2 door VAE 306H

[kevin s]

Got the machined engine parts back today, he did say he had to skim a bit more than is ideal off the block to get it flat(it still has a few faint marks) but still well within the thickness of the gasket, as we have also had the head skimmed by 1.5mm we may need to take a bit more out of the combustion chamber to get to around the 9:1 CR we are targeting.

Head looks good but new valve guides and unleaded seats but the guides do intrude into the port quite a bit so ports will need some cleaning, otherwise it will just be work on the chamber to remove some of the shrouding around the valves and get the CR about right. (all straight out of mr Vizards book)

Because we needed to isolate before my wife had an operation we rushed getting the parts to the machine shop, one thing I forgot was the bypass tube which was rusted short and thin, no point putting it back together like that. Almost inevitably it snapped rather than undo, so have drilled it as far as I can but I don't have a 9/16 drill 6+(will borrow one from my dad tomorow) and I don't have a 5/8 x16 UNS tap so that has been ordered.

Andrew has some uni work to finish and we still have some parts to order so it will probably take a couple of weeks to build it up but we are on the way now.

[kevin s]

prior to building the engine up I am sorting through the parts of 2 engines to decide which parts to use in the new engine and the best of the rest to build into the spare engine which being a standard bore block would make a good basis for a rebuild in the future if need be.

Today warmed the old pistons on the bbQ and popped the gudgen pins out (they just drop out when the piston is warm), then put the 3 standard compression ones along with the best one out of the spare engine on the spare rods.

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we are using the con rod bolts out of the spare engine because someone decided to chew the heads up on the original ones, one difference I noticed is the originals had half height heads and the spare ones full height heads (shanks are the same length), anyone know if this is going to be a problem (both are 1098's from the late 60's).

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Also sorted out a set of virtually perfect head studs (still shiny) with which I think we have everything except the crank bearings and the plastic dipstick tube (I might even turn an alloy one up instead). Also need to measure all the valve springs to check we have a good set.

First thing though will be to loosely assemble the spare engine to get all the parts out of the way.

[philthehill]

The 1098cc 'A' Series engine has fully floating guden pins and should not require any heat applied to the rods or pistons to enable the guden pins to be removed. If you need heat to remove the gudgen pin then something is wrong.
Also applying heat to the rod/piston could damage the small end bush and should be avoided.
The big end bolts should all be the same irrespective as too whether they are 12 or 6 point bolts and/or different height head sizes.. 12 point bolts from the 'A' plus engine can be used instead of 6 point bolts but must be correctly torqued.
12 point bolts do not require lock washers but I would recommend using a smear of Loctite on the bolt threads when applying the final torque.
1098cc pre 'A' Plus engines have the gudgen pin retained by two circlips.

[kevin s]

It's a 1098, According to the engine number it is circa 1969, the gudgen pins are retained by circlips and the little ends have bronze bushes, the second engine is another 1098 from 1968, identical con rods pistons etc but the 1968 had a full depth head on the bolts and the 69 one a half depth head. We plan to use the full depth ones as the half depth ones have several of the heads chewed up, the full depth ones look a better quality part as well (threads look better defined, shank is a better surface finish)

Both originally were standard bores the one we are re-building has been bored +20 and had the deck skimmed by about 3 thou, we have a fast road cam, the head has been skimmed by 1.5mm and we plan to do a bit of work on the combustion chambers and ports to get to around 9.5:1 CR, it will eventually get twin SU's and a LCB exhaust, hoping for around 60HP.

[philthehill]

Thank you for the confirmation of the engine being a 1098cc unit.
To reiterate - the gudgen pins should not require any heat to enable them to be removed. If you need heat to remove the gudgen pins the clearance between pin and bush is incorrect and needs to be rectified.
Phil

[kevin s]

The pins were not tight but I have always found on the Ford engines I usually work on it helps to warm the piston a bit (they were still cool enough to handle) so they just drop out especially when taking old ones out as here which often have a bit of carbon build up.

[kevin s]

measured all the valve springs, most were around 42mm a couple below 40, from what I can gather they are 44.5 mm when new so I would assume 42mm is Ok for them to settle to after use.

One question I am not sure about is whether we should fit dual valve springs, the cam we have is a fast road cam so I don't expect to rev it above 6000rpm not sure what sort of speed valve bounce will begin on a standard spring though.

[philthehill]

The free length of the valve springs Pt No: AEA311 ex factory should be 1.75" with a spring rate of 113lb in.
Add Pt No AEA 401 to give the same spring rate as 998cc Cooper at a total rate of 147lb in.
If you want to fit dual valve springs you will need the correct top caps and the correct bottom seats. Both available from Mini Spares.

To retain single but upgraded springs use Pt No: 12G1015.

Personally as you do not intend to go above 6000 rpm I would fit single springs Pt No: 12G1015 at 140lb in rate.

You only need dual springs for high high revving engines to help stop spring and valve bounce.

You can over egg the valve spring pressure by fitting too high a pressure spring. Use the lowest spring pressure you can.

[philthehill]

The free length of the valve springs Pt No: AEA311 ex factory should be 1.75" with a spring rate of 113lb in.
Add Pt No AEA 401 to give the same spring rate as 998cc Cooper at a total rate of 147lb in.
If you want to fit dual valve springs you will need the correct top caps and the correct bottom seats. Both available from Mini Spares.

