Engine Engine build questions 1992 GT

92NDSUgtFOX

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Mar 4, 2018
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My oil pressure drops to about 0 psi after it warms up in closed loop so I'm thinking it's time to pull it & was thinking about taking it to local machine shop & having them go through it. I plan on upgrading with better parts but don't plan on stroking nor boosting. Just want a healthy fun 302 fox.

Couple of questions here, should I bore it out .30 over to a 306? I see this often. I have a 92 5.0 5 spd, it currently has trickflow upper & lower intake, bbk spacer & 65mm TB & bbk cai. I do have shorty bbk headers & bbk long tube headers but they are not installed. Also have 3.73 gears. BBK o/r H pipe Flow Master 40 series. The cats were also deleted. Has mishimoto aluminum radiator & electric fans.

This was all done when I purchased the car. I am currently looking for some aluminum heads!! I plan on doing cam too. I guess what I'm looking for is some advise on what combo heads to add to this & what else you think I should do so its done proper. What cam? What size heads with my set up? I'm not afraid to throw some $$ at her but I wanna do it right the first time..lol
 
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You have many options. But.......
Are you using the stock gauge readings?
How many miles ?
Now about that 306, and other mods. Here are my thoughts, talk to the machine shop about costs, shop crate engines, you may find that a crate engine with cam, heads and other supporting parts for less money that the machine shop and it will have a warranty too.
 
Whatever build you decide, I recommend full balance of the rotating assembly. I think too many people overlook this very beneficial, relatively inexpensive step.

They weigh all the pistons individually and find the lightest one. They then remove material from the others until all are identical in weight. They do the same with the connecting rods. They spin balance the crank, damper and flywheel as an assembly.

The result is minimal vibration and a motor that will be easier on bearings and stay together much longer at high rpm abuse.
 
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You have many options. But.......
Are you using the stock gauge readings?
How many miles ?
Now about that 306, and other mods. Here are my thoughts, talk to the machine shop about costs, shop crate engines, you may find that a crate engine with cam, heads and other supporting parts for less money that the machine shop and it will have a warranty too.

I hooked up a Matco pressure gauge to confirm oil pressure drops. Cold start it's at around 23psi but drops to 0-3 psi after it warms up.

130k miles on this car.

I have looked into crate motors myself, they just are a lil out of reach for me to buy one straight up as I do have kids. I wouldn't mind building this motor myself as I do take great pride in Fox 5.0s & I want my kids to drive it once they are old enough. Honestly, just a good set of heads & cam with what I have & I would be good enough with that...for now haha
 
A properly maintained engine should go further than 130 before having oil pressure drops like that. I agree the pump could be worn. If it’s a product of poor maintenance, like not changing the oil or running low on oil, more than the pump is worn. Probably got worn bearings too. If the bearings are excessively worn, a pump alone is not gonna bring it back
 
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Yea I am leaning towards the main bearings needing to be replaced, that's why I figured if I go that deep into it, why not have machine shop go through it. Machine shop guy (well respected shop in town) said it very well could be crankshaft journal causing my oil pressure to drop. Who knows. I really do appreciate the replys & knowledge you guys have thrown my way!
 
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If you're interested in building your own engine this could be the perfect time.
I built my current 393w , always wanted to build my own engine and it's been pretty satisfying.
I paid the machine shop $1200 for a fully prepped 1969 351w block, they installed the cam bearings
and checked out the rotating assembly I was using.
Believe me I know about the wife and kids budget so I did it a little at a time as funds allowed,
selling whatever 302 parts I could for $.
I would guess when all is said and done I probably spent somewhere around $4-$4500 on the build,
not an all out race car just a street cruiser.
Keep us posted.
 
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I’m married and she likes spending money too. Because of this, every part I buy for my “project cars”, costs me double, or thereabouts....
 
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In 2008, I spent around $5500 to rebuild my 5.0 including around $1300 at the machine shop. The total cost included some items beyond the motor including Summit T shirts for the guys at the machine shop. My block was bored 20 over and I had the shop balance lower rotating assembly with new pistons, rods, old flywheel, balancer and reworked crank. I think that cost $250 but was well worth the $$ as this motor runs very smoothly and has over 5000 miles on it now.

My build included Edelbrock performer RPM heads, intake and Compcams cam, lifters, and roller tipped rockers. Engine still runs great and is a bunch of fun. Good luck with your build.
 
My oil pressure drops to about 0 psi after it warms up in closed loop so I'm thinking it's time to pull it & was thinking about taking it to local machine shop & having them go through it. I plan on upgrading with better parts but don't plan on stroking nor boosting. Just want a healthy fun 302 fox.

Couple of questions here, should I bore it out .30 over to a 306? I see this often. I have a 92 5.0 5 spd, it currently has trickflow upper & lower intake, bbk spacer & 65mm TB & bbk cai. I do have shorty bbk headers & bbk long tube headers but they are not installed. Also have 3.73 gears. BBK o/r H pipe Flow Master 40 series. The cats were also deleted. Has mishimoto aluminum radiator & electric fans.

This was all done when I purchased the car. I am currently looking for some aluminum heads!! I plan on doing cam too. I guess what I'm looking for is some advise on what combo heads to add to this & what else you think I should do so its done proper. What cam? What size heads with my set up? I'm not afraid to throw some $$ at her but I wanna do it right the first time..lol
 
Since you already have Trickflow UIM and LIM, why not consult TF to see what TF heads (and possibly camshaft) they recommend? For my build, I relied on the expertise of a mfgr who sells a tested package such as Edelbrock or Trickflow rather than piece-mealing something together. I went with an Edelbrock RPM "package" excepting the cam which was from Comp. I consulted both Edelbrock and Comp techs to make sure the Comp cam would play nicely with the Edelbrock heads and intake. Based on your build requirements, the mfgr can recommend a package.

As far as the volume #'s you list, these look like head intake runner volumes to me. My Edelbrock SBF 60229 heads had 170cc intake runner volume. I think combustion chamber volume is more important as it effects your compression ratio. My heads had 60cc combustion chamber volume (about 9.3:1 CR with stock head gasket and 4.020" bore).