|
|
Post by dave1800 on Jan 27, 2017 0:48:41 GMT
One thing that may have been overlooked is the need to use new head studs as the old ones (if that is what were used) may have lost their elasticity and be unable to retain their torgue as the engine heats an cools. There are some high performance ones available. The head distortion may have come sbout from the period when the engine was running weak at WOT. Certainly a good idea to speak to Peter Burgess on the torque and studs. I would anticipate a figure higher than the 45ft lbs and ensure the figure given identifies whether it is for dry or lubricated threads. I recall that Peter used to (may still?) recommend the Payen gasket. The Cometic gasket you mentioned seems to have somewhat mixed reviews on MGB forums but the key to any gasket is ensuring the head and block surfaces are accurate so it is difficult to know whether the criticisms are valid. regards David The Book says 45 lb/ft and re-torque after 500 miles. I can see this being different on a "performance" engine - did Peter not have any suggestions? Chris. |
|
|
|
Post by andrewa on Jan 27, 2017 6:51:54 GMT
Thanks gents - it's got ARP studs in it and PB's book and Payen recommend 50 lbs. Latest engine builder feels Cometic unnecessary unless running a big bore engine.
Latest issue is renewal of Competition Licence - where medical showed up high blood pressure and MSA are querying..I suppose 160/98 is a bit on the high side!
Am sure it's just Landcrab Syndrome (a state of agitation brought on by trying to make an old car do something it was never intended to do) - we shall see.
Onward and upward (but hopefully not the BP!).
Cheers
|
|
|
|
Post by dave1800 on Jan 27, 2017 7:43:42 GMT
Wow! You must be careful not to blow your head too! Relax your health is much more important. Maybe worth getting a second BP check, there is a symptom sometimes referred to as "white coat syndrome" where your BP is elevated only when it is being checked by docs, and it's not that uncommon. My mother suffered from it before it was generally recognised. As a result it is believed a significant number of patients in the UK may being treated with BP lowering drugs unnecesarily. One way of finding out is to use a home BP meter (arm / wrist) to check yourself but make sure you keep the arm at heart height or you will get misleading results. Turning to the car, as this is what the forum is about  is that 50ft lbs with the ARP lube or dry, it can make quite a difference. regards David |
|
|
|
Post by andrewa on Jan 27, 2017 18:23:02 GMT
Gets better - head back on and while checking various bits and bobs it became apparent that maximum lift varies from 10 mm to 3 mm across the piece - should be 11 mm and a bit.
Explains a lot and can only assume cam wasn't bedded in brilliantly at day one and or valve springs a bit over the top.
So cam coming out and we'll see what's what.
Doing Tommys trick of cutting the rad "jail bars".
As am likely to be getting new cam and am looking at Pipers MGB specs - do I want a post '71 18V one or pre '71 one? Head is an original 1800S one of 1970 vintage.
Cheers!
|
|
|
|
Post by snoopy11 on Jan 27, 2017 18:45:10 GMT
I would speak to the engineers who are doing the work for you.
They will be best placed to get the correct cam for what you want the engine to do.
|
|
|
|
Post by dave1800 on Jan 28, 2017 0:28:03 GMT
Whichever cam you go for it is essential that the break in lube is used as modern oils no longer have sufficient ZDDP that protects the cam and tappets against the hammering effect. It was removed /greatly reduced as it poisons catalytic converters. Modern engines generally have hydraulic tappets that considerably reduce this hammering effect but still need to follow a break in process. Camshaft manufacturers such as Piper have their own break in procedures that need to be followed carefully. The first 20 minutes can determine camshaft life. You may wish to take advice as to whether you should regularly use a ZDDP additive. You can also use the later shorter tappets and longer push rods from the 18V, 18H (Mk111 crab) engine that are claimed to have better geometry, rotate more reliably and are lighter than the earlier tappets. It is essential to fit new tappets given the problems you have experienced. Depending on your future plans I would advise retaining double valve springs but go with the lightest possible that achieve your expected rev limits (plus a bit more) to minimise wear. regards David Gets better - head back on and while checking various bits and bobs it became apparent that maximum lift varies from 10 mm to 3 mm across the piece - should be 11 mm and a bit. Explains a lot and can only assume cam wasn't bedded in brilliantly at day one and or valve springs a bit over the top. So cam coming out and we'll see what's what. Doing Tommys trick of cutting the rad "jail bars". As am likely to be getting new cam and am looking at Pipers MGB specs - do I want a post '71 18V one or pre '71 one? Head is an original 1800S one of 1970 vintage. Cheers! |
|
|
|
Post by andrewa on Feb 7, 2017 17:56:35 GMT
Well it's all done and pretty straightforward - will post some piccies of old cam later on - pretty amazing it ran at all.
