-
Disassembling veggie block w/ piston slap- rod length?
by
oblique
on 22 Mar, 2023 20:22
-
-
#1
by
ORCoaster
on 22 Mar, 2023 22:37
-
What are the head cam to lifter clearances like?
With that much mashing on the tops of the pistons I would venture a guess that they were way too tight.
-
#2
by
oblique
on 22 Mar, 2023 23:02
-
I wish i knew...i only received the shortblock. Seller 'doesn't know'.
The block is hydraulic...you're saying it mightve been run with a mech head somehow?
Wrong cam? Timed badly? Valves keepers too high?
But yeah it does look like theres been repeated contact ...i figure this might be more plausible on a hydro head since the oil pressure could soak up some of the.force of repeated contact.
-
#3
by
fatmobile
on 22 Mar, 2023 23:57
-
Those marks on the pistons are due to a broken timing belt, it wasn't running with the pistons slapping the valves.
And this one was going down the road pretty fast when it broke.
Nice find, a hydraulic TD block.
That means you can use a metal head gasket from a 1.9 AAZ block.
Or it's pretty easy to put a mechanical head on it, with a regular head gasket.
Kinda hard to read the numbers but it looks like original pistons so a second over bore to 78mm might get rid of all the rust pits.
Or since it's a hydro block you could put 1.7 pistons into it which are 79.5mm.
I've seen an I-shaft thrust surface break off like that before.
I think it's from a bad injection pump mainshaft bearing, that made the belt ride to the outside.
Then it had to skip across the I-shaft pully to get back in line with the crank sprocket.
That pulls the shaft out, then the oil pump pulls it back to ride against the thrust surface in like normal.
Bang,bang,bang break.
What's in the head bolt holes?
I would think the rod measurement would be from hole to hole.
-
#4
by
oblique
on 23 Mar, 2023 13:41
-
I've seen other TB broken pistons...nothing even close to this...these impressions are DEEP and on all the pistons...cam kept rotating after the break?
the pistons are marked 76.48 and are OE. The skirts dont actually look too bad and the ridges on the bores aren't terrible...I will try to bore this 0.5 over...I am finding 1.0mm pistons are a bit harder to come by.
The stuff in the head bolt holes is a silicone adhesive type substance, like RTV. With fine grit mixed in. Where the holes are empty there there is some rust...I will need to find a long tap to get those cleaned up.
I'll post more measurements of the rods and general condition of the block after I clean it up better.
i will be going with a hydro head...I have been collecting them and have found some decent ones.
Thank you!
-
#5
by
oblique
on 23 Mar, 2023 23:36
-
-
#6
by
fatmobile
on 23 Mar, 2023 23:56
-
I don't think I've ever noticed that little hole back in the cavity before.
Looks like it's plugged with a rivet,.. so I'm thinking maybe an oil passageway.
Like the one behind the 9/16" plug above it and to the right,.. only smaller. Also close to the oil pump so it might be a passageway.
The one down by the trany mount hole might be an oil pan bolt hole that came through the top.
You are right. I can't find any good pistons that are 1mm over either. I'll keep looking for ya. I have a spare set of new 1mm over pistons but they are kolbenshcmidts and would cost $400 for the set.
-
#7
by
oblique
on 24 Mar, 2023 13:06
-
Any ideas to remove the dipstick? Just heat it up and hammer some more?
Those holes by the vacuum pump are a bit concerning to me...i will try blowing air through them to see how theyre connected. On the other NA block (painted black) the rivet does look factory but it doesnt have the other hole like this TD block.
I measured the rods hole-to-hole and they are all within .01mm of each other...98.63mm. Is this even possible with the amount of force those pistons took?
-
#8
by
fatmobile
on 24 Mar, 2023 13:33
-
I'm thinking just heat and beat for the dipstick.
I think they usually are hard to get out.
I broke a belt once and the pistons had some bad marks,.. not quite as bad as yours.
The rods were still good.
How much are you paying for the pistons and what brand are they?
-
#9
by
oblique
on 27 Mar, 2023 00:11
-
-
#10
by
libbydiesel
on 30 Mar, 2023 11:31
-
Did you try getting pistons from Spareto? I got a couple sets a few months ago for fairly cheap. I just checked and they have them readily available.
-
#11
by
RustyCaddy
on 31 Mar, 2023 18:31
-
Not trying to hijack this thread but...
Fatmobile, you mentioned above that since Oblique has a hydraulic 1.6l block it can be bored to take 1.7l pistons. I have a mechanical 1.6 that has cylinder ridges but is already bored out to 77.51 pistons. So, KY engine code pistons are not an option from what you have written?
-
#12
by
fatmobile
on 01 Apr, 2023 20:01
-
The 1.7 pistons won't fit through a mechanical head gasket.
With a hydraulic block you can use a metal 1.9 AAZ head gasket.
They will fit through that.
There is also the expensive option to use a special custom-made gasket that has holes big enough for the pistons but without the extra oil drain hole.
-
#13
by
RustyCaddy
on 01 Apr, 2023 22:39
-
Thank you, wish i had thought of that. The local machinist said he couldn't bore the block out that far, now i understand that he was probably thinking ahead and taking the head gasket into account.
-
#14
by
fatmobile
on 02 Apr, 2023 12:56
-
Nah, he probably just thought the walls were too thin.
He can bore it out that far and use a custom gasket.
I have a block I'd like to do that to also but a $200 gasket is a little high.
Maybe we could get a discount for 2 of them.