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Engine questions


Davemate

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Today I've removed my engine and delivered it to an engineering firm to sort out the end float problem.

As I pulled it apart I've found I'm in need of a couple of questions answered
The block I'm presuming is recessed, are there any differences in what head or any other gaskets I need to buy


Secondly, the cam,is there any way of finding out what it is by useing a vernier gauge ?
for the ten mins that the engine has been run it revved ok but ticked over like an absolute lumpy son of a bitch, the tappets had been set at 10 tho.
Carl who built the engine has said that it "might be a fast road cam, possibly an isky 777 as it had 777 stamped on it"
The cam is now out of the engine I've looked all over it and the only things stamped on it are a "2x" halfway along it and the numbers 308775 (the last didgi could be an 8 ) up one end

I do have another pi cam but that one has stanpart and a few other numbers stamped or cast on it

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Hello Dave,

yes you need the gasket to match the block. It is identified by a tag at the rear,
Just tell your supplier that it's for a recessed block engine.

A 308778 is a P.I. cam ( the numbers look strange but the third and last are very similar in execution) and also has a single wide groove on the drive end bearing journal. The lift of a P.I. cam is 0.232" so you might be able to measure it (It will be more accurate with a clock gauge than a vernier thought as the quietening ramps may be started at 3 and 9 o'clock on the lobe?)

Alec

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Carl said it had a 1 in 3 chance of being a lumpy cam as he had built 3 engines and each time he just grabbed a cam from the draw and fitted it. He said one had 777 stamped on and as I said it was a lumpy tick over then it could be the 777, I don't think Carl would mistake 777 with the above longer number.
The cam is in very good condition so it's going back in with the tappets set back at 10 thou as if it's just a pi cam and I'll see how it goes, I can always to a compression test to make sure the cam is letting the valves shut properly.
Just got to now wait for the machine shop to call and tell me what they find when they pull the crank out, I've given them a spare crank that needs a re grind so it's up to them
Sort out the existing crank/thrust washers that has good shells
Or
Re grind the other crank and fit that,but this option may require new shells
I await their call

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Oddd on a min Dave,  yer setting it to 10,
Butt, think its a modded item, yes!!

well most modded items run gaps owt frae 15-24.
so if yer sett,n it at 10, and it should be 20, then its duration has increased ALOTT.

And, if the bloke woe built the engine, did nae no what cam it was, or what degs / lift it has,what timing figs, what time in data,   just hoo the hell is he to no at what degs he has to time it inat., niva mind set  the gaps,!!!(think)(think)

M

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Just to clarify the fitting of the 308778 cam.  This was for all Mk1 PI and Mk2 PI up to engine number MG75000 from CW's data on his web site.  From my database this would be up to late 1972

Reckoned to be the best standard cam for performance which many look out for so would be very surprised if it has been reground to a hotter spec.  Better to use one of the other more 'standard' spec cams. and not 'waste' one of these cams.

I have a 308778 from my Mk1 PI engine out while I am waiting to get round to rebuild it and will try to find time over the next day or so (busy sorting things out for a family 'do' at the moment) to measure the base circle to lobe peak on one of the knobbly bits.  While not a proper indication of the lobe profile it will give a reasonable idea if it is a cam that has been warmed over.

MUT

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I'm going to go for it being a standard pi cam and everything else not quite right as Andy has said.

Marcus
         One thing I have never quite understood about setting up a cam
Bolt holes in the end of the cam :- not movable
Bolt holes in cam sprocket :- not movable
Teeth on end of crank :- not movable
Cam chain :- it's a set length
Dots / marks on cam wheel and block or crank:- not movable

As long as you line the marks up then it all must be set correctly.
How can it go wrong

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Hello Dave,

if you look carefully at the camwheel the two sets of holes are not at right angles so this gives the option of getting closer to being correct, i.e. there is a phase shift between one and the other.

