The V8 Owners Forum -

Hi All.

The stripdown of my project engine is almost complete. We knew that water was getting in somehow and when the heads came off the Gaskets looked OK but pistons 3 and 5 in the right hand bank were rusty. This leads me to believe the block may be cracked between the two and this is where the problem lies.

So does anyone have any advice as to how to proceed from here? I was thinking, get everything out, down to the bare block and cleaned up and take it for pressure testing. Is this a viable rationale?

Any thoughts or advice would be appreciated. Thanks.

Rik.

first thing I would do is get it all cleaned up and check if the heads are straight. 3.9 engines arent as prone to cracking as the 4.0/4.6. If the heads and deck all come out ok and you cant see damage on the gaskets then yes a pressure test is the way to go. How rusty is rusty? If its very rusty then it might not be worth spending any more time/money on it unless you want the expense of a rebore. Its probably much more economical just to get another 3.9 block these days as they are pretty cheap. Cheaper than a rebore anyway and a long way cheaper than getting top hat liners if it is cracked.

Thanks Marki.

In assuming by checking the heads are "straight", you mean steel rule across them and feeler guages underneath? Does the same method apply for the deck?

They are rusty at the top of the bores and the top of the pistons. Do you think this could be water sitting on the top from the head rather from underneath?

Regards,
Rik

yes straight edge and feeler gauge on heads and deck. Sounds more to me like water has got in via inlet or something. Water in a running engine usually gives steam cleaned pistons, not corrosion.

Thanks again Marki,

I will check the heads and decks have a really good look at the gaskets. Just to throw a spanner in the works, although none of the pistons are shiny, quite the opposite, all grimey, there is a core plug missing. Dont think that has dropped out during the stripdown so must have happened when running. How would this be explained?

Rik

It's either been taken out, rotted out or piped through freezing. Unlikely to have completely rotted out.

Hi Rik.
A little history on the engine would be helpful.

For example have you heard the engine running?
How did you know that water was getting in?
Has it been left out in the rain?
Has it been left out in the freezing weather with water in it.?
Is the missing core plug next to the rusty cylinders?
Any other history would help.
Regards
Denis

Hi Dennis, in answer to your questions;

Have not heard it running but have been told it was, no reason to doubt.

Was told it was using water on inspection of the oil it was creamy.

The engine was in the truck until I removed it so not exposed

Yes. it has been very cold up here this winter. If it was using lots of water, perhaps it didn't get the correct amount of coolant required??

No, the missing plug is on the oppositeside of the motor.

Afraid I dont have any other history other than its a 3.5 efi from a non soft dash Classic, engine number 25D20328C

Regards,
Rik

Rik,
The RV8 has no water passages through the head gasket at cylinders 3 & 5 so water in these bores point to a crack in either the head or block.
The fact that one of the core plugs has completely departed from the block indicates that a freeze has pushed it out. Based on the facts, I would say that the freeze has cracked a head or the block.
The way forward as stated before is to have the block pressure tested and also the heads if the block is found to be sound.

Good luck
Regards Denis

Dennis,

Not quite the news I was wanting mate but thanks anyway!

Just to be ABSOLUTELY sure, measure twice, cut once and all that, Im lead to believe that standing at the front of the engine (i.e viscous fan, timing gear, water pump etc) Cylinders 1, 3, 5 and 7 are on the right, even numbers on the left. Just satisfy me!

With regard to the water channels, where do they run out of interest?

Regards,
Rik

RiktheLogger wrote:Dennis,

Not quite the news I was wanting mate but thanks anyway!

Just to be ABSOLUTELY sure, measure twice, cut once and all that, Im lead to believe that standing at the front of the engine (i.e viscous fan, timing gear, water pump etc) Cylinders 1, 3, 5 and 7 are on the right, even numbers on the left. Just satisfy me!

With regard to the water channels, where do they run out of interest?

Regards,
Rik

Yes you are correct nos 1 ,3,5 & 7 are on the right when you are standing in front of the engine and no1 is nearest you.

The water passages through the gasket are at the front and rear of the gasket only ie next to cylinders 1,7,2, & 8

regards Denis