Engine A few issues with my new 88 Foxbody that i couldnt find definitive answers to....

AydenTv

Member
Nov 19, 2020
67
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Alabama
Ok Car was a 4cyl.. now has all this is in it.... was a drag car on nitrous etc..
5.0 bored .30 over to a 306
T5 5 Speed Manual Transmission
GT40P Heads
GT40 Upper and Lower Intake
4.10 Gears
8.8 Positrac Rear End
BBK 70mm Throttle Body
BBK Shorty Headers
MSD Street Fire Ignition
140mph Dash with 7k Rpm Guages
5.0 Short Shift Throw
Specre 3M Cold Air Intake
has a Mass Air Flow sensor..
Underdrive Pulleys
Silverline Custom Exhaust
Emissions Deleted..
and a momo steering wheel
and everythin in interior screams 90 to 93.. but all vins i founds checks out
Runs and Drives GREAT..
Really Quick. .
Tried to do codes and air bag light blinks... (i know 88 they didnt have air bags... or mass air.. or back seat belts over chest.. also has power mirror center console but is manual along with manual windows and a 90 to 93 hvac...)

Now i didnt do that.. bought like this.. vins check out to a 88 lx hatch.. 4cyl.. also has the 10 pin connector extentions..

now.. When i got on it.. my dip stick tended to pop out.. and i get oil ontop of valve cover on driver side.. my temp stays at 220 on the aftermarket guage and the oil pressure starts off at about 3/8s of the after market guage, then after it goes down the road and gets into open loop itll drop slow and say right above none... i have zero power loss.. it has lots of power...
.. now months later its poping out the pcv valve and smoke comes from shifter... still has all uts power.. i toik out pcv valve and cleaned it then did the blow suck test and seemed to work like it should...
any thoughts and tests or what else i can check.. i also have been checkin oil.. it has not needed a drop and i havent out none in ever since ive got it.

now second weird thing..
checking for codes... my air bag light.. that its not suppose to be there.. will blink and not the cel... and shows code 33 which is egr...
any thoughts..

i also hear a valve tick sound but noted a header bolt missing and repkaced with a random alan head screw and is loose.. could tgat be the sound i hear..

and last but not least..
when i rev it up my tach will go past 7k rpms if i make it...... could that be dine by tune.. it has 4.10 gears and the speedo reads right for it having a 140mph dash in a 4cyl 88 lx.. and at 55mph it does a lil under 2k which seems right...
 
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Bullitt347

I have been doing it wrong this whole time
15 Year Member
Mar 23, 2007
2,702
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Middle of Maine
Sounds like the engine has a lot of blow-by, meaning the piston rings are shot.
The engine when cold is in open loop, when warmed up it goes into closed loop.
Get the tag/code off of the PCM. You may have a 93 PCM in the car and that is why you get air bag codes.
Factory tachometers are notoriously inaccurate. They track OK at low rpm, but get less accurate as the rpm's climb. Get a different tach to monitor rpm.
Dropping oil pressure is not a good thing, at all. Just a batter of time before the main or rods bearing get wiped.
 

CAMTWO1070

Active Member
Dec 17, 2021
65
26
28
52
NY
I think you may just have to bite the bullet and pull the engine and go over it.

I paid $8 grand to have a 351w punched into a 408w by a veteran in the industry and like all veterans they eventually drop off and make mistakes..

At first I thought the noise was exhaust related then Full roller rocker to guideplate noise issues as the noise went away when warmed up;- so it seemed.

I was driving in my ride and I heard like a rattling through the shifter in 3rd and when cruising in 5th it sounded like I had my timing too far advanced but dont seeings I have a Quarterhorse setup I adjust my timing the best way and leave the distributor at 10* btdc.

Never thought about piston slap until I was coming off a descent but gentle run and coming off the exit my engine sounded like a sewing machine.I thought roller rockers are loose so I bought 1.7 ratio shaft mounted rocker arms and installed them and the noise was still there and the longer it ran it got louder like a diesel truck engine....

Shut it down and pulled it out and pulled it apart......It seems even a veteran in the industry cant be trusted to do the right thing as he didnt even chamfer the bottom of the cylinders and the sharp edges gored and scored 5 out of 8 pistons to death with the remaining 3 ready to join them....

Heres a video of how badly the pistons were loose in the bores....It seems a veteran in the industry not only cant chamfer cylinders but they dont know the difference between 4032 and 2618 alloy pistons as it appears my cylinders were prepped for 2618 pistons yet theyre the high silicon content 4032 alloy pistons that hardly expand....


View: https://vimeo.com/688536226


Im so mad I just want to show up there in the morning and clean some clocks...Its not bad enough I got bent over the barrel and overpaid.IDK how it works in this forum so Ill leave the name of the shop out of it but if anyone wants to know and its cool Ill tell as I have proof of everything they did wrong and ripped me off of way beforehand which enacted me to start a small claims case against them and that was for way lesser things ....This just escalated the deal by 10 fold now....

I hope all turns out good for you but like Bullet347 stated blowby isnt good........Neither is putting trust in someone else like I did...What sucks is Im quite capable of building engines but when the pandemic hit my business shot up and I decided to give a local shop/race engine builder a lil business and boy did it come to bite me...

Lots of luck to you OP.................Now I need to find a reputable machine shop to punch my block .040" over making my 408 into a 410w and do it myself as I already ordered the SRP Pro Ultra lightweight .040" over pistons from Lethal Performance and should be here by Saturday...

Take care

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manicmechanic007

Mustang Master
Sep 26, 2017
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Ayden,
Install a direct pressure gauge on the oil pressure tap so you know actual pressure
The oil senders fail and factory oil gauges read low constantly
If the PCV valve vent (other valve cover) has vacuum the blowby is okay
It probably has been ran hard quite a bit but I would not pull the motor out until it's really burnt up
 

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
7,105
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Kearney, NE
Any update on this build?
He was lay here May 11, do maybe he will be back.
The aftermarket tach’s have 4-6-8 settings. Is the four cylinder tach in the dash also different from the 5.0?
(I think I know the answer, but it’s been a while.)