New winter project: 1641cc Rebuild with a few little changes ;)

[Lee.C]

Well after the thrash to Eindhoven/DDD and another 500 odd miles of "Racing my friends" the 1641cc Manx motor is finally dying! 

on the way home from work today she started to "Knock" and get very HOT  I know its been getting tied for a while now and I think the last few "Races" have just tipped it over the edge hehehehehehehe

It still run's and drives fine but has NO topend power and once warm it knocks really badly under load and is using ALOT of oil,  oh yeah and there is a hint of blue smoke drifting from the breather box on idle 

its not too much of a problem as winter is nearly upon us and i have been wanting to make a few internal changes for a while ie cam 

As a few of you will remember I did alot of work on her a while back (twin carbs, header, etc) http://cal-look.no/lounge/index.php/topic,6900.0.html

Here are the current engine specs:

- AS21 case - full flow oiling
- 69mm counterweighted crank with lightened and balanced rods
- Lightened and balanced and 8 dowelled 200mm flywheel
- 87mm barrells and pistons
- Stock 311 Con Rods (lightened/balanced)
- CR 9.01:1
- Engle 100 cam
- Straight cut timing gears
- "Bolt up" rocker sharfts with Porsche style swivel feet adjusters
- VW 1.1:1 rockers
- 3/8 thick walled Ali pushrods
- Stock dual port heads 040's with stock valves (mildly ported)
- 32mm oil pump (race trim)
- deep sump
- Bosch 009 dizzy with electronic ignition kit (30degs)
- Bosch Blue coil
- 8mm silicon leads
- Custom (short/reversed) Race Trim manifolds (Type3 length)
- x2 Original Weber 40DCN14's (3 bolt type)
- 32 venturis, 130 mains, 50 idles (http://cal-look.no/lounge/index.php/topic,12779.0.html)
- DDS centre pull linkage (modified with custom swivel piece) 
- Power pulley (smaller 356 diameter)
- 30hp fan housing (scat - with oil cooler out the back)
- HP1 Oil filter
- Large external oil cooler
- Braided 1/2 oil lines (with proper fittings!)
- 4 into 1 header with single glasspack muffler

So what are the plans/ideas for the rebuild:

- Engle 110 cam/new lifters
- Re-balance of crank, rods, flywheel, clutch, pistons
- slight raise in CR to nearer 10:1
- some more head work especially on the exhaust
- some chamber work, smoothing etc
- 3 angle valve job
- New valve guides
- All new bearings (cam, main, rod)
- New rings (maybe new barrels & pistons but hopefully not)
- oh and a 30mm Berg oil pump (seeing as everyone thinks my mine is too big!)
- and some tips from this handy little thread: http://cal-look.no/lounge/index.php/topic,8007.0.html

So what are your thoughts guys - let me know what you think to my ideas & plans 

Also anyone know someone who can do the guides and valve job for me

[Lids]

i think it might also need a line bore and crank regrind.

[Zach Gomulka]

I think you're going to have a tough time getting close to 10:1 with a 1641. I also think to the only way you're going to get a substantial, worthwhile power increase is through displacement. I just happen to know a guy with a sweet set of NPR 92's

[Lee.C]

Firstly Thanks to Alex/Jesus for the PM, I will look into it dude 

Lids - I will of course be measuring the case and crank, I think the case will be ok and the crank was NEW when the motor was built so hopefully it will also be ok 

Zach - the only reason I was gonna go UP in CR  is because I will loose some material when I smooth/modify the chamber so I thought I might aswell get them flycut again afterward and aim for about 9.8:1 - I think I will be ok 

Overall I am pretty happy with this little 1641 motor and I don't want to get carried away and start build a "bigger motor"

I just feel this motor needs a little refining and with a little more CR, headwork, Cam it will be AWESOME 

The main thing is that Engle 100 as it really limits the Rev's (approx 5k) 

[Zach Gomulka]

Hmm, that combo should pull past 5k. Valve float?

[Lee.C]

Hmm, that combo should pull past 5k. Valve float?

yep it starts to "float" at much above 5k and from what Mr Ratto said in my other threads it seems that the Engle100 is not really designed to go past 5k  Any thoughts

it might not help that my guides are pretty worn 

[Zach Gomulka]

IMO, the hp peak will be just below 5k, but it should keep pulling beyond that. You've got a valve spring problem, but obviously your bottom end needs attention, too. Anyway, a 11O with good springs/heads will do your motor good

[Lee.C]

IMO, the hp peak will be just below 5k, but it should keep pulling beyond that. You've got a valve spring problem, but obviously your bottom end needs attention, too. Anyway, a 11O with good springs/heads will do your motor good

Hmmmmm interesting - when I had the heads worked on a while back (flycut & ported) the guys added hardened collets and cromoly retainers and set all the valve spring heights/pressures BUT they did say the guides were pretty heavily worn 

I think with the heads reworked and a little more port work along with the 110 will be a awesome little combo

I am also thinking of having my exhaust Re-made (from scratch!) it is a little to smaller bore and I am not totally happy with the look of it, I have a few little ideas to refine "The Look"
I have a contact through my current company that makes "custom exhausts" and his work is pretty impressive - we had a set of Turbo manifolds made for a V8 the other week and they were very nice 

[Zach Gomulka]

Do you know your deck height/chamber CC's?

[Lee.C]

Do you know your deck height/chamber CC's?

I know the deck height is .060 or 1.5mm and as far as I remember the CC is around 42/44cc what ever works out to be 9.1:1 

[Zach Gomulka]

Even if you don't buy my 92's I think a displacement increase is the smartest direction to take. For example, 92's will raise you to 9.8:1, and the displacement will allow you to go even larger on the cam (12O) without loosing bottom end. Increasing bore will also allow the valves to be unshrouded for more flow...

[Lee.C]

Hmmmmmmmm I really didn't want to start "goin bigger" 

I will have a bit more of a think about things now............ I see what you mean about it being a "smart direction"

As for the 120..... what rockers do I need for that

[Zach Gomulka]

You can use your same rockers. You don't have to go to a 120, a 110 will work just fine but it's an option

[Lids]

i have 94 barrels and a 120 cam i need to sell

[Lee.C]

why O why did you put these ideas in my head Zach 

I am kinda liking the idea of a 1835cc on DCN's 

Also I have been doing a little reading on Bob Hoover's Mods:
http://bobhooversblog.blogspot.com/search?updated-min=2007-05-01T00%3A00%3A00-07%3A00&updated-max=2007-06-01T00%3A00%3A00-07%3A00&max-results=10

can someone please explain the removal of the oil cooler in a little more detail 

How do you plug the case and how do you plumb the external cooler afterwards

[Zach Gomulka]

Hmmm... can't say I agree with him on all points

What fanshroud/oil cooler are you running now??

[Lee.C]

hmmmm what don't you agree with dude - its always good to have ALL points of view.....

As for the fanhousing - I have a Scat 30hp but with the cooler "out the back" why? 

[BeetleBug]

Drop the compression and add a turbo!

[Lee.C]

Drop the compression and add a turbo!

Stop it 

I am already thinking about going bigger cc which I didn't really want to do but hey thats life 

so give me your thoughts/spec's guys  what would you do to this little buggy motor 

oh yeah I got an engine stand from work the other day 20quid!!!! Bonus