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Photos please

Cheers,
Harv

Rear-engined dragster


156 cube grenade.

Cleaning, painting then assembly. Drysump is on order, but need to cut the ends of the girdle to suit. It’s been line bored with the girdle, so will need to check it is still round once the ends are lopped off (would have been smart to know this before machining, but this thing is one great learning experience… every bit clashes with something else).

Shed is full… is it bad to do engine assembly in the house?

Cheers,
Harv

Not as bad as painting...

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Only bad if she who must be obeyed catches you

Harv wrote:Rear-engined dragster

A1D6C6B0-51FA-405D-BD2C-1C671FEDAC65.jpeg

156 cube grenade.

Cleaning, painting then assembly. Drysump is on order, but need to cut the ends of the girdle to suit. It’s been line bored with the girdle, so will need to check it is still round once the ends are lopped off (would have been smart to know this before machining, but this thing is one great learning experience… every bit clashes with something else).

Shed is full… is it bad to do engine assembly in the house?

Cheers,
Harv

I did have a chuckle about your comment on every bit clashing with something else. I reckon I did most things at least 3 times building the hambster with this exact problem. Then you get the thing down the track without grenading itself so you want to start upgrading it and going faster and the clashes happen all over again. But your right it is a great learning experience and a heap of fun!


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Got the block and crank washed down and blown out, ready for dummy assembly. Figure it can have another clean before final assembly, but for now I can bolt stuff together without worrying about getting swarf where it shouldn’t be. It’s likely I will have to flog out the pushrod “guide holes” due to the Repco pushrod angles, so final full clean and paint is not on the cards quite yet.

Chased out the block holes with a tap before washing, though didn’t chase the mains and head holes. These will have studs, so no need for the threads to be perfect for torque settings – figure they are better off slightly tight than loose, the same way Henry made flathead block holes.

Dummied up the crank, main caps and girdle. Main studs are 7/16-20UNF/14UNCx4”, with 1” of thread either end (ARP part number ARAP4.000-1LB). They are a bit longer than normal to clear the girdle and spacers – for standard main caps, they can be shorter at 3.125” long (AP3.125-1LB). Haven’t torqued them down yet, but at finger tight the girdle fouls on the second rearmost crank counterweight. It doesn’t hit by much, and might fix itself once torqued down (doubt it though). In any case, I need to butcher that part of the girdle out for the dry sump, so no tears yet. Will save the girdle butchery until the dry sump is here. When I get a chance I’ll clean up a standard sump and take some photos to show where the girdle clashes.

Found the crank and cam gears. One of the few joys of getting old and forgetful is that when you find stuff you have stashed away it is like Christmas all over again. The gearset is a Master Engineering GS138 adjustable timing set. I bought two of these sets as part of the Master Engineering closing down sale years ago. I need to do some learning though as I don't fully understand the keyway angles. Assuming that the "0" point is zero degrees, the advanced "A" keyway is 125º around the crank, whilst the retarded "R" keyway is 105º.


Gut feel is that's a lot of crank degrees, but my mind is thinking of ignition timing, not piston/valve timing so perhaps not so drastic.

Photos from places like Rollmaster show the following (this is a chain drive, but the gear drives for the red motor are similar):


This looks better... 2º, 4º, 6º, 8º of change (not 100-oddº). But how do those little degrees of timing marked on the gear change relate to the big actual angles of the keyways on the crank gear? More learning for me to do yet. Might give Clive a call and get his opinion, though for now I’ve got the crank gear set straight up.

Pressed the cam gear on (even remembered to put the retainer on first ), and got a good 5-thou end float. The iron cam gear was a lot nicer to slide on than the last steel one I did. It’s about now that I remembered that the engine front plate I need is currently propping up the dummy block in the FED. Might be a while before I get that plate home, but for now not a drama… plenty of other stuff to check. Checked the cam bearings to make sure the oil holes were aligned, must remind myself later on (when I can’t get oil to the top end ). The cam slides into place nicely. Swapped out the two GMH retainer bolts (¼-20UNCx¾”) with some ARP ones (part number 640-0750).

Replaced the oil gallery and water jacket plugs with some allan-head ones (¼-18 NPT and 1/8-27NPT). The dry sump will not need a dipstick, so that hole needs a plug too. Dipstick hole is 11/32”, which is close enough to 21/64 (the drill size for tapping 1/8 NPT)… this plug will only be under crankcase pressure, so slightly sloppy will be OK. When I get a chance I’ll run the tap down the hole and fit a plug.

