Convert R16 head to Lotus spec?

[Richard48Y]

I recall the lotus head uses larger valves.
What else to upgrade an R16 head to Lotus spec?

[jbcollier]

The 1470 was a hopped up engine from the stock R16.  It is said they were left over engines from a Mercury Marine contract.  Larger valves, higher compression, hotter cam etc.  All series 1s had the 1470.  “Lot” of 54s did as well.  Renault developed a emissions 1565 for the US and this came in 65s and became the default engine going forward.  It is a Renault engine with no mods for Lotus.

[Richard48Y]

So if these heads are from 1565cc engines they would be the same.
Doubt I need three so maybe I will recoup some of my expense.

[gideon]

I'm not sure it's correct to say that the Renault 821-30 is the same as the engine in the Renault 16 TL.   According to Dave Syer's page the Renault 16 TL had engines with numbers from 821-01 to 821-04.  They had lower compression than the 821-30

http://www.syer.net

The heads may be identical, but apparently the camshafts are different.  Renault 16 shop offers different pistons and different camshafts for Lotus Europa with 697 and 821 engines.

https://www.renault16shop.com/zuigers-en-bussen
https://www.renault16shop.com/Webwinkel-Category-4854025

The camshaft for the Lotus Europa Renault 697 and 821 engines is the same.

[GavinT]

And, how do valve sizes compare?

Did Lotus carry through the increased valve sizes from their original Lotus 697 / MerCruiser head to the later Renault 821 based head?
Or, do even stock Renault 821 heads have larger valves as per the Lotus / MerCruiser head?

[Richard48Y]

I will measure and post what these are.

[Sveris]

I recall the lotus head uses larger valves.
What else to upgrade an R16 head to Lotus spec?

The Renault R16 cylinder heads are almost identical to the Lotus cylinder heads and the Mercury Marine cylinder heads.  But as they say, the devil is in the details.

Most 1470 cc heads had each intake port shared by two cylinders, where the 1565 cc heads had separate intake runners. The MerCruiser 1470 cc heads have separate intake runners for each cylinder.

And, of course, the camshafts are different for the R16 and Lotus cylinder heads. The MerCruiser camshafts are shorter, have no extension, and cannot be used in our cars.

But in answer to your original question, here’s what you need to do to convert an R16 Sedan cylinder head to Lotus specification. The parts that are different are the valve spring pairs, and the washer shaped retainers that hold these springs in place. Swap out these parts and you’re all set. The problem you will encounter is that the springs and washers are difficult to source.

HTH.

Steve in Ohio