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PostPosted: Sat Feb 05, 2022 10:26 am 
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Is the aim a zero deck height with the 1098 crank and pistons?


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PostPosted: Sat Feb 05, 2022 12:15 pm 
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MINIRO wrote:
This sounds like a great build. I am in the process of attempting a 1098 +0.040 with 12G202 currently. trying to read everyone elese experience in these builds so hopefully i am aware of what to look out for. :-)


Awesome, let us know how you go with it!

9er wrote:
Is the aim a zero deck height with the 1098 crank and pistons?


I will be aiming for a ~0.010" deck height on this one.

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PostPosted: Sat Sep 17, 2022 11:28 am 
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Been a while since this has been updated but it hasn't been forgotten about. The engine has been at the machine shop for the last 4 months but hope to have it back this week (fingers crossed) ready to be put together in all of it's 68mm glory. In the mean time, I've built up the gearbox and the rockers.

The gearbox is a bog standard rod change, albeit with a 3.21 diff. It cleaned up really well and it seemed that a central oil pickup, bearings and baulk rings were all it needed....

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On reassembly everything seemed really tight and once a gear was selected the mainshaft would bind up. This had me scratching my head for a while until I notice that the baulk ring was binding on the first motion and not spinning on it as it should. It turned out that the new baulk rings were very inconsistent dimensions and the width of them was not uniform around the circumference of the ring -ie. one measurement of the baulk ring width came in at 8.9mm and the width measured on the other side of the ring was 9.0mm. This was the worst case of the new baulk rings and luckily the old ones weren't too bad so it took a bit of mixing and matching of "good" baulk rings new and old to get everything to go back together no issues. All good from then on. A quick lick of MOWOG green and it was beer and peanuts all round.

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On advice from timmy, I elected for the 1.5 forged rockers from minispares UK. pretty happy with these, as everything measured consistently

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-----Better is the enemy of good-----
-1976 Yellow Devil Leyland Clubman-
-1969 Morris Mini Van - Work in progress-


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PostPosted: Mon Sep 19, 2022 7:01 am 
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Keen to see the feed back on this when its on the road. Im tempted by a similar spec.
Will you be sticking it on an rr?


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PostPosted: Mon Sep 19, 2022 6:24 pm 
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1330RG wrote:
Keen to see the feed back on this when its on the road. Im tempted by a similar spec.
Will you be sticking it on an rr?


Yep I sure will be. Still undecided about carb and dissy choice. 40DCOE is very tempting!! 123 or CSI distributor I think.

Don't hold your breath for rolling road results though - check the car build thread here - viewtopic.php?f=3&t=101529

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PostPosted: Mon Sep 19, 2022 8:18 pm 
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Have you considered megajolt or similar programable maped ignition setup?

As for carb both have pros and cons I guess, as you say its more for daily I would personally stick to hs or hif carbs. But if you have a 40 sat around well……… maybe rude not to use it.


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PostPosted: Mon Sep 19, 2022 9:12 pm 
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1330RG wrote:
Have you considered megajolt or similar programable maped ignition setup?


Definitely have considered it and have gone as far as running one of my previous builds on a Haltech elite - viewtopic.php?f=5&t=96193

That was great and the level of programmability doesn't get much better but for this engine build I definitely want to keep it simple so am on the look out for a good distributor.

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-1969 Morris Mini Van - Work in progress-


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PostPosted: Thu Sep 22, 2022 6:08 pm 
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848cc
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Had a look at the other build, looks awesome!

An makes sense on the ignition front, amazing how fast things can run away with you on these builds isn't it


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PostPosted: Mon Oct 03, 2022 10:24 am 
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With the engine back from the machine shop, I've started with assembly of the head. My original plan is to use the 1.5 rocker with the standard pressed steel rockers as a backup if required (I think these are 1.3?). The 266SS cam gives .270" of lift so the total lift depending on the rockers;

1.5 rockers
270 x 1.5 - 12 (tappet clearance) = 0.393" = 9.98mm

1.3 rockers
270 x 1.3 - 12 = 0.339" = 8.61mm

With the 12G295 head machined with hardened valve seats, I checked the installed spring height to be 1.280". Tighter than what I was expecting, I wanted to make sure that I wasn't going to bind the springs with these high lift rockers. I set the head up in the drill press to make it easy to compress the valve and set up the dial gauge.

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This photo shows the high lift of the 1.5 rockers. We are a bee's peen away from binding with these AEA526 springs, but there should be a little more clearance with the AEA525 springs that I plan to use - so sweet, no spring crush.

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What I didn't realize when compressing the spring to the near 10mm valve lift was that the valve spring cap had completely crushed the valve stem seal and punched out the center of it.

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After this, I wanted to check to see if the lower lift of the 1.3 rockers saw the valve spring cap foul the valve stem seal.

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It is a little difficult to see in this photo, but the cap is just touching the valve stem seal by about 0.15mm - definitely not something I am happy to live with. I measured up the valve guide and they're currently sitting 15.00mm proud of the valve spring seat. I think I could get away with gently driving all of the valve guides down to about 14mm.

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Another option I am considering is machining about 1.5mm off the inside bottom edge of the valve spring cap. In the above photo, the collets are installed and seated as far down as they go. There looks to be about nearly 3mm of clearance between the bottom edge of the cap and the collets, so I think I could machine off about 1.5mm from these edges to get the relief I need without affecting the seating of the collets.

