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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Today 1:05 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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And another curiosity: the short, 1.2 engine pushrods are 9mm, then I have many 279 pushrods 8mm, and I have some 281mm pushrods 9mm. What are those oddball 279mm pushrods? I used tgem. On the engine because I thought they are from 1.6 engine, being much longer than the 1.2 ones. Then I read that stock 1.6 are 282mm, and as I mentioned above, everything looks better with them. Not perfect, just better. And I know the type4 pushrods are 271mm _________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Today 12:43 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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Update: I checked the valve train geometry.
First set of pictures, 283mm pushrod: no lift, half lift, max lift:
Second set, 281mm pushrod: no lift, half lift, max lift:
To me, the geometry with the shorter pushrod seems better. But the adjuster looks screwed too much in. Also, lift is smaller with 281mm pushrod: 8mm vs 8.3mm with longer pushrod.
It gets me crazy, so I crawled under my bug and checked. Pics are bad, but I can definitely see the adjuster is more out. And I measured the adjuster for wear: it is 25.70mm, stock would be 26mm. And geometry looked very well.
_________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Yesterday 11:18 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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Ok, understood, we were saying the same thing about cc and pushrod length.
New cylinders and pistons, new heads, no shims under rocker arm. Adjusters are not new, but usable. Anyway that does not explain the gap. Double and triple checked fitment (cylinders, pistons, heads, rocker arms), all good. Only way I can explain is cam and lifters, and most of the times longer pushrods are needed. Now I am so curious how it looks on my other car, but it snowed and it's outside, I have no will to crawl underneath. I have to change the head to cap gasket anyway...
So, waiting for cut to length pushrods, today plan to do the geometry properly. Hmm, I'm not sure I can stick the comparator in my other car, I am now also curious about that one. _________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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chrisflstf Samba Member

Joined: February 10, 2004 Posts: 3824 Location: San Diego
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Posted: Yesterday 3:24 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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Are those new/different cylinders?
One of the rocker adjuster screws look more flat than others? Hard to tell from pic. Maybe there is wear there? No shims under the rocker stands?
Its not umcommon to need shorter pushrods on rebuilds to get correct rocker arm geometry. |
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VW_Jimbo  Samba Member

Joined: May 22, 2016 Posts: 10709 Location: Huntington Beach, CA
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Posted: Yesterday 1:53 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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chrisflstf wrote: |
When you flycut the heads to change the combustion chamber volume, that moves the head closer to the case, which changes the pushrod length.
It could be that the pushrods fit ok before, but the geometry was wrong. Maybe the longer pushrodss are better for geometry now. but you would need to do that work to see if it is true
I think your best bet now is to cut new length pushrods and move on |
Agree with the above. But only after you go back through it all and double, even triple check it all. I have had my share of mistakes and a fresh day with fresh eyes and brain sometimes see stuff a different way! _________________ Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
TDCTDI wrote: |
Basically, a whole bunch of fuckery to achieve a look. |
67rustavenger wrote: |
GFY's Xevin and VW_Jimbo!  |
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chrisflstf Samba Member

