Engine Looking for suggestions and or ideas

PonyGTrider · Aug 25, 2026

Hi all,
After a front end accident I removed the engine and transmission, with the engine out I removed the oil pan and started inspecting the bottom end assembly. I noticed the cylinder bores are a bit too shinny. Still you can see a bit of crosshatch left.
It is a 0.030” oversized block with Speed Pro forged pistons and Molly rings (TRW-8KL2482F30) 170cc Twisted wedge, ARO studs and TFS intakes and stage 1 cam.

There is zero oil consumption and it has been running flawlessly from the time I rebuilt it some 17 - 18 years ago to date. The last issue I had was a faulty oil pump which ended up in some scratches on the mains so I pulled the crank to be polished installed a new pump and new main bearings. After that no problems.
now the only issue is extremely poor fuel economy <9.5 miles per gallon.

I went thru all kinds of troubleshooting with no improvements.
After I ran a compression and leak down tests my numbers arent’t terrible or maybe a bit too low? (See the pic below) could that be what causes my poor fuel economy?

there is no metal dust in the oil pan so the bearings are in optimum shape, oil pressure cold is about 50 psi and around 22 at normal operating temp at idle.

Can I install new bearings without machining the main and connecting rod journals??? What bearings to use?
Is it worthy or would you recommend to remove my heads and install new rings without machining the bores just with a light honing and just do a basic valves job? What grit of honing stones to use?Which rings to use???

What would you do in my case???
My ride is a weekend cruiser no track usage just a spirited driving from time to time.

Thank you all for your ideas and suggestions

AeroCoupe · Aug 25, 2026

How many miles is on the rebuild?

In the last picture it looks like there are some vertices “skiff” marks and depending on depth my not come out with a light hone.

keel · Aug 25, 2026

Personally I did a backyard rebuild on my 302 about 10,000 miles ago without any issues so far (rings, bearings, hone, crank polish, valve grind) so you can absolutely do it as long as its not too far gone. Did I do it the "right" way by taking it to a machine shop? No. Does it work for my use case? Absolutely. Could it wear out prematurely because of my shade tree work? Also yes but I can accept that risk.

Based on the pictures your cylinder walls have some bore scoring and could definitely benefit from some attention but I would crack a couple rod caps and main caps to check the condition of the crank and the bearings before you decide on what you want to do. You could also try inspecting a few valves and valve seats to see if those look good. Most of the time its better to just leave stuff alone if its working.

If you do want to go ahead and rebuild everything I can get into more detail about what parts and methods I used etc..

Overall I don't think the condition of your engine has anything to do with your fuel economy issues. I only see normal wear and tear for an older motor and the compression numbers aren't perfect but also aren't showing anything to be wildly wrong.

PonyGTrider · Aug 25, 2026

AeroCoupe said:
How many miles is on the rebuild?

In the last picture it looks like there are some vertices “skiff” marks and depending on depth my not come out with a light hone.

I hate the foxbody stangs odometers they go to 100k and then start all over. I would say that engine has a 100k or less.

Yeah I noticed those marks and haven been able to run my fingernail and see if it catches it or not. I will make a decision to take heads off and at least hone those cylinders.

Thanks man

PonyGTrider · Aug 25, 2026

keel said:
Personally I did a backyard rebuild on my 302 about 10,000 miles ago without any issues so far (rings, bearings, hone, crank polish, valve grind) so you can absolutely do it as long as its not too far gone. Did I do it the "right" way by taking it to a machine shop? No. Does it work for my use case? Absolutely. Could it wear out prematurely because of my shade tree work? Also yes but I can accept that risk.

Based on the pictures your cylinder walls have some bore scoring and could definitely benefit from some attention but I would crack a couple rod caps and main caps to check the condition of the crank and the bearings before you decide on what you want to do. You could also try inspecting a few valves and valve seats to see if those look good. Most of the time its better to just leave stuff alone if its working.

If you do want to go ahead and rebuild everything I can get into more detail about what parts and methods I used etc..

Overall I don't think the condition of your engine has anything to do with your fuel economy issues. I only see normal wear and tear for an older motor and the compression numbers aren't perfect but also aren't showing anything to be wildly wrong.

Yeah I’m debating to do a complete refreshening as you described it.
I wouldn’t think those compression numbers would affect my fuel economy but mentioned it because someone implied that on a different posting.
Soon I will make a decision if take it all apart and do a basic freshen up.

KRUISR · Aug 25, 2026

PonyGTrider said:
I hate the foxbody stangs odometers they go to 100k and then start all over.

Not directly on topic, but you need a Canadian car (or speedo) - ours will roll over at 1,000,000 km

PonyGTrider · Aug 25, 2026

KRUISR said:
Not directly on topic, but you need a Canadian car (or speedo) - ours will roll over at 1,000,000 km

Right on! That would be awesome!

PonyGTrider · Aug 29, 2026

PonyGTrider said:
Right on! That would be awesome!

Ok, I went ahead and took all the engine apart to do a freshing up process.
Below are a photo of the valves condition from right to left are 1 thru 5, also a photo of the bowls conditions. Bae and your guys expertise I all of that build up on top of the valves a sign of valve seals worn out valve seals or excessive unburned fuel?

Will it be wise to remove material inside the intake bowls on the left hand side of the the valve guides?

