Retorque question

M

Mike Quilter

Low Mileage
I have a project X1/9 in NZ with a Fiat Tipo 1.6 engine in it. The PO had had the head reconditioned and put back on but couldn’t get it going so he gave up. I have got the engine going and the car driving well so I want to retorque the head. I know I need a pair of special wrenches from Midwest Bayless to do the job, and in the book it says to torque the head down using 20nm, 40nm, +90, +90. I can only assume that was done correctly I hope. My question is how to Retorque the head now that I have got it running? Normally I would back a bolt off a quarter turn and then bring it back up to whatever number was required, but in this case I don’t have a final number?? Anybody done this before me?
IMG_4168.jpeg
 
Mike Quilter said:
I have a project X1/9 in NZ with a Fiat Tipo 1.6 engine in it. The PO had had the head reconditioned and put back on but couldn’t get it going so he gave up. I have got the engine going and the car driving well so I want to retorque the head. I know I need a pair of special wrenches from Midwest Bayless to do the job, and in the book it says to torque the head down using 20nm, 40nm, +90, +90. I can only assume that was done correctly I hope. My question is how to Retorque the head now that I have got it running? Normally I would back a bolt off a quarter turn and then bring it back up to whatever number was required, but in this case I don’t have a final number?? Anybody done this before me?View attachment 83275
Click to expand...
What type of head gasket did he use? The retorque, or not, really depends on the construction of the HG.

Great looking car by the way. Any more pics of both the car and the engine bay?
 
Hi knead, thanks for the reply. I don’t know what sort of head gasket it is cause the previous owner put it in. I don’t know much about the engine but it has a reconditioned head and good even compression. The old guy I bought it off didn’t know the engines history. It has twin Webber dcnf 40’s! I’m away at present but will put up a couple more pics when I get home. Still don’t know what to do about the retorque.
 
Mike Quilter said:
Normally I would back a bolt off a quarter turn and then bring it back up to whatever number was required, but in this case I don’t have a final number?
Click to expand...
Worth a read here for the different retorque methods for the stock X heads, but as mentioned, it depends on the gasket type for your TTY case. If you did need to retorque though, then follow the fiatfactory advice in the linked thread, as per the X service letter:
1712432758085.png
 
Thanks Ics19, that helps a lot. I don’t know what sort of head gasket it is and I don’t know how he torqued them down, to 62ft/ibs or 40,+90,+90. They are M17 bolt heads so that means M10 bolts I think, so I might just back them off a 1/2 and then bring them back up to 62 and see how that feels.
 
Hi Mike,
If you do that, I don‘t see hoe that could improve the current situation.
In my book, that can only make matters worse.
I would either leave it as it is or set your torque wrench to 62 and give them a click.
The bolts are supposed to be TTY, and AFAIK, you don‘t back them off and retighten.
On the contrary, once you back them off, most sources would say you have to replace them.
BTW, what wrench size are the bolts?

I also have a Tipo engine with TTY bolts and don‘t retorque. I run 11.5:1 CR on two engines successfully.
 
Hi Ulix, thanks for that, interesting, a bit technical for me but learning fast. I don’t know what sort of bolts were used, so maybe best to let sleeping dogs lie and get on with the rest of the car. The old previous owner put the head on and he was a long way out on the cam timing and had the rotor pointing at the wrong spark plug so no guarantees that he has pulled the head down correctly. I guess I’ll find out one day.
 
I am not sure which bolts you are using but Midwest Bayless gives a separate instruction sheet when using their bolts...
 

Attachments

  • IMG_6979.jpeg
    IMG_6979.jpeg
    356.7 KB · Views: 22
You must log in or register to reply here.
Back
Top