Port Timings - Recessed Head?

[servetakid]

Hi all,

I'm just having a look at the MB RT225 kit with someone, and we are trying to work out the port timings.

Head is pictured here: http://www.lambrettaspares.com/spares/c ... 0260k.html

The piston crown sits aprox 7mm down from the top of the barrel at TDC. However, with the head being recessed, that sits approx 5mm down inside. So would that leave the distance from piston crown from top of barrel at say 2mm?

Also, are you able to use a head gasket with the recessed heads?

http://www.lambrettaspares.com/spares/c ... p0318.html

Cheers

[speedy]

According to that web page, gaskets are sold separately for the head, so it would be assumed that the answer is yes. However the 2mm that you are left with, once a head and base gasket are added, is gonna be more like 4mm. So with this in mind, is the kit designed to have a longer rod to compensate for the clearances and to be able to set the squish?

[servetakid]

I should have mentioned we are building this with a 60/110... I'm just trying to work out where the barrel "ends". Is it where the heads sits in the barrel?

[Special X]

The only accurate way of measuring port timing is to use a degree wheel.

[eden]

If your using my port time calc just enter the measurement from top of barrel to the piston crown edge at TDC in the "Piston Crown to Top of Barrel at TDC:" the calc will work the rest out from the rod, stroke and port measurements.
before you decide what the measurement is though make sure you have set the barrel height so it gives a good squish, then remove the head and measure the distance.

PM me if that makes no sense which im sure it doesn't

[jason frost]

PM me if that makes no sense which im sure it doesn't

LOL put the crank in and use a degree disc and use Edens as well

[eden]

oi Jase ive had a hard 4 days on the p155, my brain is refusing to work

[jason frost]

oi Jase ive had a hard 4 days on the p155, my brain is refusing to work

Nice one have you put the new piston in yet ?

[eden]

no doing it after lands end to johnogroats if it lasts that long lol