| Author |
 Topic  |
|
arrocuda
United Kingdom
501 Posts |
 Posted - 08 Jan 2012 : 20:22:30
|
Had me running for my spy glass their Jason.... and you are correct it is 'E128'. The etching is a little oil stained and hard to read but the strange thing is that I had always assumed that the 'Holbay' marking was a serial number, as I had heard that all genuine Holbay parts were serialised but I've searched every where on this cam with the spy glass and I can't find any more markings on it.
I am assuming that your standard cam is 'tricky' cos it's inside the engine which is same problem I have. I have another Holbay cam but that is also 'tricky' to get at right now.
Building the 'Mark II' fastback Rapier ('Arrocuda'). |
Edited by - arrocuda on 08 Jan 2012 20:28:00 |
 |
|
|
1922
United Kingdom
549 Posts |
Posted - 08 Jan 2012 : 20:41:11
|
Lucky you - an E128 cam is a scarce thing.
Holbay reprofiled my GLS cam to the E128 profile back in the 90's - never had one in a 1725 but was lovely in my 1840. Loads of mid-range power.
Not sure about the casting numbers - I really have no idea if they can be used to identify a cam or not. But measuring the lift is a sure way to identify it - if you have something to measure it with.
Just measure a lobe at it's narrowest and widest point (does that make sense?) and work out the difference.
In thousands of an inch:
320 = H120/GLS
298 = early 1725
295 = later 1725
260 = very slow 1725
255 = 1500 (even slower)
In metric, er, 8.128, 7.5692, 7.493, 6.604 and 6.477.
While I'm on the measurements page in the workshop manual:
1725 rods are 5.625 in (14.28cm) from centre to centre.
1500 rods are 5.845 in (14.84cm) from centre to centre.
And yup - it's a bit tricky to get at because it's in an engine and 7 miles away.
 |
Edited by - 1922 on 08 Jan 2012 20:42:37 |
|
|
|
moditup
United Kingdom
83 Posts |
Posted - 08 Jan 2012 : 21:16:22
|
Thanks for the info, I will try and extract both cams from the engines tommorow and see what I have got, hopefully will be good news will post my findings.
|
|
|
|
moditup
United Kingdom
83 Posts |
Posted - 09 Jan 2012 : 19:34:48
|
| Hi all, how does the cam come out on these engines I have taken off all the bits timing cover, chain removed all lifters but it refuses to come out, knocked out the core plug at the back of the block but cannot see anything stopping it ? |
|
|
|
1922
United Kingdom
549 Posts |
Posted - 09 Jan 2012 : 19:38:44
|
Oil pump drive will be in the way.
Remove the distributor, then flip over the engine, remove the sump and unbolt the oil pump.
Then it should slide out forwards.
|
|
|
|
moditup
United Kingdom
83 Posts |
Posted - 10 Jan 2012 : 16:29:02
|
Right removed the cam from the engine I bought and it has KENT stamped between the front lobes cannot see any other numbers, engine block stamped 71981369 FRANCE 29,12,71 ?
|
|
|
|
arrocuda
United Kingdom
501 Posts |
Posted - 10 Jan 2012 : 18:50:44
|
Just when you thought.... etc etc! Kent are a specialist tuning company that grind camshafts for several different manufacturers products so that puts us right back to square one. Did a little googleing and the only reference I came across is from the forum of the American Sunbeam Alpine Owners club where a guy talks about fitting oversize 1500cc sunbeam flat top pistons into an engine he is rebuilding and then buying a Kent camshaft for it.
http://sunbeamalpine.org/forum/archive/index.php?t-4438.html
You would be best to follow Jason's (1922) advice and measure the rods.
Building the 'Mark II' fastback Rapier ('Arrocuda'). |
|
|
|
moditup
United Kingdom
83 Posts |
Posted - 11 Jan 2012 : 15:26:11
|
Phoned kent cams today and they have no data on cam grinds, also spoke to Coltec and they no longer have the gear to do the cam re-grinds at all for the 1725 engine, awaiting an email back off Newman cams, I've no idea what cam this is but was told there was quite a few variations through the years
But was told any 1725 camshaft can be more or less ground to the E128 spec.
|
Edited by - moditup on 11 Jan 2012 15:54:34 |
|
|
|
arrocuda
United Kingdom
501 Posts |
Posted - 11 Jan 2012 : 17:39:53
|
HAve you established as to whether it's a 1500 or a 1725cc engine yet?
