choosing a Camshaft

[Saltddirk]

After the 10CR ( and even before) the spit engine is due for a rework I would say.

She's using about as much oil as Broomey on a saturday night which would indicate at least a new set of scrapers and rings.

We had no time to dismantle the engine before but when replacing the headgasket noticed that the cam followers were shot, and at least one cam on #2 had rounded off enough to notice through the hole. People in the know tell me that this is fairly common lot for a high lift wild cam. 

It would make sense then to replace the camshaft, followers and rings as a minimum to get the engine in condition again.

Now for the following. The engine is a 1300 ( DG prefix, HE suffix) Toledo(?) engine worked over by jigsaw which i bought off Rob S a few years ago when he went the kent route, as far as I can tell the head had been flowed, pistons seem to be normal at +40 oversize. Not sure what else was done but I imagine a wild camshaft has been fitted. She is happy to rev but rather gutless in the lower powerband. It's a nice engine but not what i need. I do welcome the power increase but would have loved a bit more torque for daily use (and to storm the alpine passes). so here we go

See that I have absolutely no knowledge of what makes a camshaft tick (trawling the internet now to do my homework) the question is what Camshaft would I need? 

Talking to a few on the 10CR a standard Mk3 camshaft was recommended?

Opinions?

Dirk

 

[Greta]

TT fast road '83 on my 1500 has a nice compromise between a bit more oomph without loosing all tractability ... wouldn't want to change it on the 1500 ... but very interested to read what others suggest for 1300cc 

[sparky_spit]

Hi Dirk - the 1500 engine that was in my Spitfire before it broke a few days prior to the 10CR had a MK3 Spitfire profile camshaft.  Although not lasting long enough to really test it or even be set up properly on a rolling road, it was obvious that it had plenty of torque and the engine pulled well between 2000 and 4000 RPM.  The cam was installed 3deg (crank) retarded to supposedly give better torque but I don't know how effective this is, as I've got nothing to compare it with, but I was very happy with it.

Whether a MK3 cam is right for you with a 1300?  I don't know...  Mike

[Saltddirk]

Nuala, Mike,

Thanks,

from reading about cam profiles, lobe spacing, valve bounce, advance, overlap, acceleration, velocity, jerk.... my head's hurting.

The 1500 being a longer stroke engine than the 1300, so i would assume that the way to fill the cylinder is different and thus that would make the cam specifications or needs different. Or the mk3 cam was spot on for both? I would not know.

I do gather (now) that small differences in profile can make a huge difference in performance, at least if the sales literature is to be believed, and the basic idea for a roadcam is that you do not need to have too long durations, high lift preferred for better breathing and a quick profile to have better flow as early on as possible.....

Dirk 

[RobPearce]

The standard Vitesse & GT6 cam (similar to Mk3 Spitfire, I think) had a relatively long duration for a road car anyway. Higher lift and "quicker" profile both cause difficulties with valve control at high RPM, whereas longer duration doesn't (it actually helps).

[Velocita Rosso]

Dirk ,Talk to Newman Cams, Mr Newman very informative...I have one of theirs in my Spit 

 

 

[Saltddirk]

Quoted from Velocita Rosso-

Dirk ,Talk to Newman Cams, Mr Newman very informative...I have one of theirs in my Spit 

 

 

Which one you went fore mike? TRIS/280/405 ph2 or TRIS/260/375 ph1 ? (or you naughty old boy and went for the full monty ph27.5 ? ) 

it's hard to admit but I bought the wrong engine with the power way too high up in the powerband. Actually the only thing I really like and will miss is that lumpy idle, love the sound of it, and the short spinning noise you get the moment you clutch before the whole orchestra comes on again.

Na thats not all true, it is a lovely engine, rev's like hell and sound good (SWMBO doesnt think so) but I have to admit that the time I spend enjoying to rev the hell out of her is way outstripped by the time I would be using it cruising and touring so here we are....

Shall have to decide fast before Clive pipes up and shouts: put a Zetec in, and a subaru Diff, and ....! (and before brexit slams another 25% on top of it :( )

 

[Saltddirk]

Quoted from RobPearce-

The standard Vitesse & GT6 cam (similar to Mk3 Spitfire, I think) had a relatively long duration for a road car anyway. Higher lift and "quicker" profile both cause difficulties with valve control at high RPM, whereas longer duration doesn't (it actually helps).

