<div style="color:black;font: 10pt arial;">We played around with rocker ratios on a computer simulation of a TR4 engine. The added lift increased max HP by about 3 HP peak. Low end (under about 3500 rpm) torque was actually reduced a very small amount. If the TR6 results were similar, probably not worth the hassle of added valve spring issues and reduced valve guide length (greater valve guide wear).
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<div>For what it's worth....</div>
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<div>Phil<br>
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<div style="font-family:helvetica,arial;font-size:10pt;color:black">-----Original Message-----<br>
From: van.mulders.marcel--- via Fot <fot@autox.team.net><br>
To: Michael Zbarsky <mzbarsky@yahoo.com><br>
Cc: fot <fot@autox.team.net><br>
Sent: Mon, Feb 10, 2020 8:52 am<br>
Subject: Re: [Fot] Camshaft recommendation<br>
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<div>I also once bought a Goodparts 1.65 rocker roller assembly for a TR6 engine, but in the end I had to use a 1.55 roller rocker assembly, also from Goodparts, because, with the 1.65, it is difficult to find a race camshaft with a lobe lift that is low enough. With lobes of 8mm or higher, I could not find valve springs to cope with the high valve lift. I bought a G5 camshaft from Schneider, they call it the 320-F grind (duration is 268° at 0.050", timing is 57-83 87-53 , installation figure is then 103° :is that the same as the G5 grind?) with 0.340"/8.6mm cam lift and that makes for a valve lift of 12.9mm with the 1.55 rocker arms. With 1.65 rockers , valve lift would be 14.2mm and I could not find valve springs for that lift. The valve springs I used are part no 281003-063.20 from Summit (Isky), 320lb/inch spring rate. They recommend 0.45"/11.43mm (1.250" - 0.800"from closed to full open position, so it is about 1.4mm more in my engine, but there is no problem concerning coil binding : the installed height is a 1mm more than 1.250 , the pressure in closed position is lower of course, but still 34kgs (105kgs at full lift) an that seems to be enough till 7500 rpm</div>
<div>Racetorations have a race cam with 7.6mm cam lift, probably that would work with 1.65 rocker arms. I still have the 1.65 rocker assembly, it is new and it could work with a road cam or any camshaft with a maximum of 8mm cam lift.</div>
<div>Marcel</div>
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<div><b>Van: </b>"fot" <fot@autox.team.net><br clear="none"><b>Aan: </b>"fot" <fot@autox.team.net><br clear="none"><b>Verzonden: </b>Maandag 10 februari 2020 02:34:27<br clear="none"><b>Onderwerp: </b>[Fot] Camshaft recommendation<br clear="none"></div>
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Hi all, I’m building a TR6 race engine and have a set of 1.65 ratio roller rockers from Goodparts. Any recommendations for a suitable camshaft? I will be putting in cam bearings.
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<div>Thanks, Mike<br clear="none"><br clear="none"><br clear="none"></div>
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