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Isky, Piper and other performance camshafts for the 2.5 V8

fredeuce
Posts: 33
Joined: Mon Feb 29, 2016 10:56 am
Location: South Australia

Re: Isky, Piper and other performance camshafts for the 2.5 V8

Post by fredeuce » Wed Jan 09, 2019 10:25 pm

The sheet attached is a grind that I will be utilizing on my new cam I am having made here in Australia. It should be completed by the end of the month.
Will then need to re-assemble engine and install new pushrods to suit.

Key specs are : Duration @ .050 : 237 deg
Valve lash .016"
Inlet Open 39 deg BTDC Close 63 ABDC
Exhaust Open 75 deg BBDC Close 27 deg ATDC

Max valve lift : 0.434"

Runs with a rotating mushroom type lifter being a modified Ford Y-block V8.

Image

tjt77
Posts: 432
Joined: Wed Mar 23, 2016 7:01 pm

Re: Isky, Piper and other performance camshafts for the 2.5 V8

Post by tjt77 » Thu Jan 10, 2019 8:45 pm

Given that the camshaft and lifters tend to wear quite rapidly on these engines .. Im wondering if there are known ways of extending longevity in these parts.? also..what are the shortcomings of the original cam profile ? the narrow intermediate main bearing also wear at an alarmingly rapid rate.. adding power at higher RPMs will accelerate an existing well known problem.

I do recall that some 30yrs back I fitted lightly modified majestic major engine into V8 saloon with manual /odrive box attached, allied to a jaguar 3.77 'powr-lok' diff, and it performed well above expectation..all that was done above a freshen up with rings and bearings, was light porting , .040" shaved off head faces, stronger inner valve springs only (heads were sent out to my 'go to' head guy at the time) and that the engine pulled cleanly to 6,500 rpms with no obvious stress and was immensely powerful...however some 40k miles of hooligan driving, and it began to smoke and guzzle oil and got rattly on both valve train and lower end.... so the car (not in the best of condition) was broken up for parts ..

I have several majestic major engines on hand today, aquired with the intent of repeating that same powertrain formula....but decided to go a different route because a Ford 302/351 V8 is more durable, lighter, takes up far less space, and can be modified to produce an easy 260BHP for a fraction of the cost of a basic rebuild on a turner V8 and there are no issues with adapting a 5 speed or 4 speed overdrive auto box as these engines came with a variety of gearbox options.. Im aware its not 'daimler' but it is a far more practical solution if you want power,reliability. longevity and have budget concerns. I got smarter after buying an already modified car and re-commisioning it (modifications were done in 1980s) .. and I have to say whoever converted the car, got it 'right'.. so Im improving this successful formula for a 21st century but 'period correct' daimler V8 2 1/2 litre saloon that will out perform a jaguar Mk2 by a huge margin..and should run for 100k+ miles with minimal 'issues' and have the added comfort of air conditioning and 'other' niceties to improve driving experience and spend minimal time in maintenance.

daimlersteve
Posts: 293
Joined: Wed Mar 09, 2016 11:20 am

Re: Isky, Piper and other performance camshafts for the 2.5 V8

Post by daimlersteve » Thu Jan 10, 2019 9:04 pm

The cams wear due to regrinding through or near through the case hardening. The solution is to rebuild the profile the regrind or use a billet that has been hardened . The cam/follower should have a hardness difference to reduce wear. If the base circle is reduced much to give more lift the system is compromised.
This topic has been covered a few times
Steve

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