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Thinking of rebuilding the '85 2.5 engine. What bearing/piston sizes to choose? by cebix
Started on: 05-12-2018 06:12 PM
Replies: 33 (530 views)
Last post by: cebix on 03-23-2019 07:35 AM
cebix
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Report this Post05-12-2018 06:12 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

I'm thinking of rebuilding my 2.5 engine and want to order a rebuild kit but they all require main bearing, piston and rod bearing sizes. How do I tell which ones I need?

Anyway my car is an '85 but just to be sure how can I verify exactly what engine do I have?

Thanks.

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Gall757
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Report this Post05-12-2018 06:18 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

In the States, you take apart the engine, measure things, and then get the rebuild kit.

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cebix
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Report this Post05-13-2018 06:46 AM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by Gall757:

In the States, you take apart the engine, measure things, and then get the rebuild kit.


That's what I thought, thanks.

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Lou6t4gto
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Report this Post05-15-2018 07:21 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

until you "Open it up" there's no telling if the cylinders will remain standard, if the Crankshaft Needs to be turned .010/.010. you don't even know for sure if someone else has previously "done it".

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cebix
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Report this Post12-01-2018 10:32 AM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

Thanks for the replies. So I'll have to open up the engine soon and I'm wondering - are there any rebuild kits available anymore? The only company that made these I think was Enginetech but they are all out of stock. Do you guys know where can I get a rebuild kit?

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Report this Post12-01-2018 10:53 AM Click Here to See the Profile for SpadesluckSend a Private Message to SpadesluckEdit/Delete MessageReply w/QuoteDirect Link to This Post

These guys have already covered it but I figured I would share my dumb move when I rebuilt my 2.8l. I like you wanted to get a head start and just bought standard rings/bearings but when I took the motor apart it had already been rebuilt at some point. Lesson of the story open it up and then figure out what you need. Less chance to waste money.

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Dennis LaGrua
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Report this Post12-01-2018 08:25 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post

You will need to buy or borrow a micrometer to measure the crankshaft journals and an inside micrometer to measure the cylinder bores. Compare these to the specs in the service manual. Sometimes everything measures up and a simple hone of the cylinders, a new set of standard size bearings, rings, seals and cam bearings can be used but not always. Be sure to measure the cylinders for taper, out of round and inspect the crankshaft for scores on the journals. The process is more involved than this but it should give you an idea.

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[This message has been edited by Dennis LaGrua (edited 12-01-2018).]

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Lou6t4gto
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Report this Post12-03-2018 09:37 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

If you are going to rebuild it, (Being a 1985 engine) make sure it has a roller cam. (1985 was a split year)( you Can install the stock roller cam into the flat tappet block) use a metal gear drive instead of "fiber"

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cebix
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Report this Post12-08-2018 01:21 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

Thanks, I will look into that. I'm not even sure the engine is an 1985. It has the pre 87 TBI for sure though.

Anyway back to my latest question - where can I get a rebuild kit? It seems there are only some left on eBay but I'm not sure eBay is a legit place to buy these things.

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Gall757
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Report this Post12-08-2018 08:26 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

e bay would be OK if the rebuild kit has a brand name like Federal Mogul or one of the other brand names in the business like Sealed Power.

[This message has been edited by Gall757 (edited 12-08-2018).]

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Lou6t4gto
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Report this Post12-09-2018 01:24 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post

you MAY be" better" off buying your Parts Separately. that way you can get the BEST. Clevite or King Bearings, perfect circle rings, "coated" pistons. Do not buy Cut Rate cheap Gaskets !

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cebix
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Report this Post12-10-2018 05:45 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by Lou6t4gto:

you MAY be" better" off buying your Parts Separately. that way you can get the BEST. Clevite or King Bearings, perfect circle rings, "coated" pistons. Do not buy Cut Rate cheap Gaskets !


That sounds reasonable. How would I go about that? I've only seen "full" kits and not parts sold separately. Are they even available to find under "fiero" and "parts"? Or should I just measure all around buy non-specific Fiero parts?

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Iain
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Report this Post12-11-2018 07:06 AM Click Here to See the Profile for IainSend a Private Message to IainEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by cebix:

I'm thinking of rebuilding my 2.5 engine and want to order a rebuild kit but they all require main bearing, piston and rod bearing sizes. How do I tell which ones I need?

Anyway my car is an '85 but just to be sure how can I verify exactly what engine do I have?

Thanks.



No one has asked the most pertinent question.

WHY?

What makes you think it needs a rebuild? You haven't posted any compression/vacuum/leakdown/oil pressure results.

