AJP 4.2 upgrade?
Discussion
aide said:
ukkid35 said:
You can't fault Paul's superb fabrication, but since the AJP8 is SOHC that means you can't easily change the overlap so that is it more appropriate for forced induction.
When I took that pic at Ace cafe a few years ago, Paul mentioned that it dyno'd to 560bhp @ 6200 rpm and couldn't rev any higher as the wheels were spinning on the dyno! However, he didn't say if it had std cams?
ukkid35 said:
You can't fault Paul's superb fabrication, but since the AJP8 is SOHC that means you can't easily change the overlap so that is it more appropriate for forced induction.
Is there another string on Paul's project or do anyone have a link?Is it based on a 4.2?
Edited by thomas.moeller on Thursday 30th March 09:15
Jhonno said:
What torque does it make?
I can look it up when I get back home but from memory about 440ft at 5250rpm, on the Emerald rollers it was 461ft but I know this was reading wrong and was high.The engine is a 4.5. and at the engine was totally rebuilt before the charger was fitted. Gas flowed heads, act manifolds, total seal rings ect. Standard Pistons, standard cams Emerald ECU. It also had a lot of other work done to make the charger work well. I still think the biggest problem with the AJP engine and its massive fluctuation in power outputs is down to the cylinder liners, i had 2 sets of standard liners from Power and they distorted when you torqued the heads down. In the end I used undersize liners made a torque plate up and had the bored and honed whilst torqued up and bolted in the block. Result perfect round liners when the heads are fitted.
Interesting. How did you figure out the liners had distorted, did you have a lot of blow-by and removed the heads to find the liners were no longer cylindrical? They're supposed to sit slightly proud of the block face, sounds like it's a bit of a balancing act to have them proud enough to seal against the HG but not so much that they warp when the heads are torqued down.
FarmyardPants said:
Interesting. How did you figure out the liners had distorted, did you have a lot of blow-by and removed the heads to find the liners were no longer cylindrical? They're supposed to sit slightly proud of the block face, sounds like it's a bit of a balancing act to have them proud enough to seal against the HG but not so much that they warp when the heads are torqued down.
I built the engine up with the liners fitted, the cylinder head and gasket in place all torqued down but with no crank, rods, pistons in so you could spin the engine upside down and measure the bores from the underside using a dial bore gauge. The standard liners not only distorted out of round by up to 5 thou they produced a horrible step just where the liners sit in the block. I did check the liner to block protrusion and had this machined to around 4 thou. The heads were checked and all new studs and bolts were used. I gave up with the pre finished liners and used the undersize liners as previously mentioned. The engine is now also wire ringed and has copper head gaskets. It seems to work ok !!!!.I really enjoy my Cerb now but TVR made a bloody good job of making it a that task difficult.
a1rak said:
I built the engine up with the liners fitted, the cylinder head and gasket in place all torqued down but with no crank, rods, pistons in so you could spin the engine upside down and measure the bores from the underside using a dial bore gauge. The standard liners not only distorted out of round by up to 5 thou they produced a horrible step just where the liners sit in the block. I did check the liner to block protrusion and had this machined to around 4 thou. The heads were checked and all new studs and bolts were used. I gave up with the pre finished liners and used the undersize liners as previously mentioned. The engine is now also wire ringed and has copper head gaskets. It seems to work ok !!!!.
I really enjoy my Cerb now but TVR made a bloody good job of making it a that task difficult.
The difference between your posts and most others is that yours are backed up by empirical experience, rather than just idle conjecture.I really enjoy my Cerb now but TVR made a bloody good job of making it a that task difficult.
My idle conjecture is that the outside liners don't have the support that the inner liners have, and they are most likely to suffer from distortion under load. I guess there's no easy way to check that?
a1rak said:
Jhonno said:
What torque does it make?
I can look it up when I get back home but from memory about 440ft at 5250rpm, on the Emerald rollers it was 461ft but I know this was reading wrong and was high.The engine is a 4.5. and at the engine was totally rebuilt before the charger was fitted. Gas flowed heads, act manifolds, total seal rings ect. Standard Pistons, standard cams Emerald ECU. It also had a lot of other work done to make the charger work well. I still think the biggest problem with the AJP engine and its massive fluctuation in power outputs is down to the cylinder liners, i had 2 sets of standard liners from Power and they distorted when you torqued the heads down. In the end I used undersize liners made a torque plate up and had the bored and honed whilst torqued up and bolted in the block. Result perfect round liners when the heads are fitted.
I sent you a PM through here a while back btw.. I am guessing you never got it!
Incognegro said:
thomas.moeller said:
How can I see if the bottom is a 4.5?
Not being an ajp expert I know the cc is stamped on the block. Not sure where so maybe one of the more knowledgeable here can Shen more light on it. Tanguero said:
4.7 etc = £14.2k inc VAT!!!
My jaw did actually drop open. 
My 4.5 has never been modded to my knowledge apart from a back box change....and not RR'd either...feels fast enough every time I drive it....but all you guys probably would (should?) just disappear into the distance.
I am lucky enough to have another car for track days though.
thomas.moeller said:
Incognegro said:
thomas.moeller said:
How can I see if the bottom is a 4.5?
Not being an ajp expert I know the cc is stamped on the block. Not sure where so maybe one of the more knowledgeable here can Shen more light on it. Mine, a 4.2, is XXXX42XXXXX, which may be TVR's methodology or a complete coincidence.
a1rak said:
Has anyone done this on a 4.2 base? Im really loving it ! What would be expected BHP on a 4.2 and is there any indication on cost of a project like this? Outl4w said:
a1rak said:
Has anyone done this on a 4.2 base? Im really loving it ! What would be expected BHP on a 4.2 and is there any indication on cost of a project like this? Gassing Station | Cerbera | Top of Page | What's New | My Stuff