trenace
Needs a job
Posts: 3056
|
posted September 07, 2005 10:53 PM
Heck, I'll also take, "How far in the hole were pistons with stroker & given gaskets?
In the problem of figuring what rod length to order, it would also be helpful to have all figures that any have for how far their pistons were "in the hole" with a given stroker crank and set of base gaskets / spacer plate.
I may actually have to open up the top end just to do this measurement prior to ordering rods. But it seems a shame to do that, then put 'er together, then take 'er back apart in a few weeks to do the real job.
Thing is, the figures for stock, vs Entropy's motor, don't match up. He also wound up finding his height 0.010" different than expected.
Also, can one get away with running 0.010" steels on each side of the 0.100" spacer plate, or only with 0.050" on each side, or only with nothing at all (as actually is the more common practice perhaps.)
Thanks!
  
|
RA12r
Zone Head
Posts: 919
|
posted September 08, 2005 04:28 AM
Your clearances will be the same as long as you keep the rod length change and the spacer plate height the same. Your choice of spacer gasket is VS gasket sealer silicon would be the only variable however VERY small effect on compression.
Could you explain the "performance" benefit that you are shooting for with longer rods VS longer stroke?
____________
All must bow to the "Ra Supremecy"...
|
trenace
Needs a job
Posts: 3056
|
posted September 08, 2005 07:31 AM
 Edited By: trenace on 8 Sep 2005 08:33
Well, it's mixing oranges and apples to compare longer rods vs longer stroke.
I am not doing longer stroke because I want to see way more miles out of this motor than I expect a stroker will go. Not only on the track record of stroked ZX-12's, but simply in principle -- because they are running rod ratios in the 1.4 range -- I just don't think that's appropriate for a motor intended for a long life.
So the comparison really is, why bother putting in the spacer plate, why use longer rods (since ordering aftermarket rods anyway) vs using stock rods?
Because the stock rod ratio is only 1.575. A longer rod ratio gives a little more dwell time near TDC and less side loading, and typically improves top end slightly. This is worthwhile for Maxton. It might be worth only 3 hp to me or something but it's a relatively inexpensive extra 3 hp if doing aftermarket rods anyway.
Unfortunately, saying that the clearances will be "the same" doesn't help seeing as, until I tear the motor down (which I'd rather not do until I have the parts and am ready to rebuild) I don't have the present value. I have one value for stock squish that Entropy gave me, but not knowing if the stock gasket is the same thickness as Cometic that alone does not enable solving this question. And the rest of the data he supplied, for some reason, yields two substantially different answers.
And so if anyone has:
1) Stock "in the hole" value
2) "In the hole" value for their stroker motor, and saying what the stroke is and what base plate and gaskets they used, or
3) The value for the stock head gasket thickness or the difference between it and Cometic
that would be way helping me out.
|
trenace
Needs a job
Posts: 3056
|
posted September 10, 2005 02:16 PM
Well, damn, looks like I will have to pull the head simply to find the answer to this question, as I need to order the connecting rods and it would make a hell of a lot of sense to know within a reasonable margin (like at least +/- 0.005") what is going to happen. A shame to have to open the engine 12 weeks before the needed parts arrive though, while riding weather is perfectly good.
Are we sure that not one person has any of this info? (Entropy did supply his info but unfortunately, his stock figures give a different conclusion than his built figures, for unknown reason.) If anyone does know any of the above, it really would help.
Thanks!
Also, and Ra, I'd asked if you meant that two 0.010" steels can be used in addition to the 0.100" (or actually you said 2.5 mm) spacer plate. If you missed seeing the PM but are seeing this, was this the case, or did you mean two 0.005's can be used in addition to the 0.100" or 2.5 mm?
|
trenace
Needs a job
Posts: 3056
|
posted September 14, 2005 12:03 PM
Edited By: trenace on 14 Sep 2005 13:05
In case the info helps anyone else, here is what Ryan Schnitz said, paraphrased:
1) The stock cam chain will work with not only the 0.100" spacer, but with gaskets on each side as well, at least to the point of one copper and one steel (possibly more.)
