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Author Subject: Piper 285 cams help!
MCH_GTi6

formerly mch

Location: Hayle

Registered: 09 Sep 2005

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Post #1
A car I'm fixing has Piper bp285 cams and I'm trying to find out what adjustments etc I need to do.
I have a chap I know coming to help me time it etc but I want as much info as possible (he's an engine builder)

I have found the specs of the cams which are as follows

Piper BP285 Ultimate Road Camshafts
Powerband - 2500-7800
Duration - 280deg in - 280deg exh
Valve lift - .435" (11.05mm) in - .435" (11.05mm)
Timing 34-66
Timing 68-32
Full Lift inl ATDC - 106 deg
Full Lift exh BTDC - 108 deg
Lift @ TDC with clearance .107" (2.72mm) inl
Lift @ TDC with clearance .095" (2.41mm) exh
Valve clearance .010"/.25mm
Valve clearance .012"/.30mm

piper pdf clicky

any info on what needs to be set where would be greatly appreciated

EDIT:

I'm pretty sure they must be the 285h's as they don't have solid lifters just uprated springs and that was what the old owner was told to use

Piper BP285H Ultimate Road Camshafts
Powerband - 2000-7500
Duration - 264deg in - 264deg exh
Valve lift - .428" (10.87mm) in - .428" (10.87mm)
Timing 24-60
Timing 62-22
Full Lift inl ATDC - 108 deg
Full Lift exh BTDC - 110 deg
Lift @ TDC with clearance .072" (1.82mm) inl
Lift @ TDC with clearance .063" (1.60mm) exh
Valve clearance - Hydraulic

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Posted 26th May 2010 at 06:14
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pete_rallye

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Post #2
Basically means you need to set the engine to TDC and then set the inlets to 2.72mm opening and exhausts to 2.41mm closing. Not sure what the valve clearance is refering to, .25mm/.30mm is not enough valve>piston clearance, I would look to more like .5mm>1mm to be safe.

Are you using hydraulic lifters? If so you should really be using 285h cams, make sure you have the correct valve springs in also.

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Posted 26th May 2010 at 02:23
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MCH_GTi6

formerly mch

Location: Hayle

Registered: 09 Sep 2005

Posts: 2,456

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Post #3
pete_rallye wrote:
Basically means you need to set the engine to TDC and then set the inlets to 2.72mm opening and exhausts to 2.41mm closing. Not sure what the valve clearance is refering to, .25mm/.30mm is not enough valve>piston clearance, I would look to more like .5mm>1mm to be safe.

Are you using hydraulic lifters? If so you should really be using 285h cams, make sure you have the correct valve springs in also.


I know its got piper valve springs too... as far as i know other than the valve springs its a standard lifter set-up

I just wanna make sure I have all the info so it doesnt go wrong.

The old owner said something about timing the crank 110deg BTDC

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Posted 26th May 2010 at 02:25
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allanallen

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Post #4
Sorry if i'm stating the obvious but don't set the Cams to those figures if its running standard pistons.

As pete says all the info you need for setting is the lift a TDC values.
If you don't know the spec of the pistons you ideally need to whip the head off and do a dummy build to check the valve clearances.

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Posted 26th May 2010 at 04:02
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MCH_GTi6

formerly mch

Location: Hayle

Registered: 09 Sep 2005

Posts: 2,456

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Post #5
allanallen wrote:
Sorry if i'm stating the obvious but don't set the Cams to those figures if its running standard pistons.

As pete says all the info you need for setting is the lift a TDC values.
If you don't know the spec of the pistons you ideally need to whip the head off and do a dummy build to check the valve clearances.


I bought a car with them fitted. It had been run low on oil and blown up cause the guy selected 2nd instead of 4th at around 95mph.

I had the head all checked and new valves fitted, the block was scrap so thats gone (were standard pistons)
I am fitting the head to a mint low mileage engine and want to get everything right.

I am awaiting a reply from my mate who originally owned the car (not who blew it up) with info on if they are definately the 285's and not the 285h's

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Posted 26th May 2010 at 05:33
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daveyboy

aka Jim Davey

Location: Southampton

Registered: 01 Oct 2007

Posts: 8,648

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Post #6
pete_rallye wrote:
Basically means you need to set the engine to TDC and then set the inlets to 2.72mm opening and exhausts to 2.41mm closing. Not sure what the valve clearance is refering to, .25mm/.30mm is not enough valve>piston clearance, I would look to more like .5mm>1mm to be safe.

