CRAJ Posted April 22, 2008 Share Posted April 22, 2008 I have picked up an engine which I was told came from a Mk1 p.i.It has all the identifying points that I have noted from previous posts on this and the register forums, no web on the crankcase on the manifold side of the engine, stanpart stamped on the block below the alternater bracket, CR6...HES engine no., the correct p.i.head no.It also has a cross drilled crank with no.307546 which I have read is TR6, but I may be wrong, it also has the flywheel still bolted on.The p.i. euipment, manifolds, timing chain and cover and front plate, and distributor are missing, although the dizzy drive is still there.The camshaft has two wide rings on the end, one which is not as deep as the other.The engine was stored with rocker shaft unbolted and the plugs in, so it turns over very smoothly using one hand on the flywheel.Questions:What is the difference between the 'long' and 'short' cranks (apart from length!), how do you identify which one you have?The crank endfloat is 0.009'', the haynes manual quotes 0.006''-0.008'', and is there a way of telling whether the crank has been ground before without dropping the caps and checking the marks on the shells?What camshaft does it sound like I have?Is the flywheel I have likely to be lighter than the current one in my 2500s, as the ringear is perfect and the clutch mating face is unscored and flat.Would the starter motor on the 2500s fit this flywheel?Thanks in advance for any help that you can all giveColin Link to comment Share on other sites More sharing options...
thescrapman Posted April 22, 2008 Share Posted April 22, 2008 ColinIt does indeed sound like a Mk1 Pi engine.You can tell long / short by the back of the flywheel. I think it is that if teh crank goes into a recessed area on eth back of the flywheel, it is long nose. So this should be bolted straight to the back of the flywheel.The starter is the same, but of course teh flywheel is probably different.I would be concerned that you can turn teh engine over easily with all the plugs in and no rocker gear attached.No way of checking bearings without taking the engine apart, and you need to to fit new thrust washers.CheersColin Link to comment Share on other sites More sharing options...
andy thompson Posted April 22, 2008 Share Posted April 22, 2008 CRAJ wrote:Questions:What is the difference between the 'long' and 'short' cranks (apart from length!), how do you identify which one you have?The crank endfloat is 0.009'', the haynes manual quotes 0.006''-0.008'', and is there a way of telling whether the crank has been ground before without dropping the caps and checking the marks on the shells?What camshaft does it sound like I have?Is the flywheel I have likely to be lighter than the current one in my 2500s, as the ringear is perfect and the clutch mating face is unscored and flat.Would the starter motor on the 2500s fit this flywheel?Thanks in advance for any help that you can all giveColinSound exactly like a Mk1 PI engine..It sounds like a 25/65 Pi cam "132bhp"The long crank will stick out an extra inch or so compared to the Mk2 (if you have ever stripped a MK2 auto it has a spacer on the back of the crank which is dimensionally the extra length of a Mk1 crank) The flywheel will be about 8lbs less than a Mk2 one.The crank is better lubricated than a Mk2 one especially at higher revs. It is the same material though. The Mk2 starter should be fine Link to comment Share on other sites More sharing options...
CRAJ Posted April 23, 2008 Author Share Posted April 23, 2008 'I would be concerned that you can turn teh engine over easily with all the plugs in and no rocker gear attached.'Yes Colin, I would have been too, but I meant that it was stored like that, I had to remove the plugs before I could turn the engine. Looks like I will be unbolting the flywheel too, is there any peference between the long and short cranks, or is it simply something you need to know for the flywheel? Wish I knew how to box the quotes in like you did Andy, it looks far more professional!Another question for anybody would be, will my 2500s dizzy be ok/can it be modded with an electronic ignition to suit? Or will I need the correct one for the engine, as I realise the characteristics of the two engines and their torque deliveries, differ a great deal. Link to comment Share on other sites More sharing options...
CRAJ Posted April 23, 2008 Author Share Posted April 23, 2008 Sorry everyone, forgot to say thanks again in advance for any info. provided.Just need to resist the temptation to tear the engine down and start playing, I promised my girlfriend when I bought it 2 weeks ago, that it was purchased for a future upgrade, to be built up over a period of time whilst teaching my 8yr old son a little about engines. Don't think she would class 2 weeks as 'in the future' and I dont have my son staying for another week and a half!Colin. Link to comment Share on other sites More sharing options...
andy thompson Posted April 23, 2008 Share Posted April 23, 2008 CRAJ wrote:' is there any peference between the long and short cranks, or is it simply something you need to know for the flywheel? Wish I knew how to box the quotes in like you did Andy, it looks far more professional!Its that little button on the top right.....Personally I prefer the x drilled crank .. its better engineering deleted by cost accountants but the flywheel thing isn't a choice.. you must use a Mk1 flywheel on a long back crank... the lighter flywheel also leads to less crank stress.Best dizzy for a PI is a 25D no 41236... often on ebay Link to comment Share on other sites More sharing options...
