stroker help please!!

Smackfest04 · Posted: Mon Apr 21, 2014 7:55 am Post subject: stroker help please!!

Ok, I bought a used "1835" in need of new jugs and pistons, smoked alittle and burned some oil. Upon tear down I find the case is clearance and has a stroker crank, measured it the best I could and I believe it is a 78mm stroke so a 2074. I bought mahle 82x92 pistons and cylinders, used shims from previous cylinders at the case. Get it all together and the motor will only turn over less than 180 degrees and the something binds, didn't do this before new pistons and such. New to the stroker motors and not too sure what's going on with this, any help is appreciated. Thanks everyone.

GodJockey · Posted: Mon Apr 21, 2014 9:09 am Post subject:

This could be a few things. My first thought was pinched bearing but you said this was a new issue when you installed pistons. So, what size rods are you using, are they hitting some where - the base of the cylinders? Did you get B pistons?

75smith · Posted: Mon Apr 21, 2014 9:36 am Post subject:

my guess is rod nut is hitting the base of the cylinder-compare the new stuff to the old stuff
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My 1975 Beetle Build Updated 8-21-12

My engine build

Smackfest04 · Posted: Mon Apr 21, 2014 9:43 am Post subject:

Compared old to new and all I see different is the new pistons have slightly longer skirts, like 1/8 inch if that.

sambabus · Posted: Mon Apr 21, 2014 10:16 am Post subject:

Do you have the distributor in it? If not, the shaft and brass gear can bind.
_________________
1971 Westy, 2017cc 78.4 x 90.5 Tims Stage 1 plus 42x37, CB 44IDF's, 135 mains, 175 airs, F111, 50 idles, Engle 110, 30mm, 009, single QP, DD CHT 300*f, VDO oil always 180* Build: http://www.thesamba.com/vw/forum/viewtopic.php?t=541370
1970 convertible bug, 1835cc, single 40IDF, disks.
Symptoms Solved and Fixed http://www.thesamba.com/vw/forum/viewtopic.php?t=551358

Smackfest04 · Posted: Mon Apr 21, 2014 10:34 am Post subject:

Distributor is in, only thing I can think of is my measurement was off on the stroke and it's bigger than 82. I'm going to run a bore camera in and see if I can see what's going on in there.

esde · Posted: Mon Apr 21, 2014 10:35 am Post subject:

Might seem like a stupid question, but could you have replaced b pistons with a? I know you say 82x92 but did you check?

75smith · Posted: Mon Apr 21, 2014 10:36 am Post subject:

Smackfest04 · Posted: Mon Apr 21, 2014 1:03 pm Post subject:

I'll find out tonight, tear it back down if I can't see anything with the bore scope

Quokka42 · Posted: Mon Apr 21, 2014 3:11 pm Post subject:

Piston skirts hitting crank or case, original pistons were A and you have replaced with B pin height. You should have checked everything like any stroker build, or at least compared the new to the old and checked for any changes - open 'er up and have a look.
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There has only ever been one man who was perfect, and they nailed Him to a cross.

Smackfest04 · Posted: Mon Apr 21, 2014 4:13 pm Post subject:

I have A pistons, from mahle, for up to an 82mm stroke, same pin location as pistons pulled from engine, pre inspected when I first bought pistons and returned due to being B pistons, then bought the correct A pistons. Please read what has already been posted

Quokka42 · Posted: Mon Apr 21, 2014 4:30 pm Post subject:

Please read what you posted.

You should have stuck with the B pistons - as you have now discovered, you can't just throw some new pistons into a stroker and hope it will work. You won't be able to exchange your pistons now, so you will be left with shortening the skirts on the pistons you have or removing material where they are hitting. Either way, if you don't check everything properly you are probably building a grenade.
_________________
There has only ever been one man who was perfect, and they nailed Him to a cross.

Quokka42 · Posted: Mon Apr 21, 2014 4:52 pm Post subject:

Oh, there is one other little thing: it can be a little harder to get a really tight deck with 78, especially if it is a real 78.0mm crank, unless enough is taken off the deck when it is opened up. Have your machinist take it down by 60 thou' and you should be right.
_________________
There has only ever been one man who was perfect, and they nailed Him to a cross.

75smith · Posted: Mon Apr 21, 2014 6:00 pm Post subject:

1) a B piston is normally used with 78+ strokes, although they are labeled 82
2) an A piston with 78mm crank would lead to needing an absurdly large cylinder spacer to set deck

3)possible a forged replaced with cast-hence possible contact
4) a decent picture depicting B vs A piston, B

Image may have been reduced in size. Click image to view fullscreen.

pin height B is roughly 35mm, A height is roughly 40mm

but you have what you have, did you figure out what the contact was, or have you not gotten that far yet? pictures would be nice
_________________
My 1975 Beetle Build Updated 8-21-12

My engine build

sambabus · Posted: Mon Apr 21, 2014 6:32 pm Post subject:

This is what an A piston looks like with a 78 stroke

Notice any problem?
_________________
1971 Westy, 2017cc 78.4 x 90.5 Tims Stage 1 plus 42x37, CB 44IDF's, 135 mains, 175 airs, F111, 50 idles, Engle 110, 30mm, 009, single QP, DD CHT 300*f, VDO oil always 180* Build: http://www.thesamba.com/vw/forum/viewtopic.php?t=541370
1970 convertible bug, 1835cc, single 40IDF, disks.
Symptoms Solved and Fixed http://www.thesamba.com/vw/forum/viewtopic.php?t=551358

modok · Posted: Mon Apr 21, 2014 7:33 pm Post subject:

Buy dial calipers
Take the heads and cylinders and pistons off.
Does it spin now?
Put in one old piston and measure the stroke of the piston in the cylinder with calipers.
Compare old pistons to new.
Compare old cylinders to new.

No sense speculating further until he does what he shoulda done to begin with.

Smackfest04 · Posted: Tue Apr 22, 2014 6:22 pm Post subject:

Didn't get a chance to check last night, will tear into it tonight and try to get some pictures up as well, new compared to old and such along with the cylinder shims.

Smackfest04 · Posted: Tue Apr 22, 2014 9:34 pm Post subject:

These are the comparison photos, from what I can tell I DID compare correctly and bought the correct parts.

now this looks like they have been clearanced, like I said before I took a rough stroke measurement, I think it was wrong and likely an 84 stroke? I am new to stroker motors, but I would think these pistons should clear up to 82, correct me if I'm wrong.[/img]

Adam0351 · Posted: Tue Apr 22, 2014 9:44 pm Post subject:

Are they stock length rods? I had to clearance mine under the wrist pin with "b" pistons and stock length rods and an 84mm. Look to see if there's the stroke stamped on the snout of the crank

Smackfest04 · Posted: Tue Apr 22, 2014 10:01 pm Post subject:

Idk, it was supposed to be an 1835 I bought used, well it's not haha, I haven't torn the bottom end down. No stamp on the snout but I can see inside a BPP stamped onto the crank. Not stock rods, no vw stamping on them and the caps look way beefier than stock.


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