Please be patience with me

PonyGTrider · Aug 29, 2026

PonyGTrider said:
Ok, I went ahead and took all the engine apart to do a freshing up process.
Below are a photo of the valves condition from right to left are 1 thru 5, also a photo of the bowls conditions. Bae and your guys expertise I all of that build up on top of the valves a sign of valve seals worn out valve seals or excessive unburned fuel?

Will it be wise to remove material inside the intake bowls on the left hand side of the the valve guides?

Please be patience with me

This part in the intake bowl is the one I would like to blend in. My heads are the old 170cc twisted wedge I just would like to know if there could be any risks or issues doing that.
Thank you all

keel · Aug 31, 2026

PonyGTrider said:
Ok, I went ahead and took all the engine apart to do a freshing up process.
Below are a photo of the valves condition from right to left are 1 thru 5, also a photo of the bowls conditions. Bae and your guys expertise I all of that build up on top of the valves a sign of valve seals worn out valve seals or excessive unburned fuel?

That buildup is from your PCV system and EGR if you still have that stuff. It's pretty normal to see that on the intake valves and runners.

PonyGTrider said:
This part in the intake bowl is the one I would like to blend in. My heads are the old 170cc twisted wedge I just would like to know if there could be any risks or issues doing that.
Thank you all

As long as you can keep your tool under control a little blending won't cause any issues. But if you get into the valve seat by accident you will have to take your heads to a machine shop for new seats. Up to you whether or not it's worth the risk of that happening.

2000xp8 · Aug 31, 2026

Take the heads to the machine shop.
It doesn't cost that much (or at least it didn't used to).
When my buddy owned his shop, every set of heads went to the machine shop, new or used.
I can confidently say there is about 15hp in a valve job and bowl cleanup on TWs and they will also check the spring seat pressure.
Worth every cent if you ask me.

PonyGTrider · Aug 31, 2026

keel said:
That buildup is from your PCV system and EGR if you still have that stuff. It's pretty normal to see that on the intake valves and runners.

As long as you can keep your tool under control a little blending won't cause any issues. But if you get into the valve seat by accident you will have to take your heads to a machine shop for new seats. Up to you whether or not it's worth the risk of that happening.

I have an oil catch Can and I didn’t account for the EGR fumes. I’ve been debating with myself about eliminating the EGR, as a matter of fact I tried it already and ancestry I didn’t like the way she was running.

On the other hand I think I have good steady hands to do blend in that valve guide bump.
All the chambers have a high ridge about a quarter inch around the both valves so I’m smoothing it down and they look awesome so I think I can fix that bump inside the bowl.

Noobz347 · Sep 1, 2026

I mean... I've done some light port work before but I don't mess around near valve seats.

I second the notion of taking them to a machine shop to do all of the [machine shop things].

PonyGTrider · Sep 1, 2026

Noobz347 said:
I mean... I've done some light port work before but I don't mess around near valve seats.

I second the notion of taking them to a machine shop to do all of the [machine shop things].

Actually I already cleaned and polished all the chambers and blended in all four intake valves guide bosses inside the bowls on one head and not even a slight damages on the valves seats so it came out very good and that proves I have stI’ll post pics when done both cyl heads

AeroCoupe · Sep 1, 2026

I would have those heads cleaned up and have the valves run. They are off the car so now is the time.

PonyGTrider · Sep 1, 2026

AeroCoupe said:
I would have those heads cleaned up and have the valves run. They are off the car so now is the time.

Hi,
After a thoroughly inspection I’ve determinate that my valves and valve seats are in good conditions, no pitting and no bad contact and lapping them will be enough . I lapped a couple of them and the contact pattern is perfect. When lapped them I could see the tiny lines and marks left when they newly machined.
I heard that the valve guides on these heads are notorious to wear faster due to the valves rotation (Twisted). I will verify the valves lateral move just to make sure they’re in spec. If they’re out then I’ll take them to the shop to do just that.

Thank you

PonyGTrider · Sep 7, 2026

2000xp8 said:
Take the heads to the machine shop.
It doesn't cost that much (or at least it didn't used to).
When my buddy owned his shop, every set of heads went to the machine shop, new or used.
I can confidently say there is about 15hp in a valve job and bowl cleanup on TWs and they will also check the spring seat pressure.
Worth every cent if you ask me.

Well I already polished the chambers removing an irregular ridge about 1/4 of an inche out of the valves seats left by the cutter when they newly machined the heads. Also After long readings I cleaned up the bowls being careful not to touch some specific areas that could affect the air velocity and I feel very satisfied with the results. Lastly I inspected the valve seats and no machining is required I lapped a couple valves as samples and they the contact on the seats look perfect. I will check the valves springs seat pressure and replace them if needed.
I checked the piston to deck clearance and found my pistons at 0.011” below the deck. I checked pistons 1 and 5 at TDC and found the same gap on both banks. I will take the block to the shop to remove 0.010” reducing my quench area from 0.050” to 0.040” which is the sweet spot.

So this is where I’m right now on my refreshing process.

PonyGTrider · Sep 7, 2026

Since I don’t have a bore gauge I used one of my used compression rings to measure the cylinder bore taper.
Top of the bore ring gap is 0.027” and bottom is 0.026” so I assume one thousand is good for resurfacing with a light honing for moly rings.
Any comments and or suggestions will be appreciated.

Thank you

Engine Looking for suggestions and or ideas

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lube between the nut and the face. I know my lubes

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