2) The Cometic head gasket averages the same thickness as stock. So changing from stock to it has no effect on squish, on average.
4) The Cometic steels do not compress more than 0.001".
3) The 0.100" spacers are not particularly accurate and can easily vary from 0.095" to 0.103" as examples.
This information is sufficient to give a good basic estimate for needed connecting rod length, aiming at the spacer plus two coppers, with flexibility at assembly to omit a copper or switch one or both coppers to a steel to get it right, particularly if I get the spacer plate in and measure it before ordering the connecting rods, since it seems to be the largest source of variation.
Anyhow, problem solved. If the spacer is 0.100" that adds 0.100" to the rods, if one steel is needed that is basically no change compared to stock steel, tightening the squish adds another 0.017" assuming the stock squish is 0.055" (will check that), grand total = 0.117" equals +2.98 mm, subject to a little adjustment depending on current squish and thickness of the spacer plate when it arrives. Sweet! 
|
gunner
Needs a life
Posts: 5778
|
posted September 14, 2005 12:39 PM
Trenace when you jack up head what problems do you run into with the stacks where they meet the throttle bodies and frame for alignment ? Who has this answer?
____________
There's no such thing as a motor with no more power to give only people with no more intelligence to get it
|
trenace
Needs a job
Posts: 3056
|
posted September 14, 2005 12:40 PM
I am interested to know that myself. Obviously it can be done as it has been done. Figured that was a problem that would come when it arrived, but having the answer beforehand would be real good!
|
osti33
Needs a job
Posts: 2973
|
posted September 14, 2005 01:15 PM
Edited By: osti33 on 14 Sep 2005 14:36
No problem with my stacks on my stroker motor. They go in and out just as well as they ever did...
|
trenace
Needs a job
Posts: 3056
|
posted September 14, 2005 03:20 PM
Thanks, Osti!
|
osti33
Needs a job
Posts: 2973
|
posted September 14, 2005 04:13 PM
Glad to help the cause...
|
entropy
Moderator
Posts: 8671
|
posted September 14, 2005 10:09 PM
quote:
Trenace when you jack up head what problems do you run into with the stacks where they meet the throttle bodies and frame for alignment ? Who has this answer?
Gunner,
This is an excellent question, and one i have wrestled with. The increased stroke = increased head height and the stacks do stick up a bit higher in the airbox before screwing 'em down. When all screws are tightened they compress the rubber boots a titch and all seems well.
BUT, when I look closely at the seams where the stacks meet the TB's, I find one or 2 which have a small gap. At one point, I tried "shortening" the "long stack(s) to get em all to seat perfectly. I also tried shimming the "long" one(s). PITA. So now I just screw em down and don't worry about a lil gap.
BYW, last fri (89F)i dynoed with 48mm TB's, got 213hp STD, went back last Tue (88F) with 46's (stock), and got 207hp STD. Both cases were with all short stacks. Fer damn sure the 48's are going back in 
____________
This moderator uses moderation in moderation
|
trenace
Needs a job
Posts: 3056
|
posted September 14, 2005 11:14 PM
Edited By: trenace on 15 Sep 2005 00:16
Shit!! Didn't you tell me no point with bored TB's?? 
Seriously, thanks for the updated info! It is still not too late for me there. Though the technical task is more difficult in my case due to being a 2005 with the double butterflys.
|
entropy
Moderator
Posts: 8671
|
posted September 15, 2005 01:01 AM
i hope i didn't say no good for bored TB's, I THOUGHT I said that I heard that no good for oversized valves. But at my age who the hell knows what i said
My motor is 1427 w/hi CR, your results may vary
____________
This moderator uses moderation in moderation
|
osti33
Needs a job
Posts: 2973
|
posted September 15, 2005 05:02 AM
quote:
My motor is 1427 w/hi CR, your results may vary
Tren,
When he says high compression he means REALLY high compression.
|
|
|
HOME
NEW TOPIC