Timing belt issue

[Mac]

1990 Mazda Miata. Changed out the timing belt yesterday and in the
process got the cams off. Had the cams clamped in place and tied
together but the wrenches slipped. I know, should of also marked the
gears. After getting the belt on we aligned it by the cam marks but it
seems to be running rough and pinging alot when there is a load on it,
driving. What other way is there to adjust the cams? Thanks.

[XS11E]

See if this helps: http://www.miata.net/garage/timingbelt.html


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The Usenet Improvement Project:
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[Chris D'Agnolo]

"XS11E" <xs1...@SPAMyahoo.com> wrote in message
news:XnsA091A16D7B0...@127.0.0.1...

The two times I have done this (a 1.6 and a 1.8) I was disappointed with the
ease and accuracy of the alignment marks. There's too much distance between
the marks and looking at different angles can easily give you a one tooth
difference. My guess is that you are off one tooth, Look it over real good
and move it the direction that looks most likely. I'm thinking that will be
pretty obvious as going the other direction (from the point you are) will
look pretty obviously off.

Seems to me that Mazda could have done significantly better on this issue.

Chris
99BBB

[Mac]

All taken care of. we found the right marks and corrected the issue.
runs a lot better now.

[moeshefran...@yahoo.com]

I know my limitations>>LOL. When it comes time for my 2000 Miata, I will give it to a PRO. Strange here in Calif. it says to replace at 105,000, but to check it at 60,000. Well heck, it would take nearly just as much labor cost just to get to it to check it, that at that time I might as well have it done. but not sure at that time (60,000) if it really be worth also having the water pump replaced also, at 105K I would, but not 60K???!!! The car is only at 38K now

[charlie]

My 99 had it's belt, idler, tensioner, and water pump changed at about
60,000, mainly due to the fact that it's turbo'ed.
The belt showed very slight signs of wear, with the teeth slightly more
rounded than a brand new belt. The used belt was slightly longer than
the new belt and prevented using the slide on replacement method. One
idler or tensioner bearing was quite rough, so both were changed, since
I had the parts in hand.
The camshaft seals were not changed, since there was no sign of leakage.
The crud filter on the underside of the cam cover was cleaned, as it had
noticeable crud inside. Small low spots on the top of the head had
pools of very yucky oil, so that was also removed.

Original assembly turned out to be one belt tooth off. To recover, I
located TDC, checked against the various marks, and re assembled. Don't
forget to use RTV when reinstalling the cam cover, particularly at the
rear of the cover.

The big concern is to get the crank key really locked down. to this day,
I'm not sure that some minor variation in timing might be caused by
this. It's hard to tell, since the waste spark system can obscure timing
light results. We also had to reuse the original key, since the key
supplied by the Mazda dealer (30 miles away) didn't fit.

Read the service note concerning the changes from the original service
manual about proper crank key installation and torques.

[moeshefran...@yahoo.com]

Charlie>>All good points but nothing that I would ever consider doing myself leaving it to the PROs. Almost sounds like something that you should let the Miata dealer/service dept, do, rather than a general all around mechanic's shop, right??

[charlie]

Let's just say that the "local" Mazda dealer is not known for "quality"
service. The really experienced and well trained mechanics retired, or
work someplace else. It's a small dealership, part of a large chain, and
last I looked, didn't have all the "required" factory tools to work on
Miata valve trains, and other things. (What shim kit, for one)
When I changed the 5th gear ratio in my 99's 5 speed, I ended up
borrowing a couple of specialty tools from one of the Toyota dealer's
mechanics.

[moeshefran...@yahoo.com]

Now you're scaring me>>LOL. When it comes time to have my valved checked/adjusted (Book says at 60,000 mi), should it be done at the Mazda dealership, or could any competent mechanic (Maybe recommended by "Click & Clack's" cartalk.com mechanic files, do that)??

[Chris D'Agnolo]

>
> Let's just say that the "local" Mazda dealer is not known for "quality"
> service. The really experienced and well trained mechanics retired, or
> work someplace else. It's a small dealership, part of a large chain, and
> last I looked, didn't have all the "required" factory tools to work on
> Miata valve trains, and other things. (What shim kit, for one)
> When I changed the 5th gear ratio in my 99's 5 speed, I ended up borrowing
> a couple of specialty tools from one of the Toyota dealer's mechanics.

