'84 Euro S interference or not. Answer will be coming...
#31
Burning Brakes
euro pistons have valve cuts of 9mm deep, exhaust, vs 11mm deep intake. vs the 4.5mm of the euro 85, and the 5 liter 2 valve conversions. so obviously, now you see that the early euro S engines are non interference. contact with euro S 85 is at .3" or 7.6mm valve depression and a 4.5mm valve pocket. so, even with make that valve pocket a euro depth, of 9mm min, you see that you would have clearance up to .6" valve depression. way more radical than any cam ever used on a 928 valve train.
So, all euros are non interference.
So, all euros are non interference.
Do you have the official information on the lift on the ROW S cams 80 - 83 and 84 - 86?
I can only find the duration figures in the WSM and Tech spec book.
Cheers.
#32
Rennlist Member
ROW '84 and '85 are the same or different? I'm confused.
#34
Burning Brakes
Many are confused.
If you see my post above, I list the engine numbers change overs, for both Auto and manual ROW S cars. This happened somewhere mid-84 model year.
The only difference is a slight change to the pistons.
If you see my post above, I list the engine numbers change overs, for both Auto and manual ROW S cars. This happened somewhere mid-84 model year.
The only difference is a slight change to the pistons.
#35
Burning Brakes
#36
Rennlist Member
So, are you saying that if the pistons are installed in the correct orientation within the engines, that no EuroS cars theoretically are non-interference?
If not interference per se, are there operation conditions that would cause collision?
Like, as the belt breaks under load, engine RPM jumps and rips the cam belt across the DS bank at such an elevate speed that it accelerates the valves to float into the pistons?
Or carbon build-up can sum to greater than the gap distance?
Just trying to learn here. Why are we having the dialogue if the engines aren't interference? Isn't there some history of Euro belts breaking and valves bending? ( I'm glad that DougM posted the question / interesting / hope his valves aren't damaged, BTW)
If not interference per se, are there operation conditions that would cause collision?
Like, as the belt breaks under load, engine RPM jumps and rips the cam belt across the DS bank at such an elevate speed that it accelerates the valves to float into the pistons?
Or carbon build-up can sum to greater than the gap distance?
Just trying to learn here. Why are we having the dialogue if the engines aren't interference? Isn't there some history of Euro belts breaking and valves bending? ( I'm glad that DougM posted the question / interesting / hope his valves aren't damaged, BTW)
Last edited by Landseer; 02-15-2011 at 08:56 AM.
#37
Three Wheelin'
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All 32v motors (Interference!!)' the belt breaks, you cry like a baby because you know this is pain , real pain. You 'can' fix it but prepare for valve damage, piston damage, real $$($$$$$$).
So - Don't break your cam belts! They only break from neglect or improper repair.
#38
Rennlist Member
so, you have the two different pistons shown on this thread now. (thanks Glen)
euro 80-83 deep cuts
euro 84 to 85, shallow cuts
euro 80-83 non interference, because the valve pocket is near .5 deep! total lift of the cam is somewhere in the .4" range, and if you depressed a valve in the head of an assembled motor, you would see that the valve is pushed down .3" and it touches the piston, with euro 85 valve cuts. this means, if you have .2" of a deeper pocket, you have clearance up to .5" lift with no problems.
break the belt, nothing will happen.
euro 80-83 deep cuts
euro 84 to 85, shallow cuts
euro 80-83 non interference, because the valve pocket is near .5 deep! total lift of the cam is somewhere in the .4" range, and if you depressed a valve in the head of an assembled motor, you would see that the valve is pushed down .3" and it touches the piston, with euro 85 valve cuts. this means, if you have .2" of a deeper pocket, you have clearance up to .5" lift with no problems.
break the belt, nothing will happen.
#39
Rennlist Member
when the belt breaks,the valves stops, or continue to spin at some out of orientation timing due to stripped teath on the belt, which is how it usually "breaks". the valves are going up and down and at .3" the would make contact on an 85 motor, on a 82 motor, they would would have to be pushed down .5" which is greater than the cam lift.
so, no interference in a euro 80-83 motor
so, no interference in a euro 80-83 motor
So, are you saying that if the pistons are installed in the correct orientation within the engines, that no EuroS cars theoretically are non-interference?
If not interference per se, are there operation conditions that would cause collision?
Like, as the belt breaks under load, engine RPM jumps and rips the cam belt across the DS bank at such an elevate speed that it accelerates the valves to float into the pistons?
Or carbon build-up can sum to greater than the gap distance?
Just trying to learn here. Why are we having the dialogue if the engines aren't interference? Isn't there some history of Euro belts breaking and valves bending? ( I'm glad that DougM posted the question / interesting / hope his valves aren't damaged, BTW)
If not interference per se, are there operation conditions that would cause collision?
Like, as the belt breaks under load, engine RPM jumps and rips the cam belt across the DS bank at such an elevate speed that it accelerates the valves to float into the pistons?
Or carbon build-up can sum to greater than the gap distance?
Just trying to learn here. Why are we having the dialogue if the engines aren't interference? Isn't there some history of Euro belts breaking and valves bending? ( I'm glad that DougM posted the question / interesting / hope his valves aren't damaged, BTW)
#40
Rennlist Member
same lift. devek posted the lift a long time ago. I have it written down or on my computer. ill look
lift is the same for both cams!
lift is the same for both cams!
#43
Burning Brakes
84 = E
85 = F
86 = G
It always helps if you write the engine type as well. M28/ 21? or M28 / 22?
#44
Burning Brakes
10,0:1 is also the compression ratio for the EARLY 84' model year ROW S (S2) with LH-jet. The change to the 10,4:1 pistons were at the following engine numbers ( as I wrote in my previous post )
M28/21 82E 00596
M28/22 82E 06114
the change to the new 10,4:1 pistons happened sometimes in the middle of the 84 (E) model year.
#45
Burning Brakes