Top end rebuild

arthuy said:
I think there is as many ways to do this as there is people rebuilding engines.
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I'm sure you're right about that Colin. Everyone has their own favourite way with jobs!

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Anyway, I wasn't a lucky bunny today. Fiddling with my bent & filed bits of wire, preload at the mo looks to be varying between 40 & 80 thou! :evil:

I guess any bits of the componentry can affect this (particularly as some are pattern parts) so it looks like a bit of shimming's needed. Going to make up some 25 thou shims which should bring the preload down to a range of 24 to 64 thou (if I'm right in that the rocker ratio is 1.6 - looks about right)

I've done a little Excel file to calculate this - if anyone would like it, just PM me with your email address.
 
Hello Stan,

The pattern parts that you have, which parts are they? Were they by any chance packaged Britparts?

Ron.
 
SydneyRoverP6B said:
Hello Stan,

The pattern parts that you have, which parts are they? Were they by any chance packaged Britparts?

Ron.
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Hi Ron,

Camshaft was Britpart...was a bit iffy about this, but took some advice from Harvey and decided to go with it.

It's OK Harvey, I won't blame you if it dies! :)
 
OK...follower preload...

After a bit of thought, I was a bit wary of fitting 25 thou shims in case I came out under 20 thou preload on some of the followers so I made 2 sets of 12 thou. Good job too...with the full 24 thou under the pedestals I could barely get my 20 thou bit of bent wire in 3 of them! So I've opted for 12 thou shims under both rocker shaft pedestals.

Anyway...all tickety-boo now. Glad that job's out the way! :D



Trial-fitted the inlet manifold gasket to see if it all lines up...

Seals...



...and composite gasket...



Doesn't look too bad a match...maybe a little trimming needed.



 
vaultsman said:
It's OK Harvey, I won't blame you if it dies! :)
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Yeah, right, you say that now....................... :LOL:

As we discussed at the time, it's a matter of weighing up the cost of the Britpart item, and going Genuine. Some Britpart items are not fit for purpose, (had an indicator switch that was made about 1/4" smaller than the steering column it was supposed to be fitted to.....) but someone I know who uses the camshafts on a regular basis, has never had a problem with any of them.
 
I heard on another forum (which you also frequent Vaultsman and Harvey) that the Britpart hydraulic lifters of late were absolutely crap, disintegrated after no time at all, quite a few people were complaining about them the other year. I would fit Land Rover approved replacement lifters although they cost more and are/were sourced from the USA, or branded items from a company with a good rep like Comp Cams (although they just went bankrupt). Don't know anybody who has used a Britpart cam, would've thought one bump stick is the same as the next in terms of material. I don't know much though. I'll be collected some freshly skimmed heads tomorrow and expect to be shimming the rocker gear this weekend for the first time, probably be on here asking for help. My mate and I have chosen a Viper Hurricane with standard P6 dual springs and new Land Rover followers for our MG B GT V8 transplant. Compared the cam to the original today, the lobe separation angle is greater, hope it gives a nice lumpy idle and good low and mid range power in the P6 lump...
 
mrtask said:
I heard on another forum (which you also frequent Vaultsman and Harvey) that the Britpart hydraulic lifters of late were absolutely crap, disintegrated after no time at all, quite a few people were complaining about them the other year. I would fit Land Rover approved replacement lifters although they cost more and are/were sourced from the USA, or branded items from a company with a good rep like Comp Cams (although they just went bankrupt). Don't know anybody who has used a Britpart cam, would've thought one bump stick is the same as the next in terms of material. I don't know much though. I'll be collected some freshly skimmed heads tomorrow and expect to be shimming the rocker gear this weekend for the first time, probably be on here asking for help. My mate and I have chosen a Viper Hurricane with standard P6 dual springs and new Land Rover followers for our MG B GT V8 transplant. Compared the cam to the original today, the lobe separation angle is greater, hope it gives a nice lumpy idle and good low and mid range power in the P6 lump...
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Hi mrtask,

Yes, I'd agree with you all the way...if you move away from OE kit there's always an element of risk but as Harvey points out, it's a trade-off between peace of mind and the thickness of one's wallet. The OE cam was the thick end of £150 more than the Britpart, and something had to give. Having said that, I did have some second thoughts about it but decided to go with it. It looked fine when I checked it between centres...ran true and consistent lift. Seeing the largely lobe-less stumpy thing that came out of the block, it's got to be better than that! There's lots of good words said about the Viper Hurricane by the way...sounds a good choice!

