Best way to proceed with improving up 427 Windsor street setup

[Pman1961]

Fuel pressure is on my list to check at idle and under acceleration on Ace's Cobra. My brothers hot rod truck had a fuel pump issue and experienced similar problems.

[blykins]

252/262 @ .050"?

If that's duration at .050", that's a very large camshaft for a 427. My engines that are around this displacement and use hydraulic rollers have about 12-14 degrees less duration and peak at around 6000-6200.

My guess is that the cam has been changed sometime in the car's life and that cam does not match the rest of the engine/car/goals. Your compression test shows low because the cam is so large and the numbers actually jive for a cam that large.

I'm thinking that if these are .050" duration numbers, the cam is so big that you have no bottom end and you can't run high enough in the rpm range where the cam wants to be efficient.

If those numbers are advertised duration numbers, then that would be a tow truck cam....

I'd change the cam....

[DAVID GAGNARD]

My guess is that the cam has been changed sometime in the car's life and that cam does not match the rest of the engine/car/goals. Your compression test shows low because the cam is so large and the numbers actually jive for a cam that large

and the engine originally came with a dual plane intake and Davinci 950 carb.....now it has a Victor Jr. intake and another carb.....

Makes one wonder what else has been changed on the engine from the time it left the engine builder till now????????

David

[Bernica]

Originally Posted by DAVID GAGNARD

and the engine originally came with a dual plane intake and Davinci 950 carb.....now it has a Victor Jr. intake and another carb.....

Makes one wonder what else has been changed on the engine from the time it left the engine builder till now????????

David

If that current manifold is a single plane it will explain a lot of things as well, especially street performance. I'm with the folks comments above. Starting to suspect cam and intake...

[blykins]

On a big inch motor the single plane intake isn't an issue, but that cam is the root of all evil here....

[Ace23]

Originally Posted by blykins

252/262 @ .050"?

If that's duration at .050", that's a very large camshaft for a 427. My engines that are around this displacement and use hydraulic rollers have about 12-14 degrees less duration and peak at around 6000-6200.

My guess is that the cam has been changed sometime in the car's life and that cam does not match the rest of the engine/car/goals. Your compression test shows low because the cam is so large and the numbers actually jive for a cam that large.

I'm thinking that if these are .050" duration numbers, the cam is so big that you have no bottom end and you can't run high enough in the rpm range where the cam wants to be efficient.

If those numbers are advertised duration numbers, then that would be a tow truck cam....

I'd change the cam....

I will double check the build sheet that list the installed camshaft specifications as well as the sheet from Comp Cams. The previous owner had owned the car since 2009 but I cannot guarantee any changes prior to his ownership. I guess someone changin camshafts is as possible as anything else.

Originally Posted by DAVID GAGNARD

and the engine originally came with a dual plane intake and Davinci 950 carb.....now it has a Victor Jr. intake and another carb.....

Makes one wonder what else has been changed on the engine from the time it left the engine builder till now????????

David

I swapped the carb to a QuickFuel. I have a 150 page binder from when the car was brought in to the states and literally every receipt for the build and any additional parts through the years. Personally I think the motor is exactly what it says it is but thats something we can verify as the wrenches start turning. I haven' found anything on the car that hasn't matched up with the receipts......it was also a local car to me so the current group of guys in the Cobra club know that it hasn't been touched since 2009 when it was bought by the previous owner. None of the information I was given is a100% guarantee but it is better than not having any documentation on the vehicle

[Ace23]

I will update this thread as we go down the checklist on the possible issues. If we can't find anything we will pull the motor and then I guess we will all know for sure!

[DAVID GAGNARD]

Originally Posted by Ace23

I will double check the build sheet that list the installed camshaft specifications as well as the sheet from Comp Cams. The previous owner had owned the car since 2009 but I cannot guarantee any changes prior to his ownership. I guess someone changin camshafts is as possible as anything else.
I swapped the carb to a QuickFuel. I have a 150 page binder from when the car was brought in to the states and literally every receipt for the build and any additional parts through the years. Personally I think the motor is exactly what it says it is but thats something we can verify as the wrenches start turning. I haven' found anything on the car that hasn't matched up with the receipts......it was also a local car to me so the current group of guys in the Cobra club know that it hasn't been touched since 2009 when it was bought by the previous owner. None of the information I was given is a100% guarantee but it is better than not having any documentation on the vehicle

What concerns me is the Olthoff's tune/rwhp numbers correspond with the dyno numbers of the original engine,then thru the years things were changed and the engine "lost" about 100 hp......

