are 106 deg LCA). According to my measurements and assuming equal lift at TDC they have 61/83/69/47 timing with 15mm lift on inlet and 13.5mm lift on exhaust.

I understand Paul at Austec has the definitive specs of all '6' TVR grindings. I do not know if each has its own cast/grind number marked on the cam.

What are the numbers on your cams?

[cerbhead]

350matt said:

You could always contact somoeone like Kent, newman or piper cams and get them to measure the parts , they should be able to reverse engineer the profile fairly easily for a nominal sum. I heard it rumored that Newman did the original cams in any case

Matt

I heard that Kent and Piper have also been involved in the somewhat-troubled AJP8 TVR supply chain.....

[TT Tim]

Both Piper and Kent Cams are on my doorstep, Ashford and Folkestone respectively. May try and pop in to see if there's any truth that they were involved with the AJP8.

Tim

[TooTall Paul]

Why do the inlets open higher on the race cams ? (higher revs maybe)

[TT Tim]

cerbhead said:

TT Tim said:

Anyone want to post the part numbers for various cams on here?

I now have some 'spare' cams but I haven't got a clue what they are, but they do have numbers stamped on them.

Is there a OE TVR listing out there somewhere?

Tim

My road cams (2001) are marked RD3 and according to my measurements and assuming equal lift at TDC have 41/73/61/29 timing with 13.5mm lift on both valves. The race cams I have have '101' etched on them which is lobe centre angle (RD3 are 106 deg LCA). According to my measurements and assuming equal lift at TDC they have 61/83/69/47 timing with 15mm lift on inlet and 13.5mm lift on exhaust.

I understand Paul at Austec has the definitive specs of all '6' TVR grindings. I do not know if each has its own cast/grind number marked on the cam.

What are the numbers on your cams?

My 'spares' are marked up as: 1954RD3 E2867 7K2 & 1954RD3 E2866 7K1

Tim

[cerbhead]

TT Tim said:

My 'spares' are marked up as: 1954RD3 E2867 7K2 & 1954RD3 E2866 7K1

Tim

Same as my road cams.

[cerbhead]

TooTall Paul said:

Why do the inlets open higher on the race cams ? (higher revs maybe)

Lots of 'why' questions can be asked of AJP8 cams, road and race, given the engine's bottom-end will not rev past 7,500 and very long inlet durations generally only start to produce meaningful improvement after this, but lose a lot at the bottom.

I have run the std and race cams through an engine simulator with various permutations of lift, timing, durations. The higher lift on inlet on the race cam gives a 1% power increase at 8,000 rpm compared to the std inlet lift but hardly anything at 7500 rpm, as the graph shows.

[HarryW]

cerbhead said:

TooTall Paul said:

Why do the inlets open higher on the race cams ? (higher revs maybe)

Lots of 'why' questions can be asked of AJP8 cams, road and race, given the engine's bottom-end will not rev past 7,500 and very long inlet durations generally only start to produce meaningful improvement after this, but lose a lot at the bottom.

I have run the std and race cams through an engine simulator with various permutations of lift, timing, durations. The higher lift on inlet on the race cam gives a 1% power increase at 8,000 rpm compared to the std inlet lift but hardly anything at 7500 rpm, as the graph shows.

So a strong bottom end will allow the cam to be exploited with Revs, not that 1% is exactly exploiting.
I'd be interested in seeing the plots but I can't see the image

[SprintV8]

QUOTE.
Lots of 'why' questions can be asked of AJP8 cams, road and race, given the engine's bottom-end will not rev past 7,500 and very long inlet durations generally only start to produce meaningful improvement after this, but lose a lot at the bottom.

So what's wrong with the bottom end.
Anything to worry about?.

I have both cams shall I measure lift and post back here.
I cannot measure duration.

Edited by SprintV8 on Thursday 9th November 19:51

[cerbhead]

Apologies - missed a bracket off url... hope this is ok

[HarryW]

cerbhead said:

Apologies - missed a bracket off url... hope this is ok

Good I can see it now what about torque .
Hopefully I shall see first hand the differences on the bench dyno on mine .

[cerbhead]

SprintV8 said:

QUOTE.
Lots of 'why' questions can be asked of AJP8 cams, road and race, given the engine's bottom-end will not rev past 7,500 and very long inlet durations generally only start to produce meaningful improvement after this, but lose a lot at the bottom.

So what's wrong with the bottom end.
Anything to worry about?.

I have both cams shall I measure lift and post back here.
I cannot measure duration.

Edited by SprintV8 on Thursday 9th November 19:51

Crank not adequately balanced for greater than 7500 and not enough metal/space to add weight to balance it out. Nothing to worry about on steel-cranked 4.5 as long as you keep below 7,500 - zero crank failures AFIK.

When you say 'both cams' not sure what you mean. What numbers are on your cams, what year/model do they come from? By all means measure lift - assume you have DTI? - but I believe lift hasn't changed on road cams since AJP-Day1. It's the durations/lift profile (ie clatter/quiet)/timing that have changed.

[cerbhead]

HarryW said:

Good I can see it now what about torque .
Hopefully I shall see first hand the differences on the bench dyno on mine .

I didn't produce jpg output of the torque curves from the sim runs. But you can see from the power curves that the torque curve will be fatter at lower revs on the low lift, and the higher lift curve will only get ahead of the low lift curve after 7k rpm.

So Austec are planning to run tests with a race cam with high lift and a race cam with low lift on your motor??? Or do you mean different road cam profiles? Hope you get the detail specs so we can understand the results better - this is an important aspect of the motor that is largely hidden/not understood. Good luck ....