Author Topic: Milwaukee Midget  (Read 3583729 times)

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Offline Milwaukee Midget

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Re: Milwaukee Midget
« Reply #1425 on: September 04, 2012, 10:22:39 AM »
Unless you have a valve interference issue with deceleration, why do you need the tensioner?

It gets pretty busy under the spark plugs.  The rod to stroke ratio is 2.45:1, which leads to a long relative dwell at TDC and BDC, combined with the need to flip the cam open quickly.  At .050, we're looking at 252 duration, .350 lift and a 108 LCA.

I need to keep that all in check, and given the stretch that I incurred last time on the chain, I'm not going to risk it.

Both you and Jack are questioning the stud - I'm grateful for that.  It's not too late to come up with something different, and I'll mull it over, but gut level, I really think it should be sufficient.
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

Offline SPARKY

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Re: Milwaukee Midget
« Reply #1426 on: September 04, 2012, 11:49:44 AM »
Go by  a GM dealership.  wander thru the shop and ask who works on the Ecotec or North star engs.  These have OHCs on them and I am pretty sure I have seen eflon slides that work on their long chain runs---one of the guys may have somethin lying around.
Miss LIBERTY,  changing T.K.I.  to noise, dust, rust, BLUE HATS & hopefully not scrap!!

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller

We are going to explore the racing N words NITROUS & NITRO!

Offline fordboy628

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Re: Milwaukee Midget
« Reply #1427 on: September 04, 2012, 01:34:23 PM »
Although it seems like the engineering commitment has been made, Chevy parts sound like a possiblility....

Are they "rub rails" (to keep whippy chains from low speed milling of the housing?) or can they be used as a tensioning device?

 :cheers:
F/B
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"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline manta22

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Re: Milwaukee Midget
« Reply #1428 on: September 04, 2012, 01:38:08 PM »
Porsche 911 engines also used a plastic chain guide. Ferrari 128F engines used a spring-loaded chain sprocket as a timing chain tensioner.
Regards, Neil  Tucson, AZ

Offline theazoldcrow

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Re: Milwaukee Midget
« Reply #1429 on: September 04, 2012, 01:57:56 PM »
 :-D The newer Harley shovelheads and I think the twin cammers have a teflon shoe inside the primaary to keep the chain tight.  Might be able to cover your spring with one of those shoes ?  Just guessing !
The Earth, is an intergalactic insane asylum.!

Offline wisdonm

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Re: Milwaukee Midget
« Reply #1430 on: September 04, 2012, 02:48:00 PM »
I thought of running a shouldered grade 8 bolt out the front cover also.

Hey Chris our season is running down. This weekend is Vintage at RA, then the Runnoffs are the 18-23. Do you want to come? Then I'm done until Nov. 6th. Tell me when and where, and I'll be there.
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Offline Andy Cooke

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Re: Milwaukee Midget
« Reply #1431 on: September 04, 2012, 03:19:15 PM »
This is all getting exciting, I'm really looking forward to hearing it run :)

All this talk of tensioners had me thinking back, I'm sure my mini had a tensioner, and sure enough it did, but only apparently with a simplex chain.   That said I still have a vague recollection of a wider pad being available for the duplex, but maybe not...  It was a long time ago.  I'm sure I used the funky shaped cover with the lump on the side for the tensioner.  :? 

Have you considered the Slark timing gears? 
http://www.slarkraceengineering.co.uk/engine-products/#sregeardrivencamshaftkit

I know gears can bring problems of their own, so I have no idea if they'd work better or worse than a chain at 10K.

Andy

Offline fordboy628

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Re: Milwaukee Midget
« Reply #1432 on: September 04, 2012, 06:08:55 PM »
Update on Cog belt water pump drive.

Midget,

Prior water pump speed @ 7800 engine rpm (with stock pulley ratio of 1.681/1) was: 13,115 rpm!!!!! :-o

New cog drive setup 28T water pump & 15T crank drive (gives a drive ratio of 0.5357/1) @ 7800 engine rpm is:  4,179 rpm :-)  (31.86% of original water pump rpm.) Got to be worth a pony or two......

Fixed drive, no idler, no alternator & will incorporate crank trigger setup.   Will do the final fitup of bits upon my return from Lone Star state.  Will post up crank drive/water pump drive porn to your Build Diary when all bits are fitted to the mockup.  (This setup, with the 2" wide w/pump cog, could drive an alternator if required........)

Also of note, this setup has the potential to incorporate a future dry sump oiling system, if desired.   (Used the 2" wide water pump cog.) No whining about dry sump!!  Dry sump setup = more hp....... :-D
 :cheers:  (going to grab my last 3Floyds Robert the Bruce in celebration!! :evil:)
Fordboy

« Last Edit: September 04, 2012, 06:47:51 PM by fordboy628 »
Science, NOT Magic . . . .