Charlie, You got my attention with your mention of changing the 5th gear
ratio! I've been dreaming of such a modification for years and always get
the same ridiculous answers from other people when I suggest such (apparent)
blasphemy.

Tell me more please. Feel free to send me a direct emails if you prefer, I
don't want to hijack this thread but, I really would like to discuss this
with you.

Thanks,
Chris
99BBBB

[charlie]

The 99s used the more or less "classic" Miata five speed. There were
parts available in the Mazda warehouse in 2002 or so. Miata.net had some
threads and info, at least before they reorganized.
It's not difficult to do, but there was a problem that involved
borrowing a tool (I ended up borrowing one from an ex Mazda mechanic
that was working for the Toyota used car dealer.) It can be done without
the tool with some difficulty.

I had to take the tranny apart to replace a bad syncro ring, so it was
sort of worth while at the time. For the effort involved, I'd rather
change the rear axle ratio. The reduction of a few hundred RPM at 70 Mph
is not enough to really justify the 5th gear change by itself.

The cost of parts was about the same as changing the rear axle ratio.
I believe the parts used for the gear change were for an older RX-7
model that had a small rotary engine.

There is a spare tranny sitting around that has the changed 5th gear
ratio. No, I will not give it away. sadly, used 5 spd trannys go for
about the cost of the parts for the gear change.
Mazda wanted about 2k for a new one at a racers discount when I bought
the spare.

[Chris D'Agnolo]

>> 99BBBB
> The 99s used the more or less "classic" Miata five speed. There were parts
> available in the Mazda warehouse in 2002 or so. Miata.net had some threads
> and info, at least before they reorganized.
> It's not difficult to do, but there was a problem that involved borrowing
> a tool (I ended up borrowing one from an ex Mazda mechanic that was
> working for the Toyota used car dealer.) It can be done without the tool
> with some difficulty.
>
> I had to take the tranny apart to replace a bad syncro ring, so it was
> sort of worth while at the time. For the effort involved, I'd rather
> change the rear axle ratio. The reduction of a few hundred RPM at 70 Mph
> is not enough to really justify the 5th gear change by itself.
>
> The cost of parts was about the same as changing the rear axle ratio.
> I believe the parts used for the gear change were for an older RX-7 model
> that had a small rotary engine.
>
> There is a spare tranny sitting around that has the changed 5th gear
> ratio. No, I will not give it away. sadly, used 5 spd trannys go for about
> the cost of the parts for the gear change.
> Mazda wanted about 2k for a new one at a racers discount when I bought the
> spare.
>

Thanks Charlie, I appreciate the info. Ya, I would not go thru that amount
of work for a couple hundred rpm at 70. I'm looking for more like 1000 rpm
reduction at 70! So, I imagine a rear end ratio tall enough to do that would
make my little 1.8 noticeably slower in most situations. That's why I
thought just changing the one ratio would be the answer.

Anyway, I did a tranny swap out this year and had noooo fun at all with it
so, realistically, I think I'm giving up on this 'crazy' Miata idea of mine
;-) I still think it's a good one though, 5th gear 'for cruising only' ;-)

Later,
cd
99BBB

[charlie]

The gear change did noticeably reduce the buzzyness a bit at 70Mph.
Close as I could tell, the max RPM change was ~500, and the minimum
about 250. We changed such things as speedo cal from the factory high
reading setting to 1.5 or so miles high at 70, and also changed the tach
to read more accurately, unfortunately in the middle of the whole
process. The factory had set the tach to hide the fact that the redline
computer cutout was actually lower than specified by a few hundred RPM.
Mazda and Ford use the US -0 +5 speedo cal standard.
Most read about 3 to 4 miles fast at 70 from the factory.
GM (Chevrolet) seems to typically read about one mile high at 70.

The 5th gear change along with a turbo might increase the 1/4 mile end
speed a bit. (Mostly the turbo) The last time I ran the 99 on a strip
(2002), the results were consistent with 200-220 HP.
The guy in the other lane was running a stock V8 small block Camaro
auto, and ended up a ways behind. I backed off just a bit before the
light, to keep the track happy with a convertible and no roll bar.
The Miata rear wheels like to "hop" with stock suspension, and this
slows down the 60' speed. To add insult the 99 is a bit heavy, due to
added sound deadening and the things that go with the turbo.