My new RV8 3.5.

General Chat About Engine Build

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Paul B
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Post by Paul B »

dicky wrote:I used a digital caliper... Are they not acurate enough?

Would you say that the crank needs to be ground?
No no no no, too slack a tolerance on a caliper. You need the proper 50-75 micrometer for measuring the journals. Preferably not some old thing lieing in the bottom of a mates shed, but a knewish one with setting pin in the box to make sure the mic is accurate before you start.

You also need to know the tolerance and wear limits for the various journals so you can make a decision on regrinding. A certain amount of wear is acceptible, but I'm not sure the sizes offhand.


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Post by katanaman »

from factory manual

Main journal diameter 58.409 to 58.422 mm ........................ 2.29 to 2.30 in
Maximum regrind diameter 57.900 to 57.914 mm ................... 2.28 to 2.281 in
Maximum out of round 0.040 mm ....................... 0.002 in
Big-end journal diameter 50.800 to 50.812 mm ...................... 1.99 to 2.00 in
Maximum regrind diameter 50.292 to 50.305 mm ................... 1.97 to 1.98 in
Maximum out of round 0.040 mm ....................... 0.002 in
dicky
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Post by dicky »

Cheers,

Opps, :oops:, will have to get myself one tomorow then and re-measure.

I am also after a bore gauge to check the cylinder bore, main tunnels and bigend eyes for out of round. Best place for this?

I am hoping to be able to fit std bearings and have cylinder bored out a tad with oversize rings.

What are the rods like in terms of fatige?
Not likley to bend in the near futre are they?

Thanks for all your advice. :)
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Post by katanaman »

I got all my measuring stuff like that over the years from ebay. I got a set of micrometers new but my bore mic set is secondhand as new good ones cost £££££. If your not going to do a lot of this stuff then take it to the local machine shop and they will soon measure things up for you and usually for free.

Rods are pretty strong but the big end tends to go oval on them. You can get a set of recon rods from the rover specialists. I think they are about £110 with ARP rod bolts fitted.
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Post by dicky »

Well this weekend I am hoping to do some more to the block, I have bourght some Mr Muscle Oven cleaner which I will use to clean the block with.

After that take it to my local engine workshop and have them measure up the bores, tunnels, crank journals and conrod eyes.

I was wondering how you change the cam bearings, is it easy enough to do or does it reqier some specialist tools?

Also what is the best way of telling the condtion of the piston pins without removing them?

:)
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Post by kiwicar »

cam bearings are job for a machine shop, you need the right tools, and even then it's one of those jobs that initially looks easy but you can see although the chap doing it has done it a 1000 times it is fiddly and not somthing he finds easy. You have to get the bearings in square to the bores straight off or you ovalise them, they have to be lined up radialy for the oil holes and driven in the right amount while all the time working from one end with the setting tool and looking down into valley from the middle. :shock:
I assume you mean without removing the pistons from the rods not pistons from the bores if so. Piston pins are a little easier, does the piston rock from side to side in line with the pin, along the axis of the block (ie. the way they shouldn't) if they do check em with a wire type fealer gauge against the spec in the manual (though if you can feel them move chances are well out of spec. The lands of the bearings are top and bottom by the way so check them there not at the sides.
If they are still in the block I can't see how you would check them.
Hope that makes some sense.
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Post by ChrisJC »

You do need special tools - they are five thick discs of differing sizes with a threaded hole. And a long piece of studding. You use these discs to draw the old ones out and draw in the new ones (in the right order!)

Chris.
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dicky
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Post by dicky »

Yeah I meant checking the piston pins without removing the pin so with the rod still attached, the pistons have allready been removed as seen in the pics on page 2.

Right, so are the cam bearings essential to have changed?

Will check the piston pins tomorow in the manner you describe, cheers.
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Post by ian.stewart »

Just going back on the topic a little,
Oil pumps, use the SDI front cover for its better capacity, but you can use the pump base from either the P5 or SDI, this gives you the option of 2 positions for the oil filter, P5 sideways and SDI forward, this may come in useful when fitting your engine, or of course when fitting the engine there is no room for a filter you can use the remote pump base from a MGBV8, Think Automotive sell them,
if you are going to keep the points dissy you need to change the drive in the bottom for a later style wobbly drive, personally I would ditch the the points or Lucas electronics and fit a Pertronix or Aldon Ignites, both the same thing, a LOT cheaper than the Malory, and probably more reliable,
When you got your engine, did it have all the bits with it, specifically, the water pump, bottom pulley/balancer and the alternator bracket, these are all specific to this engine, and are for a conversion are probably the best to use as they are the short variant, about 25mm shorter then the SDI without the Viscous fan bits
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dicky
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Post by dicky »

It did come with all those bits, not sure about the alternator bracket though.
I have a large box with it all in and also spare inlet with SU carbs.

I will try and source an SD1 cover and proberbly fit pointsless ignition system. Where would I find those two disi's you recomend?

Cheers
dicky
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Post by dicky »

Gave it a wash today,

Image

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Image

Image

Image
dicky
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Post by dicky »

Well, havn't really done much more to the engine just yet but have been researching a little more taking on board all of your helpfull sugestions.

So far this is what I have planned:

Source SD1 front cover, failing that then uprated P5/P6 pump gears,
Source SD1 heads, failing that then fit hardend valve seats to P5 heads,
Pertronix or Aldon distributer, or use CB points distributer,
Comp gasket which will reduce CR to 9.8:1,
Fit longer duration cam which will also reduce effective CR,
Fit duplex cam chain,
Fit Webber 500 carb or recondition the SU carbs.

To start with though I still need to get the block, crank and conrods checked.

Also what exactly needs to be done to the centre main bearing when I fit new shells?

Cheers
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Post by Pocket rocket »

The central mains has the flanged bearings - the workshop manual says you must "align the thrust faces of the centre main bearing by tapping the crankshaft with a mallet, forward and rearward". After that , mains 1 to 4 are tightened (torqued) down and you then have to deal with the rear mains and the cruciform seals.
dicky
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Post by dicky »

I was more on about the grinding down of the thrust side of the center main bearing shell?
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Post by dicky »

A minimal price list I made:

• STD distributor with new rotor arm, CB points, condenser, cap, leads and coil
• Up rated oil pump
• Reconditioned SU carburettors
OR…
• SD1 front cover
• SD1 heads
• Pertronix or Aldon distributor
• Longer duration cam Hurricane + hi-rev followers/springs
• Duplex cam chain
• Webber 500 carburettor + manifold

• STD big-end bearings £18.48
• STD main bearings £24.22
• STD piston rings £37.89
• Comp gaskets set £40.35
• Lower gasket set £16.29
• Rear main rope seal £7.31
• Rocker shaft assy £88.13
• Cam kit £128.66
• Up rated oil pump £36.14
• Arm, cap, points, con £19.09
• SU carb rebuild kit £70
£471.56

• Rhodes hi-rev lifters £94.00
• Hurricane camshaft £125.71
• Up rated valve springs £33.46
• Duplex chain £65.00
• Oil pump £22.54
• Distributor £175.00
• SDI heads/cover £100.00
• Webber carb/manifold £500.00
£1333.38
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