To retain single but upgraded springs use Pt No: 12G1015.

Personally as you do not intend to go above 6000 rpm I would fit single springs Pt No: 12G1015 at 140lb in rate.

You only need dual springs for high high revving engines to help stop spring and valve bounce.

You can over egg the valve spring pressure by fitting too high a pressure spring. Use the lowest spring pressure you can.

If you are quick here is a set of suitable single springs:-

https://www.ebay.co.uk/itm/Terrys-Aero- ... SwsI1f5RrZ

[kevin s]

Thanks for the tip, managed to get them for £11, Apparently Terry's aero valve springs were the ones to go for back in the day.

Terry's is an interesting company, they are still going and mainly focus on anglepoise lamps now (they were the original makers).

[philthehill]

Well done.
I managed to get a NOS set of Terry double Aero valve springs suitable for the Cooper S off 'e' bay a few weeks back.
Terrys springs are a very good make and at least you know that the manufacturing tolerances and quality will be good not like some of the valve springs made and offered these days.

[kevin s]

Some pics of the engine parts.

Head skimmed by 1.5mm, unleaded valve seats fitted.

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He's replaced the exhaust valve guides but I have noticed the original inlets protrude into the port quite a bit, they will need trimming back.

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My next thought is valve stem seals, the new exhaust guides have grooves but the inlets don't so I assume I will have to use the original o ring types.

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Problem is the ones in the gasket kit look terrible quality, I thought of buying some viton ones.

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I

[kevin s]

It also has these shrouds which I assume are to help with oil control at the valve stem.

Block also came back looking good, he skimmed just enough off to give a perfect finish where the gasket goes, bores look perfect, but he did say 20 thou was only just enough to remove the old corrsion pitting, no wonder it was difficult to start!.

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[kevin s]

Thinking about the valve stem seals, is it worth changing the inlet guides for ones with a groove so I can use later seals?

It doesen't look difficult, seems they shouldn't trouble my 30 ton press.

Also weighed the con rods, 3 at 721 grams one at 723, this is the one that had a low compression piston, guessing somene has swapped a rod from another engine, need to set up a fixture to measure them end to end and work out where to trim some off the heavy one.

[pgp001]

Just watch out for the fit of the pistons and the top surface of the block now you have had it skimmed.
On my rebuild the pistons were protruding slightly at TDC, so I had to take a skim of the crowns to get them back flush with the block.

See this old thread
viewtopic.php?f=4&t=72031

Now you have gone to all that trouble, I would not hesitate to put some new inlet guides in the head, I did not fit any seals onto the exhaust guides, only the inlets. I would bin those O ring seals and fit the proper shroud type that are retained by the valve guide groove.

Phil P

[kevin s]

From what I can gather they just press in at room temperature?

No heating heads or putting the guides in liquid nitrogen etc?

[pgp001]

I just made a stepped mandrel to fit the bore of the guide so they get pressed in nice and square, I used a 10 ton press with no trouble.

Phil P

[philthehill]

Both the 'O' ring seal and the shroud were discontinued by BMC as they both proved to be ineffective in stopping oil going down the valve guides especially the inlet valve guide.
The best valve guide seals are the top hat seals which should only be fitted to the inlet valve guides. Unleaded petrol has no lubricating qualities and therefore some oil is required to lubricate the exhaust valve stems.
To fit the top hat seals you do need the valve guides with seal retaining groove. They are available from ESM https://www.morrisminorspares.com/engin ... l-p1209547
for either small or large block heads which have guides of different overall lengths.
The valve guides are pressed out of and into the head cold. The dimensions of the mandrel used are given in the BMC workshop manual.
I have made a height guide for the valve guides so that all are installed at the correct height.
You can drive the valve guides out and in but you do need to ream the valve guides afterwards to ensure that any burrs created are removed.
After fitting new valve guides the valve seats should be re-cut as it cannot be assumed that the valve guide is concentric to the valve seat.
Below is the mandrel for removing and fitting the valve guides.

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The facility to add additional photos has gone wrong again

[kevin s]

new valve guides ordered.

Bit of a change of plan though, Andrew has decided he would really like to build a fast road 1275, he thinks he has found an affordable block and crank, the plan would be to build the 1098 up in standard from with the original cam etc, put it back in the car with the original gearbox then build up the 1275 with the fast road cam, tweaked head etc and with the mx5 box then put it all in at a later date.

The 1275 would be built new pistons timing chain cam and oil pump, with bits from the spare 1098 and a late mini head and rocker shaft which seem plentiful, we would obviously need to find some con rods. The back plate I've modified for the mx5 box started as a 1.3 marina one so should be fine, the sump looks like it is possible to modify the seal groove on the rear of the 1098 to fit, the rest I believe should fit.

[philthehill]

The 1275cc rear engine plate is different to the 1098cc rear engine plate and whilst the 1098cc rear engine plate can be modified to suit you end up with very little metal between the aperture for the oil pump and crank aperture which often leads to cracking of the plate and oil leaks. My advise for what it is worth is to get the correct rear engine plate or purchase the alloy version.
The 1275cc sump is different to the 1098cc and personally I would not bother try to modify the 1098cc sump if that is what you are intending to do. The Marina/Ital 1275cc sump is a direct swap with the 1275cc Midget/Sprite sump and are more plentiful than the Midget/Sprite item.
With the Marina/Ital sump you need to remove the flange that connects with the bell housing.