Gt6s Posted April 23, 2008 Share Posted April 23, 2008 Actually this sounds to me to be a 150 bhp TR motor. A Mk1 PI engine number should start with MG the same as Mk 2 PI version. The pre 73 PI cam only has a single groove (aprox 3/16 wide) on end not 2 rings which is TR Link to comment Share on other sites More sharing options...
CRAJ Posted April 23, 2008 Author Share Posted April 23, 2008 I thought the 150bhp TR motors were CP numbers? Link to comment Share on other sites More sharing options...
Gt6s Posted April 23, 2008 Share Posted April 23, 2008 So did I but a Mk1 PI should definitly be MG My own engine (in Gt6) no is MG855, Mk1 PI and a mate has engine no MG75 Also Mk1.Also on a point of note only about 1000 PI motors (MG no) had the cross drilled crank. Link to comment Share on other sites More sharing options...
mikeyb Posted April 23, 2008 Share Posted April 23, 2008 er I think you are wrong - MG prefix is for Mk2 PI engines only. Mk1 PI and TR5 were the only sixes with x-drilled cranks.MG engines don't have x-drilled cranks, sorry! Link to comment Share on other sites More sharing options...
Gt6s Posted April 23, 2008 Share Posted April 23, 2008 Beg to dissagree but both MG 855 and MG 75 did both Mk1's Link to comment Share on other sites More sharing options...
andy thompson Posted April 23, 2008 Share Posted April 23, 2008 eh no..... Very early MG Mk2 engines do have x-drilled cranks... but a short crank with the heavy flywheel.. as per 69 TR6's.. I THINK 68 (G-reg) TR6's had the long TR5 crank....Mk1 PI engines are CR prefix NOT MGAlso if you read the slightly dodgy description of the cam I think the second "ring" is not the same as the first... more likely the groove for the cam keeper plate Link to comment Share on other sites More sharing options...
andy thompson Posted April 23, 2008 Share Posted April 23, 2008 ;D ;Dgotta get these facts straight aye.... unlike your GT6 ... how the hell do you keep it on the road!!! Link to comment Share on other sites More sharing options...
Gt6s Posted April 23, 2008 Share Posted April 23, 2008 I bow to the master. My engine came out of a shed beside a dead MK1 PI but come to think of it there was also a dead Mk2 nearby. I remember being wrong before. Link to comment Share on other sites More sharing options...
DJB_Harvey Posted April 23, 2008 Share Posted April 23, 2008 Spot on Andy ..ALL MK1 PI engines have CR as there prefix . MG prefix started with the MK2 PI range...132 BHP up to MG75000..125 BHP there onwards (same as late TR6).....There seems to be an on going confusion with Triumph six engine numbers ! Even i have to think sometimes ! and its coming up for 30 years of Triumph 2000 / PI ownership....Gulp where did that time go !!! Link to comment Share on other sites More sharing options...
Englishbull Posted April 23, 2008 Share Posted April 23, 2008 In the pub................most of time Dave ha ha Link to comment Share on other sites More sharing options...
marc1estate Posted April 23, 2008 Share Posted April 23, 2008 been out to the lock up just to put me mind at rest, MK1 PI engine definately CR Link to comment Share on other sites More sharing options...
mikeyb Posted April 23, 2008 Share Posted April 23, 2008 lagerzok wrote:eh no..... Very early MG Mk2 engines do have x-drilled cranks... but a short crank with the heavy flywheel.. as per 69 TR6's.. I THINK 68 (G-reg) TR6's had the long TR5 crank....I'll soon find that one out - off to pick up MG11HE in the next couple of weeks! :-) Link to comment Share on other sites More sharing options...
CRAJ Posted April 24, 2008 Author Share Posted April 24, 2008 Also if you read the slightly dodgy description of the cam I think the second "ring" is not the same as the first... more likely the groove for the cam keeper plate[/quote]Andy my engine has no front plate, timing gear or cover, and the cam keeper plate is missing too. So as you say, one 'ring' is for the keeper. Are the above missing parts and the bottom pulley interchangeable? I think it would be easier for me to get these bits s/h and have the engine completely built up, rather than 'harvesting' them from my existing engine when I remove it, and increasing the time that I can't use the car. Link to comment Share on other sites More sharing options...
andy thompson Posted April 24, 2008 Share Posted April 24, 2008 Any 2.5 will give you a duplex set of gears... they are normally pretty much indestructible... especially on any old 2500S/TC engines where the did a lot less than on a PI..Make sure you get a decent chain... not sure where from tho' there have been some dodgy "short ones" about Link to comment Share on other sites More sharing options...
CRAJ Posted April 24, 2008 Author Share Posted April 24, 2008 Ok Andy that's great, thanks again for the help.Colin. Link to comment Share on other sites More sharing options...
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