[Mikael Nielsen]

Piston 1 and 6 is in TDC on the pic.
That's got to be the fault? 😅

I don't know what brand/model gear is mounted sadly.

[steve25]

If in your photo that’s truly TDC for number 1 then your Cam is way out of time (by a number of teeth ) When number 1 is at TDC compression ( both lifters for 1 on the heel of the cam) number 6 will be at TDC also, but that will be exh so you will see the exh lifter for number 6 opening .

Your dash 8 heads will only give you at best a 8 to 1 compression, especially if the pistons are the stock ones with a chamfer around there top.

So the earlier heads you have a 1974 head casting off a 350 or 400 would have been a 4X casting.

A head with a 75 casting date off of a 350 or 400 would have been a 5C casting unless it was cast in very late 75 and then it could be a 6X casting .

What is the number they have stamped on them.

Do any of these other heads have screw in rocker studs like your 6X heads do?

[Mikael Nielsen]

Yeah, I think that definitely is the fault with the timing 😁.

The two heads that was mounted was both 6X with secondary number 8.

The extra heads are different.. One is 6X, and the other is something I can't see, but it's not 6X..
I have attached a photo.

Would you think I could mount the old ones again even tho the compression is very low?

Thank you so much for all the help

[P@blo]

That is a 75 5C head Mikael

[steve25]

The only heads I would bolt back on would be the pair that seemed to run without leaking coolant as in NOT being cracked .
That being said you still do not know if the valve springs they are set up with do not have excessive pressure .

It also seems that you don’t know what Cam is in the motor and in turn you do not know how much valve lift you have.

If I was to guess from your photos you have posted of the motors lifter valley and how much the lifters where up I would say that your Cam has less then .470” lift.

There’s a lot of if’s here that you still need to get around.
Are the heads cracked?

Are the all 16 valves in the heads sealing ?

Are all the lifters and Cam lobes good , saying they look good is not good enough as many folks have unfortunately found out.

There is a away to confirm that each lifter and Cam lobe are good and is a not too hard process that takes about a hour even if your slow and have to do it without a helper.

[johnta1]

I don't know what brand/model gear is mounted sadly.

It will need to be degreed in for sure.
Take the cam bolt off and see if the cam gear has more than one keyway cut in it.
If not the cam gear is installed way out of time to the TDC.

[Stan Weiss]

While most people talk about advancing or retarding their cam a few degrees this cam looks to be retarded 3 teeth. That is the major problem and needs to be fixed before worrying about combustion chamber size.

Stan

[steve25]

3 teeth!

So that’s like 17 degrees off from where it should be.

[Stan Weiss]

If some one has a cam gear can they count the number of teeth? I tried to count using the picture and got 48.

► (720 / 48) * 3 = 45 degree

Stan

[Mikael Nielsen]

I am very pleased the problem was found. Now I just need to correct it.
Do I "just" mount the dots in front of each other, or should I learn how to do cam phasing so they match properly?

I think I will send the X6-8 heads to a machine shop to do a cracking test and make sure they are 100%.
I will also figure out exactly which cam is mounted, so I know which springs I need.
(previously owner just told me they are a bit stronger than the originals).
I will also buy 16 new valves and make the shop mount them.

[Mikael Nielsen]

And maybe ask the shop to make the combustion chamber a bit smaller, so I get a bit more combustion. I don't know how much you can remove before it give issues tho.. Just thinking

[steve25]

The heads can be milled .060” but then the intake flange will also need to milled at least .045” and milling that amount might cost a lot, so check with your shop.

If there rebuilding the heads they might give you a better price on the milling.

Every .006” milled off of those heads removes 1 Cc from the chamber, so your 101 CC heads will be 10 CCs smaller.
This will get you a .5 more gain in your compression even though a valve job will sink the valves a bit.

[johnta1]

Do I "just" mount the dots in front of each other, or should I learn how to do cam phasing so they match properly?

Without a cam card or specs of cam, probably the best thing.

If reusing what's there, not hard to line up dot to dot.

[Stan Weiss]

Before you pick or modify any heads you need to

1) Measure everything and calculate what your current CR is.
2) Find out what the specs are for the cam that is now installed in the engine. (If you pull off the cam gear are there any markings on the front of the cam>)
3) Tells us what octane gas you plan on running.

Stan

[steve25]

By the way how do the blocks cylinders look, any ridge on top?

[Joe's Garage]

Originally Posted by Mikael Nielsen

Does this look right? 😅
Its in TDC

The BEST way to install and match them up is to have the dot on the CAM gear straight down and the dot on the CRANK gear straight up. That way they are close together and it's REALLY easy to match them up.

Once they are installed DOT-TO-DOT, rotate the crankshaft one full turn and the engine will be at Top Dead Center (TDC) on cylinder #1.

Good luck!

[Mikael Nielsen]

I will try to take of the cam gear and see if I can find any useful information besides it's a stage 1 cam.
As soon as I have some information, I will order new valves so I can match it up perfectly.

I am planning on running octane 100, as I live in Denmark and it's easy to come by.

The cylinders has been honed and there is new pistons mounted by the previous owner. One piston is pointing in the wrong direction, so I will take them all out to be sure everything looks good.

[steve25]

A piston being on the rod wrong is not the end of world, but if that rod is not on the crank journal right with the off set of the bearing facing the crank cheek then that’s an issue!

[Mikael Nielsen]

I have now aligned the crank and the cam as good as possible, and is now trying to turn the piston.

While removing, I noticed the upper rod bearing having some small scratches. Are these okay? Or do I need to replace all of them?
The previously owner replaced them all, but I am not sure if it's damaged.

Picture attached

[tom s]

When you take the heads to the shop,have them pressure test them beside magg.Tom