Question about 22RE and broken timing chain

Hi,

Broke my chain today on my '90 PU. I have 185,000 mi on it, and I
actually changed the chain 20k miles ago when the guides failed!
(Needed a new timing cover too as the chain wore through the original.)
Replacement chain was purchased at Schucks: did they sell me a cheap
brand?

Anyhow, the chain snapped while starting the engine, and the engine
died as quickly as it started. My question: what are the chances of
valve damage? How can I determine/test for damage?

Thanks,

Scotty

Scotty wrote:[color=blue]
>
> Anyhow, the chain snapped while starting the engine, and the engine
> died as quickly as it started. My question: what are the chances of
> valve damage? How can I determine/test for damage?
>
> Thanks,
>
> Scotty[/color]

I should add that I pulled the chain cover without removing the head .
.. . I wonder if a compression test would be diagnostic?

[email]sidneybek@yahoo.com[/email] wrote:[color=blue]
> Scotty I assume you only replaced the chain,guides and cover? if so
> your timing chain tensioner could be worn,read below for full details &
> do a leak down test to see if you bent the valves but I suggest you
> remove the head for full inspection and to prevent headgasket leakage
> in future:[/color]

Hi Sidney,

Thanks for the great info! I was just deciding to replace the chain
with a Genuine part as opposed to a mystery brand: I'll assume the
higher price will assure longer life! Anyhow, I'll check into the
links you provided.

As for the tensioner, I previously installed an aftermarket kit, and I
believe it included all parts. (The guide had worn out, and the chain
worked throught the housing, so I ended up replacing the cover and all
other parts. Since all parts were changed about 30k miles ago, I was
suprised to have the chain break last week!)

To clarify, is it your opinion that valves get bent EVERY time a chain
breaks, even if it happened at startup and ran at low rpm for literally
1 second?

Thanks again,

Scott

"Scotty" <canthespam@cableone.net> wrote in message
news:1159202266.939676.31500@h48g2000cwc.googlegroups.com...[color=blue]
>
> [email]sidneybek@yahoo.com[/email] wrote:[color=green]
>> Scotty I assume you only replaced the chain,guides and cover? if so
>> your timing chain tensioner could be worn,read below for full details &
>> do a leak down test to see if you bent the valves but I suggest you
>> remove the head for full inspection and to prevent headgasket leakage
>> in future:[/color]
>
> Hi Sidney,
>
> Thanks for the great info! I was just deciding to replace the chain
> with a Genuine part as opposed to a mystery brand: I'll assume the
> higher price will assure longer life! Anyhow, I'll check into the
> links you provided.
>
> As for the tensioner, I previously installed an aftermarket kit, and I
> believe it included all parts. (The guide had worn out, and the chain
> worked throught the housing, so I ended up replacing the cover and all
> other parts. Since all parts were changed about 30k miles ago, I was
> suprised to have the chain break last week!)
>
> To clarify, is it your opinion that valves get bent EVERY time a chain
> breaks, even if it happened at startup and ran at low rpm for literally
> 1 second?
>
> Thanks again,
>
> Scott[/color]

Scotty,

The 22RE is an interference engine, meaning that if valve timing is
interrupted the pistons hit the valves.

Let's say that your idle speed is ~700 rpm. That's about 12 revolutions per
second. So for that one second, each open valve will have taken 24 separate
hits from its respective piston.

Now, you might have gotten lucky and the cam stopped turning at such a
position that no valve extended far enough into any of the combustion
chambers to be hit by a piston.

So, cross your fingers, knock wood, rub that lucky rabbits foot, and do a
leakdown test as Sidney suggests. You may find that you're the recipient of
karma from leading a good and virtuous life. Be prepared to send the head
to a machine shop, though.
--
Mike Harris
Austin, TX

Mike Harris wrote:[color=blue]
>
> --
> Mike Harris
> Austin, TX[/color]

Hi Mike,

Thanks for the reply. I called a shop today and the guy said I most
likely have some valve damage. However, he DID say the rocker arms
would/should have extra play if the valves were bent. At first wiggle,
the rockers seem about normal. Fingers crossed . . .

