Explorer heads, cam and intake on lopo shortblock - PTV clearance?

[drhill]

Ok,

after driving my 90 Town Car for a few more months and taking it on a 2k mile trip I think I'm going to keep it simple. The lady who owned this car for 25 years maintained it very well - overkill on fluids and new parts etc. I'm going to leave in the stock short block and trans and just do a top end swap to explorer stuff.

My questions:

1. will I have to worry about Piston to Valve clearance with the Explorer heads and cam on the lopo pistons?
2. any idea of compression ratio with this setup?
3. is it worth it to buy 1.7 rockers with the explorer cam? Obviously this means new valve springs and more possible PTV issues...for how much HP - 5 or so?

Thanks for the help! I will also be using the stock Lincoln logs and converting over to factory duals.

[fivelstang4]

Ok,

after driving my 90 Town Car for a few more months and taking it on a 2k mile trip I think I'm going to keep it simple. The lady who owned this car for 25 years maintained it very well - overkill on fluids and new parts etc. I'm going to leave in the stock short block and trans and just do a top end swap to explorer stuff.

My questions:

1. will I have to worry about Piston to Valve clearance with the Explorer heads and cam on the lopo pistons?
2. any idea of compression ratio with this setup?
3. is it worth it to buy 1.7 rockers with the explorer cam? Obviously this means new valve springs and more possible PTV issues...for how much HP - 5 or so?

Thanks for the help! I will also be using the stock Lincoln logs and converting over to factory duals.

I just did the same swap you are wanting to do, left the stock LOPO bottom end in the car and installed GT40 Heads, Explorer Intake. I used a Mustang GT cam for the higher RPM range and have been very happy with it. No issues with PTV clearance. I used stock rockers because I couldn't justify spending the money for the low HP gain. Compression ratio isnt going to change much at all honestly. I have 3.55 gears. Once the car gets going its a screamer. But out of the whole its still a turd.

[87gtVIC]

I just did the same swap you are wanting to do, left the stock LOPO bottom end in the car and installed GT40 Heads, Explorer Intake. I used a Mustang GT cam for the higher RPM range and have been very happy with it. No issues with PTV clearance. I used stock rockers because I couldn't justify spending the money for the low HP gain. Compression ratio isnt going to change much at all honestly. I have 3.55 gears. Once the car gets going its a screamer. But out of the whole its still a turd.

Any more info on your setup? Readers ride page with a breakdown? Curious about all of it.

[pantera77]

Either way I'd be swapping valve springs, 1.7's or not.

[drhill]

I just did the same swap you are wanting to do, left the stock LOPO bottom end in the car and installed GT40 Heads, Explorer Intake. I used a Mustang GT cam for the higher RPM range and have been very happy with it. No issues with PTV clearance. I used stock rockers because I couldn't justify spending the money for the low HP gain. Compression ratio isnt going to change much at all honestly. I have 3.55 gears. Once the car gets going its a screamer. But out of the whole its still a turd.

that's great news! That's what I will do then. I will stick with the explorer cam - I have the mustang cam with 1.7's in my wagon and without a small stall converter it was not great out of the hole...screams up top for sure. I don't care about top end in my Lincoln, just strong bottom and midrange.

[fivelstang4]

Either way I'd be swapping valve springs, 1.7's or not.

I read alot about valve springs before I swapped the heads. Nothing that said hey, you gotta change springs. Ive bounced the engine over rev limiter a time or two. No issues. It takes a licking and keeps on ticking.

[fivelstang4]

Any more info on your setup? Readers ride page with a breakdown? Curious about all of it.

Email me at fivelstang4@gmail.com with your phone number and I would be glad to talk to you over the phone about it.

[pantera77]

I read alot about valve springs before I swapped the heads. Nothing that said hey, you gotta change springs. Ive bounced the engine over rev limiter a time or two. No issues. It takes a licking and keeps on ticking.

Stock explorer springs are known to be garbage though. Even with a stock cam I'd replace them, and certainly with anything above that. The cheapy ones are $100, no reason not to do them in my mind. Plus while everything's apart you can clean all the carbon out of the heads and lap the valves. Again though, that's just my opinion.

[gadget73]

I've driven cars with Explorer heads and floated the BS out of those springs at around 5000 rpm. The Explorer cam is done at that point anyway but they don't really do anything beyond it. If you retain the stock shift governor in the Lincoln, you might get by with it but honestly for the small change that they cost, I'd probably swap them just so you never have to think about why the engine might be missing and breaking up just before it shifts.

[merc91]

No issues at all. I did the explorer/ explorer and 1.7's/ mustang/ mustang and 1.7's before finally thinking why the hell haven't I just bought a performance cam as cheep as they are... I got a comp xe258 and it put out over 300ft/lbs between 2800rpm and my 6000rpm limit on a bone stock explorer setup. Those numbers haves since been bumped up by 50 after I ported everything extensively to the limits. 350hp and 400ft/lbs from an all ford parts 302 and comp cam that drives like stock with passing e-tests is pretty cool.

****This comp xe258 cam is exactly the edge of limits on PTV clearance with stock no-releif pistons. There were actually little tap marks in the carbon thin layer in all my pistons on I think it was the intake valves when I went to put the forged pistons in. As you likely know, max lift has nothing to do with ptv clearance as this occurs when the piston is at the bottom of it's stroke, but the duration and .050 open #'s are what dictate ptv clearance when the valve is just beginning to open or just finishing closing when the piston is at the top of it's stroke. The higher the lift the better, no matter what for power (tq). Duration is where you can keep efficiency/full vac/silky smooth idle if you keep it short like stock, and longer total duration and overlap gets into the righ revving power/shitty idle/crappy low end tq/vac issues... But they do sound cool and haul ass of 5000rpm converter cars lol.