1600 turbo build thread

[buguy]

Thanks.
Man I can home and threw some smaller main jets in because I'm reading 10 on my afr at cruise. Fired it up and there is terrible blow by coming out of the vent next to my oil fill. So I did a compression test and got:
1- 138
2- 138
3- 143
4- 141
I figured #3 was going to be jacked but it all looks good to me. What else could be causing it? I mean air is really coming out there! My plugs look terrible. Super crusty and black. After pulling them I expected it to read 50 on all cylinders. The readings are on a warm engine with the throttle wide open. Plugs are Bosch B6HS by the way.

[buguy]

The plot thickens!
So I went and bought some new plugs.... It wasn't until then that I noticed I didn't have B8ES plugs in it, it had B8HS in it. They are a short reach plug. I wonder if that's why I've been fighting it all along?? I ended up buying NGK B7ES plugs and it seems to run much better with the correct reach plugs in it! I was going to take it for a drive but my PLX seems to be stuck at 14.6 afr. It's been weird lately so I have a feeling I have a ground issue. I will address that asap and hope I can get it to function so I can get accurate readings. Stand by

[Clonebug]

Blowby from detonation is caused by tiny cracks in the pistons. They are not big enough to effect compression since the pressure comes on so quickly with each stroke.
It is a real and present danger when you go turbo and can't hear the detonation because your exhaust is too loud, or you are in a car that hides the noise because pinging is not very loud.
I can hear mine pretty easily because I know what I'm listening for and I have an open buggy with a really quiet exhaust.
The cracks are so small you can't even really find them.
I have a set of barrels and pistons still on the shelf to remind me of my early days. I can not find any cracks in them but once I replaced them my blowby was gone.

Here is what happens when you run cracked pistons too long........not to scare you but.........

http://www.shoptalkforums.com/viewtopic ... 8mm+forged

Blowby doesn't just happen.

My engine is still blowby free after I got W/I installed and got my intake temps down to a reasonable level.

In your case you have no idea what your IAT's are or what your ignition advance is under boost unless you can log it and you are using a CB Black Box or equivalent.

It's some labor and about 200 bucks shipped if you change them now........be very, very careful........

[Clonebug]

The plot thickens!
So I went and bought some new plugs.... It wasn't until then that I noticed I didn't have B8ES plugs in it, it had B8HS in it. They are a short reach plug. I wonder if that's why I've been fighting it all along?? I ended up buying NGK B7ES plugs and it seems to run much better with the correct reach plugs in it! I was going to take it for a drive but my PLX seems to be stuck at 14.6 afr. It's been weird lately so I have a feeling I have a ground issue. I will address that asap and hope I can get it to function so I can get accurate readings. Stand by

Are you running stock heads or aftermarket????
My stock heads use the short reach plugs...My POS DRD's use the long reach plugs.

[Chip Birks]

What heads are on that engine? I don't think Vw ever made a 3/4" reach head, at least not until the late Mexican stuff, if at all.

[buguy]

Mine are stock heads from 1974. I put one in and turned it by hand and it didn't hit anything? Mine is a California emissions engine if it matters. As far as I know it just had some weird tubes in it that was the only difference from the rest.

[buguy]

Dang. A quick search says those HS plugs are correct. Grrrr that was a waste of time and money.
Looks like I better go ahead and get some pistons and cylinders ordered too.

[Chip Birks]

Must have some deep chambers in those heads!

[buguy]

Probably a good thing I only let it idle for 20 seconds! But it sounds like I need new P/C anyway

[buguy]

So wadda y'all think. Stick with stock 1600 P/C, 87mm slip ins, or 88 slip in/machine top?

[Chip Birks]

Slippery slope! Watch out! You know you are gonna pull those heads off and they are going to be tired, then you'll think, "well maybe a set of Panchitos would be nice, and those can be ordered cut for 90.5s...so why not go with the 88s..." But then, that stock cam is gonna make those new heads feel super under used, so now its time for a new cam and lifter set. Or just stick with the 85.5s, with decent thick walls and save your $$$ for a real build.

[buguy]

Wow your a mind reader! I was just looking at Panchitos to go along with some 88's!!
I'm gunna ask the machinist at work if we have what it takes there to open the heads up. If we do I might go with the 88's. If not I will just get some stockers.

[buguy]

So the guy says he open the heads but I think I'm just going to get the stockers to get it back on the road. I was wondering though. I see cima/mahle cast sets anywhere from $130-$190. Is there any difference in these sets or is it just pricing differences? Also what does everyone do for setting deck height? Do you order the P/C, put them on, then measure and then order shims? I hate to have a delay in building but also not much point in having $100 in shims either.

[Chip Birks]

Probably just pricing differences. You are correct in your original assumption, order the pistons, test fit, measure, then order shims. Most likely there won't really be a need to change much. There are more or less industry standards for cylinder height, as well as piston compression height. "A" pistons should all be pretty close, "B" pistons should be pretty close to each other as well. Makes it fairly simple.

[buguy]

Think I should leave it 7.3:1 compression? Best fuel I can get is 93 octane.