I have put the cam back in and bolted down the retaining plate. It seems to have an arch to it - is this correct. If it is OK does the arch come out or go in?



The problem I have is the crank sprocket is 2mm lower than the cam sprocket when measured with a flat edge. More than just a few shims? The cranks end float is also 2mm.

I am thinking if the retaining plate was reversed it would decrease the cam end float and get the two sprockets more in line?

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Dave K.
1979 Moke Californian + 1981 'Coke' Moke

Sounds like the plate is bent (by overtightening the 3 screws). Common problem.
Buy a new one from Kc, they are cheap.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks Kev

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Dave K.
1979 Moke Californian + 1981 'Coke' Moke

Did you say 2mm crank end float? Sounds wayyyy to much to me.

I think Dave means the cam... not the crank.
You need to fit the sprocket before measuring endfloat. With a new plate it should only be around .005".
If much more, face a little off the back of the sprocket...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Just waiting to see if Karcraft can send me one via express post so I don't have to do another trip to Sydney. With it being flat it should be OK on the CAM end float.

Other thing I had to do was grind down the oil pump bolts as they were only just tightening against the body of the pump. Hope to get gearbox (Kev rebuild) onto the block today. Which reminds me Kev - do you put a little 515 under the half moon seal or just on the top (that goes against the gearbox).

Cheers

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Dave K.
1979 Moke Californian + 1981 'Coke' Moke

I put 515 on the front main bearing cap, and the 2 block flanges. Fit the 2 gaskets then put the 1/2 moon seal on the mains cap. I then use 515 on the gearbox flanges and the lip that sits against the 1/2 moon seal.
Don't forget that *%%$#$^& O-ring....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

It is NOT bent, they are like that! But I think yours maybe on back-to-front, looking at the witness mark on it. It is important too that it does go on the right way as it is a bearing and the babit material is only on one side!

These are not simply a retainer, they are a THRUST plate. The lobes on the cam arr NOT parallel, but tapered (on cams that are ground correctly) so that the camshaft ALWAYS thrusts in to the thrust plate, hence why it is called a thrust plate. Also because they thrust in to the plate at all times when running, there is NO specified endfloat, allthough, you do want a minimum of 0.005" - as the Doc has suggested - but even it it's 0.020" that's OK too, ie, there is no maximum.

Therefore, when checking sprocket alignment, you MUST 'thrust' the cam into the plate. Use a lever and gently push the cam in to it, then check.

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Interesting GT. I had another 998 engine in the workshop so I striped it down and removed the same thrust plate (even had some shims behind the crank sprocket! to check it against this one.

I took the wedge off the crank and put in the two shims and put the cam sprocket on with the thrust plate from the 2nd engine and it all lines up perfect now. When I had the two plates side by side I could see a noticeable difference - certainly the second one looked flat (but may have a slight dome in it).

I have a new thrust plate coming from Karcraft which I will use as I notice the cam side has a facing material which I can see is worn on both ones I have here.

I think the original plate shown in the photo has been in there for a while as I can see the wear on the crank sprocket where the chain has not been aligned. Maybe time and the constant thrust has caused the misshape or maybe someone prior has tried to force off the cam sprocket and bent the thrust plate. The engine I am rebuilding has been done up in the past by someone else but it appears as if the thrust plate was not replaced.

You always hear about main bearings, big ends etc but not many articles I have read talk about replacing the cam thrust plate as well.

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Dave K.
1979 Moke Californian + 1981 'Coke' Moke

The oil hole goes at ~10 o'clock when fitted correct. (with engine right way up!)

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

When the dots are aligned on the two sprockets does that give you TDC on number 1 . . . or 1 and 4.

I want to put the distributor drive back in but remembered last time I had to go another full revolution to get TDC on number 1 (which meant the cam sprocket was 180 degrees different from the crank dot)

I have checked the book and also remember discussion that it is wrong when talking about TDC on number 1.

Can you tell by looking at the cam lobes if it TDC at number 1?

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Dave K.
1979 Moke Californian + 1981 'Coke' Moke

Dots in line it is firing #4 (not #1).
All A series the same... God knows why (nobody else does).
Crank the motor 1 turn before fitting dizzy driveshaft as per the pic in manual.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks again Kev - I thought it was the case - and correct direction is that anti clockwise one turn??????????

When I had my 1185 engine (in the red '65 Deluxe) returned from being built I couldn't get it to fire and I then worked put that who ever put the distributer drive in had done it 180 degrees out! (must have been looking at the bloody book)

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Dave K.
1979 Moke Californian + 1981 'Coke' Moke

The books are all wrong, because they all just copied the original BMC red book shop manual (and it was wrong, I have a copy).
1 turn is 1 turn- either way it turns the camshaft 1/2 a turn.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Of course - I thought of that as I posted.

So a four cycle engine has:

inlet valve open on a down stroke
Inlet valve closes compression on up stroke

Spark fires BANG (timing point for TDC at number 1)
Both valves closed

Down stroke because of BANG
Exhaust valve opens as stroke come up


So while number 4 is TDC and firing when the dots line up, number 1 is just starting to open the inlet valve?

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Dave K.
1979 Moke Californian + 1981 'Coke' Moke