Now it's almost too quiet - now I can hear all sorts of other noises that need investigating!
Main other difference is more power earlier (no surprise - that's what it's supposed to do) but taking it easy for the first 300/400 miles.
|
|
|
|
Post by tommydp on Feb 7, 2017 19:20:38 GMT
Sounds great! Looking forward to pictures!
It's pretty easy to change the cam that way:-) Quite a difference in valve lift! I've also changed the cam, once again. Lift is fine, new chain and sprockets but it still runs like crap in period, and one valve is hammering.. Fed up with it, so putting in complete engine from a spares car. Possibly original, untouched and worn, but it's quiet, has oil pressure, good compression and pulls like a train. So much for fully restoring an engine... twice:-/
I have a new Piper 270 cam, which I'm keen to put into an engine one day. However I should manage to get a standard engine working first, I guess:-)
Good luck, and keep posting:-)
Tommy
|
|
wolseley1800
Member
Posts: 127
Attribute: The Voice of Doom!
|
Post by wolseley1800 on Feb 7, 2017 20:17:11 GMT
Fitted the 270 piper to my S. Did a rolling road to see improvement, got 63 bhp at rear wheels. Did some research and tuners recommend the MGB cam as best option.
My ignition is set about 25 degrees to allow for the required advance for the cam.
|
|
|
|
Post by snoopy11 on Feb 7, 2017 20:33:01 GMT
got 63 bhp at rear wheels That's pretty amazing for wheels that aren't connected to the engine. |
|
|
|
Post by andrewa on Feb 7, 2017 21:07:07 GMT
Almost unheard of!
|
|
wolseley1800
Member
Posts: 127
Attribute: The Voice of Doom!
|
Post by wolseley1800 on Feb 7, 2017 21:43:10 GMT
Sorry, brain is not working but I think you get the gist.
|
|
|
|
Post by dave1800 on Feb 8, 2017 0:32:19 GMT
Do you mean the idle ignition advance is 25 degrees? What is the maximum advance (static plus mechanical)? David Fitted the 270 piper to my S. Did a rolling road to see improvement, got 63 bhp at rear wheels. Did some research and tuners recommend the MGB cam as best option. My ignition is set about 25 degrees to allow for the required advance for the cam. |
|
|
|
Post by andrewa on Feb 8, 2017 8:50:06 GMT
Well this almost what it should like - although a bit worn (to the uninitiated you're looking at the lobe to the right of the drive thing)  And that was the best of the bunch..the rest looked like this! ![]()   It wasn't horrendous to drive like this and still made mid to high 60's on the dyno!! Anyway - at the risk of tempting fate - all good so far - new cam different character but I can't detect any less power really! Seems to suit the character of the car better in some ways - it just gets up and goes whereas before you really had to wait until 2/2.5k revs before she picked up her skirts. Anyway as wise man says - we shall see - it's early days. Will give it 500 miles and then carbs and timing fine tuned but ok as it is at mo. More later! Cheers Andrew |
|
|
|
Post by dave1800 on Feb 8, 2017 12:17:34 GMT
Thank for the photos, wow you certainly wore that cam out! Do you recall the manufacturer? Tt looks as though it either wasn't properly hardened or the strict bedding in routine wasn't followed when the engine was rebuilt as that will kill even the best. John Twist has some videos of worn out cams from MGBs that were still running with lobes almost missing.
A 'scope designed for modern car electronics such as a Picoscope can actually diagnose (uneven) cam wear just by connecting the leads to the battery and cranking the engine without starting the engine - all in a couple of minutes. How's that for useless or maybe not information.
regards
David
|
|
The Book says 45lb/ft and re-torque after 500 miles. I can see this being different on a "performance" engine - did Peter not have any suggestions?
is that 50ft lbs with the ARP lube or dry, it can make quite a difference.
