TheSamba.com :: View topic - Engine Build

Sun Jun 30, 2013 3:49 pm

picked up a set of 87mm Mahle pistons and cylinders, mainly for the shorter skirt, did a quick weight check 1+2 were 521grams, 3 was 522grams, and 4 was 519grams, 3 grams total difference isn't bad

was hoping to have more done, but these 60 hour weeks have been wearing me down

Sun Jul 14, 2013 4:06 pm

started some measuring and mock-up, picked up some plastigage(went to three stores, before one guy even knew what I was talking about, and he wasn't even the person helping me!)

measured bearing clearance on cam, .003 in/.076 mm across all three(no pics, forgot)

checked tang depth on the oil pump to cam, looks like it needs to be pressed in another .035 in to be safe, will double and triple check before I do though, but there was plenty of clearance from the pump to cam bolts, so happy there

mounted rods, all spun except #3, will have to go back and make sure I didn't accidentally flip the bearing cap, bearings seemed to fit fine-did not plastigage, just wanted to see if they spun first(and see how hard it was to keep them from spinning for whe I plastigage them)

did quick check of deck height(no pics again) looks like a .045 positive deck(piston out of cylinder) so a .090 spacer will put a deckheight at .045, and shooting for a .055 deckheight, means I really should either custom order .100 spacers or stack a set of spacers(most likely a .09 and .01)

and compared my new mahle forged pistons with the stock FI mahle cast pistons

my new pistons are forged 87mm slip-in, the stock are 85.5mm with a 4cc dish(+-.5cc)

put the piston on the crank, and managed to rotate it without any scraping, so will need very little if any clearancing, do know the rod nut comes close to the case, and the piston probably comes very close the the crank throws, but so far I am pleased nothing is contacting-the cast piston probably would have needed massive surgery to prevent contact

hopefully will do a little bit more tonight and maybe some during the week, but I just get too tired after work and don't want to screw anything up

Sun Jul 14, 2013 6:45 pm

gonna be an oil burning crank case pressure making machine. But as long as your willing to put up with that what can we say.

92 thin walls and 87s should have been stopped being produced 30 years ago.

Mon Jul 15, 2013 3:41 pm

we don't all live in Las Vegas, with the cooler climate here I feel the 87's will work fine, I see them all the time and a friend has a set in his bus, burns no oil, true 87's are easier to warp, but if you you don't let them get to that stage, you're fine

Sat Jul 20, 2013 3:21 pm

Did some more measuring and test fitting, made a crank stand, so I can hold it horizontally, was just using a flywheel, but I like how the new stand can let the rods hang, feel I can get a better side play reading, and I didn't move the rod as much when torqing it down, so might be better when I plasti-gauge it. won't use it much, will probably use the flywheel when I drop the gears on, but for absolutely no cost its worth it-scrap steel someone was throwing out(10 6ft angle iron of varing sizes-straight in the dumpster) and the welder at work

as you can see #3 rod is on, spins freely, must have had the rod cap on backwards last time

I'm using straight 30 as a mock-up lubricant, is there something better I could/should use?, I have used a multi-wieght, like a 10w30 before, and assembling it feels the same, just don't know if there is something better.

Sat Jul 20, 2013 3:30 pm

straight weight engine oil is OK, I prefer to use 80-90 gear oil. Thank you for not using grease :D

Sun Jul 21, 2013 5:09 am

I use redline assembly lube. Always have always will. Best stuff ive ever seen for coverage to help stuff break in.
Buy it in big tubs and slather every journal and lobe.

