R8G cylinder head.

David Cavanagh

Well-known member
1000+ Posts
Fellow Frogger
Joined
Feb 10, 2001
Messages
5,272
Location
Romsey, Victoria, Australia
I have the head off the 8G. Car is running excellent but had slight liner seal leaks so we are resealing it.
Found very slight cracks in the head. I know there prone to crack but what's a good crack and what's a bad crack?

Should we be concerned?
 

Attachments

  • 8g head 2.jpg
    8g head 2.jpg
    35.5 KB · Views: 123
The two other 8G heads I have seen both had these cracks from the flame ports. Both were used without repair and there were no problems. It will be interesting what knowledge Frans has on the subject.
 
May want to do a dye check for the cracks that aren't obvious but could develop further

"Car is running excellent, took the head off."
:dance: Love to seeing people enjoying themselves to see why their car is running so well. :dance:
 
The two other 8G heads I have seen both had these cracks from the flame ports. Both were used without repair and there were no problems. It will be interesting what knowledge Frans has on the subject.
My thoughts exactly! And Geckoeng.
 
The facebook experts say it's normal and don't do anything. This car has only done 39,000kms and it's cracked already so welding it could cause the crack to reappear in some place worse.
 
May want to do a dye check for the cracks that aren't obvious but could develop further

"Car is running excellent, took the head off."
:dance: Love to seeing people enjoying themselves to see why their car is running so well. :dance:

Not me, if it aint broke don't touch it.

This engine was rebuilt 40 years ago and when we got it going only two months ago we found a bit of water in the sump. Not much but enough to tell us a liner seal was leaking so we decided to give it a bottle of medicine to do the Yass muster and strip it down and reseal it when we got home.
 
There's a guy in NSW with a Youtube channel who casts all sort of wonderful things in his foundry, Maserati manifolds, pistons, whatever. Maybe he could do a run? Olfoundryman (sic) is his channel name.

Here's the first instalment in casting a four barrel throttle body


If anyone can pull it off, it has to be him.
 
The exact problem we had with Graeme's Gordini after it was sold. But the head was on its limits when I built the motor. The problem is the heads do not like continuous hard work. If left too long the cracks encroach on the water jacket and you get water into the bores and into the sump in small amounts. When the cracks grow some more they blow back into the coolant, and that can be soon after they get to the water jackets, or a while after. To the point a pieces could break completely, and fall into the combustion chamber, see FRANS, "2 new race cars in NZ" (it was around page 27) unfortunately a lot of the pictures have been deleted. That was a lot of welding and rebuilding. Frans we need the pictures of the piece of head that fell out.

Ray
 
By the way I believe new heads are available in France. And I believe better quality than original. Need to contact D-Jet Club of France. They had them made for club members, and Andrew Moore (buyer of Graeme's G) bought one. Not sure if it was fitted but Colliers. Story was cut short at this point, no more communications ?????
 
First find one!!
As advised in another thread some time ago & noted above by Ray, Club Djet has commissioned a run of them & one Australian R8G owner has indeed (with my mediation) availed himself of this (via joining the club).

There was a delay when the club challenged metallurgical quality but that is now resolved.

As for new ones having the same faults as the originals, I agree. One can see why the flame ports were dropped for the R5 A/G head,
 
By the way I believe new heads are available in France. And I believe better quality than original. Need to contact D-Jet Club of France. They had them made for club members, and Andrew Moore (buyer of Graeme's G) bought one. Not sure if it was fitted but Colliers. Story was cut short at this point, no more communications ?????
That's good. The earlier run of new heads was fully taken up quite a while ago if I remember correctly.
 
Top