Are you using hydraulic lifters? If so you should really be using 285h cams, make sure you have the correct valve springs in also.


Those are the clearance figures for if you are running with solid lifters, best check with Piper if that is a solid lifter cam profile. Sounds like it may well be and if it is, it's not meant to work with hydraulic lifters.

EDIT: I just read the specs on that cam mate and it is a hydraulic profile, you will need a set of solid lifters, new springs (to be safe at those rpm) and shims. Might be easier (and a lot cheaper) to send the cam back and get a hydraulic profile cam.

________________________________________

R H Davey Welding Supplies. I sell new and used welding equipment in the Hampshire area. I take on welding jobs in the evenings, ally casting repairs are one of my specialities but I can weld pretty much anything. PM me with your requirements.

Some of my services: (See my for sale threads)
Engine mount/chassis repair
Solid Beam Mounts BACK IN PRODUCTION
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Posted 26th May 2010 at 05:46
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MCH_GTi6

formerly mch

Location: Hayle

Registered: 09 Sep 2005

Posts: 2,456

Status: Offline
Post #7
daveyboy wrote:
pete_rallye wrote:
Basically means you need to set the engine to TDC and then set the inlets to 2.72mm opening and exhausts to 2.41mm closing. Not sure what the valve clearance is refering to, .25mm/.30mm is not enough valve>piston clearance, I would look to more like .5mm>1mm to be safe.

Are you using hydraulic lifters? If so you should really be using 285h cams, make sure you have the correct valve springs in also.


Those are the clearance figures for if you are running with solid lifters, best check with Piper if that is a solid lifter cam profile. Sounds like it may well be and if it is, it's not meant to work with hydraulic lifters.

EDIT: I just read the specs on that cam mate and it is a hydraulic profile, you will need a set of solid lifters, new springs (to be safe at those rpm) and shims. Might be easier (and a lot cheaper) to send the cam back and get a hydraulic profile cam.


I didnt "buy" the cams, they came in a car I bought that had been blown up due to low oil and selecting the wrong gear.
before that they had been run as they were with no issues.

I am waiting to hear back if they are the 285's or 285h's (not sure if it makes a massive difference)
But the guy who originally owned the car set them up after speaking to a guy at piper...
unfortunately he cannot remember who or the settings

after looking i would imagine they are the 285h's due to them being "hydraulic"

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Posted 26th May 2010 at 05:56
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daveyboy

aka Jim Davey

Location: Southampton

Registered: 01 Oct 2007

Posts: 8,648

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Post #8
Sorry, it's getting late and I've not properly read all the previous posts, assuming he got the right cam in the first place (he probably did because Piper would have asked about lifters at the time of purchase) then its just a case of establishing exact TDC, then using a degree wheel and a dial guage, timing the engine up so you achieve the lift figures specified in the spec sheet. Does he have pocketed pistons already? As there is sod all clearance as standard.

________________________________________

R H Davey Welding Supplies. I sell new and used welding equipment in the Hampshire area. I take on welding jobs in the evenings, ally casting repairs are one of my specialities but I can weld pretty much anything. PM me with your requirements.

Some of my services: (See my for sale threads)
Engine mount/chassis repair
Solid Beam Mounts BACK IN PRODUCTION
Harness bars
Posted 26th May 2010 at 06:01
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MCH_GTi6

formerly mch

Location: Hayle

Registered: 09 Sep 2005

Posts: 2,456

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Post #9
daveyboy wrote:
Sorry, it's getting late and I've not properly read all the previous posts, assuming he got the right cam in the first place (he probably did because Piper would have asked about lifters at the time of purchase) then its just a case of establishing exact TDC, then using a degree wheel and a dial guage, timing the engine up so you achieve the lift figures specified in the spec sheet. Does he have pocketed pistons already? As there is sod all clearance as standard.


