Liner Protrusion

[stuTHC]

If the liner protrusion on a R5GTT (liner to block) is less than the minimum 0.02mm stated in the haynes manual what effect would/could this have on the engine?
What would break and how?

[raj]

if its actually below deck height it wont seal proper

[paul b]

there would not be enough "squash" to seal the liner to the block...

oil/water mix


also can stop the fire ring on the gasket being compressed with enough force to seal on the liner top..

headgasket failure

[Scoff]

it'll mainly cause black holes and the demize of the globe's population.

oh no, that was the hadron collider ! liners have a protrusion so that the fire ring on the gasket is compressed suitably. IMO the actual protrusion isn't that imporant, aslong as its not miles out, the more important thing is to arrange them so that there is minimal difference between neighbouring liners.

but, in the real world, every liner I've come across, new or old has been the same, never yet had to worry about protrusion, so not worth worrying about.

[paul b]

it used to be more important when the liner seals were made of paper ...

they came in 3 different thicknesses and had to be measured dry and then you used the appropriate seals..

they are now rubber, more reliable and easy to use

think Colin wil agree....LOL....he maybe the only other person who has seen/used the old paper ones:cool:

[stuTHC]

Well the track5slag is in bits again. Same fault as what it died with last time it ran- blown headgasket, expansion bottle top blown off and cracked liner (No1 this time instead of 4) it has done all of 30 miles if that since been rebuilt. It felt (and sounded) to be leaking boost before it failed the first time, we couldn't see anything obvious though.
Basically since then it's had a different cyl head, inlet manifold, turbo, boost pipes all, intercooler, carb. But it still felt to be loosing boost and didn't sound right. We pressure tested the boost circuit last night and found no external leaks. But the boost gauge didn't read any pressure and the air compressor didn't knock off suggesting that it was leaking somewhere (you could hear the air moving through the boost pipes where as id have expected it to reach a certain pressure and knock off)
The only thing that is the same as before is the block and liners.
Ive just stripped it tonight and found the following protrusions-

No1- 0.02
No2- 0.05
No3- minus 0.05 (below the level of the cyl block! )
No4- 0.06

[paul b]

taaaaaa da....

now thats magic.........!

[Ian S]

That's what should happen if the valves are at overlap in one cylinder.

'Leaking' that is.

Though:
No2- 0.05
No3- minus 0.05 (below the level of the cyl block! )
No4- 0.06

is the thickness a photocopy paper between adjacent liners.

So maybe.

[stuTHC]

Tomorrow ill finish dropping the sump off and remove all 4 liners. Between robbo and me we have another 8 liners so we'll measure them all from seal face to top and pick the best 4. Refit them in the correct stepped order and see how we go from there.
If needed (although i doubt it with 11 liners to choose from) are the thicker red and green seals the haynes refers to dealer only items?

[stuTHC]

That's what should happen if the valves are at overlap in one cylinder.

'Leaking' that is.




The boost gauge we have was showing vacum and boost pressures when driving, but when we pressure tested the system with the compressor nothing regestered on the boost gauge at all, didn't even flich. The gauge on the compressor said we were putting 1.6 bar into the sysetm, it held that pressure and no extenal leaks could be heard or felt.
Surely the boost gauge should have registered 1.6bar?

[Ian S]

are the thicker red and green seals the haynes refers to dealer only items?

IIRC, not even that.

The rubber ones will be fine. That's all there is I think.

When the head is on, the liners sit on the block not the rubber, that just squashes and seals, provided you didn't get any lumps of rust or other detritus under a seal.

[Miller]

If needed (although i doubt it with 11 liners to choose from) are the thicker red and green seals the haynes refers to dealer only items?


I do not think you can use the paper seals on the gtt engine, as the area that the seal sits is different.:)

[THE MASTER]

stu when cheacking linner protrution

do it without the rubber seal , the rubber seal has no efect on the clamped down linner protrution , but will lift a linner slightly if not clamped down.

try a few linners in there and see if its the linner or the block (if all liners show low you have a streached block) :smokin:

[Trevhib]

Colin and Paul. Gold dust as usual lads :)

What on earth will the world of GTTs do when you're dead? :scared:

Hahaha ;)

[Trevhib]

Re-reading my post, it sounds like a mortal threat! :laugh:

[raj]

wtf!! a stretched block:confused: never heard that one before:eek:

[Andrew Cooke]

That's what should happen if the valves are at overlap in one cylinder.
.

it's almost impossible to stop an engine with a cylinder in overlap. Overlap occurs at TDC, and if you've ever turned an engine over by hand you'll know that they fly past TDC and have a 'tight' spot mod stroke.