I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline Dr Goggles

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Re: Milwaukee Midget
« Reply #1433 on: September 04, 2012, 06:37:09 PM »
Really great to see the work going on here Chris, Fordboy, man  did one phone call ever drag you out of retirement......great work and all seems to be hitting the schedule marks too
I got an email from the F.I.L about someguys and a mini from NZ.....hmmmmmmm
Few understand what I'm trying to do but they vastly outnumber those who understand why...................

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Current Australian E/GL record holder at 215.041mph

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Offline fordboy628

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Re: Milwaukee Midget
« Reply #1434 on: September 04, 2012, 06:43:08 PM »
Doc,

Yeah, got a soft spot in my head for BMC floggers......
 :cheers:
Fordboy
Science, NOT Magic . . . .

I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline Graham in Aus

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Re: Milwaukee Midget
« Reply #1435 on: September 04, 2012, 07:56:37 PM »
Whoa! how did I miss all this activity, one night away from the interwebs!  :-D

We didn't get the A Plus down here Chris, Mini production stopped in 78! Mokes went on a bit longer and some small amounts of A+ stuff may have filtered in.

We have had a later influx of Japanese import mini with A+ stuff and I definately have a plate / tensioner and cover set up you can have. As Andy says Chris, these are a lot more common in the UK. I believe some folks use the simplex tensioner on the duplex chain, it has a rubber / plastic rubbing strip.



With regard to your previous oil spool / seat issues I also found this!  :-o



Here: http://home.earthlink.net/~roygmisc1/convert1/convert1.html

Conversion of auto to Manual, but some really useful stuff!  8-)

« Last Edit: September 04, 2012, 09:02:01 PM by Graham in Aus »

Offline Graham in Aus

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Re: Milwaukee Midget
« Reply #1436 on: September 04, 2012, 08:42:56 PM »
Regarding the timing chain, the quality of these has really gone downhill, I'm told that these IWIS chains are very good:

http://www.calverst.com/shop1/index.php?main_page=product_info&cPath=1&products_id=72&zenid=8c328c37dd614d1747cc2279f19ab929

Kieth Calver (his site) has even run simplex chains on race engines for less drag.

Alternatively there are belt drives, I have used these and they don't stretch like chains, never revved one to 10K though!!  :-P



http://www.minispares.com/product/Classic/Engine/Block/Timing/C-AJJ3326RACE.aspx?100113&ReturnUrl=/shop/classic/Engine/Block/Camshafts.aspx|Back to shop

Offline Milwaukee Midget

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Re: Milwaukee Midget
« Reply #1437 on: September 04, 2012, 09:56:26 PM »
Graham – thanks for all the info, and the offer.  I need to stay to task for the time being, I already have a chain, and I think I have the spring thing licked - but put that plate off to the side, just in case . . .

Don, the next three weeks will find me in the garage – I’d love to get to Road America, but it just ain’t in the cards.  Tell Dick to give ‘em hell.

Brought up earlier was the concern about stress risers on the bolt.  Just to clarify how I installed this, here’s a breakdown.

I took a ¼ 28 hardened steel Allen’s cap nut and cut it off leaving just the shoulder of the shank.  This I screwed in from the back of the plate.  When the shoulder reaches the back of the plate, it stops, and is close enough to flush that the gasket permits clearance between the plate and the block.  I backed it off and locktighted it, then screwed it back into position.  It won’t pull through.

Today, I bought an aluminum spacer and tapped it ¼ 28 all the way through, and tightened it down from the front side, again, locktighting it in place.  The stud is now very stable, and will encounter no wobble.  Additionally, there will be no steel-to-threads contact on the eye of the spring, and the cover prevents the spring from falling off.





I could drive myself crazy engineering this fix, but gut level, I think this is more than adequate.

I had a long day at the zoo retrieving the sound system I put in for the dinosaur exhibit last May, I was up until way late last night, and you know what?  I’m hitting the rack.

Cam should be here Wednesday.  Doc, I hope it fits . . .
« Last Edit: September 04, 2012, 10:16:19 PM by Milwaukee Midget »
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

Offline Graham in Aus

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Re: Milwaukee Midget
« Reply #1438 on: September 04, 2012, 10:23:35 PM »
Chris, get some sleep! I could tell you were tired, then you made the quick edit and I see you are still up!

I'll gather the bits together for the other tensioner and we can organise sending them over.

I think your system will work OK too, esp. if you keep an eye on it.

Enjoy your rest!

Graham  8-)

Offline Freud

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Re: Milwaukee Midget
« Reply #1439 on: September 04, 2012, 11:20:53 PM »
I washed it off.

FREUD
Since '63