standard pistons, looking at it they must be the 285h's

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Posted 26th May 2010 at 06:03
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daveyboy

aka Jim Davey

Location: Southampton

Registered: 01 Oct 2007

Posts: 8,648

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Post #10
MCH_GTi6 wrote:
daveyboy wrote:
Sorry, it's getting late and I've not properly read all the previous posts, assuming he got the right cam in the first place (he probably did because Piper would have asked about lifters at the time of purchase) then its just a case of establishing exact TDC, then using a degree wheel and a dial guage, timing the engine up so you achieve the lift figures specified in the spec sheet. Does he have pocketed pistons already? As there is sod all clearance as standard.


standard pistons, looking at it they must be the 285h's


You will have to be super careful with your timing then. Is the engine fully stripped at present and can you check your 'piston to valve' clearance?

________________________________________

R H Davey Welding Supplies. I sell new and used welding equipment in the Hampshire area. I take on welding jobs in the evenings, ally casting repairs are one of my specialities but I can weld pretty much anything. PM me with your requirements.

Some of my services: (See my for sale threads)
Engine mount/chassis repair
Solid Beam Mounts BACK IN PRODUCTION
Harness bars
Posted 26th May 2010 at 06:10
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MCH_GTi6

formerly mch

Location: Hayle

Registered: 09 Sep 2005

Posts: 2,456

Status: Offline
Post #11
daveyboy wrote:

You will have to be super careful with your timing then. Is the engine fully stripped at present and can you check your 'piston to valve' clearance?


The engine I'm using still has the original head on (completely standard) and I have the head seperate as I've only had it back from being skimmed and checked this week.
I'll be getting my mate that builds engines to come and sort it for me but I want to know what needs doing 100%

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Posted 26th May 2010 at 06:12
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daveyboy

aka Jim Davey

Location: Southampton

Registered: 01 Oct 2007

Posts: 8,648

Status: Offline
Post #12
MCH_GTi6 wrote:
pete_rallye wrote:
Basically means you need to set the engine to TDC and then set the inlets to 2.72mm opening and exhausts to 2.41mm closing. Not sure what the valve clearance is refering to, .25mm/.30mm is not enough valve>piston clearance, I would look to more like .5mm>1mm to be safe.

Are you using hydraulic lifters? If so you should really be using 285h cams, make sure you have the correct valve springs in also.


I know its got piper valve springs too... as far as i know other than the valve springs its a standard lifter set-up

I just wanna make sure I have all the info so it doesnt go wrong.

The old owner said something about timing the crank 110deg BTDC


Piper will have a reccomended lift figure at 110 or 108 degrees BTDC (something like that anyway), this is usually a start point for safe running and during the 'dry build' of the engine the builder usually checks to see how much advance and overlap he can get away with either side of that point so he knows exactly how far he can swing the cams when it's on the rollers getting set up later on down the line.

________________________________________

R H Davey Welding Supplies. I sell new and used welding equipment in the Hampshire area. I take on welding jobs in the evenings, ally casting repairs are one of my specialities but I can weld pretty much anything. PM me with your requirements.

Some of my services: (See my for sale threads)
Engine mount/chassis repair
Solid Beam Mounts BACK IN PRODUCTION
Harness bars
Posted 26th May 2010 at 06:14
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daveyboy

aka Jim Davey

Location: Southampton

Registered: 01 Oct 2007

Posts: 8,648

Status: Offline
Post #13
MCH_GTi6 wrote:
daveyboy wrote:

You will have to be super careful with your timing then. Is the engine fully stripped at present and can you check your 'piston to valve' clearance?


The engine I'm using still has the original head on (completely standard) and I have the head seperate as I've only had it back from being skimmed and checked this week.
I'll be getting my mate that builds engines to come and sort it for me but I want to know what needs doing 100%


Does it definitely need a skim? If you take 0.25mm off the thickness of the head, and you are on standard pistons with those cams then you are taking a very serious risk of valve to piston contact, not a good look Whistle

EDIT: Too late, it's already had the skim, my reading skilz are really f*cked tonight.

________________________________________

R H Davey Welding Supplies. I sell new and used welding equipment in the Hampshire area. I take on welding jobs in the evenings, ally casting repairs are one of my specialities but I can weld pretty much anything. PM me with your requirements.