Cheers,
Harv

Technical question:

When I washed out the block, I gave the lifter bores a good scrub (soapy water and nylon bristle bottle brush, degreaser, air dry and oil with light machine oil). I can still "feel" that the bores are not perfect. Nothing nasty, but probably very light corrosion.

What's the best bet for cleaning them up? Brass or stainless wire wheel in the Dremel? Wheel cylinder hone?

Cheers,
Harv

Little finger and steel wool?

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Harv, re: your cam timing, methinks it would not retard or advance your timing by 105 degrees as it would not run , I think if you lined up the 'O ' slot on the gear and drew the outline of the corresponding tooth , then did the same with the Ä" and the "R" you will find it will be only a few degrees difference. If you have a protractor you could measure the difference ???

Aha, now I see what I was doing wrong. When the cam is "straight up", the key is in the "0" slot and the "0" crank dot aligns with the camshaft gear dot. I was assuming that to advance the cam the key is in the "A" slot and the "0" crank dot is still aligned with the camshaft gear dot. In reality, the the "A" crank dot is still aligned with the camshaft gear dot.

So the advancement (or retarding) is really the difference between the green "Standard angle" and the red "Advance angle" or blue "Retard angle".


You're right, it is only a few degrees - 2º in each case (roughly measured from the photos with a paper protractor).

Cheers,
Harv

To be honest I've never used the advance or retard marks without using a degree wheel.

If the cam specs are checked and equal zero there is no more ideal than that.

The advancing or retarding the cam just moves the valve timing to produce peak power up or down on the rev range.

Without a dyno you simply never know what works best.

Greg

Fit up the ancillaries temporarily while I wait for the dry sump and repro head.

Dummied up the angle drive, maggie and clamp. The magneto body is chunky enough that it clashes slightly with the block (the big boss of steel the engine number is stamped into). Not sure if I will relieve that boss, or just run the maggie swivelled around a few degrees.

Timing clamp is the big band around the maggie body near the cap. By marking it’s flat surface in degrees (and putting a dot on the magneto body) I can use it as a timing marker. It also lets me put a bracket onto the side plate to stop the maggie cantilevering and snapping the angle drive off (common in the McGee angle drives… both mine are cracked and rewelded).
Cheers,
Harv

Learnt a flexplate lesson. I've got one of Roger's flexplates to suit a Traumatic into a grey, which in theory should mate up to the Slide and Glide. The flexplate needs to bolt to the crank, so some bolts needed. I'm figuring on using ARP fasteners on this thing. It's overkill, but will keep me entertained (I intended whaling on this engine for quite a few years, so it may as well have decent fasteners).

The crank flange threads are 3/8-24UNF, and ARP make a good flywheel bolt (206-2802) that is designed for Mini flywheels (BMC A-series engines). These are the ones that BS used a while back on his HAMBSTR, and the same as the ones that came with the Repco headed engine I bought a while back.

Ordered some more fancy ARP fasteners, and went to bolt the flexplate up. No joy... the bolts bottom out before clamping the flexplate, as they have a shoulder (not fully threaded). They work fine in a thick flywheel, not so good in a thin flexplate. You could put a washer under the bolt head to take up the slack, but I am a little cautious. The ARP bolts do not use a locking tab (unlike the GMH bolts), and rely on thread locker + bolt head friction to hold them in. It would be just my luck for the washers to stuff up the bolt head friction. A little far fetched perhaps, but launching a flexplate at 8000rpm is not going to end well. Swore, as the ARP bolts are not cheap.

Some hunting through the ARP catalogue shows that 230-7301 are mighty similar but fully threaded. These are made to clamp a torque convertor in a TH350, so very similar load. You can see the difference in thread shoulder in the photo below.


Bought the fully-threaded ones, bolted up, and clamps the flexplate as it should.

Cheers,
Harv

Yes I noticed recently that the factory red motor flex plate bolts are shorter than flywheel ones. Hopefully you can find a home for the manual ones. Are both engines planned to be running autos?


FB ute fixer upper, EK van on rotisserie

Slide-and-Glide in the FED, and grey crashbox in the method monster. The crashie is not a smart move, but will be a “learning experience”. Let’s see what you have to do to one to make it handle abuse.

Cheers,
Harv