GT186 Squish

[Hughieboy]

I’m trying not to get to bent out of shape about this but would appreciate any advice....

I just fitted a GT186 kit to my long stroke small block engine. It was previously built with a 116mm conrod by Harry Barlow so in order to get what looked like the correct set up there we now 2 x 2.5mm packers, one 2mm packer and a couple of thick base gaskets which brought the edge of the crown of the piston to just below the top of the cylinder bore. I then added a Gt copper head gasket and torqued it all down. Everything moves ok and nothing hits but I thought I should try and do a squish measurement.

Now, I haven’t done this before and I did it using soft solder as I’ve seen recommended. As far as I can tell, and I’m not really sure if I’m doing it correctly, the squish is 0.5mm. I realise this is lower than the recommended 1.2 - 1.5mm but is it that big of a deal? I haven’t tried starting it yet but I siliconed all the gaskets and would obviously rather not tear it all down again unless really necessary and have to replace everything. Squish is beyond my normal technical know how and I’m trying to get a grasp of whether a), I’ve done it right and b), is it that critical as long as the piston isn’t touching the head on its stroke. I’m guessing a lot of folks don’t even check squish but rely on clearance.

Can anyone advise on this please?

Thanks.

[Meds]

Have a read of this
https://www.mbscooters.co.uk/info//sett ... -+167.html

Generally have a look at his tec site

[rossclark]

It's too tight. Stuff expands with heat.

I always dry build, no gaskets, check squish, workout which gaskets are required. Recheck with those gaskets then rebuild with sealant.

[Hughieboy]

Thanks guys,

Maybe I’ve been a bit too hasty in my excitement!

Back to square one then

[ULC Soulagent]

Have a read at this also
https://www.mbscooters.co.uk/info//sett ... s+190.html
And this
https://www.mbscooters.co.uk/info/engin ... ts+89.html
Read and reread over again, everything will fall into place once you’ve grasped the concept

[Storkfoot]

Yes, take your time. Just to reassure you though, I have a GT186 with an RD400 115mm Conrod. It is packed out with 2 4mm packers. I can’t recall precisely what the squish is or whether I have used cylinder base or head gaskets, but it is a lovely ride.