As it happens I have just been putting a cam in my engine and I couldn't get it as close as I wanted so I machined one set of holes to give me the necessary adjustment. I machined the holes such that the rotation of the wheel had the bolts resting against the elongated hole so it can't slip. I have the machinery to do it but it could be done with a round file and care if you want to be extra accurate.

Alec

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Don't forget that Triumph provided two sets of off-set holes in the sprocket, so that by turning through 90 degrees and turning back to front adjustment in steps of 2 degrees are possible.
If your slot, Alec, is such that the bolt is permanently against the end, it's not really adjustable, is it?

JOhn

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Hello John,

some Triumph cam wheels can be turned back to front but mine certainly cannot be as there is an oil feed at the back to lubricate the chain, possibly it is the simplex wheels that can be reversed?

No mine is not adjustable, nor did I intend it to be, merely making it fit to give a more accurate timing. I did think of an adjustable wheel but I was in the middle of the job and this was an easy solution for me.

Alec

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I'm a great fan of DiY mods, piman!

"Oil feed at the back?"   It dribbles down from the rocker gallery, onto the boss of the camshaft and sprocket, which then throws it at the chain.
There is also a little cut-out in the boss, so that oil from the front bearing can do the same thing.
Or is this on one of your other, non-Triumph cars?

John

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Hello John,

you'll need to look at a 2.5 camwheel to see what I mean but there is an oil outlet at the end of the camshaft front face and the back of the wheel has a rim through which is drilled several small holes so oil out from the cam is flung out and caught in this rim and through the oil drillings, very neat.

Alec

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Indeed, Alec, as I tried to describe in my last.
Some have one, some two such oil holes. See for an example of a used sprocket with the imprint of two grooves: http://www.ebay.co.uk/itm/Triumph-2000-Mk-1-Top-Timing-Sprocket-/261990120270?hash=item3cffd3fb4e
But the cut-out groove from hole to the rim of the cam end is in the cam  end, so rotating/turning the sprocket will still allow the oil to flow.
Plus the flow from the area around the push rods.

John

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Hello John,

yes, the smaller of the two grooves is the oil feed from the cam, the small groove in the face has a drilling into the cam journal to pick up the radial drilling. Going back to the original point, a duplex sprocket has only two options and the simplex four by turning it back to front as you said.

Alec

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  • 1 month later...

Been waiting since Aug 20

Made a phone call yesterday to enquire on progress of my engine, they did say they had a 6 week lead time as they are very busy !

They said :-
The crank in the engine is knackered and the cheapest option for me was to use a second crank I left with them.
I gave them a second crank that I knew needs a re grind to use if that was the case
They could repair the crank but after re hardening the repair the crank would need to be re ground to ensure all is true as the heating process could "and probably would" he said warp it very slightly.
So by just re grinding the "spare" crank I've saved the cost of the repair

Re grind
New shells
Re assembly (crank,pistons and flywheel)
£600

I'm not best happy at spending another £600 but if the work isn't done then I've got no engine,so it is what it is
Should get it back in two weeks,so with luck I'm back on the road in 3 or 4 weeks,depending on work and weather

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Dave I am surprised at the problem you are having with the crank from what I understood was a good engine.  

Were the machine shop saying that your original crank was so badly worn (past 40 though which is the normal limit because of shell availability up to recently) that it had to be built up again and ground back?  It is possible nowadays to get VP2 spec (same as Vandervell which are the best) in up to 60thou from Revington TR.  

Apparently 60thou is used by the TR racing boys and it was suggested to me by a very much respected CT and Register expert that such a grind (after balancing and Tuftriding) was probably a good option for a performance engine provided shells were changed every 50K miles,

This latter option is the one I took with the cross drilled Mk1 PI estate crank that I acquired and the grinders messed it up (though they won't admit it) and had to regrind to 60thou.  With balancing and tuftriding you are putting the 'strength' and hardness back into the crank.

I managed to pick up another TR5 crank with standard big ends and 10thou mains and therefor have decided to use that otherwise I would have used this '60thou' crank so am selling it.

MUT

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