Low compression after engine rebuild,1987 2F.

[Output Shaft]

The specified timing of 7° BTDC is only valid below 950 rpm with the vacuum advance cut off. As the engine spins faster, the centrifugal advance starts coming into play, and at higher rpms, the vacuum advance kicks in.
Nothing can be deduced checking timing at 1800 rpm.

If timing below 950 rpm is on the timing ball (7° BTDC) or close to that. The timing of the engine is set correctly.

 

[Rainercar]

Removed the timing gear and checked the timing of the cam to the crank and it is correct. The cam is installed properly.
Spoke with my cam grinder, Dimitri Elgin, who is one of the most knowledgable cam/engine Guru this side of the Rocky Mountains.
After guiding me thru the timing procedure, (which confirmed, how I thought it should be done, and everything checked out correct). The cam gear was never removed from the cam for polishing and could not be backwards.
The crank gear was removed and re-installed correctly, only goes on one way (key), shoulder toward engine.
When installet the gear surfaces are inline.
That only leaves the distributor timing (for the overheating problem) and the leak-down test to find, what and where the leak is coming from.
I will put everything back together tomorrow, and check the vac system and carburetor settings, before starting engine again...

 

[Rainercar]

A basic timing question:
On the flywheel, what is the line for,just after the timing circle (ball) ?

 

[Rainercar]

A basic timing question:
On the flywheel, what is the line for,just after the timing circle (ball) ?

Is the timing mark TDC and the circle (ball) 7 degrees BTDC ?
I have a timing light with an adjustable light. I adjust it, until the line lines up with the pointer and read the actual advance off my timing light.

 

[micruz60]

The line is TDC, and the bead is 7* BTDC

 

[Rainercar]

I finally got all my vacuum hoses connected, got the idle down to around 900 PRM and ran the motor a short while to set the timing., overheated right away.
Checked compression still low, no change.
Did a leak down, still same, 35,23, 25 25 28 25. no noticeable hissing from anywhere.
Increased the pressure to 30 PSI with an attachment w/o schraeder valve, getting noticeable hissing from valve cover and dip stick hole.
So, it looks I have blow-by around the rings. No idea, why.
I put new rings in, they had .025" gap clearance, more that I wanted, (specs are .008 to .015, but Haynes said, not a problem, unless its more than .040" These are Hastings rings, good brand.
Maybe I goofed on checking the bore size. I used a good dial bore gage, presetting is with calipers mounted in a vise. Should have used a mike.
But the bores were only .0015 to .002 over the specs by this measurement, no notieable wear at all, no ovality, no taper from top to bottom.
So I decided to not re-bore and use new pistons to save money... Bad move.
I have decided to take the engine out and tear it down completely, find out what is wrong. I will have the block machined and get a set of new O/S pistons etc.
Any recommendations on what brand pistons to use ?
Also, can I re-use the head gasket ?
Another problem I noticed during the brief run is, the exhaust manifold connection at cyl 1 is "spitting", indicating, that the 2 seal rings, that look like the piston rings are bad. Will replace those while I am ad it, both front and back...
Lots of additional work and probably another 1K in money... Should have done it right the first time...

 

[Shes Mad]

Just a couple things since you are tearing it down. Check that head gasket, and make sure the rings weren't installed upside down

 

[Output Shaft]

I personally wouldn't reuse a head gasket. But maybe that's just me. Use the Toyota head gasket

 

[Rainercar]

Just a couple things since you are tearing it down. Check that head gasket, and make sure the rings weren't installed upside down

Thats exactly what I was thinking. Based on my dimensional checks on the piston bores etc I should not have so much blow-by, unless I installed the rings upside down or broke them on installation (unlikely).
I will know, once I have everything down to the bare short block.

Still searching for a reasonably priced set of piston brand.
Leaning toward ITM pistons from Rock Auto. Does any body ave experience with their piston quality ? What other options are there, besides OEM ?

 

[TobyB]

Sorry if I missed it- how did you hone the bores before re- assembly? In my youth I messed that up once...

I haven't found any brand pf piston still available except ITM, and they aren't very... confidence- inspiring.
I used them, and afterwards, really wished I'd spent for OEM. Yes, it's a big difference,
but compared to the cost of the whole engine, not a big percentage.

I have not had problems, but I don't have many miles on the engine.

t

 

[gregnash]

@TobyB What specifically isn't "confidence inspiring" about the ITM pistons? Curious for posterity sake.

Also, @Rainercar have you done any further teardown and analysis????

 

[Rainercar]

Well, to up-date my engine rebuild:

Removed engine from car and dis-assembled down to the short block. When removing the head, I noticed, that the top of the pistons/combustion chamber was oily. Valves looked OK, dry.
The head gasket (OEM) sealing area showed oil at the narrow ares between cylinders. Not sure, if its due to not sealing at that area. (During previous pre-assy, I checked flatness in that area, found it to be good, could not get a .002" feeler gage under a straight edge.)
Oil could also have come from leaking out of upper head, while removing, so that observation is inconclusive.
The gasket is still stuck on the head and I left on, for the Machine shop Tech to inspect and investigate.
I spoke with (2) local shops to help me find the route cause.
The first shop wanted to check the cam in place with cylinder #1 still in engine. They suggested to check C/L of intake valve on the cam. (109 degrees).
I left all pistons in the engine, except removing pistom #2, in order for me to verify condition of bore, rings etc.
Re-checked all bores, presetting my dial bore gage with a mike, rather than caliper.
Bore sizes are w/i acceptable limits, less than .002" over nom. size of 3.7007 (3.701").
Inspected piston #2. Rings were installed correctly, orientation of gap on ring 1 and 2 not exactly 180 degrees. (I had installed them at 10 o'clock and 4 o'clock respectively to front notch.)