Rob, 

But would that not shift max BHP again into the higher regions whereas I would want it more readily available.?

I'll see if  I can find a cam spec for the GT6 (without having to refer to Mr Gareth list, for whom all cams are rubbish except the ones he makes :) )

[Velocita Rosso]

Dirk , we had numerous discussions with the boss man, and had two options

Its going back nearly four years now and I`m sure we settled on the Race Cam

http://www.erstellen.co.uk/newman-cams/PRICELIST-BROCHURE_2019-TRIUMPH.pdf

[Saltddirk]

oouch you naughty one!

I would think that that would be overcamming my engine!

only marginally related thread drift, How did yours go up the Stelvio last month? that was where we were struggling, or falling flat in 3rd, or reving the T*Ts out of her in second (refering to the engine not SWMBO) , do you run the standard diff? 

[Velocita Rosso]

Stelvio had rockfalls so it was closed both ways

We diverted in Bormio and climbed over the Foscagno to Livigno, over Offen then to the foot of Umbrail then left onto Austria

The Spit romped over every hill and dale with no faults whatsoever.....carrying an un needed half shaft 

[RobPearce]

Quoted from Saltddirk-

Quoted from RobPearce-

The standard Vitesse & GT6 cam (similar to Mk3 Spitfire, I think) had a relatively long duration for a road car anyway. Higher lift and "quicker" profile both cause difficulties with valve control at high RPM, whereas longer duration doesn't (it actually helps).

Rob, 

But would that not shift max BHP again into the higher regions whereas I would want it more readily available.?

The Mk3 profile is generally considered a good all-rounder. It's not a screamer but it does pick up a bit as you rev it - especially on a Mk2 Spitfire (same cam but on an 1147 with 4-2-1 straight-through exhaust). Max BHP is up around 5000 or 5500 RPM (I don't have the figures to hand) so readily accessible on a small-bearing 1300. Whether you'd want to rev a DG lump that high depends how well it's been built. However, it's not a wild cam and you do still get decent torque low down.

[Saltddirk]

Quoted from Velocita Rosso-

Stelvio had rockfalls so it was closed both ways

We diverted in Bormio and climbed over the Foscagno to Livigno, over Offen then to the foot of Umbrail then left onto Austria

The Spit romped over every hill and dale with no faults whatsoever.....carrying an un needed half shaft 

bummer but still good passes to climb!

better safe than sorry I would think...

[Saltddirk]

Quoted from RobPearce-

Quoted from Saltddirk-

Quoted from RobPearce-

The standard Vitesse & GT6 cam (similar to Mk3 Spitfire, I think) had a relatively long duration for a road car anyway. Higher lift and "quicker" profile both cause difficulties with valve control at high RPM, whereas longer duration doesn't (it actually helps).

Rob, 

But would that not shift max BHP again into the higher regions whereas I would want it more readily available.?

The Mk3 profile is generally considered a good all-rounder. It's not a screamer but it does pick up a bit as you rev it - especially on a Mk2 Spitfire (same cam but on an 1147 with 4-2-1 straight-through exhaust). Max BHP is up around 5000 or 5500 RPM (I don't have the figures to hand) so readily accessible on a small-bearing 1300. Whether you'd want to rev a DG lump that high depends how well it's been built. However, it's not a wild cam and you do still get decent torque low down.

Thanks Rob,

I'll start with dismantling the engine and see what is really in there, and yes all depend on how well it was build. low down torque sounds marvelous.

D

[thescrapman]

Dirk, have you driven a car with a standard Mk3 engine in it?

It is a good compromise especially when balanced.

Revs cleanly to 6000 and beyond effortlessly,

that said I have a spare engine to try in my Spitfire that has a very lumpy cam, and a pair of Webers.

That will be fun whenI get round to changing it.

Colin

p.s. I have been in Mike Banks car with the 1500 Mk3 crammed ( and now broken) engine, and it seemed a very good compromise.

If you want to start anew, a need to shift some engine for rebuilding, 

Have an FD and a few 1500 available,

[Saltddirk]

:(

despite having owned a Mk3 for over 20 years I have never driven one, not at least with the engine running... only behind a towrope. the car was a restoration project that i never came round to finish.