Scott

The 22RE is a non-interference engine. It's unlikely you have any valve
damage.

Q

Scotty wrote:[color=blue]
> Mike Harris wrote:[color=green]
>> --
>> Mike Harris
>> Austin, TX[/color]
>
> Hi Mike,
>
> Thanks for the reply. I called a shop today and the guy said I most
> likely have some valve damage. However, he DID say the rocker arms
> would/should have extra play if the valves were bent. At first wiggle,
> the rockers seem about normal. Fingers crossed . . .
>
> Scott
>[/color]

"Scotty" <canthespam@cableone.net> wrote in message
news:1159202266.939676.31500@h48g2000cwc.googlegroups.com...[color=blue]
>
> [email]sidneybek@yahoo.com[/email] wrote:[color=green]
>> Scotty I assume you only replaced the chain,guides and cover? if so
>> your timing chain tensioner could be worn,read below for full details &
>> do a leak down test to see if you bent the valves but I suggest you
>> remove the head for full inspection and to prevent headgasket leakage
>> in future:[/color]
>
> Hi Sidney,
>
> Thanks for the great info! I was just deciding to replace the chain
> with a Genuine part as opposed to a mystery brand: I'll assume the
> higher price will assure longer life! Anyhow, I'll check into the
> links you provided.
>
> As for the tensioner, I previously installed an aftermarket kit, and I
> believe it included all parts. (The guide had worn out, and the chain
> worked throught the housing, so I ended up replacing the cover and all
> other parts. Since all parts were changed about 30k miles ago, I was
> suprised to have the chain break last week!)
>
> To clarify, is it your opinion that valves get bent EVERY time a chain
> breaks, even if it happened at startup and ran at low rpm for literally
> 1 second?
>
> Thanks again,
>
> Scott[/color]


This may be of interest to you.................... particularly the
reference to interference versus non - interference bit in the first link.



[url]http://www.4crawler.com/4x4/CheapTricks/EngineMods/TimingChain.shtml[/url]



[url]http://groups.google.com.au/group/alt.autos.toyota.trucks/browse_thread/thread/e98347b3f036a212/2cefe80b49820762?lnk=st&q=22RE+engine+&rnum=2&hl=en#2cefe80b49820762[/url]

"Q" <hugemoth@access4less.net> wrote in message
news:bK_Rg.1418$Y24.875@newsread4.news.pas.earthlink.net...[color=blue]
> The 22RE is a non-interference engine. It's unlikely you have any valve
> damage.
>
> Q[/color]

That is incorrect, sir.

My understanding is that some - not all - of the earliest 22R series from
the '70s were (barely) non-interference. They had low compression heads and
notched pistons. By the time the E series came out they were most
definitely interference engines.

Unless you find yourself with a NOS early series block or the PO
deliberately overhauled it with low compression (either a purist, or with
the intent of adding a turbo or supercharger), chances are that even an
early engine would have been rebuilt using higher compression heads and/or
pistons from a later model.
--
Mike Harris
Austin, TX

I can attest from personal experience 81 22R THE valves can get bent, you
may be lucky since it happend when trying to start it. DO a leak down test
or temp install the new chain & do a compression test

In article
<d05b281dc904b0873972bb65509b1152@localhost.talkaboutautos.com>,
"sqdancerLynn" <sqdancerlynn1@verizon.net> wrote:
[color=blue]
> I can attest from personal experience 81 22R THE valves can get bent, you
> may be lucky since it happend when trying to start it. DO a leak down test
> or temp install the new chain & do a compression test[/color]

Quite often one of the valves gets bent when the rocker arms get torqued
down.