I have been accused before of coming across like God when discussing building engines. That's because I've built more than a few, and seen well meaning people tear down a perfectly well running engine 'that needs rebuilt' when it doesn't. Half the time they end up wrecking the thing.

iain


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cebix
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Report this Post12-11-2018 03:29 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

That's true, I haven't done any of these tests. There are just some symptoms that I only assume are mechanical wear. It may also be some negligence in maintenance but it's so tough to troubleshoot since so much stuff was done. And I still drive it everyday.

All I know is from observations - that it consumes oil, spits it out to the air filter area, starts poorly when cold, blows a lot of white/blue smoke when cold and when restarted hot for a few seconds. Has a rough and uneven idle when hot. Also it loses coolant with no visibile spill other than the reservoir will blow out sometimes some coolant when it's full. Oil looks "clean" as in no coolant contamination but it has a LOT of carbon buildup when I remove the valve cover. Mileage is I'd say pretty average for an automatic - I get around 28 MPG highway (65-85 MPH) currently when it's wintertime and we have ~30 degrees Fahrenheit on average.

And it hasn't done any of that a few years before. 2 to 3 years ago I rebuilt the ingnition and fuel systems so I think I can get those out of the way. If there are things I can check before rebuilding it - what would I do that would tell the most other than cylinder pressure? I would gladly make some tests to avoid a rebuild. Thanks.

[This message has been edited by cebix (edited 12-11-2018).]

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Red98422
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Report this Post12-12-2018 01:10 AM Click Here to See the Profile for Red98422Send a Private Message to Red98422Edit/Delete MessageReply w/QuoteDirect Link to This Post

IMO a compression tester is a vital tool for determining engine health, I know you said “other” than that but truly it is very important.

That being said what do your spark plugs look like?

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Iain
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Report this Post12-12-2018 06:19 AM Click Here to See the Profile for IainSend a Private Message to IainEdit/Delete MessageReply w/QuoteDirect Link to This Post

do a vacuum test if I were you. A compression test will not tell you as much if that's the symptoms you're having. If you don't know any mechanics with one, ask any motorcyclist friends, they use them for balancing carbs. Download a guide from the Web on how to use one. Gives a very accurate condition of bore wear and let's you know if you have any valve or head problems.
I suspect you may have a blown or leaking head gasket. They don't always cause the oil or water to mix. They can leak water into the chamber, which causes uneven running, water consumption and white smoke in the exhaust

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cebix
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Report this Post12-13-2018 04:49 AM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

I think I'll just buy one. Will this type do the trick?

https://goo.gl/images/nTo7Xq

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Iain
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Report this Post12-13-2018 10:37 AM Click Here to See the Profile for IainSend a Private Message to IainEdit/Delete MessageReply w/QuoteDirect Link to This Post

Yes, that will do it. run through all the tests it will list in the instruction.

Vacuum tests are generally a little more sensitive and can often be informative than compression testing, since the engine is actually running when you carry it out.
You want a nice steady vacuum reading at idle with no fluctuation.

I have a friend flying over tomorrow, I'll see if he has space for any parts I have lying about. no use to me

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Report this Post12-14-2018 04:51 AM Click Here to See the Profile for IainSend a Private Message to IainEdit/Delete MessageReply w/QuoteDirect Link to This Post

Sorry, didn't get home until stupid late.

Something an old bloke taught me which may help.

Loosen and clean the threads on the plugs before the vacuum test, reinstall, but only tight enough that they seal. Get fully up to temperature. Conduct all the vacuum tests in the instruction sheet/card and note the readings as you do them.
Let the engine idle a couple of mins.
Switch off and remove all plugs as quickly as you can.
Watch for any steam coming out of the plug holes. Because the coolant system is up to temp and pressurised, water will be forced into the chamber if the gasket is leaking slightly. Doesn't work if the gasket is leaking badly enough that the oil and water are mixing, but can be quite spectacular if only a slight leak into the chamber.

Do make sure that all the manifold hoses are clear of residue.

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Report this Post12-15-2018 06:05 AM Click Here to See the Profile for Red98422Send a Private Message to Red98422Edit/Delete MessageReply w/QuoteDirect Link to This Post

Ok so maybe I’m not understanding.

Where I’m from a vacuum test is a gauge you hook up to the base of the TB or carb to test the vacuum of the engine, it’s usually used for tuning pourposes, not engine general health. It’s the same gauge you use to setup multi cab setups on an outboard (well familiar with this).

However from the additional comments you made it almost sounds like you are talking about a leak down test?!?!?!?!