Building the 'Mark II' fastback Rapier ('Arrocuda'). |
Edited by - arrocuda on 11 Jan 2012 17:42:41 |
|
|
|
moditup
United Kingdom
83 Posts |
Posted - 11 Jan 2012 : 18:05:21
|
Yes its a 1725 engine with an overbore, rods measure up to my
other dismantled engine other than that, i assume its a standard Holbay, perhaps the saving grace is that any camshaft company can do a cam grind more or less using the original 1725 cam to more or less the E128 profile.
|
|
|
|
arrocuda
United Kingdom
501 Posts |
Posted - 11 Jan 2012 : 20:36:12
|
EXcellent!! What a find! I'm assuming the guy you bought it off sold it you for the kind of money you'd expect to pay for a 1500 Hunter engine. As far as the camshaft goes.... if you go to the link I posted 'Sunbeam Sam' says.......
" The cam in the holbay engine doesn't really have a great profile - there are much better ones out there that have oodles more torque at low speed and a more linear power delivery - I got one from Kent camshafts (UK), I know cat cams (UK) also do some profiles."
Although I accept that he's not talking about an E128..... it could be worth giving the Kent cam a try. He goes on to claim 115bhp (rolling road) with a Holbay head and bike carbs. One off weld and regrinds can be very expensive.
Building the 'Mark II' fastback Rapier ('Arrocuda'). |
Edited by - arrocuda on 11 Jan 2012 20:39:36 |
|
|
|
arrocuda
United Kingdom
501 Posts |
Posted - 11 Jan 2012 : 20:49:33
|
Here's the full SP......
Current spec:
Engine rebuilt with +030 flat top pistons (needed to bump up CR with modified head - std hunter 1500cc pistons used from http://www.speedyspares.co.uk/
Lightened Flywheel: 8.5kg
Kent camshaft (rally spec)http://www.kentcams.com/
Fast road unleaded head: from sunbeam classic spares (Chris Draycott)
Quad motorbike carbs (yamaha R1) spaced by Bogg broshttp://www.boggbros.co.uk/
R1 fuel pump
Engine balanced
Gave 115bhp at 6000rpm with the bike carbs and 98bhp on strombergs.
but am only running 9.5:1 CR (unleaded fuel)
Building the 'Mark II' fastback Rapier ('Arrocuda'). |
|
|
|
moditup
United Kingdom
83 Posts |
Posted - 11 Jan 2012 : 20:57:59
|
| Cheers arrocuda interesting link that one, I have been advised today that the engine with a high state of tune will never make that much power but I will have to see about that one. |
|
|
|
djnippa
United Kingdom
7 Posts |
Posted - 19 Apr 2013 : 12:30:55
|
Arrocuda,
I'm doing a similar rebuild with my standard 1725 engine.
I'd love to know how your engine is going?
I will be doing the following:-
1. Cylinders rebored +30
2. Flat-top pistons & rings (£75 each+carriage+VAT)
3. Fast-road cam Holbay specs (from www.kentcams.com) £95+Carriage+VAT
4. Twin Webers 40DC0E's 90/91's
5. 4 to 2 to 1, free flow stainless steel exhaust manifold from (www.vortex-performance-exhausts.co.uk/) (£400)
6. Holbay Head + Rocker Cover
7. Lightened Fly Wheel.
8. Re-cut inlet manifold by 6-7 degrees (so it's horizontal)
9. New Distributor with no vacuum, and electronic ignition (from Aldon) £210 inc Del.
Hopefully it will boost the HP from 76bhp to 120bhp.
|
Edited by - djnippa on 27 Jul 2014 13:34:28 |
|
|
|
jabe1807
Norway
192 Posts |
Posted - 19 Apr 2013 : 20:57:35
|
Hi. If you dont need the air filter box, I would like to buy it.
Jan, Norway.
quote:
Originally posted by moditup
Hi, yes its got the holbay alloy rocker cover and the heart shaped chambers on the head same has my other one,
also in a box of bits that come with it I do have the AC air filter with twin pipes, tried to post a few pictures of the engine/head but they won't download !
|
|
|
|
Topic |
|
Hunter 1500 engine