The lifters were from Rimmers, and are the only standard ones they offer, i.e. they don't offer a "value" alternative.

Good luck with the preload! I've ended up in the range 30 - 60 thou...would've liked less of a spread, but then...adjustable pushrods at 160 quid a set? :)

Cheers for now,
 
Hi Stan, you're on the home run now then.

I just started my top end overhaul last night (I know I've had all winter to do it, but I don't like working in the cold) and wanted to ask did you use new head bolts or re use the originals and how did you clean the lifter galley without dropping all the dirt into the block?

Also, is it possible to remove the inlet manifold without removing the carbs and linkages?

Cheers,
 
testrider said:
Also, is it possible to remove the inlet manifold without removing the carbs and linkages?
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You can leave the carbs on the manifold, and the linkage between them connected.

I'd re-use the head bolts, the only exception being if I knew that the heads had been off and on about half a dozen times, which is unlikely.

I would definately use the recommended bolt sealer.
 
WHS ^^^ :)

Hi Paul,

I'm assuming you're still at the stripdown stage?

I reused the head bolts after giving them a good wire brushing. In fact, if you've got access to a bench grinder invest in a rotary brass wire brush for it (if you haven't already got one). You'll find you're using it all the time as you strip down. Clean everything as you go along & I used loads of those re-sealable plastic pouches to store bolts, valves together with springs, collets, etc, etc. Even if you don't intend re-using them, you've got them for reference. Run a tap down ALL the internal threads before you start re-assembling...guess how I found out about that tip! :oops: You'll need 1/4" - 7/16" UNC taps, if you get stuck give me a shout.

As for the lifter gallery, clean it up with the lifters still in place (assuming you won't be re-using them) after you've taken the camshaft out. In it's place get the centre tube from a roll of gift wrap, slice it lengthwise a little off-centre & slide it into the camshaft bearings. Not ideal...but OK. I must admit, I didn't get the lifter gallery sparkling, but a lot better than the black hole it was! Once you've cleaned it up, slide the lifters down into your purpose-made catch tray. :) If you rig up a magnet on the end of some dowel, you can then pull them towards you...but watch those bearings!

When you come to take the camshaft out, you have to remove the front grille. Even with this out, I found it wasn't easy to pass the front cam bearing journal and shoulder past the top of the front valance - maybe my engine's sitting low! Bear down on it with one hand while withdrawing the cam - take your time though...it's easy to bump up the white metal bearings.

Even though it's a top end rebuild, plan to take the sump off for a de-sludge..it's amazing how much is in there!

Good luck! :D

PS...if you want I can PM you my mobile just in case you want to talk anything through.
 
harveyp6 said:
I would definately use the recommended bolt sealer.
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Thanks Harvey, not seen the sealer mentioned in anything I've read yet, only that you need to clean it off straight away.

What's it called?
 
Yes Stan, I'm still at the strip down stage so I'll jot any questions down as I go along.

I'm hoping to get it all to pieces over the weekend and then order parts on Monday for rebuilding over the Easter weekend. Ambitious I know but I don't want it to drag on now the sun's out.

Spoke to a fellow from RPi today who was advocating the benefits of the laters heads over the P6 ones but the ebay supply of them seems to have dried up for now. Might try some LandRover breakers yards though. Where did you get yours?
 
testrider said:
advocating the benefits of the laters heads over the P6 ones
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I don't have any history of your car, and don't know how much you have, but bearing in mind that the car must be at least 32 years old, (and yours appears to be 39 years), it's worth checking to see if the later heads have been fitted already. Short reach plugs and double valve springs are the P6 ones, long reach plugs and single valve springs are the later SD1 onwards type.
 