From all that I've read, with the 12G295 head, there probably is no need to go to the highest lift of the 1.5 rockers but making both adjustments of deepening the valve guides and machining the valve spring cap a smidge, I will have the option to run both.

While I consider what to do and where to find/buy a lathe, I started on assembling the rods and pistons. Strangely one of the piston rings for the pistons was 0.1mm wider than all the others and wouldn't fit any of the pistons! A quick call to GR and a new set are on their way. Thanks Graham! :)

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PostPosted: Mon Oct 17, 2022 8:48 pm 
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I made up a spacer exactly 13.8mm to drop the valve guides another 1.2mm into the head. I machined off 1.2mm off the inside face of the valve spring cap which doesn't effect the fitment of the collets in any way (could probably have machined off more but I didn't need to). This gave me the clearance I need to run the 1.5 rockers.

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As for valve springs the original plan was to run standard small bore springs with the Cooper S inners. At the high valve lift though this wasn't possible as the small bore springs were binding. 1275 dual springs would've been way too heavy so instead I went with just the outers of a set of AEA525's. I set up a test using some bathroom scales and two blocks of wood on the floor either side of the scales. I set a valve spring in the center of the scales and using a bar, I compressed the spring until it rest on the wood either side of the scales and I took a reading of the weight and measured the compressed spring height. Using this method and knowing that a set of AEA525s was 160lbs I could work out the spring rate of the springs I had lying around. Small bore springs came in at 90lb, AEA526 set came in at 200lbs, AEA526 outer springs came in at 130lb and the AEA525 outers came in at a perfect middle of the road figure at 115lbs which i think would've been about similar to small bore with the cooper s inners.

at full 1.5 ratio valve lift, no spring crush and no interference of the valve stem seal.
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The rest was pretty smooth sailing. I measured the cam timing for the 266ss off the #2 inlet push rod and timed that in at 104* as per the CalverST website specs for Grahams cam. A coat of mowog green and everything is looking pretty good.

Next on the list is fit the transfer case. This has to be the most frustrating job to ever do on an engine build. I always seem to struggle getting the bearing for the first motion shaft to line up with the bearing race inside the transfer case. I've tried plenty of grease to hold the rollers in and lots of patience to gently get this together but no luck at all. I think my next bet is to take out all the studs from the gearbox to help line it up. What're your tricks to make this job easier?

Picture of the most frustrating thing in the world. So close but so far.

Image

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PostPosted: Thu Oct 20, 2022 4:39 pm 
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Managed to get the transfer case on. A Red Bull can and some electrical tape over the primary gear was all that was needed to get the seal to seat properly to allow the transfer case to fit. Next up was clear coat. Very happy with how this 2k clear has come out!

Image

Flywheel and clutch next followed by intake, exhaust and ignition.

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-1969 Morris Mini Van - Work in progress-


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PostPosted: Thu Oct 20, 2022 6:40 pm 
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I wish I’d done the clear coat. It would make it so much easier to clean!

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PostPosted: Fri Oct 21, 2022 8:28 am 
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Very nice.
I see your transfer case is the same as mine - without the breather casting. I ended up adding a breather on the fuel pump port because i didnt think the chest breather was enough.

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PostPosted: Fri Oct 21, 2022 1:41 pm 
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Thanks to GR's sharp eye on this thread, he let me know that my spring choice is probably not the best for this engine build. Thanks very much for the call, Graham! Really appreciate it mate.

I didn't do the best job of explaining the spring rates above so I'll try again. I measured the following spring types and worked out the weights at 1" compressed height

Small bore springs - 90 lb
AEA526 dual springs- 200 lb
AEA526 outer springs - 130 lb
AEA525 dual springs - 160 lb
AEA525 outer springs - 115 lb

Knowing the spring weights at 1", and knowing that an uncompressed spring length is 1.8", we can bang all of these into excel and make a linear graph to work out the spring weight at any compressed length.

The installed spring height is tight at 1.280" and using the 1.5 rockers the compressed spring height at full valve lift is 1.280- 0.393 = 0.887 "

What I didn't know was that with a high lift cam and high lift rockers we want about 140-150lbs of spring pressure at full valve lift to avoid valve bounce. I hadn't even considered this before now! better check it. So now with our handy excel graphs we can figure out what the spring weight is at the compressed height and the installed height.

AEA525 outer springs
Installed spring weight = 75 lbs
Full valve lift spring weight = 131 lbs - this is too low as Graham suggested that these ones would be too soft.

AEA526 outer springs
Installed spring weight = 85 lbs
Full valve lift spring weight = 148 lbs

Turns out that the AEA526 outers on their own are perfect and the AEA525 outers that were installed were not heavy enough. I pulled the head off and changed over the springs and now we can all sleep easy at night knowing that valve bounce shouldn't be a thing on this little motor! woo!

Thanks again Graham for keeping an eye on me! :)

Andosoft wrote:
Very nice.
I see your transfer case is the same as mine - without the breather casting. I ended up adding a breather on the fuel pump port because i didnt think the chest breather was enough.


How did you do that Ando? Are you running an external fuel pump? I have thought that maybe the tappet cover and the rocker cover breathers might not be enough.

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PostPosted: Fri Oct 21, 2022 1:57 pm 
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Yes, electric fuel pump.

MED do a 'billet fuel pump breather' that I picked up on ebay a bit cheaper than shipping direct.

I was concerned it may get some oil flick up given it is a bit lower in the crankcase, but I haven't seen any.

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