Like Brent said,check the stroke,check the cam and see where your at and what you've got.........
Another question I would have is why was the intake changed and if the cam is not the original,why was it changed?????

David

[DAVID GAGNARD]

Originally Posted by Bernica

If that current manifold is a single plane it will explain a lot of things as well, especially street performance. I'm with the folks comments above. Starting to suspect cam and intake...

Back in 2009 the car was previously tuned at Dennis Olthoff''s shop in North Carolina and Olthoff's records have it making 450rwhp on their dyno.

The only variances from the build sheet are that it listed a Davinci 950 carb and Performer RPM intake. The carb on the car now is a 750QF and intake is a victor jr. The camshaft that is listed is a Comp Cam .576 intake and exhaust gross lift with 252 exhaust and 262 intake with 112 lobe separation. I hope the camshaft isn't anything proprietary....this is from 10 years back and its stamped all over the build information so it doesn't appear top secret. I was aware the car did have a Davinci carb on it but that it was removed....I'm wondering if the intake manifold listed on the build sheet is a typo as I undertand it to have always had a victor jr on it. This is purely to provide information based on peoples questions about the motor....not to debate someone's dy

Seems like a lot of things have been changed on this engine since bought from the builder and Olthoff's tune and 450rwhp correspond with the builders dyno hp numbers.......now, some years later,parts have been changed and hp is down about 100..........makes me wonder just what is in the engine at this point in time and if it is still the same basic (short block) engine as was delivered originally....
If it were me, I'd be doing some serious checking into the engine to find out just what is in it and what has been changed......and if it is the original engine at all.......

David

[Bernica]

Originally Posted by DAVID GAGNARD

If it were me, I'd be doing some serious checking into the engine to find out just what is in it and what has been changed......and if it is the original engine at all.......

David

A good lesson for all. Document EVERYTHING and when you did it. Right down to changing plugs and oil, let alone more significant mods. It not only preserves your memory but helps the next guy that puts his hands on it.

[Gaz64]

Originally Posted by blykins

252/262 @ .050"?

If that's duration at .050", that's a very large camshaft for a 427. My engines that are around this displacement and use hydraulic rollers have about 12-14 degrees less duration and peak at around 6000-6200.

My guess is that the cam has been changed sometime in the car's life and that cam does not match the rest of the engine/car/goals. Your compression test shows low because the cam is so large and the numbers actually jive for a cam that large.

I'm thinking that if these are .050" duration numbers, the cam is so big that you have no bottom end and you can't run high enough in the rpm range where the cam wants to be efficient.

If those numbers are advertised duration numbers, then that would be a tow truck cam....

I'd change the cam....

Yes, I agree also.

Either the specs the OP has quoted are incorrect, or the cam is way too big or way too small for the expected outcome.

[Ace23]

Originally Posted by blykins

252/262 @ .050"?

If that's duration at .050", that's a very large camshaft for a 427. My engines that are around this displacement and use hydraulic rollers have about 12-14 degrees less duration and peak at around 6000-6200.

My guess is that the cam has been changed sometime in the car's life and that cam does not match the rest of the engine/car/goals. Your compression test shows low because the cam is so large and the numbers actually jive for a cam that large.

I'm thinking that if these are .050" duration numbers, the cam is so big that you have no bottom end and you can't run high enough in the rpm range where the cam wants to be efficient.

If those numbers are advertised duration numbers, then that would be a tow truck cam....

I'd change the cam....

Following up on this. Per the Comp Cam Slip that is part of the motor build sheet the info below is listed. If this information makes since to you it makes you wonder why a camshaft such as this was used.

*Gross Valve Lift .576 Intake / .576 Exhaust
*Duration at .006 Valve Lift 314 Intake / 329 Exhaust
*At 112 Intake Center Line / Duration at .050 252 Intake / 262 Exhaust

[blykins]

Originally Posted by Ace23

Following up on this. Per the Comp Cam Slip that is part of the motor build sheet the info below is listed. If this information makes since to you it makes you wonder why a camshaft such as this was used.

*Gross Valve Lift .576 Intake / .576 Exhaust
*Duration at .006 Valve Lift 314 Intake / 329 Exhaust
*At 112 Intake Center Line / Duration at .050 252 Intake / 262 Exhaust

I'm not sure why it was used. Poor choice. That much duration in a hydraulic roller with a 427 inch engine will kill the bottom end and kill the top end too. As I said before, this is what all the fingers are pointing at, IMO.

Nothing wrong with the 112 LSA, BTW, it helps with vacuum and with making the curve broader, but that duration is just out of the ballpark. When you see advertised durations near 320-330 degrees, that's why your cranking compression is very low.....TONS of overlap and the intake valve is not closing until very late.