If you don’t mind could you explain in more detail for your friends in the US? Simply confused as to what you are suggesting for a test procedure...I’ve heard of doing a vacuum test on an engine before, however that was specific to a two cycle engine to crank case seal and reed flutter.

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cebix
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Report this Post12-16-2018 04:39 AM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

I think these are the tests. There are a lot of these articles if you search "vacuum test engine".

https://www.hemmings.com/ma...-Vacuum/3709071.html

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Report this Post12-16-2018 07:30 PM Click Here to See the Profile for Red98422Send a Private Message to Red98422Edit/Delete MessageReply w/QuoteDirect Link to This Post

Ok so it’s the same thing I use for tuning carburetors. I was imagining a more involved test.

I’ve never used them to diagnose internal engine problems myself, I have compression, leak down and coolant pressure tests for that, but if it can be used accurately in that manner it would be awesome for folks without the funds to buy the more specific tools.

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cebix
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Report this Post12-17-2018 05:45 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

So the question now is... where do you plug it in the '85 2.5 TBI? There doesn't seem to be a fitting for this kind of thing. Should I unplug one of the vacuum lines?

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cebix
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Report this Post03-10-2019 01:38 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

I got my engine out, head off and I'm wondering if I can rebuild it myself. What tools do you actually need to do this? What are "specialty" things that need to be made by a shop? I know there's a lot of stuff on the internet about rebuilding engines but I was wondering if there's anything peculiar about the 2.5.

So far I can only tell there's a lot of grooves on the cylinder walls where the piston ends it's travel. Head gasket was pretty much non-existent.

[This message has been edited by cebix (edited 03-10-2019).]

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Patrick
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Report this Post03-10-2019 04:37 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by cebix:

So far I can only tell there's a lot of grooves on the cylinder walls where the piston ends it's travel.


Are you referring to the ridge around the top of each cylinder, or do your cylinders have scoring (grooves) up and down the cylinder walls?

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cebix
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Report this Post03-10-2019 05:02 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

Yeah, it's the ridge.

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Gall757
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Report this Post03-10-2019 07:45 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

Got one of these?

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cebix
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Report this Post03-11-2019 03:00 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

Thanks, that would probably do the trick but... been reading up on rebuilding engines - what stuff I can diagnose myself and what I can't without proper machining skills... and I've decided to leave it to a pro shop. That way I guess I can have the car driving again by mid spring. If I would get into it, it would probably take a year or two I guess. Thanks for your input guys, really appreciate it.

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Report this Post03-11-2019 04:25 PM Click Here to See the Profile for Neils88Click Here to Email Neils88Send a Private Message to Neils88Edit/Delete MessageReply w/QuoteDirect Link to This Post

Maybe you mentioned it and I just missed it, but why exactly do you want to rebuild the engine? Had you done wet/ dry compression tests?

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cebix
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Report this Post03-11-2019 04:44 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

Didn't actually do any tests. But had overheating problems, eating oil and cooolant, massive blowby, lot of oil in air filter housing. Had bad valve stems and bad head gasket symptoms. One time when fired up hot from a freeway stop I pretty much had a blue smoke cover behind me for a mile or so... pretty embarassing. Took the head off and saw the ridges and nonexistent head gasket and a lot of carbon buildup and silicon gasket sludge... Basically wanted to refresh the engine. So when I had it all out I guessed it's going to be cheaper just to rebuilt it.

[This message has been edited by cebix (edited 03-11-2019).]

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Gall757
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Report this Post03-12-2019 06:48 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

keep us posted! This could be a helpful thread for others.

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arbakken
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Report this Post03-12-2019 10:50 PM Click Here to See the Profile for arbakkenSend a Private Message to arbakkenEdit/Delete MessageReply w/QuoteDirect Link to This Post

Do you want my engine? The head needs a valve job, but the rest was allegedly rebuilt 8k miles ago... Shipping might be a couple $$ though...

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cebix
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Report this Post03-13-2019 12:42 PM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

A second engine would always be good in the future. If you could get a shipping quote to Poland and name your price then I would be obliged. Of course all taxes and import duties would be on my side.

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cebix
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Report this Post03-23-2019 07:35 AM Click Here to See the Profile for cebixSend a Private Message to cebixEdit/Delete MessageReply w/QuoteDirect Link to This Post

Still don't know if I have roller lifters on my 85 or not. If it turns out I do have flat lifters, can I swap in a new full roller set from rockauto? Camshaft, lifters and pushrods? Or are these not swappable because of some engine block differences?

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