Mine originally had a 1147. and here lies the other problem / dilemma. I bought this engine as a quick way out to have a good running car (still took me 5 years but that's another story) the original engine was tired and at least needed new thrust washers but has always been reliable so I now have 2 tired engines, I am debating to get the original going again first while i keep the 1300 lump in the car for now, it is still mobile albeit with a thirst for oil. and then swap out the fresh engine to give this one his go, or do i go straight with the rejuvenating of the 1300?

both have merits but both will cost money.... for now i'm thinking of going for the 1300 first, who knows that with a milder cam i might actually like it better, the head has been breathed upon, so it should go better than a standard one and have more poneys than my mk2 will ever have....

D

[Tim Bancroft]

All the six cylinder boys seem to be fitting TR5 cams to their cars and these do seem to offer the best compromise between power and torque.

I had a TR5 profiled cam in my mk2 Spit that had a mk3 spec engine, it was lovely, revved but drove well without excessive revs being needed, 3.63:1 diff fitted.

What final drive ratio  is in the Spittie?

[Saltddirk]

hi Tim,

uprated to 3.61 as yours, that's why i need the low end grunt

How do i get around in fitting a TR5 cam? hacking the last 4 inches off? 😜

Which cam replicates that profile?

@ Iain,

I found a manufacturer close to where i used to live, Catcam's. They seem to sell in UK as well, although the uk website is not updated and the general .com one doesnt list triumphs. I planned to go and discuss with them. If I would decide to go with one of theirs I will surely ask what kind of machinery they use, not sure if I go with them though, if you stay with a main manufacturer, piper cams, kent cams etc they have the client and knowledge and their profiles have been used by (a lot ) others so might be a safer bet.

D

[sparky_spit]

Am I right in thinking that the Mk3 1296 FD cam has a very similar profile/duration as a TR5 one?

[TedTaylor]

Tim, not correct in that all 6 cylinder people are fitting a TR5 cam as it gives better torque.

I fitted one into Woodie (an estate) after the Chris Witor spec 308778 went nasty after the valve stem seized in the incorrectly fitted bronze valve guides (not by me I hasten to ad). 

I wish I had refitted a 308778 which is a popular choice but did not do so because CW only supplies them as reground which was part of the reason for the failure of the cam (lobes).  If I can get a CW spec cam ground from a blank I would very likely fit that.

MUT

[PeteStupps]

Quoted from sparky_spit-

Am I right in thinking that the Mk3 1296 FD cam has a very similar profile/duration as a TR5 one?

They are similar, Mk3 Spit timing is 25-65, the TR5 profile is 35-65.

Dirk - I am also camshaft shopping at the moment, and have heard most good things about Newman cams. Their PH2 profile is very similar to the TR5, and apparently they will do a TR5 copy if you ask. That is the direction I'm leaning. 

I'm sure you've discovered the same as me - that the camshaft alone doesn't determine performance. For example an over-sized exhaust or inlet manifold can hurt your low-RPM power because the gas velocity is slower. 

Incidentally I've got a standard mk3 Spit, plus a 1300FWD with the Mk3 spit camshaft and single carb. The characteristics of each engine is noticeably different, with the Spit revving freely beyond 6000 but the FWD being much less inclined to do so. Obviously the saloon is heavier but it feels like it has more torque in the 2000-4000 range. Whether this is down to slight differences in the cam timing, the different carb/inlet, or exhaust systems, I have no idea! 

[thescrapman]

Pete, unless you have changed it your FWD will not have the same cam as the Spitfire.

Assuming the FWD isn't the TC variant as well.

An SC will have the same cam as a 13/60 Herald.

[PeteStupps]

Quoted from thescrapman-

Pete, unless you have changed it your FWD will not have the same cam as the Spitfire.

Assuming the FWD isn't the TC variant as well.

An SC will have the same cam as a 13/60 Herald.

Morning Colin - I did change the camshaft during engine rebuild, using Canley's large journal 26/65. But only had a light skim on the head so it's still lower compression ratio than the Spitfire, as well as all the other differences (single stromberg, Lucas distributor, slightly different final drive ratio).

Also I don't know how good a copy the Canley shaft actually is of the original Stanpart profile.

[Saltddirk]

Quoted from PeteStupps-

 

Dirk - I am also camshaft shopping at the moment, and have heard most good things about Newman cams. Their PH2 profile is very similar to the TR5, and apparently they will do a TR5 copy if you ask. That is the direction I'm leaning. 

Pete,

Am thinking same here. From what I learned so far it seems to be a good compromise.

I have one more outing planned for the Spit this season, then it will be engine out for the rebuild.