Joined: February 10, 2004 Posts: 3824 Location: San Diego
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Posted: Yesterday 1:41 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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When you flycut the heads to change the combustion chamber volume, that moves the head closer to the case, which changes the pushrod length.
It could be that the pushrods fit ok before, but the geometry was wrong. Maybe the longer pushrodss are better for geometry now. but you would need to do that work to see if it is true
I think your best bet now is to cut new length pushrods and move on |
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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Yesterday 12:48 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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Yes, they are spot on 50cc, leading to a compression of 7.8:1. I like that you are pushing for doing everything by the book. And I know the cam needs 8-8.25, but I am not willing to di any machine work on the new parts. I do not have any trustable machinist in my area whom I can trust that would not ruin the parts, either cylinders for lower deck or the heads for lower cc. Well, maybe just one, but I don't want to risk. Remeber my target: nearly stock engine, not chasing hp.
But you got me puzzled: how does the head cc and compression influence pushrod length? Do you mean after machining?
Getting back to my topic: I borrowed two original cylinder heads and some pushrods from a friend. Pushods are 280-281mm, so 1mm at most loger than mine. Not much better, still large gap. Then tested the original cylinder head: no change. Then I used the adjustable pushrod I had, just to see the ballpark length: 282.97mm.
But to my defense, I also built a type4 to which I paid attention to all of these details. That engine has a different purpose, mainly to be very reliable and torquey for towing my Eriba (Pan, not Puck) with the bug. And it's around 130HP. I just need to finish putting the tins on the engine. Since some years.
Now to do the geometry properly and get the final value, until Friday when I can receive long pushrods, to be cut to length.
Why did it work with W100 and Engle lifters on my other engine, with stock pusbrods? No idea. And for Chris, I think I wrote before: I also did not increase the CR on that one, though iy would have deserved it more, as I have also dual 36 Dellortos and 010... Same reason, I did not want to risk ruining new parts. And patience, which is not one of my strengths . _________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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chrisflstf Samba Member

Joined: February 10, 2004 Posts: 3824 Location: San Diego
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Posted: Yesterday 9:38 am Post subject: Re: 1965 sunroof 1200 named Mushu |
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Did you measure combustion chamber volume on new heads? Versus old heads?
You need that info to determine compression ratio. It also affects pushrod length |
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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Yesterday 4:19 am Post subject: Re: 1965 sunroof 1200 named Mushu |
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Cylinders are fine, they go all the way in the case, also confirmed by deck measurement (1.4mm) and exhaust fitment. So it's not the width of the engine.
Did anyone hear about too high rocker stand/base? _________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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VW_Jimbo  Samba Member

Joined: May 22, 2016 Posts: 10709 Location: Huntington Beach, CA
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Posted: Yesterday 12:00 am Post subject: Re: 1965 sunroof 1200 named Mushu |
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Something is different. Maybe the barrels are taller than stock? Case has never been resurfaced.
Did the barrels go into the case all the way? I had a set not that long ago that was not fully machined. The cylinders would not seat into the case all the way! Like 6mm out of the case is where they all stopped. I put them on the lathe and took a few hundredth off. They worked great after that! _________________ Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
TDCTDI wrote: |
Basically, a whole bunch of fuckery to achieve a look. |
67rustavenger wrote: |
GFY's Xevin and VW_Jimbo!  |
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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Sun Feb 16, 2025 11:13 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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Agree that my solution for now is to use cut to length pushrods. But I am trying to figure out why the stock pushrods do not fit. Again, I have similar configuration in my other engine: Engle W100 with Engle lifters, and I could use stock pushrods.
W90 is nearly stock, so rocker geometry should have been ok. I'm not chasing HP here or perfect setup, but I am in the situation that I HAVE TO do something. _________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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chrisflstf Samba Member

Joined: February 10, 2004 Posts: 3824 Location: San Diego
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Posted: Sun Feb 16, 2025 4:05 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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You need an adjustable length push rod to get the right length and more importantly, the correct rocker arm geometry. But its best to do that before the case is together and sealed up. Dont want to wipe off the special lube on the cam lobes and lifter faces now.
One you get the push rods cut to length, deburr the ends, clean them internally and you can use two old lifters and a hammer to seat the new tip |
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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Sun Feb 16, 2025 1:33 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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Deck is 1.4mm, exhaust fits perfectly. So the width of the engine is good. I tested with other rocker assemblies (4 or 5, from 1.2 engine to other 1.6 engines) , same. Either the lifters (Engle) are deeper (I don't think so), pushrods too short (seem good, 280mm), or heads (Autolinea) are machined wrong (both???) with higher rocker stands, or valves too short. What on earth?
I ordered cut to length pushrods. _________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Sun Feb 16, 2025 8:00 am Post subject: Re: 1965 sunroof 1200 named Mushu |
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No issues, you were trying to help, just as Chrisflstf. Thank you!
So, final build. All spins free. I had to unscrew a bit some of the cylinder head studs. Initially I just screwed them in as much as possible, but it was too much (I did not have information on how much they should stick out, and no engine case to measure).
And, disaster. The pushrods are too short, by about 5mm. They are the correct ones for 1.6, measured 280mm, compared to 1.2 pushrods. Rockers are correct for 1.6, 1.25 ratio, the ones with two ribs. Only difference is camshaft and lifters, they are Engle W90 and Engle lifters. Strange that I had no such issue with W100 in my 1.6, using stock pushrods.
I did not flycut the heads for higher compression. Point was to build an almost stock 1.6, and I did not have a good 1.6 camshaft. Any ideas?
_________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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VW_Jimbo  Samba Member

