prestbury2

Member

• Jul 18, 2014

• #1

Anyone know what the two holes and slight flat area are for on the hotspot at the locating dowel side?
My best guess is the two holes allow some hot gases to scour the gap between it and the cylinder head?

 

D

divie

Well-Known Member

• Jul 18, 2014

• #2

No idea but if they look at all dodgy replace the buggers. I had one break up and it did huge damage to the engine. Some folk say not to skim heads with hot spots in but I did by about 0.007" and no problems.

 

jamesmartin

Well-Known Member

• Jul 18, 2014

• #3

your not supposed to for a few reasons ,not least that they are supposed to sit proud by a thou or 2,

 

prestbury2

Member

• Jul 18, 2014

• #4

But the two holes?

 

jamesmartin

Well-Known Member

• Jul 18, 2014

• #5

to help keep it hot

 

prestbury2

Member

• Jul 18, 2014

• #6

Do you think 2.25ltr hot spots get a bad press justifiably or due to head skimming etc? After all 50% of it is captive against the block, how could it fall out?

 

jamesmartin

Well-Known Member

• Jul 18, 2014

• #7

didnt know they did have a bad press, they do age ,crack and shrink to a point then bounce in head

 

prestbury2

Member

• Jul 18, 2014

• #8

Mine looked pretty good..... I only fitted new ones from Paddocks, cos the old ones had hairline cracks but to be honest the old ones are a better fit and are slightly curved on the head face whereas the new ones are ground flat

 

jamesmartin

Well-Known Member

• Jul 18, 2014

• #9

prestbury2 said:

Mine looked pretty good..... I only fitted new ones from Paddocks, cos the old ones had hairline cracks but to be honest the old ones are a better fit and are slightly curved on the head face whereas the new ones are ground flat

Click to expand...

new ones should be tight used ones loose

 

samc88

Drivels spiritual representative

• Jul 18, 2014

• #10

I got new ones from Paddocks, and they seemed to fit fine, had to get lightly tapped in til flush/ slightly proud as James Martin says. I dont have a DTI so did it by feel to what the book says. (on a 2.5 diesel btw )

 

D

divie

Well-Known Member

• Jul 19, 2014

• #11

When my hot spot broke up it wrecked the head and damaged the top of the block and piston. I was given another head and skimmed it due to some new hot spots sitting low.
I then skimmed 0.015" off the top of the block to lose the damage and the same off the top of 4 new pistons. With bores honed and new bearings it ran very well.
I did get another engine but on removing the head to start a rebuild it was in a sorry state with a hot spot loose and damage in the top of the block about 3mm deep. These engines are all 30+ years old now, maybe that is why they are getting bad reports. I have driven 2.25 diesels for over 35 years and love them.