My first engine rebuild

PostPost by: rgh0 » Thu Dec 28, 2017 11:50 am

The key issue with jackshaft endfloat is potential spark timing variation. The smaller the better but i dont think the additional .0025 thou ( I presume you meant that, not .025) is going to be significant in a road engine as its similar to the wear on the points over a few hundred miles. The spec range is .0025 to .0075 so at .005 you are at mid range

I normally put the oversize thrust in the front position so that the major load from the clutch release bearing is running on the standard thickness shell at he rear. No real reason, just habit as I use hand made oversize thrusts with Datsun cranks and this keeps the load off the hand made special which is harder to replace versus the standard one. i would not worry about crank end float at the high end of the range if both thrusts are new and standard thickness

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PostPost by: Concrete-crusher » Thu Dec 28, 2017 9:48 pm

Thanks that's reassuring to know , I did miss a zero reading the spec. For the jack shaft , the thrust washers are new and standard .

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PostPost by: Concrete-crusher » Sun Jan 07, 2018 10:23 pm

Time for an update

I have torqued up the crank , actually twice. After doing it the first time I went to bed and then wondered if I'd fitted the thrust washers the right way round. So next day I loosened of the crank bolts to check. Yes they were correct.

I got my end float to 003 thou by fitting a 005 oversize washer to the front. One small niggle , I can't quite see how the centre cap holds the thrust washers in place , it must be a very small overlap

The new qed pistons were fairly easy to fit , with the rings. The whole assembly turns quite smoothly.

Today I fitted the front cover with new water pump and timing chain. Next stage is the rear oil seal. I needed to add a helicoil to the thread on one side.

On the water pump alu to alu I have used silicon , with wellseal between the gasket and plate and engine front.

What do members recommend for the sump sealing ?

Last time I sealed the rocker cover I used silicon under the cork gasket and red hermitite on top , this worked well.

Last question , I'm using an engine stand bolted to the exhaust side engine mount , it's certainly strong enough for the engine , but would it also take the gearbox weight ?

Or should I support the engine another way before bolting on the gearbox , my intention is just to check the fit , then put the gear box back in the car first.

img_0445.jpg and


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PostPost by: MarkDa » Sun Jan 07, 2018 11:01 pm

Good progress Steve.
The stand will be strong enough but tbe eccentricity of the load may be an issue.
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PostPost by: mbell » Sun Jan 07, 2018 11:29 pm

I had the engine and gearbox on the stand as you describe without issue. I'd avoid removing the rotation pin thou.
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PostPost by: prezoom » Mon Jan 08, 2018 4:38 am

Same as above. No problems with the gearbox mounted to the engine.
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PostPost by: Peter +2 » Mon Jan 08, 2018 8:41 am

Might be worth securing the end of the stand just to be safe. Better safe than sorry until you are sure.

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PostPost by: rgh0 » Mon Jan 08, 2018 10:35 am

With all the silicone you are using you may want to plan to remove the sump after running the engine for the first 1000 miles to check that the silicone that was squeezed inside has not blocked the oil suction strainer.
I keep silicone except in small dabs in a couple of locations well away from twin cams.

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PostPost by: Concrete-crusher » Mon Jan 08, 2018 5:51 pm

Hi Rohan

I share some concerns about silicon , when I stripped the engine the rubbery sludge in the sump was silicon which does not break down.

So far I have only used it on the front cover where the two aluminium faces meet , and around the water pump o ring.

is there a better solution for the sump and rocker cover gaskets ?

thanks steve
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PostPost by: rgh0 » Mon Jan 08, 2018 7:50 pm

I use Loctite aviation gasket sealer on all the cork and paper gaskets. I think wellseal is similar.
On metal to metal joins i use Loctite 518 gasket former

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PostPost by: Concrete-crusher » Thu Jan 11, 2018 8:03 am

Thanks I have Wellseal which I think is similar and plan to use that on the sump , and rocker cover also the cork front cover gasket.

Last night I fitted the crank oil seal and flywheel , I used loctite on the six flywheel bolts , without washers hopefully this is correct in place of the old tabs which are no longer available.

Also fitted the new crank pully and marked TDC

Next job according to the miles book is to fit the sump , but I'm thinking of doing that last just in case I drop anything , as my engine stand rotates is there any reason not to rotate it after the head goes on ?

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PostPost by: rgh0 » Thu Jan 11, 2018 8:32 am

Steve I always fit the sump last in case I drop something fitting the head and timing the cams. No problem turning the engine upside down once the head is fitted

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PostPost by: englishmaninwales » Thu Jan 11, 2018 9:59 am

Whilst I used Wellseal throughout my engine build, for the cam cover cork gasket only, I found it inferior to a silicone flange sealant, used very sparingly and cured in two stages (bottom then top side).

But I guess this has been done to death on this forum :roll:
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PostPost by: el-saturn » Thu Jan 11, 2018 10:34 am

wellseal and that no3 permatex are imho crap! last time i put some faith into no.3 i ended up cleaning front cover, backplate and block etc. with acetone and used kent silicone (also "sparingly") -------------engine as tight as an oyster!! sandy
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PostPost by: rgh0 » Thu Jan 11, 2018 1:41 pm

el-saturn wrote:wellseal and that no3 permatex are imho crap! last time i put some faith into no.3 i ended up cleaning front cover, backplate and block etc. with acetone and used kent silicone (also "sparingly") -------------engine as tight as an oyster!! sandy


Silicone is not a suitable metal to metal sealant except in joints specifically designed for it with computer automated assembly. Also not a suitable gasket adhesive IMHO, but to each their own and if it works for you then I admire your skill or good luck :D

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