Extra holes in Lotus R-16 head cause overheating with Renault R-16 head gasket.

[shootingsight]

Years ago I rebuilt my R-16 engine ... several times ... because it kept overheating.  Once, I pulled the head after only a few hours running, and the gasket came off clean enough that I noticed some green coolant spots on the gasket, where there were holes in the head, but not corresponding holes in the Renault gasket, so it was choking flow and causing the overheating.  Easy solution is to punch a few extra holes in the Renault gasket - you just have to know where.

I just pulled the head again (after 30 years in storage), and figured I would put out pictures documenting the difference.

Below is a picture of the head, as well as the comparison of the original gasket, versus my modifications.




Engine is really clean inside, but there are metal shavings in the oil pump and a heavy groove scored on one of the main bearings.  I suspect there were chips in the oil galleys from the last rebuild that were not cleaned properly.  No damage to the crank, so I'll have it align bored and put in new main bearings and I should be good to go.  I hope.

[Grumblebuns]

The first question to ask is, are you sure that you have the correct head gasket?

[shootingsight]

It's a Renault R16 gasket.

[jbcollier]

These chaps sell head gaskets for the crossflow (pretty much the same thing) and there are no holes in their gaskets either:

http://www.mecaparts.com/Moteurs/page.php?lang=0&sortie=html&col=A110&page=1#ok

One nice thing they also sell are copper head shims if your head gets undersized.

I have a couple of gasket sets kicking around so I went and checked, no extra holes.  No overheating issues over here.

[Grumblebuns]

I'm confused on this, not the first time. Why do you have to make extra holes on a R16 head gasket for a R16 engine? Shouldn't the gasket match the head without modification?

[shootingsight]

I assume the Lotus head is not the same as a stock R-16 head.  I always assumed they drilled the extra holes to allow more coolant flow because the Lotus had a smaller radiator than the Renault did.  Just a guess, but the head on my Lotus definitely has holes that are not there on any of the head gaskets, and once I added the holes in the gasket, my overheating issues went away.

[dakazman]

All good points , maybe they were covered up to keep the flow of water thru the head from front to back then down to the sleeve area and back up to pump. The holes could be there to better flush out sediment from the head when off.
Dakazman

[jbcollier]

I never argue with what works.

[dakazman]

What ? If it’s not broken then don’t fix it!😀👍👍
Dakazman