This is my first time replacing a gasket. My order has arrived, 2 steel & one copper head gaskets.
1927 running a Z head.
The car had a valve replace before I purchased it in Feb and gasket was reused. I'm hoping the head was cleaned and checked then.
What I'm asking is for any hints about the process before I start. I undone the studs today but haven't lifted it yet, I'm going to town on Wed and will take a head bolt to ensure I purchase the correct bottoming tap.
So I plan to remove the head, clean it up, clean the bolt holes and check thread depth. I will number the studs and return to the same holes using the washers.
I will check the fitting of the two types of gaskets and post some pics.
Whats the best way to check if the head & block is straight?
Any hints on the refitting process?
Kevin, the Z head sometimes has some problems with the head surface not quite matching the gasket. There's not a lot you can do about that, but it is helpful if you turn the motor over so two of the pistons are at the top of their travel. This will help to position the gasket in an optimal position. Once you have all the bolts in place, crank the motor over to make sure you have no clearance problems. Then tension down as required.
I have never used other than the copper head gasket with a Z head, liberally coated both sides with Aluminised paint as a sealant. Others will have differing opinions.
Allan from down under.
I have had better luck with the steel gasket on a Z head. I had two failures with the copper gaskets an then tried the steel one which is still running. Look at the copper gaskets close when you take them out of the package. Many of them are defective when new.
I put my first T engine together in the mid 60's with the help of an old ford mechanic. He had two head bolts with the head cut off and a slot cut in the top for a screwdriver that we screwed in the block a little ways and slipped the gasket and head over. The cut bolts keep everything lined up till you get the bolts in. Then remove the cut bolts and install the last head two bolts.
To ensure the new head gasket works properly you must make sure that all surfaces are perfectly clean and dry. I use scotch brite wheels to clean everything, then vacuum the cylinders and head bolt holes to remove any residue.
I also use dull aluminum enamel as a sealant. It has never failed me.
As with any head you need to be sure there is adequate coolant when starting the car. Let the car run until the coolant gets warm, say five minutes. Then let the engine sit overnight. The next morning re-torque the head bolts. After that final torque do not touch them again!
On a '27 you'll have to raise the 2 rearmost head bolts and clip them up w/spring type clothespins or similar before removing the head and then put them back in the head before re-installing the head.
Using 2 studs as Bob S. mentioned is a good way to keep everything lined up.
Align the gasket as others have posted, 2 pistons up, coat liberally with Copper Coat or alum spray paint that has lots of metallic content. That will seal little defects in surfaces.
The take care in the bolting tightening sequence.
Many gasket blow at the tiny interface between the center of the cylinders.
Tightening first from the center in sequence, forces the head flat in the center first, which squishes the middle portions of the gasket first, then go outboard in sequence to get the head to flatten the rest of the gasket. Torque to 45-50lbs. or so. Then run the motor to warm, let it cool down, and re-torque to the amount you choose. The cool down necessary for the alum head to show any tightening loss.
I hope your steel gaskets are not the ones with silicone sealant applied. I tried one and it failed. Have two more brand new ones for sale. Going back to copper.
Steel or copper make sure you put the correct side up! See Dan's 2ed photo. The water passage holes are different size front and rear.
It's good practice to clean out the threads with a tap and if you have never checked your bolt length before set the head on the block without the gasket and run the bolts down just to make sure one doesn't bottom out.
Alan - good advice I'll try that before I tighten.
Brendan - I'm tempted to go with the steel also but will review once I lined them up.
Bob - That's a great idea which I definitely will do as I have a spare set of studs. Thanks
Royce - that makes sense, I have already made up a suction piece for my Lux. That is interesting that you suggest to only re-torque them once the next day when cold. Some people say re-check after some time as well?
Ken - didn't realize that, Ta
Dan - That's great, the pics always help.
Terry - I had a silicon gasket on hand but was advised on another thread and then read the label "can't be used with aluminium heads", hence I had to order the others.
Mark - Good point
Gene - Yes that was my plan as it makes sense to ensure the torque setting is actually working, thanks.
That's a great help guys thanks. What about how to check if the block or the head are warped?
I'm not planing to use Copper spray as it was $32 a can last time I searched. But I wonder if the Aluminised paint you refer to is cheaper. I'm going to town tomorrow so will have a look.
On a similar note I interested in your feedback - my speedster is a stock 26 and has been in storage for approx 7 yrs before I brought it a couple of months ago. It was rebuilt by the previous owner but had been well used before his death and car parked up. Following the Coupe blowing the gasket 3 weeks ago the cars have been swapped around and the speedster has been driven every day for about 30 mins doing heaps of road tests as I play with a 6v fuel pump etc and trying improve the hill climbing performance. It's been good fun and is currently running perfectly, I'm very pleased. Anyway I thought I would check the head studs yesterday since I'm in head gasket mode and they weren't tight! I used a original Ford spanner to start and could turn them easily. I then ran the torque wrench around them in sequence 3 times tighter as I went and stopped to 45 psi in case my recently purchased 2nd hand torque wrench isn't accurate. Some studs took a good half turn. Car has a steel head but I'm surprised it was so loose with no problems....yet?
I've used Krylon and other brands with equal success. It is sprayed on both sides of the gasket with the gasket hanging from a piece of wire. Let it just dry to the touch, then install the head gasket.
When you clean the threads with a tap be sure you use a bottoming tap so it cleans all the way to the bottom of the hole.
If you put New Zealand after your name, other posters will realize you can't run down to Menards or Home Depot like we can here in the States.
A bottoming tap will not clean the junk at the bottom of the hole all that much. I use a drill smaller then the threads in the hole and twist it by hand then vacuum the crud out, then clean threads, then vacuum again.
I'll look for something similar Royce, thanks.
Gary as listed in the opening I'm going to buy a "bottoming" Tap but thanks for the probe and Mark your correct the crud in the bottom needs to be broken up and removed first.
Pulled the head this arvo and it sure is blown. I sat all three gasket types on the head and they all fit well, either can be used but was surprised the silicon unit was actually the most accurate fit.
Kevin, yesterday (Monday) you said: "Anyway I thought I would check the head studs yesterday since I'm in head gasket mode and they weren't tight!"
A week ago you said: "I undone the studs today"
Maybe that's why they weren't tight?
While you have the head off it's a good time to check/clean the 5 (1/4") steam holes in the head and block.
Ken I have two T's. If you read it again you will clearly see I was referring to my other T (26 Speedster & not the 27 Coupe that the thread began with). Different car, was surprised to find the head studs loose.
I took the Coupe head to town today and found a machine shop recommended by the local vintage car club, he took a look and said it was in poor shape and pointed out why and where. The good news is he dropped his other jobs since I was from out of town and machined 20 thou for me while I was shopping and had it ready before I drove home! Didn't get to him until midday and he didn't know I was coming. Great service.
Ken I have had a quick check of the steam holes yesterday and they look clean but will re-check before cleaning up.
Found some pitting on the block around No 1 today plus looks like something has banged around the cylinder at some stage! Head shows the same marks!
I measured the gaskets and Copper is slightly thicker than the steel so i'll use that to help take up the pitting. Might need some spray. Block needs a skim really but not this time.