Cat 3306TA

Hello Jonno

Interesting have rebuilt a few 3306s etc,a few were fitted to trucks.

One I remember was fitted to a LEADER OVERLANDER and the owner had

renewed the head gasket several times. We were involved to see if there

was a unseen problem. With liner protrusion being considered, we removed

the pistons and liners and on close inspection we found the alignment was

out between the top and bottom liner bores. The owner continued the repair

himself with our recommendation to remove the engine and get the cylinder

block remachined to correct this mis-alignment problem. ???

This was over 20 years ago but I think it was either No 4 or No 5 bore.

Best regards

Gary

The protusion of the liners should be around .004" with no more than .001" variation around the liner and between adjacent liners, (someone may have figures from a spec sheet, not my memory) check the top of the block where the liner sits, you will probably find it is eroded away and the liner is 'low' . The correct long term fix is to machine the block out and fit stainless steel inserts to carry the liners. Cat dealers have the tooling to do this work 'in frame' and its worthwhile paying their labour rates to get the job done properly for a long term fix.
This problem is the whole reason that the 'spacer plate' block was designed and first showed up on the D342 and D330/333 back in the 1960's.

Thanks for the replys. I was hoping to avoid pulling the whole engine out but it seems that might be the way to go. Ill pull the head again and do some serious measuring before I go down that track Thanks Jon

Hi Catsilver, for my education, how does the spacer plate work - is it designed to "soak" up variations between liner protrusions? Does it basically sit (and seal) between the liner and the head?
Cheers,
Neil

Hi Neil I think catsilver may have got it wrong in his reply. From what I can see on my engine ( and I had plenty of looks!) the liners protrude from the block about 10mm (7/16in) and are seated at the bottom of the block.The spacer plate takes up the distance from the block to the height of the liners then the head gasket sits on top of it with the gasket sealing on a lip around the liners. Small rubber coated tubes fit in the spacer plate for the water galleries etc.Im not sure why cat would change the motor this way but it would be one way of increasing the capacity of the motor or lowering the compression.For what ever reason in my opinion its a pain in the neck.

Hello Jonno

The spacer plate design does not change any of the engine operating parameters, compression etc.

It does add extra strength in the high load area of the engine. and removes the need to counter bore

the block which created stresses which can lead to cracking in the counter bore radius resulting in

dropping liners and coolant leaks etc.

Best Regards

Gary

Hi Gary, if I'm interpreting what you wrote correctly, do the liners in a spacer plate engine sit right on top of the block deck (as opposed to in a counter-bore) and thus the space plate "makes up" the height difference for the head to sit on?
CCjersey, that would make sense to have the spacer plate "counter-bored" as you say then the only maintenance would be to plane the block and the head, and then throw in a new spacer plate, which, if was available in different thickness (e.g. std, 20 thou, 40 thou) could return your planed block/head to standard.

Cheers,
Neil

The spacer plate does away with the need for a block counterbore to fit the liners in, the block is then flat and easier to manufacture accurately, the liner flanges sit on top of the block. They are not supported at the bottom. I'm not always right and most is from memory but O M puts me right on specs, I was with a Cat dealership for over 45 years. and still enjoy solving engine problems.