Joined: May 22, 2016 Posts: 10709 Location: Huntington Beach, CA
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Posted: Fri Feb 14, 2025 12:44 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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Sorry man. That was a brain fart! K2 is awesome stuff. Played with it a few times. I still prefer Gasgacinch. I was taught by VW mechanics from back before all the new sealants emerged. He’ll, one guy swore by thick axle grease! Go figure! _________________ Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
TDCTDI wrote: |
Basically, a whole bunch of fuckery to achieve a look. |
67rustavenger wrote: |
GFY's Xevin and VW_Jimbo!  |
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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Fri Feb 14, 2025 11:11 am Post subject: Re: 1965 sunroof 1200 named Mushu |
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Victory! It was the bearings. I test fitted the Mahle Clevite. First feeling, not so tight on crank. Then, good fitment on case. Then, tighten in two steps the large bolts, 24Nm and then 33Nm. Spins free, also moves front to back for endplay adjustment. _________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Fri Feb 14, 2025 12:09 am Post subject: Re: 1965 sunroof 1200 named Mushu |
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Agree, this is why I am using K2 and not T. I did not have any issues in the past. I would use Gasgacinch or Permatex, but I can not find them in my area.
Thanks for the advice on using it on case studs, never thought of that, just using new orings. _________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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VW_Jimbo  Samba Member

Joined: May 22, 2016 Posts: 10709 Location: Huntington Beach, CA
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Posted: Thu Feb 13, 2025 11:21 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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One of the mechanics in the bay next to me swore by CurilT. He had several more cars come back with leaks than I or the other 2 mechanics. We all used Gasgacinch.
When you do get to final assembly, be sure to give those oring/case stud areas some sealant too! Seen a few leak out the studs. Heck, even VW used sealing nuts on the case nuts to offset the oil wicking out the threads!
Looking good! _________________ Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
TDCTDI wrote: |
Basically, a whole bunch of fuckery to achieve a look. |
67rustavenger wrote: |
GFY's Xevin and VW_Jimbo!  |
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tzepesh Samba Member
Joined: May 28, 2003 Posts: 826 Location: Romania
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Posted: Thu Feb 13, 2025 10:49 pm Post subject: Re: 1965 sunroof 1200 named Mushu |
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I beg to differ, this is not about luck, it is about measuring, test fitting, correcting until all fits. But thank you.
And I think you misunderstood what I wrote: from my point of view, any amount of sealant will change crush, and also the type of sealant can lead to a thicker or thinner layer after torqueing down. This is why I am using Kuril K2 (as per one of the many manuals) and not some red RTV as I have seen others do. RTV is more viscous, will create a thicker interference layer between case halves and in the end lower crush on bearings. We speak about fractions of millimeters which have an influence. But also thank you for the observation that the layer seems too thick. I have to point out that the picture is before smearing it, and even so, the crush was too tight and the crankshaft turned too hard. If the layer was too thick, the crush would have been smaller and the crankshaft would have turned easily. _________________ '74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration |
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chrisflstf Samba Member

Joined: February 10, 2004 Posts: 3824 Location: San Diego
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Posted: Thu Feb 13, 2025 10:26 am Post subject: Re: 1965 sunroof 1200 named Mushu |
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Sealant is not used to determine proper bearing crush. If you do, you have too much sealant, which you have by alot
Good luck, you will need it |
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