Hi Paul,

I got my heads from a guy on the V8 Owners Forum, well worth trying that route for SD1 or later heads. You'll need to register then pop a post in the Wanted section.

Not sure how up on the history of the design changes you are, but basically the larger valves came with the introduction of the SD1 in '76. As Harvey says, spark plugs became 3/4" reach rather than the 1/2" P6 and valve springs changed to singles. In '82 the valve seats changed from cast iron to copper/bronze. I know lots of P6B owners run normal unleaded anyway, but these later seats were definitely designed for it. Also in '82 waisted stem valves were fitted to Vitesse engines to improve flow, becoming standard across all V8's in '89.

All heads up to the end of '93 use 14-bolt retention...heads after this weren't drilled for the outer row of 4 bolts. Don't go for the 10-bolt heads as the combustion chamber volume was reduced to 28cc to compensate for composite gaskets being fitted as standard.

The '89 3.9 heads I got through the forum were £42 including postage and came complete with valves which were definitely usable. Springs I fitted new.

If you do go for larger valves you'll probably have to richen your carb needles up a bit. In fact, a service on the carbs & fitting richer needles is next on my list...tomorrow hopefully...as long as Royal Mail deliver! :)

Cheers,
 
Hello Stan,

I hope that you don't mind, but could I please suggest that you refit the carburettors as they are along with the air box and filters and use these to run in the new camshaft. My reasoning is that you know that in their current state they will run the engine, and given that a new camshaft is being installed the last thing you need is for the engine not to fire within the first few turns of the starter. ( I sent you a PM two days ago from the other forum ).

It is my understanding that a new camshaft can be all too easily ruined if the engine does not fire within the first few turns,..as the camshaft prelube will be wiped off and the lobes will then begin to scuff.

Once the running in is complete, the carburettors can be safetly rebuilt with the new needles fitted along with their K & N filters, and should the engine be difficult to start or be running far too rich, you will be secure in the knowledge that no harm will come to the camshaft during this time.

Ron.
 
Hi Ron,

I popped the dashpot & bottom cover off the carbs some time ago, and the piston, body and float chamber were pretty gummed up. So I'm giving them a good clean out, and whilst I'm at it replacing the jets. needle valves & seals.

Take your point about the K&N's though..I might leave the existing needles in and refit the airbox for starters.

Whatever I do, I'm sure it'll be a brown-trouser moment when I finally come to turn the key with the plugs in! :)
 
Carbs opened up and given a good clean. The needle valve & jet were a bit gunked up, so...

Service kits...and something far out of kilter with at least one of the piston springs!




Pistons and dashpots cleaned up & the drop tests were consistent at 5.5 to 6 seconds against a spec of 5 - 7, so that's OK. My 2 year-old phone looks a sorry thing next to the 36 year-old carb!




Now then...a question for any SU gurus on the forum. The original needle valves have a spring-loaded button where the float hinge brass tab contacts, whereas the replacements in the SU kits are solid? :? Anyone come across this? Does it matter? I've emailed Gower & Lee and will ring tomorrow, but probably won't get an answer from them till Monday now.

 
Hello Stan,

The new needle valves have a rubberised tip, while the original ones have a solid brass tip but a spring loaded button on the other end. Why the design was changed I cannot say.

The new ones that are available locally here in Sydney are also of the same solid design.

If you soak them in carburettor cleaner, does that free them up nicely? If so, I would be inclined to keep using them.

Ron.
 
SydneyRoverP6B said:
If you soak them in carburettor cleaner, does that free them up nicely? If so, I would be inclined to keep using them.
Ron.
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Hi Ron,

Many thanks for that. I'm sure the new design is adequate for the job, in fact the viton seal's probably an improvement. I can only assume the reason for the change was either lower cost and/or better design. I've got the old one's soaking overnight now actually, they're a bit gummed up. Not surprising I guess after all these years! :)

Cheers,
 
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