135 and 136 injection cylinder heads, oversized valves?

anewman · 17-01-2008, 03:32

Been poking around the parts catalogue and found something labelled as "oversize valves" for both exhaust and inlet. Assuming these are non-standard, they also appear to be cheaper than the standard one's if still available via skoda. Just wondering what advantages or disadvantages oversized valves give. (My completely uneducated guess is oversize exhaust valves are probably more useful than inlet).

I have a spare cylinder head from a 135, and was thinking of cleaning it up some time and messing with it so long as the tools needed to sort out the valve springs aren't too expensive. From what I can tell the 136 uses different outer valve springs and lower support washers, and the 135 has an inner spring base that the 136 doesn't have. I am assuming the actual cylinder head block for the 135 is the same as the 136 - but if I could simply transplant it onto a 136 set-up then mayaswell just scrape the remaining gasket off and clean it up.

KenONeill · 17-01-2008, 12:52

With larger ports, larger valves will:-
Pro - give higher peak gas flow, allowing higher peak power.
Con - reduce gas velocity at low revs, leading to potential problems of poor scavenging, and fuel dropping out of suspension in the air, leading to poor running and pickup.

pinkskud · 17-01-2008, 18:01

the 136 has better flow pattens.

i'm pretty sure the 136 can be bolted on in place of the 135 head.

surprising_skod · 18-01-2008, 00:01

Quote:

Originally Posted by pinkskud

the 136 has better flow pattens.

i'm pretty sure the 136 can be bolted on in place of the 135 head.

i sure hope so, for tomorrow i will attempt to put a favorit head on a rapid block and i'm very concerned about waterways! :o

KenONeill · 18-01-2008, 08:33

Compare the holes in the gasket with the ways in the block and head.

pinkskud · 19-01-2008, 00:14

Quote:

Originally Posted by KenONeill

Compare the holes.

yes... every friday night.

17-01-2008, 03:32	#1
anewman Briskodian Join Date: Jan 2007 Location: Leeds Posts: 2,512 Thanks: 984 Thanked 222 Times in 205 Posts	135 and 136 injection cylinder heads, oversized valves? Been poking around the parts catalogue and found something labelled as "oversize valves" for both exhaust and inlet. Assuming these are non-standard, they also appear to be cheaper than the standard one's if still available via skoda. Just wondering what advantages or disadvantages oversized valves give. (My completely uneducated guess is oversize exhaust valves are probably more useful than inlet). I have a spare cylinder head from a 135, and was thinking of cleaning it up some time and messing with it so long as the tools needed to sort out the valve springs aren't too expensive. From what I can tell the 136 uses different outer valve springs and lower support washers, and the 135 has an inner spring base that the 136 doesn't have. I am assuming the actual cylinder head block for the 135 is the same as the 136 - but if I could simply transplant it onto a 136 set-up then mayaswell just scrape the remaining gasket off and clean it up. __________________ 94 Favorit GLXIe Estate Last edited by anewman; 17-01-2008 at 03:38.

17-01-2008, 12:52	#2
KenONeill Briskodian Join Date: May 2006 Location: Normally somewhere in Scotland! Posts: 10,381 Thanks: 56 Thanked 490 Times in 481 Posts	Re: 135 and 136 injection cylinder heads, oversized valves? With larger ports, larger valves will:- Pro - give higher peak gas flow, allowing higher peak power. Con - reduce gas velocity at low revs, leading to potential problems of poor scavenging, and fuel dropping out of suspension in the air, leading to poor running and pickup.

17-01-2008, 18:01	#3
pinkskud not a bird!!! Join Date: Sep 2006 Location: pixi said not to fill my box Posts: 2,133 Thanks: 1 Thanked 77 Times in 73 Posts	Re: 135 and 136 injection cylinder heads, oversized valves? the 136 has better flow pattens. i'm pretty sure the 136 can be bolted on in place of the 135 head. __________________ also found on http://skodafelicia.freeforums.org/index.php

18-01-2008, 08:33	#5
KenONeill Briskodian Join Date: May 2006 Location: Normally somewhere in Scotland! Posts: 10,381 Thanks: 56 Thanked 490 Times in 481 Posts	Re: 135 and 136 injection cylinder heads, oversized valves? Compare the holes in the gasket with the ways in the block and head.

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