I have custom hydraulic rollers that I like to use for my 427's and as I mentioned before, you're about 12-14 degrees too high...

[Ace23]

Originally Posted by blykins

I'm not sure why it was used. Poor choice. That much duration in a hydraulic roller with a 427 inch engine will kill the bottom end and kill the top end too. As I said before, this is what all the fingers are pointing at, IMO.

Nothing wrong with the 112 LSA, BTW, it helps with vacuum and with making the curve broader, but that duration is just out of the ballpark. When you see advertised durations near 320-330 degrees, that's why your cranking compression is very low.....TONS of overlap and the intake valve is not closing until very late.

I have custom hydraulic rollers that I like to use for my 427's and as I mentioned before, you're about 12-14 degrees too high...

Given that it was 10 years ago and I didn't have the motor built I can't really blame the motor builder. The builder may have highly advised against this but the owner may have insisted even against the builders advice.....who knows. We still have a list of things to go through but it sounds like I could be giving you a ring to spec a cam.

[blykins]

That's the assumption I'm going under....it was changed at some point in its life, not built with that cam from the get-go.

[Ace23]

Originally Posted by blykins

I'm not sure why it was used. Poor choice. That much duration in a hydraulic roller with a 427 inch engine will kill the bottom end and kill the top end too. As I said before, this is what all the fingers are pointing at, IMO.

Nothing wrong with the 112 LSA, BTW, it helps with vacuum and with making the curve broader, but that duration is just out of the ballpark. When you see advertised durations near 320-330 degrees, that's why your cranking compression is very low.....TONS of overlap and the intake valve is not closing until very late.

I have custom hydraulic rollers that I like to use for my 427's and as I mentioned before, you're about 12-14 degrees too high...

You will get a kick out of this. Just come across an 11 year old copy of a second strike article in all the information that came with my car. There was a specific article on a 427 camshaft.....and there right before my eyes my exact camshaft duration numbers were spelled out with a description following that called it a turd cam with no bottom end and not enough top end that required 2400rpm in top gear!

[CraftEngines]

That is not the typical camshaft we use in these engines. Although alot of times our customers like to dictate what goes in their engine whether it is a good choice or not. We also do not use 950cfm or Davinci carbs on our engines. That being said we have had customers go with this camshaft and be very happy with the performance in the lightweight, stick shift Cobra. If a customer prefers a more radical engine, so be it. All we can do is make recommendations, but end the end it is the customer's engine. We have received the heads and we have to question the mileage that has been put on this engine. There was crazy amounts of carbon built up in the heads along with alot more wear than usual on valves and guides. We honestly thought these were off a 50K mile engine or more.

[blykins]

What brand were the valves, Lance?

I had to do some warranty work on some Pond FE heads because the valves/guides were completely worn in about 3000 miles. They had Ferrea hollow stems....same deal, was sucking oil down the valve stems. Valve heads were covered in oil/carbon.

[CraftEngines]

These valves had Manley part numbers on them.

[Ace23]

Originally Posted by CraftEngines

That is not the typical camshaft we use in these engines. Although alot of times our customers like to dictate what goes in their engine whether it is a good choice or not. We also do not use 950cfm or Davinci carbs on our engines. That being said we have had customers go with this camshaft and be very happy with the performance in the lightweight, stick shift Cobra. If a customer prefers a more radical engine, so be it. All we can do is make recommendations, but end the end it is the customer's engine. We have received the heads and we have to question the mileage that has been put on this engine. There was crazy amounts of carbon built up in the heads along with alot more wear than usual on valves and guides. We honestly thought these were off a 50K mile engine or more.

I am out of town so I can't reflect back on the record book for the car but I believe the original build when purchased from you guys had a Holley carb. The previous owner swapped it to a Davinci as the receipt for the carb is in my book.....the Davinci did not run well so Oltoff put a Holley back on it.

I have put 3000 miles on the car since I bought it. Could the following contribute to what you found? The car ran a PCV setup and it consumed a good bit of oil but it never smoked. It was pig rich with the Holley carb that was on it when I had it tuned on the dyno....I believe cylinder pressures were 150 to 160 with majority being closer to 150. We ran a leak down test prior to the tear down last month and saw 7-12% on all but the passenger side front cylinder and we think it was a head gasket that was leaking.

I cannot guarantee there are not more miles that what the car indicates but I do know the car was purchased with an indicated 6k miles in 2009 and was sold to me with 11k in 2015. The remainder of the car does not seem to have wear that would indicate higher mileage than shown.