Discussion
I am looking to learn about the RV8 cylinder heads.
Reading on the Rimmers website , it says post '94 heads have just two row of bolts.
So my '92 precat will( and has) 3 rows of bolts.
Does this mean the 4.6 engines have 2 rows of bolts??
How many rows do the 4.3's have?(Are they the crossbolted block?)
What size valves will mine have?
What would be the best size valve for this size of engine?(obviously toward performance)
Also whats the CC of the head? Is this the shape and size of the recess??
Just curious and looking to learn.
Any help and info most appreciated.
>> Edited by antonyj on Thursday 1st December 20:30
Reading on the Rimmers website , it says post '94 heads have just two row of bolts.
So my '92 precat will( and has) 3 rows of bolts.
Does this mean the 4.6 engines have 2 rows of bolts??
How many rows do the 4.3's have?(Are they the crossbolted block?)
What size valves will mine have?
What would be the best size valve for this size of engine?(obviously toward performance)
Also whats the CC of the head? Is this the shape and size of the recess??
Just curious and looking to learn.
Any help and info most appreciated.
>> Edited by antonyj on Thursday 1st December 20:30
Might be worth posting the same question here,
Great site for V8's and appear to know there stuff.
www.v-8.org.uk/forum/
Great site for V8's and appear to know there stuff.
www.v-8.org.uk/forum/
antonyj said:
Hi Anthony
The Griff & Chim 500 cylinder head are the best Big valve ported heads available using the standard castings. Not including the old Rover powered Tuscan racers. IMHO
But do they have the same 3 bolt rows?
Which TVR RV8's have the 2 bolt rows?
Hi Antony, as I understand it, all heads up to early '94 would be 14 bolt (3 row). My own 4.3 has these heads, but following a gasket failure a few years back, it was rebuilt using studs rather than bolts (highly recommended by the likes of JE) and only using 10 bolts, as were the later engines, thus avoiding potential problems with the extra row of bolts giving uneven clamping of the head.
You might find this interesting reading - I did: www.veloce.co.uk/shop/products/productDetail.php?prod_id=V217&prod_group=Performance%20Tuning%20&%20Modification&
7.
My question to add to the confusion is what combustion chamber sizes are in each variant? even if the 500 pre 94 is the best 14 bolt big valve ported head from the standard casting, is the combustion chamber larger for the 5L, thus lowering the CR on a 4L? or is the cr varied using oly dished pistons?
griffsmith said:
My question to add to the confusion is what combustion chamber sizes are in each variant? even if the 500 pre 94 is the best 14 bolt big valve ported head from the standard casting, is the combustion chamber larger for the 5L, thus lowering the CR on a 4L? or is the cr varied using oly dished pistons?
AFAIK the pre-94 type had 36cc chambers, whereas the later ones had 28cc chambers, with thicker composite gaskets which kept the cr the same. HOWEVER, what TVR may have done to them by way of porting/skimming is anybody's guess. An engine builder would be best placed to know.
7.
the 500 combustion chambers are around 31 cc which gives them a cr of 10.2-1, the the porting work and valve size are the same as what was on all the early big valve motors such as wedges etc and the 4.3/4.5 early big valve griffs, there is still quite a lot you can do with standard castings if you are starting from scratch that will vastly out perform the 500 head in both performance and fuel economy
Its upto you which way you go as getting the heads getting yours done means they will be ready to bolt on, buying second hand ones there is always the risk there me be something wrong with them, as for the early or late type one of the biggest factors to making horsepower in an engine is to keep a tight squish area (the are between the top of the piston and the head face] by maintaing your heads and running a tin head gasket you have around a 40 though squish clearence, by fitting later heads and a composite gasket you will double this, 40 thou in reality may not sound alot but in bhp terms is worth a hell of a lot.
All the 450 chims are cross bolted using the 4.6 range rover engine, the 500's pre serp none of them serp, they have the facility to cross bolt them but were never done apart from the last few that again ran the range rover block and large journal crank
All the 450 chims are cross bolted using the 4.6 range rover engine, the 500's pre serp none of them serp, they have the facility to cross bolt them but were never done apart from the last few that again ran the range rover block and large journal crank
v8 racing said:
..... as for the early or late type one of the biggest factors to making horsepower in an engine is to keep a tight squish area (the are between the top of the piston and the head face] by maintaing your heads and running a tin head gasket you have around a 40 though squish clearence, by fitting later heads and a composite gasket you will double this, 40 thou in reality may not sound alot but in bhp terms is worth a hell of a lot.
......
Rob so are you saying later 28cc heads with a tin gasket then
. Only asking as I have a pair of your finest matched (Stage 3) 28cc ones and wondered what gasket was there
. Harry
>> Edited by HarryW on Friday 2nd December 20:41
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