B7100 hard to start

[Brandonallen]

Could be, But how good is the cylinder bore? New rings won't seal very good if the cylinders aren't round.

Brand new sleeves, bored to spec at machine shop

 

[eserv]

Brand new sleeves, bored to spec at machine shop

Sorry! I just went back and reread your original post! Have you checked the piston to cylinder head clearance yet?

 

[Brandonallen]

Ok, there is extra info embedded in your statement:
If material was taken off of the block that amount is super important for mutiple reasons.
Head gasket height would be one reason you could have an issue.
Also the a the amount of material taken off the block needs to be added as a shim to the shims under the injection pump as that sets the timing (Super Important).
Did all of these happen?
Rods checked for length?
Rods installed in the correct direction?
Pistons installed in the right orientation?
Ring installed in the proper direction?
Timing gears double checked for proper alignment.

There was no material taken off at the injection pump mounting surface. He made a point to tell us he did not take any off there because he knew it would mess up timing.
Timing gears are correct, we did not check rod length as I did not though that was possibly a concern because the engine was running great just had a lot of blowby(broken ring). Piston ring gaps were oriented correctly. Ring gaps were checked also. Did not see any orientation on pistons, no arrows or marking, and all oil ports are symmetrical

 

[Brandonallen]

Sorry! I just went back and reread your original post! Have you checked the piston to cylinder head clearance yet?

I stuck some solder in there earlier (electrical solder) is all I had and it hardly made any impression at all in it. I’m not sure what correct solder would be. When assembling the bottom end the pistons did not protrude from the deck height

 

[eserv]

I stuck some solder in there earlier (electrical solder) is all I had and it hardly made any impression at all in it. I’m not sure what correct solder would be. When assembling the bottom end the pistons did not protrude from the deck height

The clearance should be about .024" you would need solder larger than this to measure it.

 

[Brandonallen]

The clearance should be about .024" you would need solder larger than this to measure it.

What do you recommend? I’m all ears trying to get to the bottom of this

 

[eserv]

What do you recommend? I’m all ears trying to get to the bottom of this

ordinary solder that is greater in diameter than the expected clearance ( .025) insert it into the cylinder a small amount through the injector port and precup then turn the engine a complete revolution. remove the solder and measure the squashed thickness.

 

[North Idaho Wolfman]

I stuck some solder in there earlier (electrical solder) is all I had and it hardly made any impression at all in it. I’m not sure what correct solder would be. When assembling the bottom end the pistons did not protrude from the deck height

Plumbing (soft) solder is what I use.

 

[Brandonallen]

ordinary solder that is greater in diameter than the expected clearance ( .025) insert it into the cylinder a small amount through the injector port and precup then turn the engine a complete revolution. remove the solder and measure the squashed thickness.

I will try to get some thicker solder and get it rechecked within the next day or two. If it is too large could I just get an oem head gasket and torque down then check for smooth rotation? Or does it need a certain amount of clearance between valves and piston

 

[eserv]

I will try to get some thicker solder and get it rechecked within the next day or two. If it is too large could I just get an oem head gasket and torque down then check for smooth rotation? Or does it need a certain amount of clearance between valves and piston

The spec. is .022 to .027" I would not be satisfied until I had it within that spec. It is the clearance between the head and the piston between the valves. The valves will have greater clearance.

 

[Brandonallen]

The spec. is .022 to .027" I would not be satisfied until I had it within that spec. It is the clearance between the head and the piston between the valves. The valves will have greater clearance.

I agree, should I back off the valves before I test with solder to prevent the valve from
Opening and causing a bad measurement

 

[eserv]

I agree, should I back off the valves before I test with solder to prevent the valve from
Opening and causing a bad measurement

Don't have the solder at the valves, but even if you did the valves never come that close to the pistons ( if the valve timing is right)

 

[North Idaho Wolfman]

I agree, should I back off the valves before I test with solder to prevent the valve from
Opening and causing a bad measurement

No need as @eserv said.
The valves won't change your measurements no matter how the valves move.

 

[North Idaho Wolfman]

I will try to get some thicker solder and get it rechecked within the next day or two. If it is too large could I just get an oem head gasket and torque down then check for smooth rotation? Or does it need a certain amount of clearance between valves and piston

If you get a bad measurement then you'll have to pull the head then do other checks to make sure you know where the issue is exactly.

 

[Brandonallen]

If you get a bad measurement then you'll have to pull the head then do other checks to make sure you know where the issue is exactly.

I just got a response from the aftermarket supplier where we got the head gasket. They said it’s 1.6mm. According to the manual the torqued thickness of stock is 1.05-1.15mm plus the shim of 0.2mm if needed. Seems like my head gasket is 0.25 or more too tall. Any idea how much a gasket compresses when torqued?
still planning on getting correct solder to double check but seems as if that could be our whole issue here

 

[North Idaho Wolfman]

I just got a response from the aftermarket supplier where we got the head gasket. They said it’s 1.6mm. According to the manual the torqued thickness of stock is 1.05-1.15mm plus the shim of 0.2mm if needed. Seems like my head gasket is 0.25 or more too tall. Any idea how much a gasket compresses when torqued?
still planning on getting correct solder to double check but seems as if that could be our whole issue here

There is no way for me to know how much quash that head gasket has.
But .4 mm squash seams like a stretch, that's a lot of material.
You DO NOT need a shim as that only makes things thicker, you need thinner.

 

[Brandonallen]

There is no way for me to know how much quash that head gasket has.
But .4 mm squash seams like a stretch, that's a lot of material.
You DO NOT need a shim as that only makes things thicker, you need thinner.

Yes sir I agree. I was meaning once I get an oem head gasket if I would need a shim with that to give me the proper clearance. Still planning on doing the fuse test as soon as time permits

 

[Brandonallen]

There is no way for me to know how much quash that head gasket has.
But .4 mm squash seams like a stretch, that's a lot of material.
You DO NOT need a shim as that only makes things thicker, you need thinner.

Just did the solder test. It is 1.2mm so I believe that is 0.6mm to much clearance. Is that right? How Do I know if I only need an oem head gasket or shim also?

 

[North Idaho Wolfman]

Just did the solder test. It is 1.2mm so I believe that is 0.6mm to much clearance. Is that right? How Do I know if I only need an oem head gasket or shim also?

I've said it before and I'll say it again, you do not need the shim!
But just to prove it, get the head off then measure the piston height to the block deck and you will have an exact answer.

 

[Brandonallen]

I've said it before and I'll say it again, you do not need the shim!
But just to prove it, get the head off then measure the piston height to the block deck and you will have an exact answer.

i understand what you are saying, my current head gasket is 1.6mm… once I remove it and install the factory head gasket I was unsure if I would have the proper clearance 0.6mm or if I would need a shim to get enough clearance. Because both the cylinder head and block surface were machined.
per the book factory gasket is 1.05-1.15 after torqued.