Mechanical head to hydraulic block.

[truckoSaurus08]

 Dag nabbit! Can't remember what you need to do to mate these together. Something with the oil passages? Filling in the hole in the block or head? I remember  reading something bout it but apparantly I suck at the search function. Reason I ask is because I found a  91 TD block at the junk yard and happent to have a mechanical TD head lying around. Worth the effort? Thanks for any help.

[riceatingrabbit]

i am currently running this same setup....

just plug the oil return in the block and the coolant passage in the head....and slap it together...

heres some pics of my stuff...

[truckoSaurus08]

Thanks alot! What would be the best ways to plug these passages?

[Rabbit on Roids]

thread the block and put a pipe plug in it with teflon tape on the plug for if you ever decided to go back to hydro.

as for the head, i would have the coolant passage welded closed. or do it yourself if you have a mig welder set up for aluminum and have decent skills. then knock the pre chambers out and get it milled and the pre chamber pockets fly cut.
the prechambers sometimes dont mill as easy as the head and then you have an uneven surface.

[macka]

My MIG set up for aluminum is a fair chunk of change. Its an add on spool gun. He is better getting the head tapped and get an aluminum plug made that will sit flush. Once the head is mated to the block the plug has no where to go. The head from welding will require that the block be annealled and re hardenned to spec.

[mean88]

I used a 3/8 aluminum pipe plug from summit racing.  It was an internal allen head plug, and went in nicely to the head.  Much easier than welding it IMHO.

[macka]

I used a 3/8 aluminum pipe plug from summit racing.  It was an internal allen head plug, and went in nicely to the head.  Much easier than welding it IMHO.

3/8-10mm pretty darned close.

[Rabbit on Roids]

what you guys dont realise is that there is a coolant passage in the head, THAT IS NOT ROUND OR TAP-ABLE! how are you going to get a round plug to fit in a holw that is more the shape of a triangle? thats why i said weld that hole shut. the head is mechanical, so there is no second oil return on the front. you gotta plug the hone in the block, not the one in the head. there is a coolant channel in the head that sits over the second oil drian in the block, so you would fill it up with water, and it would leak right into the oil. go look at the pics of the head and the block, look at the 2nd bolt hole from the left, on the front, where the drains are. there is only one coolant passage there unlike all the other spots that have 2 passages.

the head will either need to be welded or epoxied.

[MJF]

No need to do anything to head. Just plug the oil return hole from block and gasket. I used steel bar that i glued with locktite to block and piece of rubber to gasket hole. Worked fine.

[truckoSaurus08]

Hmmm... Lots of different opinions on what to do. From what I can see it looks like there really is no reason to block the coolant passage in the head if the one in the block is plugged. Or is there a reason? maybe it will leak? what about j-b weld in the coolant passage? I don't know maybe the best thing to do is try it for myself because there seems to be alot of differernt ways to make it work. Really apreciate all the input.

[Kantdrivefast]

what you guys dont realise is that there is a coolant passage in the head, THAT IS NOT ROUND OR TAP-ABLE! how are you going to get a round plug to fit in a holw that is more the shape of a triangle? thats why i said weld that hole shut. the head is mechanical, so there is no second oil return on the front. you gotta plug the hone in the block, not the one in the head. there is a coolant channel in the head that sits over the second oil drian in the block, so you would fill it up with water, and it would leak right into the oil. go look at the pics of the head and the block, look at the 2nd bolt hole from the left, on the front, where the drains are. there is only one coolant passage there unlike all the other spots that have 2 passages.

the head will either need to be welded or epoxied.

Weird then, how I managed to put a threaded plug in that hole when I put my mech head on my hydro block. I'm not proud of not blocking the oil return on the block, but I havent had problems yet, and im creeping up on 5000km so far.

No need to get so butt hurt.... you just dont get their internet sarcasm

[Rabbit on Roids]

ok, well i was suggesting what i would do. i would never leave a coolant passage with nothing on the other side of it. i have bad luck with head gaskets, i would have welded that extra coolant channel closed. but thats just me. and i do have access to a welder, and if i cant weld it with my welder, good chance my uncle can. sure, you can take a dremel and make the hole round, but i would rather weld it, i can do that way way faster than making a triangular hole round then threading it.