Thought I'd offer an update on my broken timing chain. I decided to
order replacement parts (Toyota), and replace the chain without tearing
into the head. (Hoping I lucked out and didn't ruin a valve when the
chain broke) I finished up last night, and . . . it runs like crap:
Barely idles, no accelleration, and smelly exhaust. I did a
compression test this afternoon, and found the following (after 4
cranks):

1 -155
2 - 120
3 - 150
4 - 152

First crank yields 90 pounds for all cylinders. When I repeat with a
squirt of oil, all cylinders gain about 30 pounds.

So, does #2 suggest a tweaked valve, or did I simply screw up my timing
when I re-assembled with new parts?

Thanks,

Scott

"Scotty" <canthespam@cableone.net> wrote in message
news:1161639524.842966.197890@b28g2000cwb.googlegroups.com...[color=blue]
>
> Thought I'd offer an update on my broken timing chain. I decided to
> order replacement parts (Toyota), and replace the chain without tearing
> into the head. (Hoping I lucked out and didn't ruin a valve when the
> chain broke) I finished up last night, and . . . it runs like crap:
> Barely idles, no accelleration, and smelly exhaust. I did a
> compression test this afternoon, and found the following (after 4
> cranks):
>
> 1 -155
> 2 - 120
> 3 - 150
> 4 - 152
>
> First crank yields 90 pounds for all cylinders. When I repeat with a
> squirt of oil, all cylinders gain about 30 pounds.
>
> So, does #2 suggest a tweaked valve, or did I simply screw up my timing
> when I re-assembled with new parts?
>
> Thanks,
>
> Scott
>[/color]

Sounds like you didnt get your timming quite right. Your compression
readings are only really good with a warm motor.


Scotty (the other one)

Scotty wrote:[color=blue]
>
> Sounds like you didnt get your timming quite right. Your compression
> readings are only really good with a warm motor.
>
>
> Scotty (the other one)[/color]

Thanks for the reply; I'll inspect my chain and TDC settings tonight.
I was sure I had it right the first time, but it runs so badly that it
has to be more than a busted valve or two!

Cheers,

Scott

Scotty wrote:[color=blue]
> Scotty wrote:[color=green]
> >
> > Sounds like you didnt get your timming quite right. Your compression
> > readings are only really good with a warm motor.
> >
> >
> > Scotty (the other one)[/color]
>
> Thanks for the reply; I'll inspect my chain and TDC settings tonight.
> I was sure I had it right the first time, but it runs so badly that it
> has to be more than a busted valve or two!
>
> Cheers,
>
> Scott[/color]

Yep, I failed to sync the distributor gear properly with the cam gear:
runs fine now! ;>)

As for "broken chain" = "busted valves", not true in this case. I
noticed when I began the repair that the chain had wedged, freezing the
cam sprocket into the 10 'o clock position. Since it broke
instantaneously when I tried starting the engine, I hoped that this
meant no valves were stuck out as the pistons cycled. Looks like that
was the case!

Thanks for all the help,

Scott

"Scotty" <canthespam@cableone.net> wrote in message
news:1161659143.330877.253540@i3g2000cwc.googlegroups.com...[color=blue]
>
> Scotty wrote:[color=green]
>> Scotty wrote:[color=darkred]
>> >
>> > Sounds like you didnt get your timming quite right. Your compression
>> > readings are only really good with a warm motor.
>> >
>> >
>> > Scotty (the other one)[/color]
>>
>> Thanks for the reply; I'll inspect my chain and TDC settings tonight.
>> I was sure I had it right the first time, but it runs so badly that it
>> has to be more than a busted valve or two!
>>
>> Cheers,
>>
>> Scott[/color]
>
> Yep, I failed to sync the distributor gear properly with the cam gear:
> runs fine now! ;>)
>
> As for "broken chain" = "busted valves", not true in this case. I
> noticed when I began the repair that the chain had wedged, freezing the
> cam sprocket into the 10 'o clock position. Since it broke
> instantaneously when I tried starting the engine, I hoped that this
> meant no valves were stuck out as the pistons cycled. Looks like that
> was the case!
>
> Thanks for all the help,
>
> Scott
>[/color]

Now its able to get to full running temp have you done another compression
test yet?