So far, no smoking gun.

First shop could not take my job, due to their back-log. (Best 3 weeks, worst 2 month lead time.)
Found another shop (Good reputation-Paul's Empire Head Shop in Santa Rosa, Ca). They have the block and head right now.

I discussed the problems i am having and asked them to do the following:
1. Verify timing of cam in the engine in relation ship to the crank.
2. Verify that cam gear is on cam correctly- no sheared woodruff key.
3. Check bores for size, surface condition of honing marks
4. Check all piston rings etc
5. Dis-assy completely, including removing of cam bearings
6. Bore and hone cylinder bores to next size, hopefully +0,50 MM (+.020")
7. Boil block
8. Select new pistons and install on old con. rods ( My choice is 1. Sealed Power, 2. ITM 3. OEM) They will assist me with selection, depending of what's is available.
(Rock Auto lists ITM at $33/ea, also saw some Sealed Power on Ebay for $73.00. Not sure, what OEM prices are...)

So thats where I am right now. Waiting for a report from my Machine Shop, what they found.

When I spoke with the shop, who re-ground my cam, he said I should set my valve lash to .012 intake and .020" exhaust. tighten if the make noise. That is based on the grind. (Standard). Not sure why, the book calls for .008" intake, .014" exhaust. That's what I set them to.
I will still investigate that further, as to why he wants more clearance.

To be continued...

 

[gregnash]

Wonder why the last shop said to set the lash at .012 and .020??? Seems a little strange as even cold you should only be setting them at something like .010 and .016 respectively... So even with your new settings from the shop they would be SUPER loose.

Hope it is something stupid cheap and random.

 

[LAMBCRUSHER]

Sorry if I missed it- how did you hone the bores before re- assembly? In my youth I messed that up once...

I haven't found any brand pf piston still available except ITM, and they aren't very... confidence- inspiring.
I used them, and afterwards, really wished I'd spent for OEM. Yes, it's a big difference,
but compared to the cost of the whole engine, not a big percentage.

I have not had problems, but I don't have many miles on the engine.

t

I will knock on wood...I've HAMMERD on the ones they used in my 2f...about 20-24K or more, hard, hard, bumpy miles, rockin 3500 and more.


you can set lash loose-ish(ie .020" )to start and tighten to quiet(running lash = ID loose valves via feeler while running and note valves needing adjusting; shut down and adjust; refire and retest; repeat as needed...), although, that seems like a large window...how steep is the cam???
there is alot going on with cam timing and compression...

 

[Rainercar]

I just spoke with the machine shop.
They checked the head (which was rebuild to the tune of 1,500 by a shop near me...)
Found, that the intake valves were leaking. Exhaust valves are OK. I took the head back to that shop, they will re-inspect and correct,
most likely by lapping the valves to suit. They also stated, that the valves should be initially looser during break-in. As I said before, I set the valves as per Haynes to IV .008". EV .012". They said its too tight for break-in. TBD what I will set them to initially...

Got the cam grinding spec's from Elkin:
232 deg seat (? - cant read handwriting)
109 deg lobe centers
cam lift right about 250 int
255 exh
rise
lobe area 17.6" int ramp .013-.014" tall 020 050
220 188
lobe area 18.2" exh ramp .017-.018" tall 227 191

Not sure if that makes sense, cant read his hand writing very well... But for those of you, who know cams, here it is.

I passed this info on to the machine shop, they will check everything and machine the engine block next week.
Hope to have it back w/i 2 weeks and start re-assy. (They cant assy, due to their backlog. (all machine shops are busy around here ...)

Still not sure what piston brand to use.. Toyota dealer said: No longer available. So I have to go with aftermarket...

 

[roscoFJ73]

Still not sure what piston brand to use.. Toyota dealer said: No longer available. So I have to go with aftermarket...

Try sending Engines Australia an email. They have some high quality engine parts for landcruisers. A few of the guys on the diesel forum have used their engine kits over the years , including me. The owner of the company is a mechanical engineer who has high quality parts made in Taiwan to his specs.
Many Taiwanese parts/tools are very close to Japanese quality these days.

 

[Rainercar]

Try sending Engines Australia an email. They have some high quality engine parts for landcruisers. A few of the guys on the diesel forum have used their engine kits over the years , including me. The owner of the company is a mechanical engineer who has high quality parts made in Taiwan to his specs.
Many Taiwanese parts/tools are very close to Japanese quality these days.

 

[Rainercar]

I will send them an email... I saw some pistons on ebay from Australia, wonder if its the same company...

 

[Spike Strip]

You can't reuse the Head Gasket, it's already been compressed. NHK/Pillar is the OEM and you can find it for about $80 to save a little. I personally use and like the stock profile cam to avoid these issues.

Here's a thread on different profiles... Camshaft

You can get a good American-made Melling/sealed Power for a 2F for under $200.

If all else fails, you could take the engine to Georg @orangefj45 in Stockton and let him figure it out....

Valley Hybirds

Valley Hybrids | Facebook

 

[Rainercar]

You can't reuse the Head Gasket, it's already been compressed. NHK/Pillar is the OEM and you can find it for about $80 to save a little. I personally use and like the stock profile cam to avoid these issues.

Here's a thread on different profiles... Camshaft

You can get a good American-made Melling/sealed Power for a 2F for under $200.

If all else fails, you could take the engine to Georg @orangefj45 in Stockton and let him figure it out....

Valley Hybirds

Valley Hybrids | Facebook

I agree, about the head gasket... didn't look too good anymore, when taking the head off...

I too heard good things about sealed power pistons.
Will give them a try, once I know the final bore size. May use their rings, too. Didn't like the Hastings big ring gap of .025". But then again, that may have been due to piston bore size...(+.002" over nom.)