Sun Sep 01, 2013 10:00 am

Wow, it's been while...well it seems like a while.

anyways, did a little more mock-up; had bought .090" cylinder spacers/shims, deburred them little,

first I torqued case and using rubber bands, made sure everything spun(was prety sure I already done this, but never hurts to check, and check again)

Sorry for the blurry picture...stupid camera is acting up again

assembled #2 piston and cylinder, and torqued down my head plate

if you notice, I did something stupid and thus damaged the cylinder a little :oops:

Installed spacer(gots to be an optical illusion, cause it is seated properly)

and finally measuring the deck height, got to redo this, did it backwards, but shouldn't have that much effect on it-zeroed the dial at TDC, then measured to the top of the cylinder(using a mirror pressed up to the steel plate)

I'm still trying to decide on heads, but might do these now http://vwparts.aircooled.net/Dual-Port-Cylinder-Head-35-x-32mm-Valves-PAIR-p/500-400.htm,

or use a set of stock heads, run .07" DH and the ~48cc chambers they have, I still have to email aircooled, see if those heads come with the 53cc chambers

Sun Sep 01, 2013 10:29 am

run the tighter deck and do some chamber work to get to the cc s you need

Sun Sep 01, 2013 10:39 am

Hello.
One thing that is VERY important when using thin wall cylinders, (well, its always imporant, but even more here) is to run minimum deck height so you get all of the burn up into the heads instead of down in the cylinder.
If it was me that was to build one like that I would zero deck it (or close to) and have the heads cut to get 1,1 max 1,2 mm for clearance or deck the cylinders to the same. The tight deck gives you much better heat control.
If i read your dial gauge correct you are at 0,070" That is WAAY too much.

You still have time since you havent bought the heads yet. May I recommend Tims Super stock heads. I like the way they perform.

T

Sun Sep 01, 2013 12:33 pm

Completely forgot about the "super" stock heads, I was originally gonna save money by just getting another stock head to match the one I have now, but then started looking at the L3's(which are back-ordered or something right now), and no the deck height is not at .070", it is .045" which I would consider the absolute minimum(well, .040") DH needed

If I was to use the stock heads with the step, I would set the DH at .02 in the cylinder, and use the .05" step in the head to make my total DH .07, thus making more of the burn in the head, flycutting around here is expensive($150 per head) so getting rid of the step is stupid right now, as would be reworking the chamber(after the fly cut)

this is one of the reasons this build is taking a while, I want to do it right, but my budget is choking me, so I have to spend wisely

Sun Sep 01, 2013 1:31 pm

our L3 "situation" will be resolved by Wed. We have new castings on the way to us, and after they are reviewed we'll update the L3 status as active again.

Until this is done, I don't know WHICH castings we are using, so the product description and pictures would be "wrong", and we didn't want to mislead anyone.

Sun Sep 01, 2013 1:44 pm

75smith wrote: Completely forgot about the "super" stock heads, I was originally gonna save money by just getting another stock head to match the one I have now, but then started looking at the L3's(which are back-ordered or something right now), and no the deck height is not at .070", it is .045" which I would consider the absolute minimum(well, .040") DH needed

If I was to use the stock heads with the step, I would set the DH at .02 in the cylinder, and use the .05" step in the head to make my total DH .07, thus making more of the burn in the head, flycutting around here is expensive($150 per head) so getting rid of the step is stupid right now, as would be reworking the chamber(after the fly cut)

this is one of the reasons this build is taking a while, I want to do it right, but my budget is choking me, so I have to spend wisely

OK. Very well. I just was´nt sure of what I saw.

T

Sun Sep 01, 2013 5:11 pm

what happened to the cyl? cracked? trippin me out

Mon Sep 02, 2013 2:40 am

mightymouse wrote: what happened to the cyl? cracked? trippin me out

Broke off a top fin, wasn't thinking and put on my normal four spacers, but I forgot I needed to make something else so I could actually use four spacers, right now I can only use three

probably gonna try to make another deck height tool, but cut it so I can use all four studs

Sun Feb 19, 2017 9:09 am

What happened to the engine?

Sun Feb 19, 2017 10:06 am

Life got in the way, still have the car and engine, maybe this summer I can get back on it. Between actual work, working on other vehicles, and my own, I decided to put this car and engine to the back burner-realized I didn't want this as a daily because of the winters, so rebuilding one of my trucks became a priority.

I do still browse the forums here, so I haven't completely dropped off the face of the earth, but posting has been extremely limited.