drilling out a z20e for l series head.

[RedBanner]

So I pulled the head off of my newly aquired z20e, I heard there was a sliggt chance it would have the proper jackets in the block for an l series head, doesnt seem to be the case.

U67 head.

Z20e block.

L gasket on z block,

front driver side I see a missing hole,

The u67 is missing holes the z block has as well the passenger side hiles or much bigger than the block, and between 1&2 and 3&4 driverside there are missing holes in the head.

I drill out the block on the one missing hole front driver side im prety shure, but what about the little holes on the passenger side, do I enlarge those to match? What about the missing holes in the head down the driver side? Between 1&2 and 3&4 I know the l gasket usualy has holes there and I assume thet because this is a u67, and has a dray intake flange, then just leave em blocked.

[RedBanner]

The hole on the drivers front I think I drill out.

[datzenmike]

Ask Sealick he's done this with another Z series head.

 

The way I see it the L series needs more cooling on the drivers side because both manifolds are on that side. Heat from the exhaust will leak into the intake port.

[RedBanner]

Are you reffering to the missing hole up front? Or the the missing intake cooling passeges? Im running a dry side draft makuni mani so im hoping to avoid drilling those ones out.

[Sealik]

The hole on the drivers front I think I drill out.

 

There is no corresponding hole in the L20B block either....so i might leave it.

My build was the Z22 with a U67 head...sooooo.....a little different than your 'engine'

Pic of your U67 without HG?  

Here's mine.

 

Is there any difference between the Z20E and L20B HG....?.....other than the front for the TC cover.

I drilled seven 1/4" holes in the passenger side block to match the U67 head. (total of 8....one was already in block)

9 holes in Z24 HG.

 

[RedBanner]

Ok thanks for.clearing up on the front drivers little hole, would have drilled that for shure, the 1/4 ones in your pic I have in the block, but there alot smaller than 1/4 inch, maybe I should drill those out larger?

[Xnke]

It's not altogether needed to drill out those holes, but the way I'd do it (and the way I do it on the L6, which has some issues with cooling due to the length of the engine), includes blocking off a few of the holes around 1 and 2 on the passenger side of the block. This forces water to circulate to the back of the block, go up into the head, and back to the front of the head to reach the thermostat.

 

The other cooling path I use in higher specific power engines is to open up all the ports on the passenger side of the head, and bring the water out over the exhaust ports of 5 and 6 in a 3/8" copper line; returning to the bottom of the thermostat housing. This results in much more even combustion chamber temperatures, on the L6...I don't think the L4 has the same issues.

[Stoffregen Motorsports]

I would leave them alone, except for the one at the rear of the gasket. You want the coolant to rush to the back of the block and then up into the head and then forward. If they were all drilled out, the coolant would just migrate upward without any circuitous path.

[metalmonkey47]

Weird, I have a Z20E block that is literally identical to an L20B block, except the dipstick tube location

[RedBanner]

I would leave them alone, except for the one at the rear of the gasket. You want the coolant to rush to the back of the block and then up into the head and then forward. If they were all drilled out, the coolant would just migrate upward without any circuitous path.

thank you for your reply. Is.this the hole your referring to? Wich I thought was a oil passage.

Here I kinds gave all the rear holes a color code, becouse I thought you ment the red one but im not sure.

 

Red is the one I think you meen, pink and orange are head bolts.

 

Mm, this one has extra holes down the one side. Wich my l 20b does not

[RedBanner]

Bump.

[Suspect]

I have the same thoughts when I go to finish my Z22 with A87 head.  I think I have to do some drilling in the block.

[Sealik]

L20B block for reference...

 

The Z22 has those extra holes running down the drivers side of the block also...no need to drill any extra holes in the U67 head to match

 

I think this will work fine....as is. Looks like everything lines up.

L gasket on z block,

 

[RedBanner]

Thanks for checkin back, that is great news.

[izzo]

When you going to start the build on this one?

[Stoffregen Motorsports]

Bump.

Sorry.

 

It depends on the gasket. Some gaskets don't have that extra oil return hole in the back of the head, some gaskets need the water hole punched out. So which gasket are you using? Z20, Z22 or Z24? There may be differences between the gaskets other than bore size.

[RedBanner]

L20b gasket, well that has be the plan so far.

[Stoffregen Motorsports]

L20b gasket, well that has be the plan so far.

You shouldn't have to dril anything.

[RedBanner]

Thank you sir.