Some of my services: (See my for sale threads)
Engine mount/chassis repair
Solid Beam Mounts BACK IN PRODUCTION
Harness bars
Posted 26th May 2010 at 06:19
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MCH_GTi6

formerly mch

Location: Hayle

Registered: 09 Sep 2005

Posts: 2,456

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Post #14
daveyboy wrote:

Does it definitely need a skim? If you take 0.25mm off the thickness of the head, and you are on standard pistons with those cams then you are taking a very serious risk of valve to piston contact, not a good look Whistle


it did unfortunately and its been done Sad
I can use a thicker gasket though cant I?

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Posted 26th May 2010 at 06:19
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daveyboy

aka Jim Davey

Location: Southampton

Registered: 01 Oct 2007

Posts: 8,648

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Post #15
MCH_GTi6 wrote:
daveyboy wrote:

Does it definitely need a skim? If you take 0.25mm off the thickness of the head, and you are on standard pistons with those cams then you are taking a very serious risk of valve to piston contact, not a good look Whistle


it did unfortunately and its been done Sad
I can use a thicker gasket though cant I?


You can, but for what it would cost, you would be best off getting the pistons pocketed by a reputable machinist, the tiny decrease in compression ratio will be more than made up for by the increase in power you will get from bieng safely able to run more advance. It's the proper way to do it as clearance is marginal even on standard cams.

________________________________________

R H Davey Welding Supplies. I sell new and used welding equipment in the Hampshire area. I take on welding jobs in the evenings, ally casting repairs are one of my specialities but I can weld pretty much anything. PM me with your requirements.

Some of my services: (See my for sale threads)
Engine mount/chassis repair
Solid Beam Mounts BACK IN PRODUCTION
Harness bars
Posted 26th May 2010 at 06:22
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MCH_GTi6

formerly mch

Location: Hayle

Registered: 09 Sep 2005

Posts: 2,456

Status: Offline
Post #16
daveyboy wrote:
MCH_GTi6 wrote:
daveyboy wrote:

Does it definitely need a skim? If you take 0.25mm off the thickness of the head, and you are on standard pistons with those cams then you are taking a very serious risk of valve to piston contact, not a good look Whistle


it did unfortunately and its been done Sad
I can use a thicker gasket though cant I?


You can, but for what it would cost, you would be best off getting the pistons pocketed by a reputable machinist, the tiny decrease in compression ratio will be more than made up for by the increase in power you will get from bieng safely able to run more advance. It's the proper way to do it as clearance is marginal even on standard cams.


So there's enough "meat" on standard pistons to do this?

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Posted 26th May 2010 at 06:24
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daveyboy

aka Jim Davey

Location: Southampton

Registered: 01 Oct 2007

Posts: 8,648

Status: Offline
Post #17
MCH_GTi6 wrote:
daveyboy wrote:
MCH_GTi6 wrote:
daveyboy wrote:

Does it definitely need a skim? If you take 0.25mm off the thickness of the head, and you are on standard pistons with those cams then you are taking a very serious risk of valve to piston contact, not a good look Whistle


it did unfortunately and its been done Sad
I can use a thicker gasket though cant I?


You can, but for what it would cost, you would be best off getting the pistons pocketed by a reputable machinist, the tiny decrease in compression ratio will be more than made up for by the increase in power you will get from bieng safely able to run more advance. It's the proper way to do it as clearance is marginal even on standard cams.


So there's enough "meat" on standard pistons to do this?


Plenty, if its done in exactly the right place, with the centre dotted in stu with an old valve stem gropund to a point, then set up in a mill the the correct angle he would probably ony need to go down an extra mm (radial clearance would need checking too) but there is plenty of metal on the crown for a little pocketing. Accuracy is essential though, that way the ammount of material removed is kept minimum.

________________________________________

R H Davey Welding Supplies. I sell new and used welding equipment in the Hampshire area. I take on welding jobs in the evenings, ally casting repairs are one of my specialities but I can weld pretty much anything. PM me with your requirements.

Some of my services: (See my for sale threads)
Engine mount/chassis repair
Solid Beam Mounts BACK IN PRODUCTION
Harness bars
Posted 26th May 2010 at 06:27
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