Messages

1

Swaps, Turbos, Buildups / 2.0l M42

« on: April 12, 2010, 03:08:00 AM »

YES! Now you're on the right track with calcs. I wouldn't cut the deck for structural purposes. I know it's not much.
I'm not sure where you live or what your availability is for parts, but if you will let your machine shop deck your block and bore it, then I think they could fly cut your pistons. Also we don't know what your budget is and where you're money is best spent.  If you're going all out with a crank and rods and pistons, basically a complete rebuild with gaskets and who knows what else, I would make them work together for you somehow. Just my .02 worth.

Good luck with your decision and your build.

Cheers,
~Ralph

PS... You do have one option if you want to do some more math:-)
Figure out what your compression will be with .40mm above the deck instead of .15 with a stock M44 1.74mm HG and then with a 2.04mm HG.

Thanks Ralph Again

most interesting thing is that I'm not in US
I'm almost on opposide side of planet I live in Georgia (Not US state)
so for us cutting pistons and then pocketing them for valves sounds frightening
so I was talking about cutting block because I have heared that some guys have done such manipulations here not sure about M42 block but they have done that on M20 and M50.

about budget that works will go below 300$ (including M47 crank, m44 pistons, M50VN or M52B28 135mm rods, with works). not mentioning price for new parts.

2

Swaps, Turbos, Buildups / 2.0l M42

« on: April 11, 2010, 04:02:10 PM »

To get .15mm above deck with your calculations.

M44 has 30.4mm CH

30.4 = X-44-134.85
X = 209.25mm
You need to only cut 2.75mm off the block. I wouldn't do it. Change something else.

Why are you so persistent with wanting to cut the block?

If you do your -15mm Calcs then :
30.4 = 197-44-135 -X
30.4 = 18 - X
X = -12.4mm "above" the deck.
Doesn't add up.

Where are you getting your information from? Why are you using this combination of parts? I'm very confused and don't think that I can help.
I'm Sorry:-(

Can someone else chime in and clear this up?

~Ralph

Thanks Ralph for your reply, probably I had not correct M44 piston specs.

I just rechecked everything and understood that I had huge mistake, my mistake was thinking that I made mistake:( (really stupid from my side)

my calculations: standard m42 stroke is 81mm m47 stroke is 88
so in case of M42 crank and 140mm rods with M42 pistons (standard M42 engine) we have 0.15mm over deck
in case of using M47 crank, 135mm rods with m42 pistons we got:
(140-135)-(88-81)/2 -0.15 = 1.35mm below deck so to normalize to over deck (0.15), decided to cut block from top on 1.5 mm .

so in case of using M44 pistons to get 0.15 over deck will need to cut 2.75mm off block.

I chosen that parts because I can get everything used for cheap and budget of build will be quite small.

also I'm afraid about cutting off top of pistons because I'm not sure how well it will be done at machine shop. so much more simpler is to cut block. also in case of M44 pistons will need to overbore cylinders to 85.

so just 1 question why you don't recommend cutting off the top of block?

3

Swaps, Turbos, Buildups / 2.0l M42

« on: April 11, 2010, 01:53:13 PM »

Please be more specific about what you're asking.  WE have no idea what crank, piston, rods etc.. you're talking about.

Why would you want to cut 15mm of the block anyway when you can manipulate the crank throw, rod length and compression height on pistons??

As a hypothetical:M47 crank/ 138mm rods
     CH   =             Deck   -          Stroke    -        Rod    -       Above Deck
30.15mm = 212mm - (88mm/2) - 138mm -.15mm*

NOW with -15mm deck height with stock crank / 135mm rods
x = 197 - 40.5 - 134.85
x = 21.65mm compression height: Not  happening
With Stock 140mm rods it gets even worse.
x = 197 - 40.5 - 139.85
x= 16.65mm CH

~Ralph

sorry not for noting that:

so my idea is:
M44 Pistons,
M50 (Non Vanos) 135mm rods
m44 head gasket
m47 crank with 88 stroke.
 -15 mm from cylinder block

we will get 0.15mm over deck

we get:

85*85*3.142*88=1997cc
cylinder volume ~ 499cc
head chamber volume (33cc) + M44 gasket voume(10.1cc) + M44 piston compression volume (not sure : ~ 9 cc) = 52cc

so compression

(499+52)/52=10.59 compression.

so will that configuration work?

so maybe cutting of top of block is possible but what with in case that configuration piston lower dead position will be 8.5 mm lower than standard m42 (8.5 mm = (88-81)/2 + (140-135))

4

Swaps, Turbos, Buildups / 2.0l M42

« on: April 10, 2010, 05:12:00 PM »

Hello guys I'm new to that forum, was reading some topics and I have next quiestion:

is it possible to shave 1.5 mm off the top of engine block??? in that case with 135mm rods we will have 0.15 mm above deck, and will have standard compression

is that possible or not???

I calculated and in case of that we will have something about 10.5~10.6 CR, instead of standard CR 10.1.

my question again:

is there possible to shave 15mm off the to cylinder block?

P.S. in previous post I have mistake writing 1.5 mm, there should be 15mm.

5

Swaps, Turbos, Buildups / 2.0l M42

« on: March 24, 2010, 02:21:18 PM »

With 135mm rod,M42 piston, and no shaving, the piston would be about 1,35mm below deck and 9,3:1 CR but only with 1951cc.
With 135mm rod, S52 piston(86,4mm) and no shaving, the piston would be 1,35mm below deck, 9,8 CR, and 2064cc.

Hello guys I'm new to that forum, was reading some topics and I have next quiestion:

is it possible to shave 1.5 mm off the top of engine block??? in that case with 135mm rods we will have 0.15 mm above deck, and will have standard compression

is that possible or not???