Euro 2.7 RS deck height question

[Silvertip]

I installed #'s 1 & 4 on the case with the normal copper shim and measured the deck height on the small flat rim of the piston - came up with 0.66mm. I went ahead and did the acid core solder crush test on them. Not surprisingly the only contact with the solder was right at the edge of the piston on that flat rim, at 0.6 mm. With the low dome 2.7 pistons and the high dome early S heads it appears that the only area of worry is that small flat edge of the piston - I guess the edges of the smaller dome heads intrude a bit onto the piston area of the 2.7's.

Question is - Is the recommended deck height of the 2.7RS the same 1.5mm as for the other cars, requiring an additional 1.0mm shim? Or do I need to have the head combustion chambers opened up?

Piston / Cylinder set is new Mahle, heads are off of a 2.2S.

Thanks,

Kevin

[gled49]

I would comp the motor and try to use the .66 deck. The compression is so low that is a way to raise comp. 1.0 mm is our norm but have use less deck. The 73 RS didn’t chamfer the combustion chamber (cc) to 90mm, so your 2.2 heads have the same shape as the 2.4-2.7RS. I don’t recall 2.2 head cc so it should be confirmed. Valve to piston shouldn’t be a problem with S cams, but should be confirmed. If you take an assembled P&C, set it on top or a head, push the piston down until it hits the head, you can add that to your deck clearance for piston to head clearance. Measure twice, maybe a .5 base gasket would just what the doctor ordered. G

[Silvertip]

Thanks for the info - even tho there is a lot of room except for the very edge of the piston, I ordered a set of .5mm shims. Now to decide if .91mm is enough or 1.16mm is too much. I am not comfortable with 0.66mm - just standing there looking at it gave me the chills.

[gled49]

U will be fine at .91mm.

[Richy]

You will be ok at .66 mm . When I did the math the engineered deck height is .7mm . If you are concerned and want to be cautious have a small bevel machined in the cylinder heads . As gled49 says , you want to maintain a decent compression ratio . I have worked on later stock '73 RS engines with cylinder heads with a small bevel or chamfer .